# Upload and Download

The **request** module provides applications with basic upload, download, and background transmission agent capabilities.

> **NOTE**
>
> The initial APIs of this module are supported since API version 6. Newly added APIs will be marked with a superscript to indicate their earliest API version.


## Modules to Import


```js
import request from '@ohos.request';
```


## Constraints

HTTPS is supported by default in the FA model. To support HTTP, add **network** to the **config.json** file and set the **cleartextTraffic** attribute to **true**.

```js
var config = {
  "deviceConfig": {
    "default": {
      "network": {
        "cleartextTraffic": true
      }
      //...
    }
  }
}
```

The **cleartextTraffic** attribute is not involved during the development of applications in the stage model.



## Constants

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

| Name| Type| Readable| Writable| Description|
| -------- | -------- | -------- | -------- | -------- |
| NETWORK_MOBILE | number | Yes| No| Whether download is allowed on a mobile network.|
| NETWORK_WIFI | number | Yes| No| Whether download is allowed on a WLAN.|
| ERROR_CANNOT_RESUME<sup>7+</sup> | number | Yes| No| Failure to resume the download due to an error.|
| ERROR_DEVICE_NOT_FOUND<sup>7+</sup> | number | Yes| No| Failure to find a storage device such as a memory card.|
| ERROR_FILE_ALREADY_EXISTS<sup>7+</sup> | number | Yes| No| Failure to download the file because it already exists.|
| ERROR_FILE_ERROR<sup>7+</sup> | number | Yes| No| File operation failure.|
| ERROR_HTTP_DATA_ERROR<sup>7+</sup> | number | Yes| No| HTTP transmission failure.|
| ERROR_INSUFFICIENT_SPACE<sup>7+</sup> | number | Yes| No| Insufficient storage space.|
| ERROR_TOO_MANY_REDIRECTS<sup>7+</sup> | number | Yes| No| Error caused by too many network redirections.|
| ERROR_UNHANDLED_HTTP_CODE<sup>7+</sup> | number | Yes| No| Unidentified HTTP code.|
| ERROR_UNKNOWN<sup>7+</sup> | number | Yes| No| Unknown error.|
| PAUSED_QUEUED_FOR_WIFI<sup>7+</sup> | number | Yes| No| Download paused and queuing for a WLAN connection, because the file size exceeds the maximum value allowed by a mobile network session.|
| PAUSED_UNKNOWN<sup>7+</sup> | number | Yes| No| Download paused due to unknown reasons.|
| PAUSED_WAITING_FOR_NETWORK<sup>7+</sup> | number | Yes| No| Download paused due to a network connection problem, for example, network disconnection.|
| PAUSED_WAITING_TO_RETRY<sup>7+</sup> | number | Yes| No| Download paused and then retried.|
| SESSION_FAILED<sup>7+</sup> | number | Yes| No| Download failure without retry.|
| SESSION_PAUSED<sup>7+</sup> | number | Yes| No| Download paused.|
| SESSION_PENDING<sup>7+</sup> | number | Yes| No| Download pending.|
| SESSION_RUNNING<sup>7+</sup> | number | Yes| No| Download in progress.|
| SESSION_SUCCESSFUL<sup>7+</sup> | number | Yes| No| Successful download.|


## request.upload

upload(config: UploadConfig): Promise&lt;UploadTask&gt;

Uploads files. This API uses a promise to return the result.

This API can be used only in the FA model.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| config | [UploadConfig](#uploadconfig) | Yes| Upload configurations.|

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;[UploadTask](#uploadtask)&gt; | Promise used to return the **UploadTask** object.|

**Example**

  ```js
  let uploadTask;
  let uploadConfig = {
    url: 'https://patch',
    header: { key1: "value1", key2: "value2" },
    method: "POST",
    files: [{ filename: "test", name: "test", uri: "internal://cache/test.jpg", type: "jpg" }],
    data: [{ name: "name123", value: "123" }],
  };
  request.upload(uploadConfig).then((data) => {
      uploadTask = data;
  }).catch((err) => {
      console.error('Failed to request the upload. Cause: ' + JSON.stringify(err));
  })
  ```


## request.upload

upload(config: UploadConfig, callback: AsyncCallback&lt;UploadTask&gt;): void

Uploads files. This API uses an asynchronous callback to return the result.

