# @ohos.rpc (RPC)
The **RPC** module implements communication between processes, including inter-process communication (IPC) on a single device and remote procedure call (RPC) between processes on difference devices. IPC is implemented based on the binder driver, and RPC is based on the DSoftBus driver.
> **NOTE**
>
> - The initial APIs of this module are supported since API version 7. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>
> - This module supports return of error codes since API version 9.
## Modules to Import
```
import rpc from '@ohos.rpc';
```
## ErrorCode<sup>9+</sup>
The APIs of this module return exceptions since API version 9. The following table lists the error codes.
**System capability**: SystemCapability.Communication.IPC.Core
| Name | Value | Description |
| ------------------------------------- | ------- | --------------------------------------------- |
| CHECK_PARAM_ERROR | 401 | Parameter check failed. |
| OS_MMAP_ERROR | 1900001 | Failed to call mmap. |
| OS_IOCTL_ERROR | 1900002 | Failed to call **ioctl** with the shared memory file descriptor.|
| WRITE_TO_ASHMEM_ERROR | 1900003 | Failed to write data to the shared memory. |
| READ_FROM_ASHMEM_ERROR | 1900004 | Failed to read data from the shared memory. |
| ONLY_PROXY_OBJECT_PERMITTED_ERROR | 1900005 | This operation is allowed only on the proxy object. |
| ONLY_REMOTE_OBJECT_PERMITTED_ERROR | 1900006 | This operation is allowed only on the remote object. |
| COMMUNICATION_ERROR | 1900007 | Failed to communicate with the remote object over IPC. |
| PROXY_OR_REMOTE_OBJECT_INVALID_ERROR | 1900008 | Invalid proxy or remote object. |
| WRITE_DATA_TO_MESSAGE_SEQUENCE_ERROR | 1900009 | Failed to write data to MessageSequence. |
| READ_DATA_FROM_MESSAGE_SEQUENCE_ERROR | 1900010 | Failed to read data from MessageSequence. |
| PARCEL_MEMORY_ALLOC_ERROR | 1900011 | Failed to allocate memory during serialization. |
| CALL_JS_METHOD_ERROR | 1900012 | Failed to invoke the JS callback. |
| OS_DUP_ERROR | 1900013 | Failed to call dup. |
## MessageSequence<sup>9+</sup>
Provides APIs for reading and writing data in specific format. During RPC or IPC, the sender can use the **write()** method provided by **MessageSequence** to write data in specific format to a **MessageSequence** object. The receiver can use the **read()** method provided by **MessageSequence** to read data in specific format from a **MessageSequence** object. The data formats include basic data types and arrays, IPC objects, interface tokens, and custom sequenceable objects.
### create
static create(): MessageSequence
Creates a **MessageSequence** object. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| --------------- | ------------------------------- |
| [MessageSequence](#messagesequence9) | **MessageSequence** object created.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageSequence.create();
hilog.info(0x0000, 'testTag', 'RpcClient: data is ' + data);
```
### reclaim
reclaim(): void
Reclaims the **MessageSequence** object that is no longer used.
**System capability**: SystemCapability.Communication.IPC.Core
**Example**
```ts
let reply = rpc.MessageSequence.create();
reply.reclaim();
```
### writeRemoteObject
writeRemoteObject(object: IRemoteObject): void
Serializes a remote object and writes it to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------------------------------- | ---- | ----------------------------------------- |
| object | [IRemoteObject](#iremoteobject) | Yes | Remote object to serialize and write to the **MessageSequence** object.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
}
let data = rpc.MessageSequence.create();
let testRemoteObject = new TestRemoteObject("testObject");
try {
data.writeRemoteObject(testRemoteObject);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc write remote object fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc write remote object fail, errorMessage ' + e.message);
}
```
### readRemoteObject
readRemoteObject(): IRemoteObject
Reads the remote object from **MessageSequence**. You can use this API to deserialize the **MessageSequence** object to generate an **IRemoteObject**. The remote object is read in the order in which it is written to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------------------------------- | ------------------ |
| [IRemoteObject](#iremoteobject) | Remote object obtained.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
}
let data = rpc.MessageSequence.create();
let testRemoteObject = new TestRemoteObject("testObject");
try {
data.writeRemoteObject(testRemoteObject);
let proxy = data.readRemoteObject();
hilog.info(0x0000, 'testTag', 'RpcClient: readRemoteObject is ' + proxy);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc write remote object fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc write remote object fail, errorMessage ' + e.message);
}
```
### writeInterfaceToken
writeInterfaceToken(token: string): void
Writes an interface token to this **MessageSequence** object. The remote object can use this interface token to verify the communication.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------ |
| token | string | Yes | Interface token to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeInterfaceToken("aaa");
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write interface fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write interface fail, errorMessage ' + e.message);
}
```
### readInterfaceToken
readInterfaceToken(): string
Reads the interface token from this **MessageSequence** object. The interface token is read in the sequence in which it is written to the **MessageSequence** object. The local object can use it to verify the communication.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------------ |
| string | Interface token obtained.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
try {
let interfaceToken = data.readInterfaceToken();
hilog.info(0x0000, 'testTag', 'RpcServer: interfaceToken is ' + interfaceToken);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'RpcServer: read interfaceToken failed, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'RpcServer: read interfaceToken failed, errorMessage ' + e.message);
}
return true;
}
}
```
### getSize
getSize(): number
Obtains the data size of this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----------------------------------------------- |
| number | Size of the **MessageSequence** instance obtained, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageSequence.create();
let size = data.getSize();
hilog.info(0x0000, 'testTag', 'RpcClient: size is ' + size);
```
### getCapacity
getCapacity(): number
Obtains the capacity of this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----- |
| number | Capacity of the obtained **MessageSequence** object, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageSequence.create();
let result = data.getCapacity();
hilog.info(0x0000, 'testTag', 'RpcClient: capacity is ' + result);
```
### setSize
setSize(size: number): void
Sets the size of the data contained in this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------ |
| size | number | Yes | Data size to set, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
data.writeString('Hello World');
try {
data.setSize(16);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc set size of MessageSequence fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc set size of MessageSequence fail, errorMessage ' + e.message);
}
```
### setCapacity
setCapacity(size: number): void
Sets the storage capacity of this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | --------------------------------------------- |
| size | number | Yes | Storage capacity of the **MessageSequence** object to set, in bytes.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900011 | parcel memory alloc failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.setCapacity(100);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc memory alloc fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc memory alloc fail, errorMessage ' + e.message);
}
```
### getWritableBytes
getWritableBytes(): number
Obtains the writable capacity (in bytes) of this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------ |
| number | Writable capacity of the **MessageSequence** instance, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let getWritableBytes = data.getWritableBytes();
hilog.info(0x0000, 'testTag', 'RpcServer: getWritableBytes is ' + getWritableBytes);
return true;
}
}
```
### getReadableBytes
getReadableBytes(): number
Obtains the readable capacity of this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------- |
| number | Readable capacity of the **MessageSequence** instance, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let result = data.getReadableBytes();
hilog.info(0x0000, 'testTag', 'RpcServer: getReadableBytes is ' + result);
return true;
}
}
```
### getReadPosition
getReadPosition(): number
Obtains the read position of this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------ |
| number | Read position obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageSequence.create();
let readPos = data.getReadPosition();
hilog.info(0x0000, 'testTag', 'RpcClient: readPos is ' + readPos);
```
### getWritePosition
getWritePosition(): number
Obtains the write position of this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----- |
| number | Write position obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageSequence.create();
data.writeInt(10);
let bwPos = data.getWritePosition();
hilog.info(0x0000, 'testTag', 'RpcClient: bwPos is ' + bwPos);
```
### rewindRead
rewindRead(pos: number): void
Moves the read pointer to the specified position.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------- |
| pos | number | Yes | Position from which data is to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
data.writeInt(12);
data.writeString("sequence");
let number = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: number is ' + number);
try {
data.rewindRead(0);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc rewind read data fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc rewind read data fail, errorMessage ' + e.message);
}
let number2 = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: rewindRead is ' + number2);
```
### rewindWrite
rewindWrite(pos: number): void
Moves the write pointer to the specified position.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ----- |
| pos | number | Yes | Position from which data is to write.|
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
data.writeInt(4);
try {
data.rewindWrite(0);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc rewindWrite fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc rewindWrite fail, errorMessage ' + e.message);
}
data.writeInt(5);
let number = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: rewindWrite is: ' + number);
```
### writeByte
writeByte(val: number): void
Writes a byte value to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ----- |
| val | number | Yes | Byte value to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | ------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeByte(2);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write byte fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write byte fail, errorMessage ' + e.message);
}
```
### readByte
readByte(): number
Reads the byte value from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----- |
| number | Byte value read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| ------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeByte(2);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write byte fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write byte fail, errorMessage ' + e.message);
}
try {
let ret = data.readByte();
hilog.info(0x0000, 'testTag', 'RpcClient: readByte is: ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read byte fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read byte fail, errorMessage ' + e.message);
}
```
### writeShort
writeShort(val: number): void
Writes a short integer to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description|
| ------ | ------ | --- | --- |
| val | number | Yes | Short integer to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeShort(8);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write short fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write short fail, errorMessage ' + e.message);
}
```
### readShort
readShort(): number
Reads the short integer from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | -------------- |
| number | Short integer read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeShort(8);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write short fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write short fail, errorMessage ' + e.message);
}
try {
let ret = data.readShort();
hilog.info(0x0000, 'testTag', 'RpcClient: readByte is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read short fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read short fail, errorMessage ' + e.message);
}
```
### writeInt
writeInt(val: number): void
Writes an integer to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------- |
| val | number | Yes | Integer to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeInt(10);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write int fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write int fail, errorMessage ' + e.message);
}
```
### readInt
readInt(): number
Reads the integer from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------ |
| number | Integer read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeInt(10);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write int fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write int fail, errorMessage ' + e.message);
}
try {
let ret = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: readInt is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read int fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read int fail, errorMessage ' + e.message);
}
```
### writeLong
writeLong(val: number): void
Writes a long integer to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------- |
| val | number | Yes | Long integer to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeLong(10000);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write long fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write long fail, errorMessage ' + e.message);
}
```
### readLong
readLong(): number
Reads the long integer from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | -------------- |
| number | Long integer read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeLong(10000);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write long fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write long fail, errorMessage ' + e.message);
}
try {
let ret = data.readLong();
hilog.info(0x0000, 'testTag', 'RpcClient: readLong is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read long fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read long fail, errorMessage ' + e.message);
}
```
### writeFloat
writeFloat(val: number): void
Writes a floating-point number to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ----- |
| val | number | Yes | Floating-point number to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeFloat(1.2);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write float fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write float fail, errorMessage ' + e.message);
}
```
### readFloat
readFloat(): number
Reads the floating-pointer number from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------ |
| number | Floating-point number read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeFloat(1.2);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write float fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write float fail, errorMessage ' + e.message);
}
try {
let ret = data.readFloat();
hilog.info(0x0000, 'testTag', 'RpcClient: readFloat is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read float fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read float fail, errorMessage ' + e.message);
}
```
### writeDouble
writeDouble(val: number): void
Writes a double-precision floating-point number to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------------- |
| val | number | Yes | Double-precision floating-point number to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeDouble(10.2);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write double fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write double fail, errorMessage ' + e.message);
}
```
### readDouble
readDouble(): number
Reads the double-precision floating-point number from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------ |
| number | Double-precision floating-point number read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeDouble(10.2);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write double fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write double fail, errorMessage ' + e.message);
}
try {
let ret = data.readDouble();
hilog.info(0x0000, 'testTag', 'RpcClient: readDouble is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read double fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read double fail, errorMessage ' + e.message);
}
```
### writeBoolean
writeBoolean(val: boolean): void
Writes a Boolean value to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------- | ---- | ---------------- |
| val | boolean | Yes | Boolean value to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeBoolean(false);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write boolean fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write boolean fail, errorMessage ' + e.message);
}
```
### readBoolean
readBoolean(): boolean
Reads the Boolean value from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | -------------------- |
| boolean | Boolean value read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeBoolean(false);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write boolean fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write boolean fail, errorMessage ' + e.message);
}
try {
let ret = data.readBoolean();
hilog.info(0x0000, 'testTag', 'RpcClient: readBoolean is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read boolean fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read boolean fail, errorMessage ' + e.message);
}
```
### writeChar
writeChar(val: number): void
Writes a character to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------- |
| val | number | Yes | Single character to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeChar(97);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write char fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write char fail, errorMessage ' + e.message);
}
```
### readChar
readChar(): number
Reads the character from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description|
| ------ | ---- |
| number | Character read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeChar(97);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write char fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write char fail, errorMessage ' + e.message);
}
try {
let ret = data.readChar();
hilog.info(0x0000, 'testTag', 'RpcClient: readChar is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read char fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read char fail, errorMessage ' + e.message);
}
```
### writeString
writeString(val: string): void
Writes a string to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ----------------------------------------- |
| val | string | Yes | String to write. The length of the string must be less than 40960 bytes.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeString('abc');
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write string fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write string fail, errorMessage ' + e.message);
}
```
### readString
readString(): string
Reads the string from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | -------------- |
| string | String read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeString('abc');
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write string fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write string fail, errorMessage ' + e.message);
}
try {
let ret = data.readString();
hilog.info(0x0000, 'testTag', 'RpcClient: readString is ' + ret);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read string fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read string fail, errorMessage ' + e.message);
}
```
### writeParcelable
writeParcelable(val: Parcelable): void
Writes a **Parcelable** object to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type| Mandatory| Description|
| ------ | --------- | ---- | ------ |
| val | [Parcelable](#parcelable9) | Yes | **Parcelable** object to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyParcelable implements rpc.Parcelable {
num: number = 0;
str: string = '';
constructor( num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageSequence: rpc.MessageSequence): boolean {
messageSequence.writeInt(this.num);
messageSequence.writeString(this.str);
return true;
}
unmarshalling(messageSequence: rpc.MessageSequence): boolean {
this.num = messageSequence.readInt();
this.str = messageSequence.readString();
return true;
}
}
let parcelable = new MyParcelable(1, "aaa");
let data = rpc.MessageSequence.create();
try {
data.writeParcelable(parcelable);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write parcelable fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write parcelable fail, errorMessage ' + e.message);
}
```
### readParcelable
readParcelable(dataIn: Parcelable): void
Reads a **Parcelable** object from this **MessageSequence** object to the specified object (**dataIn**).
