# Interface (Session)
<!--Kit: Camera Kit-->
<!--Subsystem: Multimedia-->
<!--Owner: @qano-->
<!--SE: @leo_ysl-->
<!--TSE: @xchaosioda-->

> **NOTE**
>
> - The initial APIs of this module are supported since API version 10. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The initial APIs of this interface are supported since API version 11.

Session implements a session, which saves all [CameraInput](arkts-apis-camera-CameraInput.md) and [CameraOutput](arkts-apis-camera-CameraOutput.md) instances required to run the camera and requests the camera to take a photo or record a video.

## Modules to Import

```ts
import { camera } from '@kit.CameraKit';
```

## beginConfig<sup>11+</sup>

beginConfig(): void

Starts configuration for the session.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400105                |  Session config locked.               |
| 7400201                |  Camera service fatal error.               |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function beginConfig(session: camera.Session): void {
  try {
    session.beginConfig();
  } catch (error) {
    // If the operation fails, error.code is returned and processed.
    let err = error as BusinessError;
    console.error(`The beginConfig call failed. error code: ${err.code}`);
  }
}
```

## commitConfig<sup>11+</sup>

commitConfig(callback: AsyncCallback\<void\>): void

Commits the configuration for this session. This API uses an asynchronous callback to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name    | Type                  | Mandatory| Description                 |
| -------- | -------------------- | ---- | -------------------- |
| callback | AsyncCallback\<void\> | Yes  | Callback used to return the result. If the operation fails, an error code defined in [CameraErrorCode](arkts-apis-camera-e.md#cameraerrorcode) is returned. For example, if the aspect ratio of the preview stream is different from that of the video output stream, error code 7400201 is returned.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400102                |  Operation not allowed.                                  |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function commitConfig(session: camera.Session): void {
  session.commitConfig((err: BusinessError) => {
    if (err) {
      console.error(`The commitConfig call failed. error code: ${err.code}`);
      return;
    }
    console.info('Callback invoked to indicate the commit config success.');
  });
}
```

## commitConfig<sup>11+</sup>

commitConfig(): Promise\<void\>

Commits the configuration for this session. This API uses a promise to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Return value**

| Type           | Description                    |
| -------------- | ------------------------ |
| Promise\<void\> | Promise that returns no value.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400102                |  Operation not allowed.                                  |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function commitConfig(session: camera.Session): void {
  session.commitConfig().then(() => {
    console.info('Promise returned to indicate the commit config success.');
  }).catch((error: BusinessError) => {
    // If the operation fails, error.code is returned and processed.
    console.error(`The commitConfig call failed. error code: ${error.code}`);
  });
}
```

## canAddInput<sup>11+</sup>

canAddInput(cameraInput: CameraInput): boolean

Checks whether a CameraInput instance can be added to this session. This API must be called after [beginConfig](#beginconfig11) and before [commitConfig](#commitconfig11-1).

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name       | Type                         | Mandatory| Description                    |
| ----------- | --------------------------- | ---- | ------------------------ |
| cameraInput | [CameraInput](arkts-apis-camera-CameraInput.md) | Yes  | CameraInput instance to add. The API does not take effect if the input parameter is invalid (for example, the value is out of range, null, or undefined).|

**Return value**

| Type           | Description                    |
| -------------- | ------------------------ |
| boolean | Check result for adding the CameraInput instance. **true** if it can be added, **false** otherwise.|

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function canAddInput(session: camera.Session, cameraInput: camera.CameraInput): void {
  let canAdd: boolean = session.canAddInput(cameraInput);
  console.info(`The input canAddInput: ${canAdd}`);
}
```