This API can be used only in the FA model.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| config | [UploadConfig](#uploadconfig) | Yes| Upload configurations.|
| callback | AsyncCallback&lt;[UploadTask](#uploadtask)&gt; | No| Callback used to return the **UploadTask** object.|

**Example**

  ```js
  let uploadTask;
  let uploadConfig = {
    url: 'https://patch',
    header: { key1: "value1", key2: "value2" },
    method: "POST",
    files: [{ filename: "test", name: "test", uri: "internal://cache/test.jpg", type: "jpg" }],
    data: [{ name: "name123", value: "123" }],
  };
  request.upload(uploadConfig, (err, data) => {
      if (err) {
          console.error('Failed to request the upload. Cause: ' + JSON.stringify(err));
          return;
      }
      uploadTask = data;
  });
  ```
## request.upload<sup>9+</sup>

upload(context: BaseContext, config: UploadConfig): Promise&lt;UploadTask&gt;

Uploads files. This API uses a promise to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| context | BaseContext | Yes| Application-based context.|
| config | [UploadConfig](#uploadconfig) | Yes| Upload configurations.|


**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;[UploadTask](#uploadtask)&gt; | Promise used to return the **UploadTask** object.|

**Example**

  ```js
  let uploadTask;
  let uploadConfig = {
    url: 'https://patch',
    header: { key1: "value1", key2: "value2" },
    method: "POST",
    files: { filename: "test", name: "test", uri: "internal://cache/test.jpg", type: "jpg" },
    data: { name: "name123", value: "123" },
  };
  request.upload(globalThis.abilityContext, uploadConfig).then((data) => {
      uploadTask = data;
  }).catch((err) => {
      console.error('Failed to request the upload. Cause: ' + JSON.stringify(err));
  });
  ```


## request.upload<sup>9+</sup>

upload(context: BaseContext, config: UploadConfig, callback: AsyncCallback&lt;UploadTask&gt;): void

Uploads files. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| context | BaseContext | Yes| Application-based context.|
| config | [UploadConfig](#uploadconfig) | Yes| Upload configurations.|
| callback | AsyncCallback&lt;[UploadTask](#uploadtask)&gt; | No| Callback used to return the **UploadTask** object.|

**Example**

  ```js
  let uploadTask;
  let uploadConfig = {
    url: 'https://patch',
    header: { key1: "value1", key2: "value2" },
    method: "POST",
    files: [{ filename: "test", name: "test", uri: "internal://cache/test.jpg", type: "jpg" }],
    data: [{ name: "name123", value: "123" }],
  };
  request.upload(globalThis.abilityContext, uploadConfig, (err, data) => {
      if (err) {
          console.error('Failed to request the upload. Cause: ' + JSON.stringify(err));
          return;
      }
      uploadTask = data;
  });
  ```

## UploadTask

Implements file uploads. Before using any APIs of this class, you must obtain an **UploadTask** object.


### on('progress')

on(type: 'progress', callback:(uploadedSize: number, totalSize: number) =&gt; void): void

Subscribes to an upload event. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to subscribe to. The value is **'progress'** (upload progress).|
| callback | function | Yes| Callback for the upload progress event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| uploadedSize | number | Yes| Size of the uploaded files, in KB.|
| totalSize | number | Yes| Total size of the files to upload, in KB.|

**Example**

  ```js
  uploadTask.on('progress', function callback(uploadedSize, totalSize) {
      console.info("upload totalSize:" + totalSize + "  uploadedSize:" + uploadedSize);
  }
  );
  ```


### on('headerReceive')<sup>7+</sup>

on(type: 'headerReceive', callback:  (header: object) =&gt; void): void

Subscribes to an upload event. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to subscribe to. The value is **'headerReceive'** (response header).|
| callback | function | Yes| Callback for the HTTP Response Header event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| header | object | Yes| HTTP Response Header.|

**Example**

  ```js
  uploadTask.on('headerReceive', function callback(headers){   
      console.info("upOnHeader headers:" + JSON.stringify(headers));
  }
  );
  ```


### off('progress')

off(type:  'progress',  callback?: (uploadedSize: number, totalSize: number) =&gt;  void): void

Unsubscribes from an upload event. This API uses an asynchronous callback to return the result. 