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------------------------- | ---- | ----------------------------------------- |
| dataIn | [Parcelable](#parcelable9) | Yes | **Parcelable** object to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
| 1900012 | call js callback function failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyParcelable implements rpc.Parcelable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageSequence: rpc.MessageSequence): boolean {
messageSequence.writeInt(this.num);
messageSequence.writeString(this.str);
return true;
}
unmarshalling(messageSequence: rpc.MessageSequence): boolean {
this.num = messageSequence.readInt();
this.str = messageSequence.readString();
return true;
}
}
let parcelable = new MyParcelable(1, "aaa");
let data = rpc.MessageSequence.create();
data.writeParcelable(parcelable);
let ret = new MyParcelable(0, "");
try {
data.readParcelable(ret);
}catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read parcelable fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read parcelable fail, errorMessage ' + e.message);
}
```
### writeByteArray
writeByteArray(byteArray: number[]): void
Writes a byte array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | -------- | ---- | ------------------ |
| byteArray | number[] | Yes | Byte array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
let ByteArrayVar = [1, 2, 3, 4, 5];
try {
data.writeByteArray(ByteArrayVar);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write byteArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write byteArray fail, errorMessage ' + e.message);
}
```
### readByteArray
readByteArray(dataIn: number[]): void
Reads a byte array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ------------------ |
| dataIn | number[] | Yes | Byte array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
let ByteArrayVar = [1, 2, 3, 4, 5];
try {
data.writeByteArray(ByteArrayVar);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write byteArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write byteArray fail, errorMessage ' + e.message);
}
try {
let array: Array<number> = new Array(5);
data.readByteArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read byteArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read byteArray fail, errorMessage ' + e.message);
}
```
### readByteArray
readByteArray(): number[]
Reads the byte array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------- |
| number[] | Byte array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
let byteArrayVar = [1, 2, 3, 4, 5];
try {
data.writeByteArray(byteArrayVar);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write byteArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write byteArray fail, errorMessage ' + e.message);
}
try {
let array = data.readByteArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readByteArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read byteArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read byteArray fail, errorMessage ' + e.message);
}
```
### writeShortArray
writeShortArray(shortArray: number[]): void
Writes a short array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | -------- | ---- | -------------------- |
| shortArray | number[] | Yes | Short array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeShortArray([11, 12, 13]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write shortArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write shortArray fail, errorMessage ' + e.message);
}
```
### readShortArray
readShortArray(dataIn: number[]): void
Reads a short array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------- |
| dataIn | number[] | Yes | Short array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeShortArray([11, 12, 13]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write shortArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write shortArray fail, errorMessage ' + e.message);
}
try {
let array: Array<number> = new Array(3);
data.readShortArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read shortArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read shortArray fail, errorMessage ' + e.message);
}
```
### readShortArray
readShortArray(): number[]
Reads the short array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ---------------- |
| number[] | Short array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeShortArray([11, 12, 13]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write shortArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write shortArray fail, errorMessage ' + e.message);
}
try {
let array = data.readShortArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readShortArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read shortArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read shortArray fail, errorMessage ' + e.message);
}
```
### writeIntArray
writeIntArray(intArray: number[]): void
Writes an integer array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | -------- | ---- | ------------------ |
| intArray | number[] | Yes | Integer array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeIntArray([100, 111, 112]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write intArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write intArray fail, errorMessage ' + e.message);
}
```
### readIntArray
readIntArray(dataIn: number[]): void
Reads an integer array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ------------------ |
| dataIn | number[] | Yes | Integer array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeIntArray([100, 111, 112]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write intArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write intArray fail, errorMessage ' + e.message);
}
let array: Array<number> = new Array(3);
try {
data.readIntArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read intArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read intArray fail, errorMessage ' + e.message);
}
```
### readIntArray
readIntArray(): number[]
Reads the integer array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------- |
| number[] | Integer array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeIntArray([100, 111, 112]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write intArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write intArray fail, errorMessage ' + e.message);
}
try {
let array = data.readIntArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readIntArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read intArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read intArray fail, errorMessage ' + e.message);
}
```
### writeLongArray
writeLongArray(longArray: number[]): void
Writes a long array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | -------- | ---- | -------------------- |
| longArray | number[] | Yes | Long array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeLongArray([1111, 1112, 1113]);
}catch(error){
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write longArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write longArray fail, errorMessage ' + e.message);
}
```
### readLongArray
readLongArray(dataIn: number[]): void
Reads a long array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------- |
| dataIn | number[] | Yes | Long array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeLongArray([1111, 1112, 1113]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write longArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write longArray fail, errorMessage ' + e.message);
}
let array: Array<number> = new Array(3);
try {
data.readLongArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read longArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read longArray fail, errorMessage ' + e.message);
}
```
### readLongArray
readLongArray(): number[]
Reads the long array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ---------------- |
| number[] | Long array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeLongArray([1111, 1112, 1113]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write longArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write longArray fail, errorMessage ' + e.message);
}
try {
let array = data.readLongArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readLongArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read longArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read longArray fail, errorMessage ' + e.message);
}
```
### writeFloatArray
writeFloatArray(floatArray: number[]): void
Writes a floating-point array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | -------- | ---- | ----------------------------------------------------------------------------------------------------------------------- |
| floatArray | number[] | Yes | Floating-point array to write. The system processes Float data as that of the Double type. Therefore, the total number of bytes occupied by a FloatArray must be calculated as the Double type.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeFloatArray([1.2, 1.3, 1.4]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write floatArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write floatArray fail, errorMessage ' + e.message);
}
```
### readFloatArray
readFloatArray(dataIn: number[]): void
Reads a floating-point array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ----------------------------------------------------------------------------------------------------------------------- |
| dataIn | number[] | Yes | Floating-point array to read. The system processes Float data as that of the Double type. Therefore, the total number of bytes occupied by a FloatArray must be calculated as the Double type.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeFloatArray([1.2, 1.3, 1.4]);
}catch(error){
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write floatArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write floatArray fail, errorMessage ' + e.message);
}
let array: Array<number> = new Array(3);
try {
data.readFloatArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read floatArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read floatArray fail, errorMessage ' + e.message);
}
```
### readFloatArray
readFloatArray(): number[]
Reads the floating-point array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------- |
| number[] | Floating-point array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeFloatArray([1.2, 1.3, 1.4]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write floatArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write floatArray fail, errorMessage ' + e.message);
}
try {
let array = data.readFloatArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readFloatArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read floatArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read floatArray fail, errorMessage ' + e.message);
}
```
### writeDoubleArray
writeDoubleArray(doubleArray: number[]): void
Writes a double-precision floating-point array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------- | -------- | ---- | ------------------------ |
| doubleArray | number[] | Yes | Double-precision floating-point array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeDoubleArray([11.1, 12.2, 13.3]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write doubleArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write doubleArray fail, errorMessage ' + e.message);
}
```
### readDoubleArray
readDoubleArray(dataIn: number[]): void
Reads a double-precision floating-point array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ------------------------ |
| dataIn | number[] | Yes | Double-precision floating-point array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeDoubleArray([11.1, 12.2, 13.3]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write doubleArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write doubleArray fail, errorMessage ' + e.message);
}
let array: Array<number> = new Array(3);
try {
data.readDoubleArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read doubleArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read doubleArray fail, errorMessage ' + e.message);
}
```
### readDoubleArray
readDoubleArray(): number[]
Reads the double-precision floating-point array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------------- |
| number[] | Double-precision floating-point array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeDoubleArray([11.1, 12.2, 13.3]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write doubleArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write doubleArray fail, errorMessage ' + e.message);
}
try {
let array = data.readDoubleArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readDoubleArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read doubleArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read doubleArray fail, errorMessage ' + e.message);
}
```
### writeBooleanArray
writeBooleanArray(booleanArray: boolean[]): void
Writes a Boolean array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------------ | --------- | ---- | ------------------ |
| booleanArray | boolean[] | Yes | Boolean array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeBooleanArray([false, true, false]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write booleanArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write booleanArray fail, errorMessage ' + e.message);
}
```
### readBooleanArray
readBooleanArray(dataIn: boolean[]): void
Reads a Boolean array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | --------- | ---- | ------------------ |
| dataIn | boolean[] | Yes | Boolean array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeBooleanArray([false, true, false]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write booleanArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write booleanArray fail, errorMessage ' + e.message);
}
let array: Array<boolean> = new Array(3);
try {
data.readBooleanArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read booleanArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read booleanArray fail, errorMessage ' + e.message);
}
```
### readBooleanArray
readBooleanArray(): boolean[]
Reads the Boolean array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| --------- | -------------- |
| boolean[] | Boolean array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeBooleanArray([false, true, false]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write booleanArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write booleanArray fail, errorMessage ' + e.message);
}
try {
let array = data.readBooleanArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readBooleanArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read booleanArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read booleanArray fail, errorMessage ' + e.message);
}
```
### writeCharArray
writeCharArray(charArray: number[]): void
Writes a character array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | -------- | ---- | ---------------------- |
| charArray | number[] | Yes | Character array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeCharArray([97, 98, 88]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write charArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write charArray fail, errorMessage ' + e.message);
}
```
### readCharArray
readCharArray(dataIn: number[]): void
Reads a character array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ---------------------- |
| dataIn | number[] | Yes | Character array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeCharArray([97, 98, 88]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write charArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write charArray fail, errorMessage ' + e.message);
}
let array: Array<number> = new Array(3);
try {
data.readCharArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read charArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read charArray fail, errorMessage ' + e.message);
}
```
### readCharArray
readCharArray(): number[]
Reads the character array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ------------------ |
| number[] | Character array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeCharArray([97, 98, 88]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write charArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write charArray fail, errorMessage ' + e.message);
}
try {
let array = data.readCharArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readCharArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read charArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read charArray fail, errorMessage ' + e.message);
}
```
### writeStringArray
writeStringArray(stringArray: string[]): void
Writes a string array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------- | -------- | ---- | ------------------------------------------------------- |
| stringArray | string[] | Yes | String array to write. The length of a single element in the array must be less than 40960 bytes.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeStringArray(["abc", "def"]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write stringArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write stringArray fail, errorMessage ' + e.message);
}
```
### readStringArray
readStringArray(dataIn: string[]): void
Reads a string array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------- |
| dataIn | string[] | Yes | String array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeStringArray(["abc", "def"]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write stringArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write stringArray fail, errorMessage ' + e.message);
}
let array: Array<string> = new Array(2);
try {
data.readStringArray(array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read stringArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read stringArray fail, errorMessage ' + e.message);
}
```
### readStringArray
readStringArray(): string[]
Reads the string array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ---------------- |
| string[] | String array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let data = rpc.MessageSequence.create();
try {
data.writeStringArray(["abc", "def"]);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write stringArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write stringArray fail, errorMessage ' + e.message);
}
try {
let array = data.readStringArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readStringArray is ' + array);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read stringArray fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read stringArray fail, errorMessage ' + e.message);
}
```
### writeNoException
writeNoException(): void
Writes information to this **MessageSequence** object indicating that no exception occurred.
**System capability**: SystemCapability.Communication.IPC.Core
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: onRemoteMessageRequest called');
try {
reply.writeNoException();
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write no exception fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write no exception fail, errorMessage ' + e.message);
}
return true;
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
}
}
```
### readException
readException(): void
Reads the exception information from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **sendMessageRequest()** of the proxy object is called to send a message.
```ts
import { BusinessError } from '@ohos.base';
import hilog from '@ohos.hilog';
let option = new rpc.MessageOption();
let data = rpc.MessageSequence.create();
let reply = rpc.MessageSequence.create();
data.writeNoException();
data.writeInt(6);
if (proxy != undefined) {
proxy.sendMessageRequest(1, data, reply, option)
.then((result: rpc.RequestResult) => {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendMessageRequest got result');
try {
result.reply.readException();
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read exception fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read exception fail, errorMessage ' + e.message);
}
let num = result.reply.readInt();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendMessageRequest failed, errCode: ' + result.errCode);
}
}).catch((e: Error) => {
hilog.error(0x0000, 'testTag', 'RPCTest: sendMessageRequest got exception: ' + e.message);
}).finally (() => {
hilog.info(0x0000, 'testTag', 'RPCTest: sendMessageRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
});
}
```
### writeParcelableArray
writeParcelableArray(parcelableArray: Parcelable[]): void
Writes a **Parcelable** array to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------------- | ------------ | ---- | -------------------------- |
| parcelableArray | [Parcelable](#parcelable9)[] | Yes | **Parcelable** array to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyParcelable implements rpc.Parcelable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageSequence: rpc.MessageSequence): boolean {
messageSequence.writeInt(this.num);
messageSequence.writeString(this.str);
return true;
}
unmarshalling(messageSequence: rpc.MessageSequence): boolean {
this.num = messageSequence.readInt();
this.str = messageSequence.readString();
return true;
}
}
let parcelable = new MyParcelable(1, "aaa");
let parcelable2 = new MyParcelable(2, "bbb");
let parcelable3 = new MyParcelable(3, "ccc");
let a = [parcelable, parcelable2, parcelable3];
let data = rpc.MessageSequence.create();
try {
data.writeParcelableArray(a);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write parcelable array fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write parcelable array fail, errorMessage ' + e.message);
}
```
### readParcelableArray
readParcelableArray(parcelableArray: Parcelable[]): void
Reads a **Parcelable** array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------------- | ------------ | ---- | -------------------------- |
| parcelableArray | [Parcelable](#parcelable9)[] | Yes | **Parcelable** array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
| 1900012 | call js callback function failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyParcelable implements rpc.Parcelable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageSequence: rpc.MessageSequence): boolean {
messageSequence.writeInt(this.num);
messageSequence.writeString(this.str);
return true;
}
unmarshalling(messageSequence: rpc.MessageSequence): boolean {
this.num = messageSequence.readInt();
this.str = messageSequence.readString();
return true;
}
}
let parcelable = new MyParcelable(1, "aaa");
let parcelable2 = new MyParcelable(2, "bbb");
let parcelable3 = new MyParcelable(3, "ccc");
let a = [parcelable, parcelable2, parcelable3];
let data = rpc.MessageSequence.create();
data.writeParcelableArray(a);
let b = [new MyParcelable(0, ""), new MyParcelable(0, ""), new MyParcelable(0, "")];
try {
data.readParcelableArray(b);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read parcelable array fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read parcelable array fail, errorMessage ' + e.message);
}
```
### writeRemoteObjectArray
writeRemoteObjectArray(objectArray: IRemoteObject[]): void
Writes an array of **IRemoteObject** objects to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------- | --------------- | ---- | ---------------------------------------------- |
| objectArray | [IRemoteObject](#iremoteobject)[] | Yes | Array of **IRemoteObject** objects to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.modifyLocalInterface(this, descriptor);
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let a = [new TestRemoteObject("testObject1"), new TestRemoteObject("testObject2"), new TestRemoteObject("testObject3")];
let data = rpc.MessageSequence.create();
try {
data.writeRemoteObjectArray(a);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write remote object array fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write remote object array fail, errorMessage ' + e.message);
}
```
### readRemoteObjectArray
readRemoteObjectArray(objects: IRemoteObject[]): void
Reads an array of **IRemoteObject** objects from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | --------------- | ---- | ---------------------------------------------- |
| objects | [IRemoteObject](#iremoteobject)[] | Yes | **IRemoteObject** array to read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.modifyLocalInterface(this, descriptor);
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let a = [new TestRemoteObject("testObject1"), new TestRemoteObject("testObject2"), new TestRemoteObject("testObject3")];
let data = rpc.MessageSequence.create();
data.writeRemoteObjectArray(a);
let b: Array<rpc.IRemoteObject> = new Array(3);
try {
data.readRemoteObjectArray(b);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read remote object array fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read remote object array fail, errorMessage ' + e.message);
}
```
### readRemoteObjectArray
readRemoteObjectArray(): IRemoteObject[]
Reads the **IRemoteObject** object array from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| --------------- | --------------------------- |
| [IRemoteObject](#iremoteobject)[] | **IRemoteObject** object array read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.modifyLocalInterface(this, descriptor);
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let a = [new TestRemoteObject("testObject1"), new TestRemoteObject("testObject2"), new TestRemoteObject("testObject3")];
let data = rpc.MessageSequence.create();
data.writeRemoteObjectArray(a);
try {
let b = data.readRemoteObjectArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readRemoteObjectArray is ' + b);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read remote object array fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read remote object array fail, errorMessage ' + e.message);
}
```
### closeFileDescriptor
static closeFileDescriptor(fd: number): void
Closes a file descriptor. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------- |
| fd | number | Yes | File descriptor to close.|
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
try {
rpc.MessageSequence.closeFileDescriptor(file.fd);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc close file descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc close file descriptor fail, errorMessage ' + e.message);
}
```
### dupFileDescriptor
static dupFileDescriptor(fd: number) :number
Duplicates a file descriptor. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------ |
| fd | number | Yes | File descriptor to duplicate.|
**Return value**
| Type | Description |
| ------ | -------------------- |
| number | New file descriptor.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900013 | call os dup function failed |
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
try {
rpc.MessageSequence.dupFileDescriptor(file.fd);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc dup file descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc dup file descriptor fail, errorMessage ' + e.message);
}
```
### containFileDescriptors
containFileDescriptors(): boolean
Checks whether this **MessageSequence** object contains file descriptors.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | -------------------------------------------------------------------- |
| boolean | Returns **true** if the **MessageSequence** object contains file descriptors; returns **false** otherwise.|
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let sequence = new rpc.MessageSequence();
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
try {
sequence.writeFileDescriptor(file.fd);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write file descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write file descriptor fail, errorMessage ' + e.message);
}
try {
let containFD = sequence.containFileDescriptors();
hilog.info(0x0000, 'testTag', 'RpcTest: sequence after write fd containFd result is ' + containFD);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc contain file descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc contain file descriptor fail, errorMessage ' + e.message);
}
```
### writeFileDescriptor
writeFileDescriptor(fd: number): void
Writes a file descriptor to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------ |
| fd | number | Yes | File descriptor to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let sequence = new rpc.MessageSequence();
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
try {
sequence.writeFileDescriptor(file.fd);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write file descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write file descriptor fail, errorMessage ' + e.message);
}
```
### readFileDescriptor
readFileDescriptor(): number
Reads the file descriptor from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| number | File descriptor read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let sequence = new rpc.MessageSequence();
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
try {
sequence.writeFileDescriptor(file.fd);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write file descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write file descriptor fail, errorMessage ' + e.message);
}
try {
let readFD = sequence.readFileDescriptor();
hilog.info(0x0000, 'testTag', 'RpcClient: readFileDescriptor is ' + readFD);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read file descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read file descriptor fail, errorMessage ' + e.message);
}
```
### writeAshmem
writeAshmem(ashmem: Ashmem): void
Writes an anonymous shared object to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------- |
| ashmem | [Ashmem](#ashmem8) | Yes | Anonymous shared object to write.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | ------- |
| 1900003 | write to ashmem failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let sequence = new rpc.MessageSequence();
let ashmem: rpc.Ashmem | undefined = undefined;
try {
ashmem = rpc.Ashmem.create("ashmem", 1024);
try {
sequence.writeAshmem(ashmem);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write ashmem fail, errorMessage ' + e.message);
}
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc create ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc create ashmem fail, errorMessage ' + e.message);
}
```
### readAshmem
readAshmem(): Ashmem
Reads the anonymous shared object from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------ |
| [Ashmem](#ashmem8) | Anonymous share object obtained.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900004 | read from ashmem failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let sequence = new rpc.MessageSequence();
let ashmem: rpc.Ashmem | undefined = undefined;
try {
ashmem = rpc.Ashmem.create("ashmem", 1024);
try {
sequence.writeAshmem(ashmem);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write ashmem fail, errorMessage ' + e.message);
}
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc create ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc create ashmem fail, errorMessage ' + e.message);
}
try {
sequence.readAshmem();
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read ashmem fail, errorMessage ' + e.message);
}
```
### getRawDataCapacity
getRawDataCapacity(): number
Obtains the maximum amount of raw data that can be held by this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------------------------------------------------ |
| number | 128 MB, which is the maximum amount of raw data that can be held by this **MessageSequence** object.|
**Example**
```ts
import hilog from '@ohos.hilog';
let sequence = new rpc.MessageSequence();
let result = sequence.getRawDataCapacity();
hilog.info(0x0000, 'testTag', 'RpcTest: sequence get RawDataCapacity result is ' + result);
```
### writeRawData
writeRawData(rawData: number[], size: number): void
Writes raw data to this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | -------- | ---- | ---------------------------------- |
| rawData | number[] | Yes | Raw data to write. |
| size | number | Yes | Size of the raw data, in bytes.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900009 | write data to message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let sequence = new rpc.MessageSequence();
let arr = [1, 2, 3, 4, 5];
try {
sequence.writeRawData(arr, arr.length);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write rawdata fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write rawdata fail, errorMessage ' + e.message);
}
```
### readRawData
readRawData(size: number): number[]
Reads raw data from this **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------ |
| size | number | Yes | Size of the raw data to read.|
**Return value**
| Type | Description |
| -------- | ------------------------------ |
| number[] | Raw data obtained, in bytes.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900010 | read data from message sequence failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let sequence = new rpc.MessageSequence();
let arr = [1, 2, 3, 4, 5];
try {
sequence.writeRawData(arr, arr.length);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc write rawdata fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc write rawdata fail, errorMessage ' + e.message);
}
try {
let result = sequence.readRawData(5);
hilog.info(0x0000, 'testTag', 'RpcTest: sequence read raw data result is ' + result);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc read rawdata fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc read rawdata fail, errorMessage ' + e.message);
}
```
## MessageParcel<sup>(deprecated)</sup>
>This class is no longer maintained since API version 9. You are advised to use [MessageSequence](#messagesequence9).