## addInput<sup>11+</sup>

addInput(cameraInput: CameraInput): void

Adds a [CameraInput](arkts-apis-camera-CameraInput.md) instance to this session.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name       | Type                         | Mandatory| Description                    |
| ----------- | --------------------------- | ---- | ------------------------ |
| cameraInput | [CameraInput](arkts-apis-camera-CameraInput.md) | Yes  | CameraInput instance to add.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400101                |  Parameter missing or parameter type incorrect.        |
| 7400102                |  Operation not allowed.                                  |
| 7400201                |  Camera service fatal error.                                   |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function addInput(session: camera.Session, cameraInput: camera.CameraInput): void {
  try {
    session.addInput(cameraInput);
  } catch (error) {
    // If the operation fails, error.code is returned and processed.
    let err = error as BusinessError;
    console.error(`The addInput call failed. error code: ${err.code}`);
  }
}
```

## removeInput<sup>11+</sup>

removeInput(cameraInput: CameraInput): void

Removes a [CameraInput](arkts-apis-camera-CameraInput.md) instance from this session. This API must be called after [beginConfig](#beginconfig11) and before [commitConfig](#commitconfig11-1).

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name       | Type                         | Mandatory| Description                     |
| ----------- | --------------------------- | ---- | ------------------------ |
| cameraInput | [CameraInput](arkts-apis-camera-CameraInput.md) | Yes  | CameraInput instance to remove.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400101                |  Parameter missing or parameter type incorrect.        |
| 7400102                |  Operation not allowed.                                  |
| 7400201                |  Camera service fatal error.                                   |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function removeInput(session: camera.Session, cameraInput: camera.CameraInput): void {
  try {
    session.removeInput(cameraInput);
  } catch (error) {
    // If the operation fails, error.code is returned and processed.
    let err = error as BusinessError;
    console.error(`The removeInput call failed. error code: ${err.code}`);
  }
}
```

## canAddOutput<sup>11+</sup>

canAddOutput(cameraOutput: CameraOutput): boolean

Determines whether a CameraOutput instance can be added to this session. This API must be called after [addInput](#addinput11) and before [commitConfig](#commitconfig11-1).

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name       | Type                         | Mandatory| Description                    |
| ----------- | --------------------------- | ---- | ------------------------ |
| cameraOutput | [CameraOutput](arkts-apis-camera-CameraOutput.md) | Yes  | CameraOutput instance to add. The API does not take effect if the input parameter is invalid (for example, the value is out of range, null, or undefined).|

**Return value**

| Type           | Description                    |
| -------------- | ------------------------ |
| boolean | Check result for adding the CameraOutput instance. **true** if it can be added, **false** otherwise.|

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function canAddOutput(session: camera.Session, cameraOutput: camera.CameraOutput): void {
  let canAdd: boolean = session.canAddOutput(cameraOutput);
  console.info(`This addOutput can add: ${canAdd}`);
}
```

## addOutput<sup>11+</sup>

addOutput(cameraOutput: CameraOutput): void

Adds a [CameraOutput](arkts-apis-camera-CameraOutput.md) instance to this session.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name          | Type                            | Mandatory| Description                     |
| ------------- | ------------------------------- | ---- | ------------------------ |
| cameraOutput  | [CameraOutput](arkts-apis-camera-CameraOutput.md)   | Yes  | CameraOutput instance to add.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400101                |  Parameter missing or parameter type incorrect.        |
| 7400102                |  Operation not allowed.                                  |
| 7400201                |  Camera service fatal error.                                   |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function addOutput(session: camera.Session, cameraOutput: camera.CameraOutput): void {
  try {
    session.addOutput(cameraOutput);
  } catch (error) {
    // If the operation fails, error.code is returned and processed.
    let err = error as BusinessError;
    console.error(`The addOutput call failed. error code: ${err.code}`);
  }
}
```

