js-apis-fileAccess.md

# @ohos.file.fileAccess (User File Access and Management)

The **fileAccess** module provides a framework for accessing and operating user files based on the ExtensionAbility mechanism. This module interacts with file management services, such as the media library and external storage management service, and provides a set of unified interfaces for system applications to access and manage files. The media library service allows access to user files on local and distributed devices. The external storage management service allows access to the user files stored on devices, such as shared disks, USB flash drives, and SD cards.

>**NOTE**
>
> - The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The APIs provided by this module are system APIs and cannot be called by third-party applications. Currently, the APIs can be called only by **FilePicker** and **FileManager**.

## Modules to Import

```js
import fileAccess from '@ohos.file.fileAccess';
```

## fileAccess.getFileAccessAbilityInfo

getFileAccessAbilityInfo() : Promise<Array<Want>>

Obtains information about all Wants with **extension** set to **fileAccess** in the system. A Want contains information for starting an ability. This API uses a promise to return the result.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

**Return value**

  | Type| Description|
  | --- | -- |
  | Promise<Array<[Want](js-apis-app-ability-want.md)>> | Promise used to return the Want information obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  async getFileAccessAbilityInfo() {
    let wantInfos = [];
    try {
      wantInfos = await fileAccess.getFileAccessAbilityInfo();
      console.log("getFileAccessAbilityInfo data " + JSON.stringify(wantInfos));
    } catch (error) {
      console.error("getFileAccessAbilityInfo failed, errCode:" + error.code + ", errMessage:" + error.message);
    }
  }
  ```

## fileAccess.getFileAccessAbilityInfo

getFileAccessAbilityInfo(callback: AsyncCallback<Array<Want>>): void

Obtains information about all Wants with **extension** set to **fileAccess** in the system. A Want contains information for starting an ability. This API uses an asynchronous callback to return the result.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | --- | -- |
  | callback | AsyncCallback<Array<[Want](js-apis-app-ability-want.md)>> | Yes| Promise used to return the Want information obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  async getFileAccessAbilityInfo() {
    try {
      fileAccess.getFileAccessAbilityInfo(function (err, wantInfos) {
        if (err) {
          console.error("Failed to getFileAccessAbilityInfo in async, errCode:" + err.code + ", errMessage:" + err.message);
          return;
        }
        console.log("getFileAccessAbilityInfo data " + JSON.stringify(wantInfos));
      });
    } catch (error) {
      console.error("getFileAccessAbilityInfo failed, errCode:" + error.code + ", errMessage:" + error.message);
    }
  }
  ```

## fileAccess.createFileAccessHelper

createFileAccessHelper(context: Context, wants: Array<Want>) : FileAccessHelper

Synchronously creates a **Helper** object to connect to the specified Wants. The **Helper** object provides file access and management capabilities.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | --- | -- |
  | context | [Context](js-apis-inner-application-context.md) | Yes| Context of the ability.|
  | wants | Array<[Want](js-apis-app-ability-want.md)> | Yes| Wants to connect.|

**Return value**

  | Type| Description|
  | --- | -- |
  | [FileAccessHelper](#fileaccesshelper) | **Helper** object created.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  createFileAccessHelper() {
    let fileAccessHelper = null;
    // Obtain wantInfos by using getFileAccessAbilityInfo().
    // Create a helper object to interact with the media library service only.
    let wantInfos = [
      {
        "bundleName": "com.ohos.medialibrary.medialibrarydata",
        "abilityName": "FileExtensionAbility",
      },
    ]
    try {
      // this.context is passed by EntryAbility.
      fileAccessHelper = fileAccess.createFileAccessHelper(this.context, wantInfos);
      if (!fileAccessHelper)
        console.error("createFileAccessHelper interface returns an undefined object");
    } catch (error) {
      console.error("createFileAccessHelper failed, errCode:" + error.code + ", errMessage:" + error.message);
    }
  }
  ```

## fileAccess.createFileAccessHelper

createFileAccessHelper(context: Context) : FileAccessHelper

Synchronously creates a **Helper** object to connect to all file management services in the system.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER and ohos.permission.GET_BUNDLE_INFO_PRIVILEGED

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | --- | -- |
  | context | [Context](js-apis-inner-application-context.md) | Yes| Context of the ability.|

**Return value**

  | Type| Description|
  | --- | -- |
  | [FileAccessHelper](#fileaccesshelper) | **Helper** object created.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  createFileAccessHelper() {
    let fileAccessHelperAllServer = null;
    // Create a Helper object to interact with all file management services configured with fileAccess in the system.
    try {
      // this.context is passed by EntryAbility.
      fileAccessHelperAllServer = fileAccess.createFileAccessHelper(this.context);
      if (!fileAccessHelperAllServer)
        console.error("createFileAccessHelper interface returns an undefined object");
    } catch (error) {
      console.error("createFileAccessHelper failed, errCode:" + error.code + ", errMessage:" + error.message);
    }
  }
  ```