Provides APIs for reading and writing data in specific format. During RPC, the sender can use the **write()** method provided by **MessageParcel** to write data in specific format to a **MessageParcel** object. The receiver can use the **read()** method provided by **MessageParcel** to read data in specific format from a **MessageParcel** object. The data formats include basic data types and arrays, IPC objects, interface tokens, and custom sequenceable objects.
### create
static create(): MessageParcel
Creates a **MessageParcel** object. This method is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------------- | ----------------------------- |
| [MessageParcel](#messageparceldeprecated) | **MessageParcel** object created.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
hilog.info(0x0000, 'testTag', 'RpcClient: data is ' + data);
```
### reclaim
reclaim(): void
Reclaims the **MessageParcel** object that is no longer used.
**System capability**: SystemCapability.Communication.IPC.Core
**Example**
```ts
let reply = rpc.MessageParcel.create();
reply.reclaim();
```
### writeRemoteObject
writeRemoteObject(object: IRemoteObject): boolean
Serializes a remote object and writes it to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------------------------------- | ---- | --------------------------------------- |
| object | [IRemoteObject](#iremoteobject) | Yes | Remote object to serialize and write to the **MessageParcel** object.|
**Return value**
| Type | Description |
| ------- | ----------------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
}
let data = rpc.MessageParcel.create();
let testRemoteObject = new TestRemoteObject("testObject");
data.writeRemoteObject(testRemoteObject);
```
### readRemoteObject
readRemoteObject(): IRemoteObject
Reads the remote object from this **MessageParcel** object. You can use this method to deserialize the **MessageParcel** object to generate an **IRemoteObject**. The remote objects are read in the order in which they are written to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------------------------------- | ------------------ |
| [IRemoteObject](#iremoteobject) | Remote object obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
}
let data = rpc.MessageParcel.create();
let testRemoteObject = new TestRemoteObject("testObject");
data.writeRemoteObject(testRemoteObject);
let proxy = data.readRemoteObject();
hilog.info(0x0000, 'testTag', 'readRemoteObject is ' + proxy);
```
### writeInterfaceToken
writeInterfaceToken(token: string): boolean
Writes an interface token to this **MessageParcel** object. The remote object can use this interface token to verify the communication.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------ |
| token | string | Yes | Interface token to write.|
**Return value**
| Type | Description |
| ------- | ----------------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeInterfaceToken("aaa");
hilog.info(0x0000, 'testTag', 'RpcServer: writeInterfaceToken is ' + result);
```
### readInterfaceToken
readInterfaceToken(): string
Reads the interface token from this **MessageParcel** object. The interface token is read in the sequence in which it is written to the **MessageParcel** object. The local object can use it to verify the communication.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------------ |
| string | Interface token obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteRequest(code: number, data: rpc.MessageParcel, reply: rpc.MessageParcel, option: rpc.MessageOption): boolean {
let interfaceToken = data.readInterfaceToken();
hilog.info(0x0000, 'testTag', 'RpcServer: interfaceToken is ' + interfaceToken);
return true;
}
}
```
### getSize
getSize(): number
Obtains the data size of this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | --------------------------------------------- |
| number | Size of the **MessageParcel** object obtained, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let size = data.getSize();
hilog.info(0x0000, 'testTag', 'RpcClient: size is ' + size);
```
### getCapacity
getCapacity(): number
Obtains the capacity of this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | --------------------------------------------- |
| number | **MessageParcel** capacity obtained, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.getCapacity();
hilog.info(0x0000, 'testTag', 'RpcClient: capacity is ' + result);
```
### setSize
setSize(size: number): boolean
Sets the size of data contained in this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------- |
| size | number | Yes | Data size to set, in bytes.|
**Return value**
| Type | Description |
| ------- | --------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let setSize = data.setSize(16);
hilog.info(0x0000, 'testTag', 'RpcClient: setSize is ' + setSize);
```
### setCapacity
setCapacity(size: number): boolean
Sets the storage capacity of this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------------------------- |
| size | number | Yes | Storage capacity to set, in bytes.|
**Return value**
| Type | Description |
| ------- | --------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.setCapacity(100);
hilog.info(0x0000, 'testTag', 'RpcClient: setCapacity is ' + result);
```
### getWritableBytes
getWritableBytes(): number
Obtains the writable capacity of this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | --------------------------------------------------- |
| number | **MessageParcel** writable capacity obtained, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteRequest(code: number, data: rpc.MessageParcel, reply: rpc.MessageParcel, option: rpc.MessageOption): boolean {
let getWritableBytes = data.getWritableBytes();
hilog.info(0x0000, 'testTag', 'RpcServer: getWritableBytes is ' + getWritableBytes);
return true;
}
}
```
### getReadableBytes
getReadableBytes(): number
Obtains the readable capacity of this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | --------------------------------------------------- |
| number | **MessageParcel** object readable capacity, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteRequest(code: number, data: rpc.MessageParcel, reply: rpc.MessageParcel, option: rpc.MessageOption): boolean {
let result = data.getReadableBytes();
hilog.info(0x0000, 'testTag', 'RpcServer: getReadableBytes is ' + result);
return true;
}
}
```
### getReadPosition
getReadPosition(): number
Obtains the read position of this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | --------------------------------------- |
| number | Current read position of the **MessageParcel** object.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let readPos = data.getReadPosition();
hilog.info(0x0000, 'testTag', 'RpcClient: readPos is ' + readPos);
```
### getWritePosition
getWritePosition(): number
Obtains the write position of this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | --------------------------------------- |
| number | Current write position of the **MessageParcel** object.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
data.writeInt(10);
let bwPos = data.getWritePosition();
hilog.info(0x0000, 'testTag', 'RpcClient: bwPos is ' + bwPos);
```
### rewindRead
rewindRead(pos: number): boolean
Moves the read pointer to the specified position.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------ |
| pos | number | Yes | Position from which data is to read.|
**Return value**
| Type | Description |
| ------- | ------------------------------------------------- |
| boolean | Returns **true** if the read position changes; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
data.writeInt(12);
data.writeString("parcel");
let number = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: number is ' + number);
data.rewindRead(0);
let number2 = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: rewindRead is ' + number2);
```
### rewindWrite
rewindWrite(pos: number): boolean
Moves the write pointer to the specified position.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------ |
| pos | number | Yes | Position from which data is to write.|
**Return value**
| Type | Description |
| ------- | --------------------------------------------- |
| boolean | Returns **true** if the write position changes; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
data.writeInt(4);
data.rewindWrite(0);
data.writeInt(5);
let number = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: rewindWrite is ' + number);
```
### writeByte
writeByte(val: number): boolean
Writes a Byte value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------- |
| val | number | Yes | Byte value to write.|
**Return value**
| Type | Description |
| ------- | ----------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeByte(2);
hilog.info(0x0000, 'testTag', 'RpcClient: writeByte is ' + result);
```
### readByte
readByte(): number
Reads the Byte value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------ |
| number | Byte value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeByte(2);
hilog.info(0x0000, 'testTag', 'RpcClient: writeByte is ' + result);
let ret = data.readByte();
hilog.info(0x0000, 'testTag', 'RpcClient: readByte is ' + ret);
```
### writeShort
writeShort(val: number): boolean
Writes a Short int value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------ |
| val | number | Yes | Short int value to write.|
**Return value**
| Type | Description |
| ------- | ----------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeShort(8);
hilog.info(0x0000, 'testTag', 'RpcClient: writeShort is ' + result);
```
### readShort
readShort(): number
Reads the Short int value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | -------------- |
| number | Short int value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeShort(8);
hilog.info(0x0000, 'testTag', 'RpcClient: writeShort is ' + result);
let ret = data.readShort();
hilog.info(0x0000, 'testTag', 'RpcClient: readShort is ' + ret);
```
### writeInt
writeInt(val: number): boolean
Writes an Int value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------- |
| val | number | Yes | Int value to write.|
**Return value**
| Type | Description |
| ------- | ----------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeInt(10);
hilog.info(0x0000, 'testTag', 'RpcClient: writeInt is ' + result);
```
### readInt
readInt(): number
Reads the Int value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------ |
| number | Int value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeInt(10);
hilog.info(0x0000, 'testTag', 'RpcClient: writeInt is ' + result);
let ret = data.readInt();
hilog.info(0x0000, 'testTag', 'RpcClient: readInt is ' + ret);
```
### writeLong
writeLong(val: number): boolean
Writes a Long int value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------- |
| val | number | Yes | Long int value to write.|
**Return value**
| Type | Description |
| ------- | --------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeLong(10000);
hilog.info(0x0000, 'testTag', 'RpcClient: writeLong is ' + result);
```
### readLong
readLong(): number
Reads the Long int value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | -------------- |
| number | Long int value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeLong(10000);
hilog.info(0x0000, 'testTag', 'RpcClient: writeLong is ' + result);
let ret = data.readLong();
hilog.info(0x0000, 'testTag', 'RpcClient: readLong is ' + ret);
```
### writeFloat
writeFloat(val: number): boolean
Writes a Float value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------- |
| val | number | Yes | Float value to write.|
**Return value**
| Type | Description |
| ------- | --------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeFloat(1.2);
hilog.info(0x0000, 'testTag', 'RpcClient: writeFloat is ' + result);
```
### readFloat
readFloat(): number
Reads the Float value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------ |
| number | Float value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeFloat(1.2);
hilog.info(0x0000, 'testTag', 'RpcClient: writeFloat is ' + result);
let ret = data.readFloat();
hilog.info(0x0000, 'testTag', 'RpcClient: readFloat is ' + ret);
```
### writeDouble
writeDouble(val: number): boolean
Writes a Double value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------------- |
| val | number | Yes | Double value to write.|
**Return value**
| Type | Description |
| ------- | --------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeDouble(10.2);
hilog.info(0x0000, 'testTag', 'RpcClient: writeDouble is ' + result);
```
### readDouble
readDouble(): number
Reads the Double value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------ |
| number | Double value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeDouble(10.2);
hilog.info(0x0000, 'testTag', 'RpcClient: writeDouble is ' + result);
let ret = data.readDouble();
hilog.info(0x0000, 'testTag', 'RpcClient: readDouble is ' + ret);
```
### writeBoolean
writeBoolean(val: boolean): boolean
Writes a Boolean value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------- | ---- | ---------------- |
| val | boolean | Yes | Boolean value to write.|
**Return value**
| Type | Description |
| ------- | --------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeBoolean(false);
hilog.info(0x0000, 'testTag', 'RpcClient: writeBoolean is ' + result);
```
### readBoolean
readBoolean(): boolean
Reads the Boolean value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | -------------------- |
| boolean | Boolean value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeBoolean(false);
hilog.info(0x0000, 'testTag', 'RpcClient: writeBoolean is ' + result);
let ret = data.readBoolean();
hilog.info(0x0000, 'testTag', 'RpcClient: readBoolean is ' + ret);
```
### writeChar
writeChar(val: number): boolean
Writes a Char value to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------- |
| val | number | Yes | Char value to write.|
**Return value**
| Type | Description |
| ------- | ----------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeChar(97);
hilog.info(0x0000, 'testTag', 'RpcClient: writeChar is ' + result);
```
### readChar
readChar(): number
Reads the Char value from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| number | Char value read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeChar(97);
hilog.info(0x0000, 'testTag', 'RpcClient: writeChar is ' + result);
let ret = data.readChar();
hilog.info(0x0000, 'testTag', 'RpcClient: readChar is ' + ret);
```
### writeString
writeString(val: string): boolean
Writes a string to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ----------------------------------------- |
| val | string | Yes | String to write. The length of the string must be less than 40960 bytes.|
**Return value**
| Type | Description |
| ------- | --------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeString('abc');
hilog.info(0x0000, 'testTag', 'RpcClient: writeString is ' + result);
```
### readString
readString(): string
Reads the string from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | -------------- |
| string | String read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeString('abc');
hilog.info(0x0000, 'testTag', 'RpcClient: writeString is ' + result);
let ret = data.readString();
hilog.info(0x0000, 'testTag', 'RpcClient: readString is ' + ret);
```
### writeSequenceable
writeSequenceable(val: Sequenceable): boolean
Writes a sequenceable object to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ----------------------------- | ---- | -------------------- |
| val | [Sequenceable](#sequenceabledeprecated) | Yes | Sequenceable object to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MySequenceable implements rpc.Sequenceable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageParcel: rpc.MessageParcel): boolean {
messageParcel.writeInt(this.num);
messageParcel.writeString(this.str);
return true;
}
unmarshalling(messageParcel: rpc.MessageParcel): boolean {
this.num = messageParcel.readInt();
this.str = messageParcel.readString();
return true;
}
}
let sequenceable = new MySequenceable(1, "aaa");
let data = rpc.MessageParcel.create();
let result = data.writeSequenceable(sequenceable);
hilog.info(0x0000, 'testTag', 'RpcClient: writeSequenceable is ' + result);
```
### readSequenceable
readSequenceable(dataIn: Sequenceable): boolean
Reads member variables from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory | Description |
| ------ | ----------------------------- | ------- | ---------------------------------------------- |
| dataIn | [Sequenceable](#sequenceabledeprecated) | Yes | Object that reads member variables from the **MessageParcel** object.|
**Return value**
| Type | Description |
| ------- | ---------------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MySequenceable implements rpc.Sequenceable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageParcel: rpc.MessageParcel): boolean {
messageParcel.writeInt(this.num);
messageParcel.writeString(this.str);
return true;
}
unmarshalling(messageParcel: rpc.MessageParcel): boolean {
this.num = messageParcel.readInt();
this.str = messageParcel.readString();
return true;
}
}
let sequenceable = new MySequenceable(1, "aaa");
let data = rpc.MessageParcel.create();
let result = data.writeSequenceable(sequenceable);
hilog.info(0x0000, 'testTag', 'RpcClient: writeSequenceable is ' + result);
let ret = new MySequenceable(0, "");
let result2 = data.readSequenceable(ret);
hilog.info(0x0000, 'testTag', 'RpcClient: readSequenceable is ' + result2);
```
### writeByteArray
writeByteArray(byteArray: number[]): boolean
Writes a byte array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | -------- | ---- | ------------------ |
| byteArray | number[] | Yes | Byte array to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let ByteArrayVar = [1, 2, 3, 4, 5];
let result = data.writeByteArray(ByteArrayVar);
hilog.info(0x0000, 'testTag', 'RpcClient: writeByteArray is ' + result);
```
### readByteArray
readByteArray(dataIn: number[]): void
Reads a byte array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ------------------ |
| dataIn | number[] | Yes | Byte array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let ByteArrayVar = [1, 2, 3, 4, 5];
let result = data.writeByteArray(ByteArrayVar);
hilog.info(0x0000, 'testTag', 'RpcClient: writeByteArray is ' + result);
let array: Array<number> = new Array(5);
data.readByteArray(array);
```
### readByteArray
readByteArray(): number[]
Reads the byte array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------- |
| number[] | Byte array read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let ByteArrayVar = [1, 2, 3, 4, 5];
let result = data.writeByteArray(ByteArrayVar);
hilog.info(0x0000, 'testTag', 'RpcClient: writeByteArray is ' + result);
let array = data.readByteArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readByteArray is ' + array);
```
### writeShortArray
writeShortArray(shortArray: number[]): boolean
Writes a short array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | -------- | ---- | -------------------- |
| shortArray | number[] | Yes | Short array to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeShortArray([11, 12, 13]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeShortArray is ' + result);
```
### readShortArray
readShortArray(dataIn: number[]): void
Reads a short array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------- |
| dataIn | number[] | Yes | Short array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeShortArray([11, 12, 13]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeShortArray is ' + result);
let array: Array<number> = new Array(3);
data.readShortArray(array);
```
### readShortArray
readShortArray(): number[]
Reads the short array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ---------------- |
| number[] | Short array read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeShortArray([11, 12, 13]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeShortArray is ' + result);
let array = data.readShortArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readShortArray is ' + array);
```
### writeIntArray
writeIntArray(intArray: number[]): boolean
Writes an integer array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | -------- | ---- | ------------------ |
| intArray | number[] | Yes | Integer array to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeIntArray([100, 111, 112]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeIntArray is ' + result);
```
### readIntArray
readIntArray(dataIn: number[]): void
Reads an integer array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ------------------ |