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to unsubscribe from. The value is **'progress'** (upload progress).|
| callback | function | No| Callback for the upload progress event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| uploadedSize | number | Yes| Size of the uploaded files, in KB.|
| totalSize | number | Yes| Total size of the files to upload, in KB.|

**Example**

  ```js
  uploadTask.off('progress', function callback(uploadedSize, totalSize) {
      console.info('uploadedSize: ' + uploadedSize, 'totalSize: ' + totalSize);
  }
  );
  ```


### off('headerReceive')<sup>7+</sup>

off(type: 'headerReceive', callback?: (header: object) =&gt; void): void

Unsubscribes from an upload event. This API uses an asynchronous callback to return the result. 

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to unsubscribe from. The value is **'headerReceive'** (response header).|
| callback | function | No| Callback for the HTTP Response Header event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| header | object | Yes| HTTP Response Header.|

**Example**

  ```js
  uploadTask.off('headerReceive', function callback(headers) {
      console.info("upOnHeader headers:" + JSON.stringify(headers));
  }
  );
  ```


### remove

remove(): Promise&lt;boolean&gt;

Removes this upload task. This API uses a promise to return the result. 

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;boolean&gt; | Promise used to return the task removal result. If **true** is returned, the task is removed. If **false** is returned, the task fails to be removed.|

**Example**

  ```js
  uploadTask.remove().then((result) => {
      if (result) {
          console.info('Upload task removed successfully. ');
      } else {
          console.error('Failed to remove the upload task. ');
      }
  }).catch((err) => {
      console.error('Failed to remove the upload task. Cause: ' + JSON.stringify(err));
  });
  ```


### remove

remove(callback: AsyncCallback&lt;boolean&gt;): void

Removes this upload task. This API uses an asynchronous callback to return the result. 

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;boolean&gt; | Yes| Callback used to return the result.|

**Example**

  ```js
  uploadTask.remove((err, result) => {
      if (err) {
          console.error('Failed to remove the upload task. Cause: ' + JSON.stringify(err));
          return;
      }
      if (result) {
          console.info('Upload task removed successfully.');
      } else {
          console.error('Failed to remove the upload task.');
      }
  });
  ```


## UploadConfig

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Upload

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| url | string | Yes| Resource URL.|
| header | object | Yes| HTTP or HTTPS header added to an upload request.|
| method | string | Yes| Request method, which can be **'POST'** or **'PUT'**. The default value is **'POST'**.|
| files | Array&lt;[File](#file)&gt; | Yes| List of files to upload, which is submitted through **multipart/form-data**.|
| data | Array&lt;[RequestData](#requestdata)&gt; | Yes| Form data in the request body.|


## File

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| filename | string | No| File name in the header when **multipart** is used.|
| name | string | No| Name of a form item when **multipart** is used. The default value is **file**.|
| uri | string | Yes| Local path for storing files.<br>The **dataability** and **internal** protocol types are supported. However, the **internal** protocol type supports only temporary directories. Below are examples:<br>dataability:///com.domainname.dataability.persondata/person/10/file.txt<br><br>internal://cache/path/to/file.txt |
| type | string | No| Type of the file content. By default, the type is obtained based on the extension of the file name or URI.|


## RequestData

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download
| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| name | string | Yes| Name of a form element.|
| value | string | Yes| Value of a form element.|


## request.download

download(config: DownloadConfig): Promise&lt;DownloadTask&gt;

Downloads files. This API uses a promise to return the result.

This API can be used only in the FA model.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| config | [DownloadConfig](#downloadconfig) | Yes| Download configurations.|

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;[DownloadTask](#downloadtask)&gt; | Promise used to return the result.|

**Example**

  ```js
  let downloadTask;
  request.download({ url: 'https://xxxx/xxxx.hap' }).then((data) => {
      downloadTask = data;
  }).catch((err) => {
      console.error('Failed to request the download. Cause: ' + JSON.stringify(err));
  })
  ```


## request.download

download(config: DownloadConfig, callback: AsyncCallback&lt;DownloadTask&gt;): void

Downloads files. This API uses an asynchronous callback to return the result.