## removeOutput<sup>11+</sup>

removeOutput(cameraOutput: CameraOutput): void

Removes a [CameraOutput](arkts-apis-camera-CameraOutput.md) instance from this session.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name          | Type                            | Mandatory| Description                     |
| ------------- | ------------------------------- | ---- | ------------------------ |
| cameraOutput  | [CameraOutput](arkts-apis-camera-CameraOutput.md)   | Yes  | CameraOutput instance to remove.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400101                |  Parameter missing or parameter type incorrect.        |
| 7400102                |  Operation not allowed.                                  |
| 7400201                |  Camera service fatal error.                                   |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function removeOutput(session: camera.Session, previewOutput: camera.PreviewOutput): void {
  try {
    session.removeOutput(previewOutput);
  } catch (error) {
    // If the operation fails, error.code is returned and processed.
    let err = error as BusinessError;
    console.error(`The removeOutput call failed. error code: ${err.code}`);
  }
}
```

## start<sup>11+</sup>

start(callback: AsyncCallback\<void\>): void

Starts this session. This API uses an asynchronous callback to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                |
| -------- | -------------------- | ---- | -------------------- |
| callback | AsyncCallback\<void\> | Yes  | Callback used to return the result. If the operation fails, an error code defined in [CameraErrorCode](arkts-apis-camera-e.md#cameraerrorcode) is returned.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400102                |  Operation not allowed.                                |
| 7400103                |  Session not config.                                   |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function startCaptureSession(session: camera.Session): void {
  session.start((err: BusinessError) => {
    if (err) {
      console.error(`Failed to start the session, error code: ${err.code}.`);
      return;
    }
    console.info('Callback invoked to indicate the session start success.');
  });
}
```

## start<sup>11+</sup>

start(): Promise\<void\>

Starts this session. This API uses a promise to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Return value**

| Type           | Description                    |
| -------------- | ------------------------ |
| Promise\<void\> | Promise that returns no value.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400102                |  Operation not allowed.                                |
| 7400103                |  Session not config.                                   |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function startCaptureSession(session: camera.Session): void {
  session.start().then(() => {
    console.info('Promise returned to indicate the session start success.');
  }).catch((error: BusinessError) => {
    console.error(`Failed to start the session, error code: ${error.code}.`);
  });
}
```

## stop<sup>11+</sup>

stop(callback: AsyncCallback\<void\>): void

Stops this session. This API uses an asynchronous callback to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                |
| -------- | -------------------- | ---- | ------------------- |
| callback | AsyncCallback\<void\> | Yes  | Callback used to return the result. If the operation fails, an error code defined in [CameraErrorCode](arkts-apis-camera-e.md#cameraerrorcode) is returned.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function stopCaptureSession(session: camera.Session): void {
  session.stop((err: BusinessError) => {
    if (err) {
      console.error(`Failed to stop the session, error code: ${err.code}.`);
      return;
    }
    console.info('Callback invoked to indicate the session stop success.');
  });
}
```

## stop<sup>11+</sup>

stop(): Promise\<void\>

Stops this session. This API uses a promise to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Return value**

| Type           | Description               |
| -------------- |-------------------|
| Promise\<void\> | Promise that returns no value. |

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function stopCaptureSession(session: camera.Session): void {
  session.stop().then(() => {
    console.info('Promise returned to indicate the session stop success.');
  }).catch((error: BusinessError) => {
    console.error(`Failed to stop the session, error code: ${error.code}.`);
  });
}
```

## release<sup>11+</sup>

release(callback: AsyncCallback\<void\>): void

Releases this session. This API uses an asynchronous callback to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name     | Type                 | Mandatory| Description                |
| -------- | -------------------- | ---- | -------------------- |
| callback | AsyncCallback\<void\> | Yes  | Callback used to return the result. If the operation fails, an error code defined in [CameraErrorCode](arkts-apis-camera-e.md#cameraerrorcode) is returned.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function releaseCaptureSession(session: camera.Session): void {
  session.release((err: BusinessError) => {
    if (err) {
      console.error(`Failed to release the session instance, error code: ${err.code}.`);
      return;
    }
    console.info('Callback invoked to indicate that the session instance is released successfully.');
  });
}
```

## release<sup>11+</sup>

release(): Promise\<void\>

Releases this session. This API uses a promise to return the result.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Return value**

| Type           | Description                    |
| -------------- | ------------------------ |
| Promise\<void\> | Promise that returns no value.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function releaseCaptureSession(session: camera.Session): void {
  session.release().then(() => {
    console.info('Promise returned to indicate that the session instance is released successfully.');
  }).catch((error: BusinessError) => {
    console.error(`Failed to release the session instance, error code: ${error.code}.`);
  });
}
```