| dataIn | number[] | Yes | Integer array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeIntArray([100, 111, 112]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeIntArray is ' + result);
let array: Array<number> = new Array(3);
data.readIntArray(array);
```
### readIntArray
readIntArray(): number[]
Reads the integer array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------- |
| number[] | Integer array read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeIntArray([100, 111, 112]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeIntArray is ' + result);
let array = data.readIntArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readIntArray is ' + array);
```
### writeLongArray
writeLongArray(longArray: number[]): boolean
Writes a long array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | -------- | ---- | -------------------- |
| longArray | number[] | Yes | Long array to write.|
**Return value**
| Type | Description |
| ------- | ----------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeLongArray([1111, 1112, 1113]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeLongArray is ' + result);
```
### readLongArray
readLongArray(dataIn: number[]): void
Reads a long array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------- |
| dataIn | number[] | Yes | Long array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeLongArray([1111, 1112, 1113]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeLongArray is ' + result);
let array: Array<number> = new Array(3);
data.readLongArray(array);
```
### readLongArray
readLongArray(): number[]
Reads the long array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ---------------- |
| number[] | Long array read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeLongArray([1111, 1112, 1113]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeLongArray is ' + result);
let array = data.readLongArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readLongArray is ' + array);
```
### writeFloatArray
writeFloatArray(floatArray: number[]): boolean
Writes a FloatArray to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type| Mandatory| Description |
| ---------- | -------- | ---- | --- |
| floatArray | number[] | Yes | Floating-point array to write. The system processes Float data as that of the Double type. Therefore, the total number of bytes occupied by a FloatArray must be calculated as the Double type.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeFloatArray([1.2, 1.3, 1.4]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeFloatArray is ' + result);
```
### readFloatArray
readFloatArray(dataIn: number[]): void
Reads a FloatArray from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ------ |
| dataIn | number[] | Yes | Floating-point array to read. The system processes Float data as that of the Double type. Therefore, the total number of bytes occupied by a FloatArray must be calculated as the Double type.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeFloatArray([1.2, 1.3, 1.4]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeFloatArray is ' + result);
let array: Array<number> = new Array(3);
data.readFloatArray(array);
```
### readFloatArray
readFloatArray(): number[]
Reads the FloatArray from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------- |
| number[] | FloatArray read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeFloatArray([1.2, 1.3, 1.4]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeFloatArray is ' + result);
let array = data.readFloatArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readFloatArray is ' + array);
```
### writeDoubleArray
writeDoubleArray(doubleArray: number[]): boolean
Writes a DoubleArray to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------- | -------- | ---- | ------------------------ |
| doubleArray | number[] | Yes | DoubleArray to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeDoubleArray([11.1, 12.2, 13.3]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeDoubleArray is ' + result);
```
### readDoubleArray
readDoubleArray(dataIn: number[]): void
Reads a DoubleArray from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ------------------------ |
| dataIn | number[] | Yes | DoubleArray to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeDoubleArray([11.1, 12.2, 13.3]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeDoubleArray is ' + result);
let array: Array<number> = new Array(3);
data.readDoubleArray(array);
```
### readDoubleArray
readDoubleArray(): number[]
Reads the DoubleArray from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | -------------------- |
| number[] | DoubleArray read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeDoubleArray([11.1, 12.2, 13.3]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeDoubleArray is ' + result);
let array = data.readDoubleArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readDoubleArray is ' + array);
```
### writeBooleanArray
writeBooleanArray(booleanArray: boolean[]): boolean
Writes a Boolean array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------------ | --------- | ---- | ------------------ |
| booleanArray | boolean[] | Yes | Boolean array to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeBooleanArray([false, true, false]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeBooleanArray is ' + result);
```
### readBooleanArray
readBooleanArray(dataIn: boolean[]): void
Reads a Boolean array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | --------- | ---- | ------------------ |
| dataIn | boolean[] | Yes | Boolean array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeBooleanArray([false, true, false]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeBooleanArray is ' + result);
let array: Array<boolean> = new Array(3);
data.readBooleanArray(array);
```
### readBooleanArray
readBooleanArray(): boolean[]
Reads the Boolean array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| --------- | -------------- |
| boolean[] | Boolean array read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeBooleanArray([false, true, false]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeBooleanArray is ' + result);
let array = data.readBooleanArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readBooleanArray is ' + array);
```
### writeCharArray
writeCharArray(charArray: number[]): boolean
Writes a character array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | -------- | ---- | ---------------------- |
| charArray | number[] | Yes | Character array to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeCharArray([97, 98, 88]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeCharArray is ' + result);
```
### readCharArray
readCharArray(dataIn: number[]): void
Reads a character array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | ---------------------- |
| dataIn | number[] | Yes | Character array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeCharArray([97, 98, 99]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeCharArray is ' + result);
let array: Array<number> = new Array(3);
data.readCharArray(array);
```
### readCharArray
readCharArray(): number[]
Reads the character array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ------------------ |
| number[] | Character array read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeCharArray([97, 98, 99]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeCharArray is ' + result);
let array = data.readCharArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readCharArray is ' + array);
```
### writeStringArray
writeStringArray(stringArray: string[]): boolean
Writes a string array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------- | -------- | ---- | ---------------- |
| stringArray | string[] | Yes | String array to write. The length of a single element in the array must be less than 40960 bytes.|
**Return value**
| Type | Description|
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeStringArray(["abc", "def"]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeStringArray is ' + result);
```
### readStringArray
readStringArray(dataIn: string[]): void
Reads a string array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------- |
| dataIn | string[] | Yes | String array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeStringArray(["abc", "def"]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeStringArray is ' + result);
let array: Array<string> = new Array(2);
data.readStringArray(array);
```
### readStringArray
readStringArray(): string[]
Reads the string array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| -------- | ---------------- |
| string[] | String array read.|
**Example**
```ts
import hilog from '@ohos.hilog';
let data = rpc.MessageParcel.create();
let result = data.writeStringArray(["abc", "def"]);
hilog.info(0x0000, 'testTag', 'RpcClient: writeStringArray is ' + result);
let array = data.readStringArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readStringArray is ' + array);
```
### writeNoException<sup>8+</sup>
writeNoException(): void
Writes information to this **MessageParcel** object indicating that no exception occurred.
**System capability**: SystemCapability.Communication.IPC.Core
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
onRemoteRequest(code: number, data: rpc.MessageParcel, reply: rpc.MessageParcel, option: rpc.MessageOption): boolean {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: onRemoteRequest called');
reply.writeNoException();
return true;
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
}
}
```
### readException<sup>8+</sup>
readException(): void
Reads the exception information from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **sendMessageRequest()** of the proxy object is called to send a message.
```ts
import hilog from '@ohos.hilog';
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
data.writeNoException();
data.writeString('hello');
if (proxy != undefined) {
let a = proxy.sendRequest(1, data, reply, option) as Object;
let b = a as Promise<rpc.SendRequestResult>;
b.then((result: rpc.SendRequestResult) => {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
result.reply.readException();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, errCode: ' + result.errCode);
}
}).catch((e: Error) => {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest got exception: ' + e.message);
}).finally (() => {
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
});
}
```
### writeSequenceableArray
writeSequenceableArray(sequenceableArray: Sequenceable[]): boolean
Writes a sequenceable array to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------------- | ----------------------------------------- | ---- | -------------------------- |
| sequenceableArray | [Sequenceable](#sequenceabledeprecated)[] | Yes | Sequenceable array to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MySequenceable implements rpc.Sequenceable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageParcel: rpc.MessageParcel): boolean {
messageParcel.writeInt(this.num);
messageParcel.writeString(this.str);
return true;
}
unmarshalling(messageParcel: rpc.MessageParcel): boolean {
this.num = messageParcel.readInt();
this.str = messageParcel.readString();
return true;
}
}
let sequenceable = new MySequenceable(1, "aaa");
let sequenceable2 = new MySequenceable(2, "bbb");
let sequenceable3 = new MySequenceable(3, "ccc");
let a = [sequenceable, sequenceable2, sequenceable3];
let data = rpc.MessageParcel.create();
let result = data.writeSequenceableArray(a);
hilog.info(0x0000, 'testTag', 'RpcClient: writeSequenceableArray is ' + result);
```
### readSequenceableArray<sup>8+</sup>
readSequenceableArray(sequenceableArray: Sequenceable[]): void
Reads a sequenceable array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------------- | ----------------------------------------- | ---- | -------------------------- |
| sequenceableArray | [Sequenceable](#sequenceabledeprecated)[] | Yes | Sequenceable array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MySequenceable implements rpc.Sequenceable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageParcel: rpc.MessageParcel): boolean {
messageParcel.writeInt(this.num);
messageParcel.writeString(this.str);
return true;
}
unmarshalling(messageParcel: rpc.MessageParcel): boolean {
this.num = messageParcel.readInt();
this.str = messageParcel.readString();
return true;
}
}
let sequenceable = new MySequenceable(1, "aaa");
let sequenceable2 = new MySequenceable(2, "bbb");
let sequenceable3 = new MySequenceable(3, "ccc");
let a = [sequenceable, sequenceable2, sequenceable3];
let data = rpc.MessageParcel.create();
let result = data.writeSequenceableArray(a);
hilog.info(0x0000, 'testTag', 'RpcClient: writeSequenceableArray is ' + result);
let b = [new MySequenceable(0, ""), new MySequenceable(0, ""), new MySequenceable(0, "")];
data.readSequenceableArray(b);
```
### writeRemoteObjectArray<sup>8+</sup>
writeRemoteObjectArray(objectArray: IRemoteObject[]): boolean
Writes an array of **IRemoteObject** objects to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ----------- | --------------- | ---- | ----- |
| objectArray | [IRemoteObject](#iremoteobject)[] | Yes | Array of **IRemoteObject** objects to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.attachLocalInterface(this, descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let a = [new TestRemoteObject("testObject1"), new TestRemoteObject("testObject2"), new TestRemoteObject("testObject3")];
let data = rpc.MessageParcel.create();
let result = data.writeRemoteObjectArray(a);
hilog.info(0x0000, 'testTag', 'RpcClient: writeRemoteObjectArray is ' + result);
```
### readRemoteObjectArray<sup>8+</sup>
readRemoteObjectArray(objects: IRemoteObject[]): void
Reads an **IRemoteObject** array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | --------------- | ---- | --------- |
| objects | [IRemoteObject](#iremoteobject)[] | Yes | **IRemoteObject** array to read.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.attachLocalInterface(this, descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let a = [new TestRemoteObject("testObject1"), new TestRemoteObject("testObject2"), new TestRemoteObject("testObject3")];
let data = rpc.MessageParcel.create();
data.writeRemoteObjectArray(a);
let b: Array<rpc.IRemoteObject> = new Array(3);
data.readRemoteObjectArray(b);
```
### readRemoteObjectArray<sup>8+</sup>
readRemoteObjectArray(): IRemoteObject[]
Reads the **IRemoteObject** array from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| --------------- | --------------------------- |
| [IRemoteObject](#iremoteobject)[] | **IRemoteObject** object array obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.attachLocalInterface(this, descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let a = [new TestRemoteObject("testObject1"), new TestRemoteObject("testObject2"), new TestRemoteObject("testObject3")];
let data = rpc.MessageParcel.create();
let result = data.writeRemoteObjectArray(a);
hilog.info(0x0000, 'testTag', 'RpcClient: readRemoteObjectArray is ' + result);
let b = data.readRemoteObjectArray();
hilog.info(0x0000, 'testTag', 'RpcClient: readRemoteObjectArray is ' + b);
```
### closeFileDescriptor<sup>8+</sup>
static closeFileDescriptor(fd: number): void
Closes a file descriptor. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------- |
| fd | number | Yes | File descriptor to close.|
**Example**
```ts
import fs from '@ohos.file.fs';
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
rpc.MessageParcel.closeFileDescriptor(file.fd);
```
### dupFileDescriptor<sup>8+</sup>
static dupFileDescriptor(fd: number) :number
Duplicates a file descriptor. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------ |
| fd | number | Yes | File descriptor to duplicate.|
**Return value**
| Type | Description |
| ------ | -------------------- |
| number | New file descriptor.|
**Example**
```ts
import fs from '@ohos.file.fs';
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
rpc.MessageParcel.dupFileDescriptor(file.fd);
```
### containFileDescriptors<sup>8+</sup>
containFileDescriptors(): boolean
Checks whether this **MessageParcel** object contains file descriptors.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | --------------------------------------------- |
| boolean |Returns **true** if the **MessageParcel** object contains file descriptors; returns **false** otherwise.|
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
let writeResult = parcel.writeFileDescriptor(file.fd);
hilog.info(0x0000, 'testTag', 'RpcTest: parcel writeFd result is ' + writeResult);
let containFD = parcel.containFileDescriptors();
hilog.info(0x0000, 'testTag', 'RpcTest: parcel after write fd containFd result is ' + containFD);
```
### writeFileDescriptor<sup>8+</sup>
writeFileDescriptor(fd: number): boolean
Writes a file descriptor to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------ |
| fd | number | Yes | File descriptor to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
let writeResult = parcel.writeFileDescriptor(file.fd);
hilog.info(0x0000, 'testTag', 'RpcTest: parcel writeFd result is ' + writeResult);
```
### readFileDescriptor<sup>8+</sup>
readFileDescriptor(): number
Reads the file descriptor from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| number | File descriptor read.|
**Example**
```ts
import fs from '@ohos.file.fs';
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let filePath = "path/to/file";
let file = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
parcel.writeFileDescriptor(file.fd);
let readFD = parcel.readFileDescriptor();
hilog.info(0x0000, 'testTag', 'RpcTest: parcel read fd is ' + readFD);
```
### writeAshmem<sup>8+</sup>
writeAshmem(ashmem: Ashmem): boolean
Writes an anonymous shared object to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ----------------------------------- |
| ashmem | [Ashmem](#ashmem8) | Yes | Anonymous shared object to write.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let ashmem = rpc.Ashmem.createAshmem("ashmem", 1024);
let isWriteSuccess = parcel.writeAshmem(ashmem);
hilog.info(0x0000, 'testTag', 'RpcTest: write ashmem to result is ' + isWriteSuccess);
```
### readAshmem<sup>8+</sup>
readAshmem(): Ashmem
Reads the anonymous shared object from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------ |
| [Ashmem](#ashmem8) | Anonymous share object obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let ashmem = rpc.Ashmem.createAshmem("ashmem", 1024);
let isWriteSuccess = parcel.writeAshmem(ashmem);
hilog.info(0x0000, 'testTag', 'RpcTest: write ashmem to result is ' + isWriteSuccess);
let readAshmem = parcel.readAshmem();
hilog.info(0x0000, 'testTag', 'RpcTest: read ashmem to result is ' + readAshmem);
```
### getRawDataCapacity<sup>8+</sup>
getRawDataCapacity(): number
Obtains the maximum amount of raw data that can be held by this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------------------------------------------------- |
| number | 128 MB, which is the maximum amount of raw data that can be held by this **MessageParcel** object.|
**Example**
```ts
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let result = parcel.getRawDataCapacity();
hilog.info(0x0000, 'testTag', 'RpcTest: parcel get RawDataCapacity result is ' + result);
```
### writeRawData<sup>8+</sup>
writeRawData(rawData: number[], size: number): boolean
Writes raw data to this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | -------- | ---- | ---------------------------------- |
| rawData | number[] | Yes | Raw data to write. |
| size | number | Yes | Size of the raw data, in bytes.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let arr = [1, 2, 3, 4, 5];
let isWriteSuccess = parcel.writeRawData(arr, arr.length);
hilog.info(0x0000, 'testTag', 'RpcTest: parcel write raw data result is ' + isWriteSuccess);
```
### readRawData<sup>8+</sup>
readRawData(size: number): number[]
Reads raw data from this **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------ |
| size | number | Yes | Size of the raw data to read.|
**Return value**
| Type | Description |
| -------- | ------------------------------ |
| number[] | Raw data obtained, in bytes.|
**Example**
```ts
import hilog from '@ohos.hilog';
let parcel = new rpc.MessageParcel();
let arr = [1, 2, 3, 4, 5];
let isWriteSuccess = parcel.writeRawData(arr, arr.length);
hilog.info(0x0000, 'testTag', 'RpcTest: parcel write raw data result is ' + isWriteSuccess);
let result = parcel.readRawData(5);
hilog.info(0x0000, 'testTag', 'RpcTest: parcel read raw data result is ' + result);
```
## Parcelable<sup>9+</sup>
Writes an object to a **MessageSequence** and reads it from the **MessageSequence** during IPC.