This API can be used only in the FA model.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| config | [DownloadConfig](#downloadconfig) | Yes| Download configurations.|
| callback | AsyncCallback&lt;[DownloadTask](#downloadtask)&gt; | No| Callback used to return the result.|

**Example**

  ```js
  let downloadTask;
  request.download({ url: 'https://xxxx/xxxxx.hap', 
  filePath: 'xxx/xxxxx.hap'}, (err, data) => {
      if (err) {
          console.error('Failed to request the download. Cause: ' + JSON.stringify(err));
          return;
      }
      downloadTask = data;
  });
  ```

## request.download<sup>9+</sup>

download(context: BaseContext, config: DownloadConfig): Promise&lt;DownloadTask&gt;

Downloads files. This API uses a promise to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| context | BaseContext | Yes| Application-based context.|
| config | [DownloadConfig](#downloadconfig) | Yes| Download configurations.|

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;[DownloadTask](#downloadtask)&gt; | Promise used to return the result.|

**Example**

  ```js
  let downloadTask;
  request.download(globalThis.abilityContext, { url: 'https://xxxx/xxxx.hap' }).then((data) => {
      downloadTask = data;
  }).catch((err) => {
      console.error('Failed to request the download. Cause: ' + JSON.stringify(err));
  })
  ```


## request.download<sup>9+</sup>

download(context: BaseContext, config: DownloadConfig, callback: AsyncCallback&lt;DownloadTask&gt;): void;

Downloads files. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| context | BaseContext | Yes| Application-based context.|
| config | [DownloadConfig](#downloadconfig) | Yes| Download configurations.|
| callback | AsyncCallback&lt;[DownloadTask](#downloadtask)&gt; | No| Callback used to return the result.|

**Example**

  ```js
  let downloadTask;
  request.download(globalThis.abilityContext, { url: 'https://xxxx/xxxxx.hap', 
  filePath: 'xxx/xxxxx.hap'}, (err, data) => {
      if (err) {
          console.error('Failed to request the download. Cause: ' + JSON.stringify(err));
          return;
      }
      downloadTask = data;
  });
  ```
## DownloadTask

Implements file downloads.


### on('progress')

on(type: 'progress', callback:(receivedSize: number, totalSize: number) =&gt; void): void

Subscribes to a download event. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to subscribe to. The value is **'progress'** (download progress).|
| callback | function | Yes| Callback for the download progress event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| receivedSize | number | Yes| Size of the downloaded files, in KB.|
| totalSize | number | Yes| Total size of the files to download, in KB.|

**Example**

  ```js
  downloadTask.on('progress', function download_callback(receivedSize, totalSize) {
      console.info("download receivedSize:" + receivedSize + " totalSize:" + totalSize);
  }
  );
  ```


### off('progress')

off(type: 'progress', callback?: (receivedSize: number, totalSize: number) =&gt; void): void

Unsubscribes from a download event. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to unsubscribe from. The value is **'progress'** (download progress).|
| callback | function | No| Callback for the download progress event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| receivedSize | number | Yes| Size of the downloaded files.|
| totalSize | number | Yes| Total size of the files to download.|

**Example**

  ```js
  downloadTask .off('progress', function download_callback(receivedSize, totalSize) {
      console.info("download receivedSize:" + receivedSize + " totalSize:" + totalSize);
  }
  );
  ```


### on('complete'|'pause'|'remove')<sup>7+</sup>

on(type: 'complete'|'pause'|'remove', callback:() =&gt; void): void

Subscribes to a download event. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to subscribe to.<br>- **'complete'**: download task completion event.<br>- **'pause'**: download task pause event.<br>- **'remove'**: download task removal event.|
| callback | function | Yes| Callback used to return the result.|

**Example**

  ```js
  downloadTask.on('complete', function callback() {
      console.info('Download task completed.');
  }
  );
  ```


### off('complete'|'pause'|'remove')<sup>7+</sup>

off(type: 'complete'|'pause'|'remove', callback?:() =&gt; void): void

Unsubscribes from a download event. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to unsubscribe from.<br>- **'complete'**: download task completion event.<br>- **'pause'**: download task pause event.<br>- **'remove'**: download task removal event.|
| callback | function | No| Callback used to return the result.|

