# Uploading and Downloading Application Files

This topic describes how to upload an application file to a network server and download a network resource file from a network server to a local application file directory.

## Uploading an Application File

You can use **uploadFile()** in [ohos.request](../../reference/apis-basic-services-kit/js-apis-request.md) to upload local files. The system service agent uploads the files. In API version 12, you can set the address of the agent in **request.agent.create()**.

> **NOTE**
>
> Currently, only the files in the **cache/** directory (specified by **cacheDir**) can be uploaded.
>
> To use **uploadFile()** in **ohos.request**, you need to [declare permissions](../../security/AccessToken/declare-permissions.md): ohos.permission.INTERNET.

The following code demonstrates how to upload files from a cache directory of an application to a network server in two ways:

```ts
// Way 1: Use request.uploadFile.
// pages/xxx.ets
import { common } from '@kit.AbilityKit';
import fs from '@ohos.file.fs';
import { BusinessError, request } from '@kit.BasicServicesKit';

// Obtain the application file path.
let context = getContext(this) as common.UIAbilityContext;
let cacheDir = context.cacheDir;

// Create an application file locally.
let file = fs.openSync(cacheDir + '/test.txt', fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
fs.writeSync(file.fd, 'upload file test');
fs.closeSync(file);

// Configure the upload task.
let files: Array<request.File> = [
// "internal://cache" in uri corresponds to the cacheDir directory.
  { filename: 'test.txt', name: 'test', uri: 'internal://cache/test.txt', type: 'txt' }
]
let data: Array<request.RequestData> = [{ name: 'name', value: 'value' }];
let uploadConfig: request.UploadConfig = {
  url: 'https://xxx',
  header: {
    'key1':'value1',
    'key2':'value2'
  },
  method: 'POST',
  files: files,
  data: data
}

// Upload the created application file to the network server.
try {
  request.uploadFile(context, uploadConfig)
    .then((uploadTask: request.UploadTask) => {
      uploadTask.on('complete', (taskStates: Array<request.TaskState>) => {
        for (let i = 0; i < taskStates.length; i++) {
          console.info(`upload complete taskState: ${JSON.stringify(taskStates[i])}`);
        }
      });
    })
    .catch((err: BusinessError) => {
      console.error(`Invoke uploadFile failed, code is ${err.code}, message is ${err.message}`);
    })
} catch (error) {
  let err: BusinessError = error as BusinessError;
  console.error(`Invoke uploadFile failed, code is ${err.code}, message is ${err.message}`);
}
```

```ts
// Way 2: Use request.agent.
// pages/xxx.ets
import { common } from '@kit.AbilityKit';
import fs from '@ohos.file.fs';
import { BusinessError, request } from '@kit.BasicServicesKit';
// Obtain the application file path.
let context = getContext(this) as common.UIAbilityContext;
let cacheDir = context.cacheDir;

// Create an application file locally.
let file = fs.openSync(cacheDir + '/test.txt', fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
fs.writeSync(file.fd, 'upload file test');
fs.closeSync(file);
let attachments: Array<request.agent.FormItem> = [{
  name: "test",
  value: [
    {
      filename: "test.txt",
      path: "./test.txt",
    },
  ]
}];
let config: request.agent.Config = {
  action: request.agent.Action.UPLOAD,
  url: 'http://xxx',
  mode: request.agent.Mode.FOREGROUND,
  overwrite: true,
  method: "POST",
  headers: {
    'key1':'value1',
    'key2':'value2'
  },
  data: attachments,
  saveas: "./"
};
request.agent.create(getContext(), config).then((task: request.agent.Task) => {
  task.start((err: BusinessError) => {
    if (err) {
      console.error(`Failed to start the upload task, Code: ${err.code}  message: ${err.message}`);
      return;
    }
  });
  task.on('progress', async(progress) => {
    console.warn(`/Request upload status ${progress.state}, uploaded ${progress.processed}`);
  })
  task.on('completed', async() => {
    console.warn(`/Request upload completed`);
    // This method requires the user to manage the task lifecycle. After the task is complete, call the remove method to release the task object.
    request.agent.remove(task.tid);
  })
}).catch((err: BusinessError) => {
  console.error(`Failed to create a upload task, Code: ${err.code}, message: ${err.message}`);
});
```

## Downloading a Network Resource File to an Application Directory

You can use **downloadFile()** in [ohos.request](../../reference/apis-basic-services-kit/js-apis-request.md) to download network resource files to a local application directory. You can use the [ohos.file.fs](../../reference/apis-core-file-kit/js-apis-file-fs.md) APIs to access the downloaded files. For details, see [Accessing Application Files](../../file-management/app-file-access.md). The system service agent downloads the files. In API version 12, you can set the address of the agent in **request.agent.create()**.

> **NOTE**
>
> Currently, network resource files can be downloaded only to the application file directory.
>
> To use **uploadFile()** in **ohos.request**, you need to [declare permissions](../../security/AccessToken/declare-permissions.md): ohos.permission.INTERNET.