### marshalling
marshalling(dataOut: MessageSequence): boolean
Marshals this **Parcelable** object into a **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | --------------- | ---- | ------------------------------------------- |
| dataOut |[MessageSequence](#messagesequence9)| Yes | **MessageSequence** object to which the **Parcelable** object is to be marshaled.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyParcelable implements rpc.Parcelable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageSequence: rpc.MessageSequence): boolean {
messageSequence.writeInt(this.num);
messageSequence.writeString(this.str);
return true;
}
unmarshalling(messageSequence: rpc.MessageSequence): boolean {
this.num = messageSequence.readInt();
this.str = messageSequence.readString();
return true;
}
}
let parcelable = new MyParcelable(1, "aaa");
let data = rpc.MessageSequence.create();
let result = data.writeParcelable(parcelable);
hilog.info(0x0000, 'testTag', 'RpcClient: writeParcelable is ' + result);
let ret = new MyParcelable(0, "");
let result2 = data.readParcelable(ret);
hilog.info(0x0000, 'testTag', 'RpcClient: readParcelable is ' + result2);
```
### unmarshalling
unmarshalling(dataIn: MessageSequence): boolean
Unmarshals this **Parcelable** object from a **MessageSequence** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | --------------- | ---- | ----------------------------------------------- |
| dataIn | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object from which the **Parcelable** object is to be unmarshaled.|
**Return value**
| Type | Description |
| ------- | ---------------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyParcelable implements rpc.Parcelable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageSequence: rpc.MessageSequence): boolean {
messageSequence.writeInt(this.num);
messageSequence.writeString(this.str);
return true;
}
unmarshalling(messageSequence: rpc.MessageSequence): boolean {
this.num = messageSequence.readInt();
this.str = messageSequence.readString();
return true;
}
}
let parcelable = new MyParcelable(1, "aaa");
let data = rpc.MessageSequence.create();
let result = data.writeParcelable(parcelable);
hilog.info(0x0000, 'testTag', 'RpcClient: writeParcelable is ' + result);
let ret = new MyParcelable(0, "");
let result2 = data.readParcelable(ret);
hilog.info(0x0000, 'testTag', 'RpcClient: readParcelable is ' + result2);
```
## Sequenceable<sup>(deprecated)</sup>
>This class is no longer maintained since API version 9. You are advised to use the [Parcelable](#parcelable9).
Writes objects of classes to a **MessageParcel** and reads them from the **MessageParcel** during IPC.
### marshalling
marshalling(dataOut: MessageParcel): boolean
Marshals the sequenceable object into a **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ----------------------------------------- | ---- | ----------------------------------------- |
| dataOut | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object to which the sequenceable object is to be marshaled.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MySequenceable implements rpc.Sequenceable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageParcel: rpc.MessageParcel): boolean {
messageParcel.writeInt(this.num);
messageParcel.writeString(this.str);
return true;
}
unmarshalling(messageParcel: rpc.MessageParcel): boolean {
this.num = messageParcel.readInt();
this.str = messageParcel.readString();
return true;
}
}
let sequenceable = new MySequenceable(1, "aaa");
let data = rpc.MessageParcel.create();
let result = data.writeSequenceable(sequenceable);
hilog.info(0x0000, 'testTag', 'RpcClient: writeSequenceable is ' + result);
let ret = new MySequenceable(0, "");
let result2 = data.readSequenceable(ret);
hilog.info(0x0000, 'testTag', 'RpcClient: readSequenceable is ' + result2);
```
### unmarshalling
unmarshalling(dataIn: MessageParcel): boolean
Unmarshals this sequenceable object from a **MessageParcel** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ----------------------------------------- | ---- | --------------------------------------------- |
| dataIn | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object in which the sequenceable object is to be unmarshaled.|
**Return value**
| Type | Description |
| ------- | ---------------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MySequenceable implements rpc.Sequenceable {
num: number = 0;
str: string = '';
constructor(num: number, str: string) {
this.num = num;
this.str = str;
}
marshalling(messageParcel: rpc.MessageParcel): boolean {
messageParcel.writeInt(this.num);
messageParcel.writeString(this.str);
return true;
}
unmarshalling(messageParcel: rpc.MessageParcel): boolean {
this.num = messageParcel.readInt();
this.str = messageParcel.readString();
return true;
}
}
let sequenceable = new MySequenceable(1, "aaa");
let data = rpc.MessageParcel.create();
let result = data.writeSequenceable(sequenceable);
hilog.info(0x0000, 'testTag', 'RpcClient: writeSequenceable is ' + result);
let ret = new MySequenceable(0, "");
let result2 = data.readSequenceable(ret);
hilog.info(0x0000, 'testTag', 'RpcClient: readSequenceable is ' + result2);
```
## IRemoteBroker
Provides the holder of a remote proxy object.
### asObject
asObject(): IRemoteObject
Obtains a proxy or remote object. This API must be implemented by its derived classes.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ----- | ----- |
| [IRemoteObject](#iremoteobject) | Returns the **RemoteObject** if it is the caller; returns the [IRemoteObject](#iremoteobject), the holder of this **RemoteProxy** object, if the caller is a [RemoteProxy](#remoteproxy) object.|
**Example**
```ts
class TestAbility extends rpc.RemoteObject {
asObject() {
return this;
}
}
let remoteObject = new TestAbility("testObject").asObject();
```
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **asObject()** of the proxy object is called to obtain the proxy or remote object.
```ts
class TestProxy {
remote: rpc.IRemoteObject;
constructor(remote: rpc.IRemoteObject) {
this.remote = remote;
}
asObject() {
return this.remote;
}
}
if (proxy != undefined) {
let iRemoteObject = new TestProxy(proxy).asObject();
}
```
## DeathRecipient
Subscribes to death notifications of a remote object. When the remote object is dead, the local end will receive a notification and **[onRemoteDied](#onremotedied)** will be called. A remote object is dead when the process holding the object is terminated or the device of the remote object is shut down or restarted. If the local and remote objects belong to different devices, the remote object is dead when the device holding the remote object is detached from the network.
### onRemoteDied
onRemoteDied(): void
Called to perform subsequent operations when a death notification of the remote object is received.
**System capability**: SystemCapability.Communication.IPC.Core
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
```
## RequestResult<sup>9+</sup>
Defines the response to the request.
**System capability**: SystemCapability.Communication.IPC.Core
| Name | Type | Readable| Writable| Description |
| ------- | --------------- | ---- | ---- |-------------------------------------- |
| errCode | number | Yes | No | Error code. |
| code | number | Yes | No | Message code. |
| data | [MessageSequence](#messagesequence9) | Yes | No | **MessageSequence** object sent to the remote process.|
| reply | [MessageSequence](#messagesequence9) | Yes | No | **MessageSequence** object returned by the remote process. |
## SendRequestResult<sup>8+(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [RequestResult](#requestresult9).
Defines the response to the request.
**System capability**: SystemCapability.Communication.IPC.Core
| Name | Type | Readable| Writable| Description |
| ------- | ------------- | ---- | ---- | ----------------------------------- |
| errCode | number | Yes | No | Error code. |
| code | number | Yes | No | Message code. |
| data | [MessageParcel](#messageparceldeprecated) | Yes | No | **MessageParcel** object sent to the remote process.|
| reply | [MessageParcel](#messageparceldeprecated) | Yes | No | **MessageParcel** object returned by the remote process. |
## IRemoteObject
Provides methods to query of obtain interface descriptors, add or delete death notifications, dump object status to specific files, and send messages.
### getLocalInterface<sup>9+</sup>
getLocalInterface(descriptor: string): IRemoteBroker
Obtains the string of the interface descriptor.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | ------ | ---- | -------------------- |
| descriptor | string | Yes | Interface descriptor.|
**Return value**
| Type | Description |
| ------------- | --------------------------------------------- |
| [IRemoteBroker](#iremotebroker) | **IRemoteBroker** object bound to the specified interface token.|
### queryLocalInterface<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [getLocalInterface](#getlocalinterface9).
queryLocalInterface(descriptor: string): IRemoteBroker
Queries the string of the interface descriptor.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | ------ | ---- | -------------------- |
| descriptor | string | Yes | Interface descriptor.|
**Return value**
| Type | Description |
| ------------- | --------------------------------------------- |
| [IRemoteBroker](#iremotebroker) | **IRemoteBroker** object bound to the specified interface token.|
### sendRequest<sup>(deprecated)</sup>
>This API is no longer maintained since API version 8. You are advised to use [sendRequest](#sendrequest8deprecated).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption): boolean
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message does not contain any content. If synchronous mode is set in **options** , a promise will be fulfilled when the response to **sendRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ----------------------------------------- | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the message is sent successfully; returns **false** otherwise.|
### sendMessageRequest<sup>9+</sup>
sendMessageRequest(code: number, data: MessageSequence, reply: MessageSequence, options: MessageOption): Promise<RequestResult>
Sends a **MessageSequence** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendMessageRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------------------------------------ | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object holding the data to send. |
| reply | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ---------------------------- | ----------------------------------------- |
| Promise<[RequestResult](#requestresult9)> | Promise used to return the **requestResult** object.|
### sendRequest<sup>8+(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [sendMessageRequest](#sendmessagerequest9).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption): Promise<SendRequestResult>
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ---------------------------------------- | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ------------------------------------------------------------ | --------------------------------------------- |
| Promise<[SendRequestResult](#sendrequestresult8deprecated)> | Promise used to return the **sendRequestResult** object.|
### sendMessageRequest<sup>9+</sup>
sendMessageRequest(code: number, data: MessageSequence, reply: MessageSequence, options: MessageOption, callback: AsyncCallback<RequestResult>): void
Sends a **MessageSequence** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a callback will be called immediately, and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a callback will be invoked when the response to sendRequest is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------------------ | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object holding the data to send. |
| reply | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
| callback | AsyncCallback<[RequestResult](#requestresult9)> | Yes | Callback for receiving the sending result. |
### sendRequest<sup>8+(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [sendMessageRequest](#sendmessagerequest9-1).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption, callback: AsyncCallback<SendRequestResult>): void
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a callback will be called immediately, and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a callback will be invoked when the response to sendRequest is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
| callback | AsyncCallback<[SendRequestResult](#sendrequestresult8deprecated)> | Yes | Callback for receiving the sending result. |
### registerDeathRecipient<sup>9+</sup>
registerDeathRecipient(recipient: DeathRecipient, flags: number): void
Registers a callback for receiving death notifications of the remote object. The callback will be called if the remote object process matching the **RemoteProxy** object is killed.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | -------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to register.|
| flags | number | Yes | Flag of the death notification.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
### addDeathrecipient<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [registerDeathRecipient](#registerdeathrecipient9).
addDeathRecipient(recipient: DeathRecipient, flags: number): boolean
Adds a callback for receiving death notifications of the remote object. This method is called if the remote object process matching the **RemoteProxy** object is killed.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | -------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to add.|
| flags | number | Yes | Flag of the death notification.|
**Return value**
| Type | Description |
| ------- | ---------------------------------------- |
| boolean | Returns **true** if the callback is added successfully; returns **false** otherwise.|
### unregisterDeathRecipient<sup>9+</sup>
unregisterDeathRecipient(recipient: DeathRecipient, flags: number): void
Unregisters the callback used to receive death notifications of the remote object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | -------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to unregister.|
| flags | number | Yes | Flag of the death notification.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
### removeDeathRecipient<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [unregisterDeathRecipient](#unregisterdeathrecipient9).
removeDeathRecipient(recipient: DeathRecipient, flags: number): boolean
Removes the callback used to receive death notifications of the remote object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | -------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to remove.|
| flags | number | Yes | Flag of the death notification.|
**Return value**
| Type | Description |
| ------- | -----------------------------------------|
| boolean | Returns **true** if the callback is removed; returns **false** otherwise.|
### getDescriptor<sup>9+</sup>
getDescriptor(): string
Obtains the interface descriptor (which is a string) of this object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| string | Interface descriptor obtained.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
### getInterfaceDescriptor<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [getDescriptor](#getdescriptor9).
getInterfaceDescriptor(): string
Obtains the interface descriptor (which is a string) of this object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| string | Interface descriptor obtained.|
### isObjectDead
isObjectDead(): boolean
Checks whether this object is dead.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | ---------------------------------- |
| boolean | Returns **true** if the object is dead; returns **false** otherwise.|
## RemoteProxy
Provides APIs to implement **IRemoteObject**.
**System capability**: SystemCapability.Communication.IPC.Core
| Name | Value | Description |
| --------------------- | ----------------------- | --------------------------------- |
| PING_TRANSACTION | 1599098439 (0x5f504e47) | Internal instruction code used to test whether the IPC service is normal.|
| DUMP_TRANSACTION | 1598311760 (0x5f444d50) | Internal instruction code used to obtain the internal status of the binder. |
| INTERFACE_TRANSACTION | 1598968902 (0x5f4e5446) | Internal instruction code used to obtain the remote interface token. |
| MIN_TRANSACTION_ID | 1 (0x00000001) | Minimum valid instruction code. |
| MAX_TRANSACTION_ID | 16777215 (0x00FFFFFF) | Maximum valid instruction code. |
### sendRequest<sup>(deprecated)</sup>
>This API is no longer maintained since API version 8. You are advised to use [sendRequest](#sendrequest8deprecated-2).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption): boolean
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ----------------------------------------- | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ------- | ---------------------------------|
| boolean | Returns **true** if the message is sent successfully; returns **false** otherwise.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **sendMessageRequest()** of the proxy object is called to send a message.
```ts
import hilog from '@ohos.hilog';
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
data.writeInt(1);
data.writeString("hello");
if (proxy != undefined) {
let ret: boolean = proxy.sendRequest(1, data, reply, option);
if (ret) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
let msg = reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed');
}
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
}
```
### sendMessageRequest<sup>9+</sup>
sendMessageRequest(code: number, data: MessageSequence, reply: MessageSequence, options: MessageOption): Promise<RequestResult>
Sends a **MessageSequence** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendMessageRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------------------------------------ | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object holding the data to send. |
| reply | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ---------------------------- | ----------------------------------------- |
| Promise<[RequestResult](#requestresult9)> | Promise used to return the **requestResult** object.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **sendMessageRequest()** of the proxy object is called to send a message.
```ts
import hilog from '@ohos.hilog';
let option = new rpc.MessageOption();
let data = rpc.MessageSequence.create();
let reply = rpc.MessageSequence.create();
data.writeInt(1);
data.writeString("hello");
if (proxy != undefined) {
proxy.sendMessageRequest(1, data, reply, option)
.then((result: rpc.RequestResult) => {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendMessageRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendMessageRequest failed, errCode: ' + result.errCode);
}
}).catch((e: Error) => {
hilog.error(0x0000, 'testTag', 'RPCTest: sendMessageRequest failed, message: ' + e.message);
}).finally (() => {
hilog.info(0x0000, 'testTag', 'RPCTest: sendMessageRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
});
}
```
### sendRequest<sup>8+(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [sendMessageRequest](#sendmessagerequest9-2).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption): Promise<SendRequestResult>
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ----------------------------------------- | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ------------------------------------------------------------ | --------------------------------------------- |
| Promise<[SendRequestResult](#sendrequestresult8deprecated)> | Promise used to return the **sendRequestResult** object.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **sendMessageRequest()** of the proxy object is called to send a message.