**Example**

  ```js
  downloadTask.off('complete', function callback() {
      console.info('Download task completed.');
  }
  );
  ```


### on('fail')<sup>7+</sup>

on(type: 'fail', callback: (err: number) =&gt; void): void

Subscribes to the download task failure event. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to subscribe to. The value is **'fail'** (download failure).|
| callback | function | Yes| Callback for the download task failure event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| err | number | Yes| Error code of the download failure. For details about the error codes, see [ERROR_*](#constants).|

**Example**

  ```js 
  downloadTask.on('fail', function callBack(err) {
      console.info('Download task failed. Cause:' + err);
  }
  );
  ```


### off('fail')<sup>7+</sup>

off(type: 'fail', callback?: (err: number) =&gt; void): void

Unsubscribes from the download task failure event. This API uses an asynchronous callback to return the result. 

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| type | string | Yes| Type of the event to unsubscribe from. The value is **'fail'** (download failure).|
| callback | function | No| Callback for the download task failure event.|

Parameters of the callback function

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| err | number | Yes| Error code of the download failure. For details about the error codes, see [ERROR_*](#constants).|

**Example**

  ```js
  downloadTask.off('fail', function callBack(err) {
      console.info('Download task failed. Cause:' + err);
  } 
  );
  ```


### remove

remove(): Promise&lt;boolean&gt;

Removes this download task. This API uses a promise to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;boolean&gt; | Promise used to return the task removal result.|

**Example**

  ```js
  downloadTask.remove().then((result) => {
      if (result) {
          console.info('Download task removed.');
      } else {
          console.error('Failed to remove the download task.');
      }
  }).catch ((err) => {
      console.error('Failed to remove the download task.');
  });
  ```


### remove

remove(callback: AsyncCallback&lt;boolean&gt;): void

Removes this download task. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;boolean&gt; | Yes| Callback used to return the task removal result.|

**Example**

  ```js
  downloadTask.remove((err, result)=>{
      if(err) {
          console.error('Failed to remove the download task.');
          return;
      } 
      if (result) {
          console.info('Download task removed.');
      } else {
          console.error('Failed to remove the download task.');
      } 
  });
  ```


### query<sup>7+</sup>

query(): Promise&lt;DownloadInfo&gt;

Queries this download task. This API uses a promise to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**
    | Type| Description|
  | -------- | -------- |
  | Promise&lt;[DownloadInfo](#downloadinfo7)&gt; | Promise used to return the download task information.|

**Example**

  ```js
  downloadTask.query().then((downloadInfo) => {    
      console.info('Download task queried. Data:' + JSON.stringify(downloadInfo))
  }) .catch((err) => {
      console.error('Failed to query the download task. Cause:' + err)
  });
  ```


### query<sup>7+</sup>

query(callback: AsyncCallback&lt;DownloadInfo&gt;): void

Queries this download task. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;[DownloadInfo](#downloadinfo7)&gt; | Yes| Callback used to return the download task information.|

**Example**

  ```js
  downloadTask.query((err, downloadInfo)=>{
      if(err) {
          console.error('Failed to query the download mimeType. Cause:' + JSON.stringify(err));
      } else {
          console.info('download query success. data:'+ JSON.stringify(downloadInfo));
      }
  });
  ```


### queryMimeType<sup>7+</sup>

queryMimeType(): Promise&lt;string&gt;

Queries the **MimeType** of this download task. This API uses a promise to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;string&gt; | Promise used to return the **MimeType** of the download task.|

**Example**

  ```js
  downloadTask.queryMimeType().then((data) => {    
      console.info('Download task queried. Data:' + JSON.stringify(data));
  }).catch((err) => {
      console.error('Failed to query the download MimeType. Cause:' + JSON.stringify(err))
  });
  ```


### queryMimeType<sup>7+</sup>

queryMimeType(callback: AsyncCallback&lt;string&gt;): void;

Queries the **MimeType** of this download task. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;string&gt; | Yes| Callback used to return the **MimeType** of the download task.|

**Example**

  ```js
  downloadTask.queryMimeType((err, data)=>{
      if(err) {
          console.error('Failed to query the download mimeType. Cause:' + JSON.stringify(err));
      } else {
          console.info('Download task queried. data:' + JSON.stringify(data));
      }
  });
  ```