The following code demonstrates how to download files from a network server to an application directory in two ways:

```ts
// Way 1: Use request.downloadFile.
// pages/xxx.ets
// Download the network resource file to the local application file directory, and read data from the file.
import { common } from '@kit.AbilityKit';
import fs from '@ohos.file.fs';
import { BusinessError, request } from '@kit.BasicServicesKit';
import { buffer } from '@kit.ArkTS';

// Obtain the application file path.
let context = getContext(this) as common.UIAbilityContext;
let filesDir = context.filesDir;

try {
  request.downloadFile(context, {
    url: 'https://xxxx/xxxx.txt',
    filePath: filesDir + '/xxxx.txt'
  }).then((downloadTask: request.DownloadTask) => {
    downloadTask.on('complete', () => {
      console.info('download complete');
      let file = fs.openSync(filesDir + '/xxxx.txt', fs.OpenMode.READ_WRITE);
      let arrayBuffer = new ArrayBuffer(1024);
      let readLen = fs.readSync(file.fd, arrayBuffer);
      let buf = buffer.from(arrayBuffer, 0, readLen);
      console.info(`The content of file: ${buf.toString()}`);
      fs.closeSync(file);
    })
  }).catch((err: BusinessError) => {
    console.error(`Invoke downloadTask failed, code is ${err.code}, message is ${err.message}`);
  });
} catch (error) {
  let err: BusinessError = error as BusinessError;
  console.error(`Invoke downloadFile failed, code is ${err.code}, message is ${err.message}`);
}
```
```ts
// Way 2: Use request.agent.
// pages/xxx.ets
// Download the network resource file to the local application file directory, and read data from the file.
import { common } from '@kit.AbilityKit';
import fs from '@ohos.file.fs';
import { BusinessError, request } from '@kit.BasicServicesKit';
import { buffer } from '@kit.ArkTS';

// Obtain the application file path.
let context = getContext(this) as common.UIAbilityContext;
let filesDir = context.filesDir;

let config: request.agent.Config = {
  action: request.agent.Action.DOWNLOAD,
  url: 'https://xxxx/test.txt',
  saveas: 'xxxx.txt',
  gauge: true,
  overwrite: true,
  network: request.agent.Network.WIFI,
};
request.agent.create(context, config).then((task: request.agent.Task) => {
  task.start((err: BusinessError) => {
    if (err) {
      console.error(`Failed to start the download task, Code: ${err.code}  message: ${err.message}`);
      return;
    }
  });
  task.on('progress', async(progress) => {
    console.warn(`/Request download status ${progress.state}, downloaded ${progress.processed}`);
  })
  task.on('completed', async() => {
    console.warn(`/Request download completed`);
    let file = fs.openSync(filesDir + '/xxxx.txt', fs.OpenMode.READ_WRITE);
    let arrayBuffer = new ArrayBuffer(1024);
    let readLen = fs.readSync(file.fd, arrayBuffer);
    let buf = buffer.from(arrayBuffer, 0, readLen);
    console.info(`The content of file: ${buf.toString()}`);
    fs.closeSync(file);
    // This method requires the user to manage the task lifecycle. After the task is complete, call the remove method to release the task object.
    request.agent.remove(task.tid);
  })
}).catch((err: BusinessError) => {
  console.error(`Failed to create a download task, Code: ${err.code}, message: ${err.message}`);
});
```

## Adding Network Configuration

### Intercepting HTTP

You can set the configuration file to intercept HTTP. After HTTP is disabled for the upload and download module, upload and download tasks using plaintext HTTP cannot be created. The configuration file is stored in the **src/main/resources/base/profile/network_config.json** directory of the application.

The sample configuration file is as follows:

```ts
{
  "network-security-config": {
    "base-config": {
      "cleartextTrafficPermitted": true, 
      "trust-anchors": [
        {
          "certificates": "/etc/security/certificates"
        }
      ]
    },
    "domain-config": [
      {
        "cleartextTrafficPermitted": true,
        "domains": [
          {
            "include-subdomains": true,
            "name": "*.example.com"
          }
        ],
      }
    ]
  }
}

```

The table below lists the description of each field.

| Field                     | Type           | Description                                  |   
| --------------------------| --------------- | -------------------------------------- |
| base-config:<br> cleartextTrafficPermitted | boolean | Whether plaintext transfer is allowed in the global configuration. The value **true** means that plaintext transfer is allowed, that is, HTTP is not intercepted, and **false** means the opposite.|
| domain-config:<br> cleartextTrafficPermitted | boolean | Whether plaintext transfer is allowed in a specified domain. The value **true** means that plaintext transfer is allowed, that is, HTTP is not intercepted, and **false** means the opposite.|
| include-subdomains | boolean | Whether a rule applies to subdomains. The value **true** means that the regular expression is used to match the domain name, and **false** means the opposite.|