```ts
import hilog from '@ohos.hilog';
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
data.writeInt(1);
data.writeString("hello");
if (proxy != undefined) {
let a = proxy.sendRequest(1, data, reply, option) as Object;
let b = a as Promise<rpc.SendRequestResult>;
b.then((result: rpc.SendRequestResult) => {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, errCode: ' + result.errCode);
}
}).catch((e: Error) => {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, message: ' + e.message);
}).finally (() => {
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
});
}
```
### sendMessageRequest<sup>9+</sup>
sendMessageRequest(code: number, data: MessageSequence, reply: MessageSequence, options: MessageOption, callback: AsyncCallback<RequestResult>): void
Sends a **MessageSequence** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a callback will be called immediately, and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a callback will be invoked at certain time after the response to **sendMessageRequest** is returned, and the reply contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------------------ | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object holding the data to send. |
| reply | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
| callback | AsyncCallback<[RequestResult](#requestresult9)> | Yes | Callback for receiving the sending result. |
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
function sendMessageRequestCallback(err: BusinessError, result: rpc.RequestResult) {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendMessageRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendMessageRequest failed, errCode: ' + result.errCode);
}
hilog.info(0x0000, 'testTag', 'RPCTest: sendMessageRequest ends, reclaim parcel');
result.data.reclaim();
result.reply.reclaim();
}
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **sendMessageRequest()** of the proxy object is called to send a message.
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let option = new rpc.MessageOption();
let data = rpc.MessageSequence.create();
let reply = rpc.MessageSequence.create();
data.writeInt(1);
data.writeString("hello");
if (proxy != undefined) {
try {
proxy.sendMessageRequest(1, data, reply, option, sendMessageRequestCallback);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc sendMessageRequest fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc sendMessageRequest fail, errorMessage ' + e.message);
}
}
```
### sendRequest<sup>8+(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [sendMessageRequest](#sendmessagerequest9-3).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption, callback: AsyncCallback<SendRequestResult>): void
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a callback will be called immediately, and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a callback will be invoked when the response to sendRequest is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
| callback | AsyncCallback<[SendRequestResult](#sendrequestresult8deprecated)> | Yes | Callback for receiving the sending result. |
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
function sendRequestCallback(err: BusinessError, result: rpc.SendRequestResult) {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, errCode: ' + result.errCode);
}
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
result.data.reclaim();
result.reply.reclaim();
}
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **sendMessageRequest()** of the proxy object is called to send a message.
```ts
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
data.writeInt(1);
data.writeString("hello");
if (proxy != undefined) {
proxy.sendRequest(1, data, reply, option, sendRequestCallback);
}
```
### getLocalInterface<sup>9+</sup>
getLocalInterface(interface: string): IRemoteBroker
Obtains the **LocalInterface** object of an interface token.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | ------ | ---- | ---------------------- |
| interface | string | Yes | Interface descriptor.|
**Return value**
| Type | Description |
| ------------------------------- | ------------------------------------------ |
| [IRemoteBroker](#iremotebroker) | Returns **Null** by default, which indicates a proxy interface.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900006 | only remote object permitted |
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **getLocalInterface()** of the proxy object is called to obtain the interface descriptor.
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
if (proxy != undefined) {
try {
let broker: rpc.IRemoteBroker = proxy.getLocalInterface("testObject");
hilog.info(0x0000, 'testTag', 'RpcClient: getLocalInterface is ' + broker);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc get local interface fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc get local interface fail, errorMessage ' + e.message);
}
}
```
### queryLocalInterface<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [getLocalInterface](#getlocalinterface9-1).
queryLocalInterface(interface: string): IRemoteBroker
Obtains the **LocalInterface** object of an interface token.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | ------ | ---- | ---------------------- |
| interface | string | Yes | Interface descriptor.|
**Return value**
| Type | Description |
| ------------------------------- | ------------------------------------------ |
| [IRemoteBroker](#iremotebroker) | Returns **Null** by default, which indicates a proxy interface.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **queryLocalInterface()** of the proxy object is called to obtain the interface descriptor.
```ts
import hilog from '@ohos.hilog';
if (proxy != undefined) {
let broker: rpc.IRemoteBroker = proxy.queryLocalInterface("testObject");
hilog.info(0x0000, 'testTag', 'RpcClient: queryLocalInterface is ' + broker);
}
```
### registerDeathRecipient<sup>9+</sup>
registerDeathRecipient(recipient: DeathRecipient, flags: number): void
Registers a callback for receiving death notifications of the remote object. The callback will be invoked when the remote object process matching the **RemoteProxy** object is killed.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | -------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to register.|
| flags | number | Yes | Flag of the death notification.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **registerDeathRecipient()** of the proxy object is called to register a callback for receiving the death notification of the remote object.
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
let deathRecipient = new MyDeathRecipient();
if (proxy != undefined) {
try {
proxy.registerDeathRecipient(deathRecipient, 0);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'proxy register deathRecipient fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'proxy register deathRecipient fail, errorMessage ' + e.message);
}
}
```
### addDeathRecipient<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [registerDeathRecipient](#registerdeathrecipient9-1).
addDeathRecipient(recipient: DeathRecipient, flags: number): boolean
Adds a callback for receiving the death notifications of the remote object, including the death notifications of the remote proxy.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | --------------------------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to add. |
| flags | number | Yes | Flag of the death notification. This parameter is reserved. It is set to **0**.|
**Return value**
| Type | Description |
| ------- | ---------------------------------------- |
| boolean | Returns **true** if the callback is added successfully; returns **false** otherwise.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **addDeathRecipient()** of the proxy object is called to add a callback for receiving the death notification of the remove object.
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
let deathRecipient = new MyDeathRecipient();
if (proxy != undefined) {
proxy.addDeathRecipient(deathRecipient, 0);
}
```
### unregisterDeathRecipient<sup>9+</sup>
unregisterDeathRecipient(recipient: DeathRecipient, flags: number): void
Unregisters the callback used to receive death notifications of the remote object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | -------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to unregister.|
| flags | number | Yes | Flag of the death notification.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **unregisterDeathRecipient()** of the proxy object is called to unregister the callback for receiving the death notification of the remote object.
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
let deathRecipient = new MyDeathRecipient();
if (proxy != undefined) {
try {
proxy.registerDeathRecipient(deathRecipient, 0);
proxy.unregisterDeathRecipient(deathRecipient, 0);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'proxy unregister deathRecipient fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'proxy unregister deathRecipient fail, errorMessage ' + e.message);
}
}
```
### removeDeathRecipient<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [unregisterDeathRecipient](#unregisterdeathrecipient9-1).
removeDeathRecipient(recipient: DeathRecipient, flags: number): boolean
Removes the callback used to receive death notifications of the remote object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | --------------------------------- | ---- | --------------------------------- |
| recipient | [DeathRecipient](#deathrecipient) | Yes | Callback to remove. |
| flags | number | Yes | Flag of the death notification. This parameter is reserved. It is set to **0**.|
**Return value**
| Type | Description |
| ------- | ---------------------------------------- |
| boolean | Returns **true** if the callback is removed; returns **false** otherwise.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **removeDeathRecipient()** of the proxy object is called to remove the callback used to receive the death notification of the remote object.
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
let deathRecipient = new MyDeathRecipient();
if (proxy != undefined) {
proxy.addDeathRecipient(deathRecipient, 0);
proxy.removeDeathRecipient(deathRecipient, 0);
}
```
### getDescriptor<sup>9+</sup>
getDescriptor(): string
Obtains the interface descriptor (which is a string) of this object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| string | Interface descriptor obtained.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
| 1900007 | communication failed |
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **getDescriptor()** of the proxy object is called to obtain the interface descriptor of the object.
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
if (proxy != undefined) {
try {
let descriptor: string = proxy.getDescriptor();
hilog.info(0x0000, 'testTag', 'RpcClient: descriptor is ' + descriptor);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc get interface descriptor fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc get interface descriptor fail, errorMessage ' + e.message);
}
}
```
### getInterfaceDescriptor<sup>(deprecated)</sup>
>This API is no longer maintained since API version 9. You are advised to use [getDescriptor](#getdescriptor9-1).
getInterfaceDescriptor(): string
Obtains the interface descriptor of this proxy object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------ |
| string | Interface descriptor obtained.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **getInterfaceDescriptor()** of the proxy object is called to obtain the interface descriptor of the current proxy object.
```ts
import hilog from '@ohos.hilog';
if (proxy != undefined) {
let descriptor: string = proxy.getInterfaceDescriptor();
hilog.info(0x0000, 'testTag', 'RpcClient: descriptor is ' + descriptor);
}
```
### isObjectDead
isObjectDead(): boolean
Checks whether the **RemoteObject** is dead.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | ------------------------------------------------- |
| boolean | Returns **true** if the **RemoteObject** is dead; returns **false** otherwise.|
**Example**
Before obtaining the ability for the application developed based on the stage model, obtain the context. For details, see [Obtaining the Context](#obtaining-the-context).
```ts
// Import @ohos.ability.featureAbility only for the application developed based on the FA model.
// import FA from "@ohos.ability.featureAbility";
import Want from '@ohos.app.ability.Want';
import common from '@ohos.app.ability.common';
import hilog from '@ohos.hilog';
let proxy: rpc.IRemoteObject | undefined;
let connect: common.ConnectOptions = {
onConnect: (elementName, remoteProxy) => {
hilog.info(0x0000, 'testTag', 'RpcClient: js onConnect called');
proxy = remoteProxy;
},
onDisconnect: (elementName) => {
hilog.info(0x0000, 'testTag', 'RpcClient: onDisconnect');
},
onFailed: () => {
hilog.info(0x0000, 'testTag', 'RpcClient: onFailed');
}
};
let want: Want = {
bundleName: "com.ohos.server",
abilityName: "com.ohos.server.EntryAbility",
};
// Use this method to connect to the ability for the FA model.
// FA.connectAbility(want,connect);
this.context.connectServiceExtensionAbility(want, connect);
```
The proxy object in the **onConnect** callback can be assigned a value only after the ability is connected asynchronously. Then, **isObjectDead()** of the proxy object is called to check whether this object is dead.
```ts
import hilog from '@ohos.hilog';
if (proxy != undefined) {
let isDead: boolean = proxy.isObjectDead();
hilog.info(0x0000, 'testTag', 'RpcClient: isObjectDead is ' + isDead);
}
```
## MessageOption
Defines the options used to construct the **MessageOption** object.
**System capability**: SystemCapability.Communication.IPC.Core
| Name | Value | Description |
| ------------- | --------- | ----------------------------------------------------------- |
| TF_SYNC | 0 (0x00) | Synchronous call. |
| TF_ASYNC | 1 (0x01) | Asynchronous call. |
| TF_ACCEPT_FDS | 16 (0x10) | Indication to **sendMessageRequest<sup>9+</sup>** for returning the file descriptor.|
| TF_WAIT_TIME | 4 (0x4) | RPC wait time, in seconds. This parameter is not used in IPC. |
### constructor<sup>9+</sup>
constructor(async?: boolean)
A constructor used to create a **MessageOption** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------- | ---- | ------------------------------------------------------------ |
| async | boolean | No | Calling mode. The value **true** indicates asynchronous calling; the value **false** (default) indicates synchronous calling.|
**Example**
```ts
class TestRemoteObject extends rpc.MessageOption {
constructor(async: boolean) {
super(async);
}
}
```
### constructor
constructor(syncFlags?: number, waitTime?: number)
A constructor used to create a **MessageOption** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| --------- | ------ | ---- | --------------------------------------------- |
| syncFlags | number | No | Call flag, which can be synchronous or asynchronous. The default value is **synchronous**. |
| waitTime | number | No | Maximum wait time for an RPC call. The default value is **TF_WAIT_TIME**.|
**Example**
```ts
class TestRemoteObject extends rpc.MessageOption {
constructor(syncFlags?: number,waitTime?: number) {
super(syncFlags,waitTime);
}
}
```
### isAsync<sup>9+</sup>
isAsync(): boolean
Checks whether **SendMessageRequest** is called synchronously or asynchronously.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | ---------------------------------------- |
| boolean | Returns **true** if **SendMessageRequest** is called asynchronously; returns **false** if it is called synchronously.|
**Example**
```ts
let option = new rpc.MessageOption();
option.isAsync();
```
### setAsync<sup>9+</sup>
setAsync(async: boolean): void
Sets the calling flag in **SendMessageRequest**.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------- | ---- | ------------------------------------------------- |
| async | boolean | Yes | Calling mode to set. The value **true** indicates asynchronous calling; the value **false** indicates synchronous calling.|
**Example**
```ts
import hilog from '@ohos.hilog';
let option = new rpc.MessageOption();
option.setAsync(true);
hilog.info(0x0000, 'testTag', 'Set asynchronization flag');
```
### getFlags
getFlags(): number
Obtains the call flag, which can be synchronous or asynchronous.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------------------------ |
| number | Call mode obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
try {
let option = new rpc.MessageOption();
hilog.info(0x0000, 'testTag', 'create object successfully');
let flog = option.getFlags();
hilog.info(0x0000, 'testTag', 'run getFlags success, flog is ' + flog);
option.setFlags(1)
hilog.info(0x0000, 'testTag', 'run setFlags success');
let flog2 = option.getFlags();
hilog.info(0x0000, 'testTag', 'run getFlags success, flog2 is ' + flog2);
} catch (error) {
hilog.error(0x0000, 'testTag', 'error ' + error);
}
```
### setFlags
setFlags(flags: number): void
Sets the call flag, which can be synchronous or asynchronous.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ------------------------ |
| flags | number | Yes | Call flag to set.|
**Example**
```ts
import hilog from '@ohos.hilog';
try {
let option = new rpc.MessageOption();
option.setFlags(1)
hilog.info(0x0000, 'testTag', 'run setFlags success');
let flog = option.getFlags();
hilog.info(0x0000, 'testTag', 'run getFlags success, flog is ' + flog);
} catch (error) {
hilog.error(0x0000, 'testTag', 'error ' + error);
}
```
### getWaitTime
getWaitTime(): number
Obtains the maximum wait time for this RPC call.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----------------- |
| number | Maximum wait time obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
try {
let option = new rpc.MessageOption();
let time = option.getWaitTime();
hilog.info(0x0000, 'testTag', 'run getWaitTime success, time is ' + time);
option.setWaitTime(16);
let time2 = option.getWaitTime();
hilog.info(0x0000, 'testTag', 'run getWaitTime success, time is ' + time2);
} catch (error) {
hilog.error(0x0000, 'testTag', 'error ' + error);
}
```
### setWaitTime
setWaitTime(waitTime: number): void
Sets the maximum wait time for this RPC call.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------ | ---- | --------------------- |
| waitTime | number | Yes | Maximum wait time to set. The upper limit is 3000 seconds.|
**Example**
```ts
import hilog from '@ohos.hilog';
try {
let option = new rpc.MessageOption();
option.setWaitTime(16);
let time = option.getWaitTime();
hilog.info(0x0000, 'testTag', 'run getWaitTime success, time is ' + time);
} catch (error) {
hilog.error(0x0000, 'testTag', 'error ' + error);
}
```
## IPCSkeleton
Obtains IPC context information, including the UID and PID, local and remote device IDs, and whether the method is invoked on the same device.