### pause<sup>7+</sup>

pause(): Promise&lt;void&gt;

Pauses this download task. This API uses a promise to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Return value**

| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the download task pause result.|

**Example**

  ```js
  downloadTask.pause().then((result) => {    
      if (result) {
           console.info('Download task paused. ');
      } else {
          console.error('Failed to pause the download task. Cause:' + JSON.stringify(result));
      }
  }).catch((err) => {
      console.error('Failed to pause the download task. Cause:' + JSON.stringify(err));
  });
  ```


### pause<sup>7+</sup>

pause(callback: AsyncCallback&lt;void&gt;): void

Pauses this download task. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result.|

**Example**

  ```js
  downloadTask.pause((err, result)=>{
      if(err) {
          console.error('Failed to pause the download task. Cause:' + JSON.stringify(err));
          return;
      }
      if (result) {
           console.info('Download task paused. ');
      } else {
          console.error('Failed to pause the download task. Cause:' + JSON.stringify(result));
      }
  });
  ```


### resume<sup>7+</sup>

resume(): Promise&lt;void&gt;

Resumes this download task. This API uses a promise to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Type| Description|
| -------- | -------- |
| Promise&lt;void&gt; | Promise used to return the result.|

**Example**

  ```js
  downloadTask.resume().then((result) => {
      if (result) {
          console.info('Download task resumed.')
      } else {
          console.error('Failed to resume the download task. ');
      }
      console.info('Download task resumed.')
  }).catch((err) => {
      console.error('Failed to resume the download task. Cause:' + err);
  });
  ```


### resume<sup>7+</sup>

resume(callback: AsyncCallback&lt;void&gt;): void

Resumes this download task. This API uses an asynchronous callback to return the result.

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

**Parameters**

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| callback | AsyncCallback&lt;void&gt; | Yes| Callback used to return the result.|

**Example**

  ```js
  downloadTask.resume((err, result)=>{
      if (err) {
          console.error('Failed to resume the download task. Cause:' + err);
          return;
      } 
      if (result) {
          console.info('Download task resumed.');
      } else {
          console.error('Failed to resume the download task.');
      }
  });
  ```


## DownloadConfig

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| url | string | Yes| Resource URL.|
| header | object | No| HTTP or HTTPS header added to a download request.|
| enableMetered | boolean | No| Whether download is allowed on a metered connection.<br>- **true**: yes<br> **false**: no|
| enableRoaming | boolean | No| Whether download is allowed on a roaming network.<br>- **true**: yes<br> **false**: no|
| description | string | No| Description of the download session.|
| filePath<sup>7+</sup> | string | No| Download path. (The default path is **'internal://cache/'**.)<br>- filePath:'workspace/test.txt': The **workspace** directory is created in the default path to store files.<br>- filePath:'test.txt': Files are stored in the default path.<br>- filePath:'workspace/': The **workspace** directory is created in the default path to store files.|
| networkType | number | No| Network type allowed for download.<br>- NETWORK_MOBILE: 0x00000001<br>- NETWORK_WIFI: 0x00010000|
| title | string | No| Title of the download session.|
| background | boolean | No| Whether to enable the background task notification. When this parameter is enabled, the download status is displayed in the notification panel.|


## DownloadInfo<sup>7+</sup>

**Required permissions**: ohos.permission.INTERNET

**System capability**: SystemCapability.MiscServices.Download

| Name| Type| Mandatory| Description|
| -------- | -------- | -------- | -------- |
| downloadId | number | Yes| ID of the downloaded file.|
| failedReason | number | No| Download failure cause, which can be any constant of [ERROR_*](#constants).|
| fileName | string | Yes| Name of the downloaded file.|
| filePath | string | Yes| URI of the saved file.|
| pausedReason | number | No| Reason for session pause, which can be any constant of [PAUSED_*](#constants).|
| status | number | Yes| Download status code, which can be any constant of [SESSION_*](#constants).|
| targetURI | string | Yes| URI of the downloaded file.|
| downloadTitle | string | Yes| Title of the downloaded file.|
| downloadTotalBytes | number | Yes| Total size of the files to download (int bytes).|
| description | string | Yes| Description of the file to download.|
| downloadedBytes | number | Yes| Size of the files downloaded (int bytes).|