### getContextObject
static getContextObject(): IRemoteObject
Obtains the system capability manager. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------------------------------- | -------------------- |
| [IRemoteObject](#iremoteobject) | System capability manager obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
let samgr = rpc.IPCSkeleton.getContextObject();
hilog.info(0x0000, 'testTag', 'RpcServer: getContextObject result: ' + samgr);
```
### getCallingPid
static getCallingPid(): number
Obtains the PID of the caller. This API is a static method, which is invoked by the **RemoteObject** object in the **onRemoteRequest** method. If this method is not invoked in the IPC context (**onRemoteRequest**), the PID of the process will be returned.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----------------- |
| number | PID of the caller.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let callerPid = rpc.IPCSkeleton.getCallingPid();
hilog.info(0x0000, 'testTag', 'RpcServer: getCallingPid result: ' + callerPid);
return true;
}
}
```
### getCallingUid
static getCallingUid(): number
Obtains the UID of the caller. This API is a static method, which is invoked by the **RemoteObject** object in the **onRemoteRequest** method. If this method is not invoked in the IPC context (**onRemoteRequest**), the UID of the process will be returned.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----------------- |
| number | UID of the caller.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let callerUid = rpc.IPCSkeleton.getCallingUid();
hilog.info(0x0000, 'testTag', 'RpcServer: getCallingUid result: ' + callerUid);
return true;
}
}
```
### getCallingTokenId<sup>8+</sup>
static getCallingTokenId(): number
Obtains the caller's token ID, which is used to verify the caller identity.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | --------------------- |
| number | Token ID of the caller obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let callerTokenId = rpc.IPCSkeleton.getCallingTokenId();
hilog.info(0x0000, 'testTag', 'RpcServer: getCallingTokenId result: ' + callerTokenId);
return true;
}
}
```
### getCallingDeviceID
static getCallingDeviceID(): string
Obtains the ID of the device hosting the caller's process. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------------------- |
| string | Device ID obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let callerDeviceID = rpc.IPCSkeleton.getCallingDeviceID();
hilog.info(0x0000, 'testTag', 'RpcServer: callerDeviceID is ' + callerDeviceID);
return true;
}
}
```
### getLocalDeviceID
static getLocalDeviceID(): string
Obtains the local device ID. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------ |
| string | Local device ID obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let localDeviceID = rpc.IPCSkeleton.getLocalDeviceID();
hilog.info(0x0000, 'testTag', 'RpcServer: localDeviceID is ' + localDeviceID);
return true;
}
}
```
### isLocalCalling
static isLocalCalling(): boolean
Checks whether the remote process is a process of the local device. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | -------------------------------------------------- |
| boolean | Returns **true** if the local and remote processes are on the same device; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let isLocalCalling = rpc.IPCSkeleton.isLocalCalling();
hilog.info(0x0000, 'testTag', 'RpcServer: isLocalCalling is ' + isLocalCalling);
return true;
}
}
```
### flushCmdBuffer<sup>9+</sup>
static flushCmdBuffer(object: IRemoteObject): void
Flushes all suspended commands from the specified **RemoteProxy** to the corresponding **RemoteObject**. This API is a static method. You are advised to call this API before performing any sensitive operation.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------------------------------- | ---- | ------------------- |
| object | [IRemoteObject](#iremoteobject) | Yes | **RemoteProxy** specified. |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
}
let remoteObject = new TestRemoteObject("aaa");
try {
rpc.IPCSkeleton.flushCmdBuffer(remoteObject);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'proxy flushCmdBuffer fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'proxy flushCmdBuffer fail, errorMessage ' + e.message);
}
```
### flushCommands<sup>(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [flushCmdBuffer](#flushcmdbuffer9).
static flushCommands(object: IRemoteObject): number
Flushes all suspended commands from the specified **RemoteProxy** to the corresponding **RemoteObject**. This API is a static method. You are advised to call this API before performing any sensitive operation.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------------------------------- | ---- | ------------------- |
| object | [IRemoteObject](#iremoteobject) | Yes | **RemoteProxy** specified. |
**Return value**
| Type | Description |
| ------ | --------------------------------------------------------------------------------- |
| number | Returns **0** if the operation is successful; returns an error code if the input object is null or a **RemoteObject**, or if the operation fails.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
}
let remoteObject = new TestRemoteObject("aaa");
let ret = rpc.IPCSkeleton.flushCommands(remoteObject);
hilog.info(0x0000, 'testTag', 'RpcServer: flushCommands result: ' + ret);
```
### resetCallingIdentity
static resetCallingIdentity(): string
Changes the UID and PID of the remote user to the UID and PID of the local user. This API is a static method. You can use it in scenarios such as identity authentication.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ------------------------------------ |
| string | String containing the UID and PID of the remote user.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let callingIdentity = rpc.IPCSkeleton.resetCallingIdentity();
hilog.info(0x0000, 'testTag', 'RpcServer: callingIdentity is ' + callingIdentity);
return true;
}
}
```
### restoreCallingIdentity<sup>9+</sup>
static restoreCallingIdentity(identity: string): void
Restores the UID and PID of the remote user. This API is a static method. It is called after **resetCallingIdentity**, which returns the UID and PID of the remote user.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------ | ---- | ------------------------------------------------------------------ |
| identity | string | Yes | String containing the remote user UID and PID, which are returned by **resetCallingIdentity**.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let callingIdentity = rpc.IPCSkeleton.resetCallingIdentity();
hilog.info(0x0000, 'testTag', 'RpcServer: callingIdentity is ' + callingIdentity);
rpc.IPCSkeleton.restoreCallingIdentity(callingIdentity);
return true;
}
}
```
### setCallingIdentity<sup>(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [restoreCallingIdentity](#restorecallingidentity9).
static setCallingIdentity(identity: string): boolean
Sets the UID and PID to that of the remote user. This API is a static method. It is called after **resetCallingIdentity**, which returns the UID and PID of the remote user.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------- | ------ | ---- | ------------------------------------------------------------------ |
| identity | string | Yes | String containing the remote user's UID and PID, which are returned by **resetCallingIdentity**. |
**Return value**
| Type | Description |
| ------- | ---------------------------------|
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class Stub extends rpc.RemoteObject {
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
let callingIdentity = rpc.IPCSkeleton.resetCallingIdentity();
hilog.info(0x0000, 'testTag', 'RpcServer: callingIdentity is ' + callingIdentity);
let ret = rpc.IPCSkeleton.setCallingIdentity(callingIdentity);
hilog.info(0x0000, 'testTag', 'RpcServer: setCallingIdentity is ' + ret);
return true;
}
}
```
## RemoteObject
Provides methods to implement **RemoteObject**. The service provider must inherit from this class.
### constructor
constructor(descriptor: string)
A constructor used to create a **RemoteObject** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | ------ | ---- | ------------ |
| descriptor | string | Yes | Interface descriptor.|
### sendRequest<sup>(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 8. You are advised to use [sendRequest](#sendrequest8deprecated-4).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption): boolean
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ----------------------------------------- | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the message is sent successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
data.writeInt(1);
data.writeString("hello");
let ret: boolean = testRemoteObject.sendRequest(1, data, reply, option);
if (ret) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
let msg = reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed');
}
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
```
### sendMessageRequest<sup>9+</sup>
sendMessageRequest(code: number, data: MessageSequence, reply: MessageSequence, options: MessageOption): Promise<RequestResult>
Sends a **MessageSequence** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendMessageRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------------------------------------ | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object holding the data to send. |
| reply | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ----------------------------------------------- | ----------------------------------------- |
| Promise<[RequestResult](#requestresult9)> | Promise used to return a **RequestResult** instance.|
**Example**
```ts
import hilog from '@ohos.hilog';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
}
let testRemoteObject = new TestRemoteObject("testObject");
let option = new rpc.MessageOption();
let data = rpc.MessageSequence.create();
let reply = rpc.MessageSequence.create();
data.writeInt(1);
data.writeString("hello");
testRemoteObject.sendMessageRequest(1, data, reply, option)
.then((result: rpc.RequestResult) => {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendMessageRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendMessageRequest failed, errCode: ' + result.errCode);
}
}).catch((e: Error) => {
hilog.error(0x0000, 'testTag', 'RPCTest: sendMessageRequest failed, message: ' + e.message);
}).finally (() => {
hilog.info(0x0000, 'testTag', 'RPCTest: sendMessageRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
});
```
### sendRequest<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [sendMessageRequest](#sendmessagerequest9-4).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption): Promise<SendRequestResult>
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a promise will be fulfilled immediately and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a promise will be fulfilled when the response to **sendRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ----------------------------------------- | ---- | -------------------------------------------------------------------------------------- |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
**Return value**
| Type | Description |
| ------------------------------------------------------------ | --------------------------------------------- |
| Promise<[SendRequestResult](#sendrequestresult8deprecated)> | Promise used to return the **sendRequestResult** object.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
data.writeInt(1);
data.writeString("hello");
let a = testRemoteObject.sendRequest(1, data, reply, option) as Object;
let b = a as Promise<rpc.SendRequestResult>;
b.then((result: rpc.SendRequestResult) => {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, errCode: ' + result.errCode);
}
}).catch((e: Error) => {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, message: ' + e.message);
}).finally (() => {
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
data.reclaim();
reply.reclaim();
});
```
### sendMessageRequest<sup>9+</sup>
sendMessageRequest(code: number, data: MessageSequence, reply: MessageSequence, options: MessageOption, callback: AsyncCallback<RequestResult>): void
Sends a **MessageSequence** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a callback will be called immediately, and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a callback will be invoked when the response to **sendMessageRequest** is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------------- | ----------------------------------------------------- | ---- | ------------------------------------------------------------ |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object holding the data to send. |
| reply | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
| AsyncCallback | AsyncCallback<[RequestResult](#requestresult9)> | Yes | Callback for receiving the sending result. |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
}
function sendRequestCallback(err: BusinessError, result: rpc.RequestResult) {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, errCode: ' + result.errCode);
}
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
result.data.reclaim();
result.reply.reclaim();
}
let testRemoteObject = new TestRemoteObject("testObject");
let option = new rpc.MessageOption();
let data = rpc.MessageSequence.create();
let reply = rpc.MessageSequence.create();
data.writeInt(1);
data.writeString("hello");
testRemoteObject.sendMessageRequest(1, data, reply, option, sendRequestCallback);
```
### sendRequest<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [sendMessageRequest](#sendmessagerequest9-5).
sendRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption, callback: AsyncCallback<SendRequestResult>): void
Sends a **MessageParcel** message to the remote process in synchronous or asynchronous mode. If asynchronous mode is set in **options**, a callback will be called immediately, and the reply message is empty. The specific reply needs to be obtained from the callback on the service side. If synchronous mode is set in **options**, a callback will be invoked when the response to sendRequest is returned, and the reply message contains the returned information.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------------- | ------------------------------------------------------------ | ---- | ------------------------------------------------------------ |
| code | number | Yes | Message code (1-16777215) called by the request, which is determined by the communication parties. If the method is generated by an IDL tool, the message code is automatically generated by the IDL tool.|
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object holding the data to send. |
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that receives the response. |
| options | [MessageOption](#messageoption) | Yes | Request sending mode, which can be synchronous (default) or asynchronous. |
| AsyncCallback | AsyncCallback<[SendRequestResult](#sendrequestresult8deprecated)> | Yes | Callback for receiving the sending result. |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
}
function sendRequestCallback(err: BusinessError, result: rpc.SendRequestResult) {
if (result.errCode === 0) {
hilog.info(0x0000, 'testTag', 'sendRequest got result');
let num = result.reply.readInt();
let msg = result.reply.readString();
hilog.info(0x0000, 'testTag', 'RPCTest: reply num: ' + num);
hilog.info(0x0000, 'testTag', 'RPCTest: reply msg: ' + msg);
} else {
hilog.error(0x0000, 'testTag', 'RPCTest: sendRequest failed, errCode: ' + result.errCode);
}
hilog.info(0x0000, 'testTag', 'RPCTest: sendRequest ends, reclaim parcel');
result.data.reclaim();
result.reply.reclaim();
}
let testRemoteObject = new TestRemoteObject("testObject");
let option = new rpc.MessageOption();
let data = rpc.MessageParcel.create();
let reply = rpc.MessageParcel.create();
data.writeInt(1);
data.writeString("hello");
testRemoteObject.sendRequest(1, data, reply, option, sendRequestCallback);
```
### onRemoteMessageRequest<sup>9+</sup>
onRemoteMessageRequest(code: number, data: MessageSequence, reply: MessageSequence, options: MessageOption): boolean | Promise\<boolean>
> **NOTE**
>
>* You are advised to overload **onRemoteMessageRequest** preferentially, which implements synchronous and asynchronous message processing.
>* If both **onRemoteRequest()** and **onRemoteMessageRequest()** are overloaded, only the onRemoteMessageRequest() takes effect.
Called to return a response to **sendMessageRequest()**. The server processes the request synchronously or asynchronously and returns the result in this API.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------------------------------------ | ---- | ----------------------------------------- |
| code | number | Yes | Service request code sent by the remote end. |
| data | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object that holds the parameters called by the client.|
| reply | [MessageSequence](#messagesequence9) | Yes | **MessageSequence** object to which the result is written. |
| option | [MessageOption](#messageoption) | Yes | Whether the operation is synchronous or asynchronous. |
**Return value**
| Type | Description |
| ----------------- | ----------------------------------------------------------------------------------------------- |
| boolean | Returns a Boolean value if the request is processed synchronously in **onRemoteMessageRequest**. The value **true** means the operation is successful; the value **false** means the opposite.|
| Promise\<boolean> | Returns a promise object if the request is processed asynchronously in **onRemoteMessageRequest**. |
**Example**: Overload **onRemoteMessageRequest** to process requests synchronously.
```ts
import hilog from '@ohos.hilog';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: sync onRemoteMessageRequest is called');
return true;
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
}
}
```
**Example**: Overload **onRemoteMessageRequest** to process requests asynchronously.
```ts
import hilog from '@ohos.hilog';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
async onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): Promise<boolean> {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: async onRemoteMessageRequest is called');
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
await new Promise((resolve: (data: rpc.RequestResult) => void) => {
setTimeout(resolve, 100);
})
return true;
}
}
```
**Example**: Overload **onRemoteMessageRequest** and **onRemoteRequest** to process requests synchronously.
```ts
import hilog from '@ohos.hilog';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
onRemoteRequest(code: number, data: rpc.MessageParcel, reply: rpc.MessageParcel, option: rpc.MessageOption): boolean {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: sync onRemoteMessageRequest is called');
return true;
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
}
// Only onRemoteMessageRequest is executed.
onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): boolean | Promise<boolean> {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: async onRemoteMessageRequest is called');
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
return true;
}
}
```
**Example**: Overload **onRemoteMessageRequest** and **onRemoteRequest** to process requests asynchronously.
```ts
import hilog from '@ohos.hilog';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
onRemoteRequest(code: number, data: rpc.MessageParcel, reply: rpc.MessageParcel, option: rpc.MessageOption): boolean {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: sync onRemoteRequest is called');
return true;
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
}
// Only onRemoteMessageRequest is executed.
async onRemoteMessageRequest(code: number, data: rpc.MessageSequence, reply: rpc.MessageSequence, option: rpc.MessageOption): Promise<boolean> {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: async onRemoteMessageRequest is called');
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
await new Promise((resolve: (data: rpc.RequestResult) => void) => {
setTimeout(resolve, 100);
})
return true;
}
}
```
### onRemoteRequest<sup>(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [onRemoteMessageRequest](#onremotemessagerequest9).
onRemoteRequest(code: number, data: MessageParcel, reply: MessageParcel, options: MessageOption): boolean
Called to return a response to **sendRequest()**. The server processes the request and returns a response in this function.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ----------------------------------------- | ---- | --------------------------------------- |
| code | number | Yes | Service request code sent by the remote end. |
| data | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object that holds the parameters called by the client.|
| reply | [MessageParcel](#messageparceldeprecated) | Yes | **MessageParcel** object carrying the result. |
| option | [MessageOption](#messageoption) | Yes | Whether the operation is synchronous or asynchronous. |
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
onRemoteRequest(code: number, data: rpc.MessageParcel, reply: rpc.MessageParcel, option: rpc.MessageOption): boolean {
if (code === 1) {
hilog.info(0x0000, 'testTag', 'RpcServer: onRemoteRequest called');
return true;
} else {
hilog.error(0x0000, 'testTag', 'RpcServer: unknown code: ' + code);
return false;
}
}
}
```
### getCallingUid
getCallingUid(): number
Obtains the UID of the remote process.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----------------------- |
| number | UID of the remote process obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
}
let testRemoteObject = new TestRemoteObject("testObject");
hilog.info(0x0000, 'testTag', 'RpcServer: getCallingUid: ' + testRemoteObject.getCallingUid());
```
### getCallingPid
getCallingPid(): number
Obtains the PID of the remote process.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ----------------------- |
| number | PID of the remote process obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
}
let testRemoteObject = new TestRemoteObject("testObject");
hilog.info(0x0000, 'testTag', 'RpcServer: getCallingPid: ' + testRemoteObject.getCallingPid());
```
### getLocalInterface<sup>9+</sup>
getLocalInterface(descriptor: string): IRemoteBroker
Obtains the interface descriptor.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | ------ | ---- | -------------------- |
| descriptor | string | Yes | Interface descriptor.|
**Return value**
| Type | Description |
| ------------- | --------------------------------------------- |
| IRemoteBroker | **IRemoteBroker** object bound to the specified interface token.|
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.modifyLocalInterface(this, descriptor);
}
registerDeathRecipient(recipient: MyDeathRecipient, flags: number) {
// Implement the method logic based on service requirements.
}
unregisterDeathRecipient(recipient: MyDeathRecipient, flags: number) {
// Implement the method logic based on service requirements.
}
isObjectDead(): boolean {
return false;
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
try {
testRemoteObject.getLocalInterface("testObject");
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc get local interface fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc get local interface fail, errorMessage ' + e.message);
}
```
### queryLocalInterface<sup>(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [getLocalInterface](#getlocalinterface9-2).
queryLocalInterface(descriptor: string): IRemoteBroker
Checks whether the remote object corresponding to the specified interface token exists.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ---------- | ------ | ---- | ---------------------- |
| descriptor | string | Yes | Interface descriptor.|
**Return value**
| Type | Description |
| ------------- | ------------------------------------------------------------------ |
| IRemoteBroker | Returns the remote object if a match is found; returns **Null** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.attachLocalInterface(this, descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
testRemoteObject.queryLocalInterface("testObject");
```
### getDescriptor<sup>9+</sup>
getDescriptor(): string
Obtains the interface descriptor of this object. The interface descriptor is a string.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| string | Interface descriptor obtained.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900008 | proxy or remote object is invalid |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
registerDeathRecipient(recipient: MyDeathRecipient, flags: number) {
// Implement the method logic based on service requirements.
}
unregisterDeathRecipient(recipient: MyDeathRecipient, flags: number) {
// Implement the method logic based on service requirements.
}
isObjectDead(): boolean {
return false;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
try {
let descriptor = testRemoteObject.getDescriptor();
hilog.info(0x0000, 'testTag', 'RpcServer: descriptor is ' + descriptor);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'rpc get local interface fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'rpc get local interface fail, errorMessage ' + e.message);
}
```
### getInterfaceDescriptor<sup>(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [getDescriptor](#getdescriptor9-2).
getInterfaceDescriptor(): string
Obtains the interface descriptor.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | ---------------- |
| string | Interface descriptor obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
let descriptor = testRemoteObject.getInterfaceDescriptor();
hilog.info(0x0000, 'testTag', 'RpcServer: descriptor is: ' + descriptor);
```
### modifyLocalInterface<sup>9+</sup>
modifyLocalInterface(localInterface: IRemoteBroker, descriptor: string): void
Binds an interface descriptor to an **IRemoteBroker** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------------- | ------------------------------- | ---- | ------------------------------------- |
| localInterface | [IRemoteBroker](#iremotebroker) | Yes | **IRemoteBroker** object. |
| descriptor | string | Yes | Interface descriptor.|
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
try {
this.modifyLocalInterface(this, descriptor);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', ' rpc attach local interface fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', ' rpc attach local interface fail, errorMessage ' + e.message);
}
}
registerDeathRecipient(recipient: MyDeathRecipient, flags: number) {
// Implement the method logic based on service requirements.
}
unregisterDeathRecipient(recipient: MyDeathRecipient, flags: number) {
// Implement the method logic based on service requirements.
}
isObjectDead(): boolean {
return false;
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
```
### attachLocalInterface<sup>(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [modifyLocalInterface](#modifylocalinterface9).
attachLocalInterface(localInterface: IRemoteBroker, descriptor: string): void
Binds an interface descriptor to an **IRemoteBroker** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------------- | ------------------------------- | ---- | ------------------------------------- |
| localInterface | [IRemoteBroker](#iremotebroker) | Yes | **IRemoteBroker** object. |
| descriptor | string | Yes | Interface descriptor.|
**Example**
```ts
import hilog from '@ohos.hilog';
class MyDeathRecipient implements rpc.DeathRecipient {
onRemoteDied() {
hilog.info(0x0000, 'testTag', 'server died');
}
}
class TestRemoteObject extends rpc.RemoteObject {
constructor(descriptor: string) {
super(descriptor);
this.attachLocalInterface(this, descriptor);
}
addDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
removeDeathRecipient(recipient: MyDeathRecipient, flags: number): boolean {
return true;
}
isObjectDead(): boolean {
return false;
}
asObject(): rpc.IRemoteObject {
return this;
}
}
let testRemoteObject = new TestRemoteObject("testObject");
```
## Ashmem<sup>8+</sup>
Provides methods related to anonymous shared memory objects, including creating, closing, mapping, and unmapping an **Ashmem** object, reading data from and writing data to an **Ashmem** object, obtaining the **Ashmem** size, and setting **Ashmem** protection.
**System capability**: SystemCapability.Communication.IPC.Core
The table below describes the protection types of the mapped memory.
| Name | Value | Description |
| ---------- | --- | ------------------ |
| PROT_EXEC | 4 | The mapped memory is executable. |
| PROT_NONE | 0 | The mapped memory is inaccessible.|
| PROT_READ | 1 | The mapped memory is readable. |
| PROT_WRITE | 2 | The mapped memory is writeable. |
### create<sup>9+</sup>
static create(name: string, size: number): Ashmem
Creates an **Ashmem** object with the specified name and size. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------------------- |
| name | string | Yes | Name of the **Ashmem** object to create. |
| size | number | Yes | Size (in bytes) of the **Ashmem** object to create.|
**Return value**
| Type | Description |
| ------------------ | ---------------------------------------------- |
| [Ashmem](#ashmem8) | Returns the **Ashmem** object if it is created successfully; returns null otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let ashmem: rpc.Ashmem | undefined = undefined;
try {
ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let size = ashmem.getAshmemSize();
hilog.info(0x0000, 'testTag', 'RpcTest: get ashemm by create: ' + ashmem + ' size is ' + size);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc creat ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc creat ashmem fail, errorMessage ' + e.message);
}
```
### createAshmem<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [create](#create9).
static createAshmem(name: string, size: number): Ashmem
Creates an **Ashmem** object with the specified name and size. This API is a static method.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | ---------------------------- |
| name | string | Yes | Name of the **Ashmem** object to create. |
| size | number | Yes | Size (in bytes) of the **Ashmem** object to create.|
**Return value**
| Type | Description |
| ------------------ | ---------------------------------------------- |
| [Ashmem](#ashmem8) | Returns the **Ashmem** object if it is created successfully; returns null otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.createAshmem("ashmem", 1024*1024);
let size = ashmem.getAshmemSize();
hilog.info(0x0000, 'testTag', 'RpcTest: get ashemm by createAshmem: ' + ashmem + ' size is ' + size);
```
### create<sup>9+</sup>
static create(ashmem: Ashmem): Ashmem
Creates an **Ashmem** object by copying the file descriptor of an existing **Ashmem** object. The two **Ashmem** objects point to the same shared memory region.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------------------ | ---- | -------------------- |
| ashmem | [Ashmem](#ashmem8) | Yes | Existing **Ashmem** object.|
**Return value**
| Type | Description |
| ------------------ | ---------------------- |
| [Ashmem](#ashmem8) | **Ashmem** object created.|
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
try {
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let ashmem2 = rpc.Ashmem.create(ashmem);
let size = ashmem2.getAshmemSize();
hilog.info(0x0000, 'testTag', 'RpcTest: get ashemm by create: ' + ashmem2 + ' size is ' + size);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc creat ashmem from existing fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc creat ashmem from existing fail, errorMessage ' + e.message);
}
```
### createAshmemFromExisting<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [create](#create9-1).
static createAshmemFromExisting(ashmem: Ashmem): Ashmem
Creates an **Ashmem** object by copying the file descriptor of an existing **Ashmem** object. The two **Ashmem** objects point to the same shared memory region.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------------------ | ---- | -------------------- |
| ashmem | [Ashmem](#ashmem8) | Yes | Existing **Ashmem** object.|
**Return value**
| Type | Description |
| ------------------ | ---------------------- |
| [Ashmem](#ashmem8) | **Ashmem** object created.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let ashmem2 = rpc.Ashmem.createAshmemFromExisting(ashmem);
let size = ashmem2.getAshmemSize();
hilog.info(0x0000, 'testTag', 'RpcTest: get ashemm by createAshmemFromExisting: ' + ashmem2 + ' size is ' + size);
```
### closeAshmem<sup>8+</sup>
closeAshmem(): void
Closes this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Example**
```ts
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
ashmem.closeAshmem();
```
### unmapAshmem<sup>8+</sup>
unmapAshmem(): void
Deletes the mappings for the specified address range of this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Example**
```ts
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
ashmem.unmapAshmem();
```
### getAshmemSize<sup>8+</sup>
getAshmemSize(): number
Obtains the memory size of this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------ | -------------------------- |
| number | **Ashmem** size obtained.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let size = ashmem.getAshmemSize();
hilog.info(0x0000, 'testTag', 'RpcTest: get ashmem is ' + ashmem + ' size is ' + size);
```
### mapTypedAshmem<sup>9+</sup>
mapTypedAshmem(mapType: number): void
Creates the shared file mapping on the virtual address space of this process. The size of the mapping region is specified by this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------ | ---- | ------------------------------ |
| mapType | number | Yes | Protection level of the memory region to which the shared file is mapped.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900001 | call mmap function failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
try {
ashmem.mapTypedAshmem(ashmem.PROT_READ | ashmem.PROT_WRITE);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc map ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc map ashmem fail, errorMessage ' + e.message);
}
```
### mapAshmem<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [mapTypedAshmem](#maptypedashmem9).
mapAshmem(mapType: number): boolean
Creates the shared file mapping on the virtual address space of this process. The size of the mapping region is specified by this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| ------- | ------ | ---- | ------------------------------ |
| mapType | number | Yes | Protection level of the memory region to which the shared file is mapped.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the mapping is created; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let mapReadAndWrite = ashmem.mapAshmem(ashmem.PROT_READ | ashmem.PROT_WRITE);
hilog.info(0x0000, 'testTag', 'RpcTest: map ashmem result is ' + mapReadAndWrite);
```
### mapReadWriteAshmem<sup>9+</sup>
mapReadWriteAshmem(): void
Maps the shared file to the readable and writable virtual address space of the process.
**System capability**: SystemCapability.Communication.IPC.Core
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900001 | call mmap function failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
try {
ashmem.mapReadWriteAshmem();
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc map read and write ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc map read and write ashmem fail, errorMessage ' + e.message);
}
```
### mapReadAndWriteAshmem<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [mapReadWriteAshmem](#mapreadwriteashmem9).
mapReadAndWriteAshmem(): boolean
Maps the shared file to the readable and writable virtual address space of the process.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the mapping is created; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let mapResult = ashmem.mapReadAndWriteAshmem();
hilog.info(0x0000, 'testTag', 'RpcTest: map ashmem result is ' + mapResult);
```
### mapReadonlyAshmem<sup>9+</sup>
mapReadonlyAshmem(): void
Maps the shared file to the read-only virtual address space of the process.
**System capability**: SystemCapability.Communication.IPC.Core
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900001 | call mmap function failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
try {
ashmem.mapReadonlyAshmem();
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc map read and write ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc map read and write ashmem fail, errorMessage ' + e.message);
}
```
### mapReadOnlyAshmem<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [mapReadonlyAshmem](#mapreadonlyashmem9).
mapReadOnlyAshmem(): boolean
Maps the shared file to the read-only virtual address space of the process.
**System capability**: SystemCapability.Communication.IPC.Core
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the mapping is created; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let mapResult = ashmem.mapReadOnlyAshmem();
hilog.info(0x0000, 'testTag', 'RpcTest: Ashmem mapReadOnlyAshmem result is ' + mapResult);
```
### setProtectionType<sup>9+</sup>
setProtectionType(protectionType: number): void
Sets the protection level of the memory region to which the shared file is mapped.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------------- | ------ | ---- | ------------------ |
| protectionType | number | Yes | Protection type to set.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900002 | call os ioctl function failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
try {
ashmem.setProtection(ashmem.PROT_READ);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc set protection type fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc set protection type fail, errorMessage ' + e.message);
}
```
### setProtection<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [setProtectionType](#setprotectiontype9).
setProtection(protectionType: number): boolean
Sets the protection level of the memory region to which the shared file is mapped.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name | Type | Mandatory| Description |
| -------------- | ------ | ---- | ------------------ |
| protectionType | number | Yes | Protection type to set.|
**Return value**
| Type | Description |
| ------- | -------------------------------- |
| boolean | Returns **true** if the operation is successful; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let result = ashmem.setProtection(ashmem.PROT_READ);
hilog.info(0x0000, 'testTag', 'RpcTest: Ashmem setProtection result is ' + result);
```
### writeAshmem<sup>9+</sup>
writeAshmem(buf: number[], size: number, offset: number): void
Writes data to the shared file associated with this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------------------------------------- |
| buf | number[] | Yes | Data to write. |
| size | number | Yes | Size of the data to write. |
| offset | number | Yes | Start position of the data to write in the memory region associated with this **Ashmem** object.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900003 | write to ashmem failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
ashmem.mapReadWriteAshmem();
let ByteArrayVar = [1, 2, 3, 4, 5];
try {
ashmem.writeAshmem(ByteArrayVar, 5, 0);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc write to ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc write to ashmem fail, errorMessage ' + e.message);
}
```
### writeToAshmem<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [writeAshmem](#writeashmem9).
writeToAshmem(buf: number[], size: number, offset: number): boolean
Writes data to the shared file associated with this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | -------- | ---- | -------------------------------------------------- |
| buf | number[] | Yes | Data to write. |
| size | number | Yes | Size of the data to write. |
| offset | number | Yes | Start position of the data to write in the memory region associated with this **Ashmem** object.|
**Return value**
| Type | Description |
| ------- | ----------------------------------------------------------------------------- |
| boolean | Returns **true** if the data is written successfully; returns **false** otherwise.|
**Example**
```ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let mapResult = ashmem.mapReadAndWriteAshmem();
hilog.info(0x0000, 'testTag', 'RpcTest map ashmem result is ' + mapResult);
let ByteArrayVar = [1, 2, 3, 4, 5];
let writeResult = ashmem.writeToAshmem(ByteArrayVar, 5, 0);
hilog.info(0x0000, 'testTag', 'RpcTest: write to Ashmem result is ' + writeResult);
```
### readAshmem<sup>9+</sup>
readAshmem(size: number, offset: number): number[]
Reads data from the shared file associated with this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------------------------------- |
| size | number | Yes | Size of the data to read. |
| offset | number | Yes | Start position of the data to read in the memory region associated with this **Ashmem** object.|
**Return value**
| Type | Description |
| -------- | ---------------- |
| number[] | Data read.|
**Error codes**
For details about the error codes, see [RPC Error Codes](../errorcodes/errorcode-rpc.md).
| ID| Error Message|
| -------- | -------- |
| 1900004 | read from ashmem failed |
**Example**
```ts
import hilog from '@ohos.hilog';
import { BusinessError } from '@ohos.base';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
ashmem.mapReadWriteAshmem();
let ByteArrayVar = [1, 2, 3, 4, 5];
ashmem.writeAshmem(ByteArrayVar, 5, 0);
try {
let readResult = ashmem.readAshmem(5, 0);
hilog.info(0x0000, 'testTag', 'RpcTest: read from Ashmem result is ' + readResult);
} catch(error) {
let e: BusinessError = error as BusinessError;
hilog.error(0x0000, 'testTag', 'Rpc read from ashmem fail, errorCode ' + e.code);
hilog.error(0x0000, 'testTag', 'Rpc read from ashmem fail, errorMessage ' + e.message);
}
```
### readFromAshmem<sup>8+(deprecated)</sup>
>**NOTE**<br>This API is no longer maintained since API version 9. You are advised to use [readAshmem](#readashmem9).
readFromAshmem(size: number, offset: number): number[]
Reads data from the shared file associated with this **Ashmem** object.
**System capability**: SystemCapability.Communication.IPC.Core
**Parameters**
| Name| Type | Mandatory| Description |
| ------ | ------ | ---- | -------------------------------------------------- |
| size | number | Yes | Size of the data to read. |
| offset | number | Yes | Start position of the data to read in the memory region associated with this **Ashmem** object.|
**Return value**
| Type | Description |
| -------- | ---------------- |
| number[] | Data read.|
**Example**
``` ts
import hilog from '@ohos.hilog';
let ashmem = rpc.Ashmem.create("ashmem", 1024*1024);
let mapResult = ashmem.mapReadAndWriteAshmem();
hilog.info(0x0000, 'testTag', 'RpcTest map ashmem result is ' + mapResult);
let ByteArrayVar = [1, 2, 3, 4, 5];
let writeResult = ashmem.writeToAshmem(ByteArrayVar, 5, 0);
hilog.info(0x0000, 'testTag', 'RpcTest: write to Ashmem result is ' + writeResult);
let readResult = ashmem.readFromAshmem(5, 0);
hilog.info(0x0000, 'testTag', 'RpcTest: read to Ashmem result is ' + readResult);
```
## Obtaining the Context
**Example**
This example describes only one method of obtaining the context. For details about more methods, see [Obtaining the Context of UIAbility](../../application-models/uiability-usage.md#obtaining-the-context-of-uiability).
```ts
import UIAbility from '@ohos.app.ability.UIAbility';
import Want from '@ohos.app.ability.Want';
import hilog from '@ohos.hilog';
import AbilityConstant from '@ohos.app.ability.AbilityConstant';
import window from '@ohos.window';
export default class MainAbility extends UIAbility {
onCreate(want: Want, launchParam: AbilityConstant.LaunchParam) {
hilog.info(0x0000, 'testTag', '%{public}s', 'UIAbility onCreate');
let context = this.context;
}
onDestroy() {
hilog.info(0x0000, 'testTag', '%{public}s', 'UIAbility onDestroy');
}
onWindowStageCreate(windowStage: window.WindowStage) {
// Main window is created, set main page for this ability
hilog.info(0x0000, 'testTag', '%{public}s', 'UIAbility onWindowStageCreate');
}
onWindowStageDestroy() {
// Main window is destroyed, release UI related resources
hilog.info(0x0000, 'testTag', '%{public}s', 'UIAbility onWindowStageDestroy');
}
onForeground() {
// Ability has brought to foreground
hilog.info(0x0000, 'testTag', '%{public}s', 'UIAbility onForeground');
}
onBackground() {
// Ability has back to background
hilog.info(0x0000, 'testTag', '%{public}s', 'UIAbility onBackground');
}
}
```