## FileInfo

Provides the file or directory attribute information and APIs.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

### Attributes

| Name| Type  | Readable| Writable| Description    |
| ------ | ------ | -------- | ------ | -------- |
| uri | string | Yes| No| URI of the file or directory.|
| relativePath<sup>10+</sup> | string | Yes| No| Relative path of the file or directory.|
| fileName | string | Yes| No| Name of the file or directory.|
| mode | number | Yes| No| Permissions on the file or directory.|
| size | number | Yes| No|  Size of the file or directory.|
| mtime | number | Yes| No|  Time when the file or directory was last modified.|
| mimeType | string | Yes| No|  Multipurpose Internet Mail Extensions (MIME) type of the file or directory.|

### listFile

listFile(filter?: Filter) : FileIterator

Synchronously obtains a **FileIterator** object that lists the next-level files (directories) matching the conditions of the filter from a directory and returns [FileInfo](#fileinfo) using [next()](#next). Currently, only built-in storage devices support the file filter.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | -- | -- |
  | filter | [Filter](js-apis-file-fs.md#filter) | No| **Filter** object. |

**Return value**

  | Type| Description|
  | --- | -- |
  | [FileIterator](#fileiterator) | **FileIterator** object obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // fileInfoDir indicates information about a directory.
  // let filter = { suffix : [".txt", ".jpg", ".xlsx"] };
  let fileInfoDir = fileInfos[0];
  let subfileInfos = [];
  let isDone = false;
  try {
    let fileIterator = fileInfoDir.listFile();
    // listFile() with the filter implementation.
    // let fileIterator = rootInfo.listFile(filter);
    if (!fileIterator) {
      console.error("listFile interface returns an undefined object");
      return;
    }
    while (!isDone) {
      let result = fileIterator.next();
      console.log("next result = " + JSON.stringify(result));
      isDone = result.done;
      if (!isDone)
        subfileInfos.push(result.value);
    }
  } catch (error) {
    console.error("listFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
  ```

### scanFile

scanFile(filter?: Filter) : FileIterator;

Synchronously obtains a **FileIterator** object that recursively retrieves the files matching the conditions of the filter from a directory and returns [FileInfo](#fileinfo) using [next()](#next). Currently, this API supports only built-in storage devices.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | -- | -- |
  | filter | [Filter](js-apis-file-fs.md#filter) | No| **Filter** object. |

**Return value**

  | Type| Description|
  | --- | -- |
  | [FileIterator](#fileiterator) | **FileIterator** object obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // fileInfoDir indicates information about a directory.
  // let filter = {suffix : [".txt", ".jpg", ".xlsx"]};
  let fileInfoDir = fileInfos[0];
  let subfileInfos = [];
  let isDone = false;
  try {
    let fileIterator = fileInfoDir.scanFile();
    // scanFile() with the filter implementation.
    // let fileIterator = rootInfo.scanFile(filter);
    if (!fileIterator) {
      console.error("scanFile interface returns an undefined object");
      return;
    }
    while (!isDone) {
      let result = fileIterator.next();
      console.log("next result = " + JSON.stringify(result));
      isDone = result.done;
      if (!isDone)
        subfileInfos.push(result.value);
    }
  } catch (error) {
    console.error("scanFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
  ```

## FileIterator

Provides the **FileIterator** object.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

### next

next() : { value: FileInfo, done: boolean }

Obtains information about the next-level files or directories.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Return value**

| Type| Description|
| --- | -- |
| {value: [FileInfo](#fileinfo), done: boolean} | File or directory information obtained. This method traverses the specified directory until **true** is returned. The **value** field contains the file or directory information obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

## RootInfo

Provides the device's root attribute information and APIs.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

### Attributes

| Name| Type  | Readable| Writable| Description    |
| ------ | ------ | -------- | ------ | -------- |
| deviceType | number | Yes| No|Type of the device.|
| uri | string | Yes| No| Root directory URI of the device.|
| relativePath<sup>10+</sup> | string | Yes| No| Relative path of the root directory.|
| displayName | string | Yes| No| Device name.|
| deviceFlags | number | Yes| No| Capabilities supported by the device.|

### listFile

listFile(filter?: Filter) : FileIterator

Synchronously obtains a **FileIterator** object that lists the first-level files (directories) matching the conditions of the filter from the device root directory and returns [FileInfo](#fileinfo) using [next()](#next). Currently, only built-in storage devices support the file filter.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | -- | -- |
  | filter | [Filter](js-apis-file-fs.md#filter) | No| **Filter** object. |

**Return value**

  | Type| Description|
  | --- | -- |
  | [FileIterator](#fileiterator) | **FileIterator** object obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // Obtain rootInfos by using getRoots().
  // let filter = {suffix : [".txt", ".jpg", ".xlsx"]};
  let rootInfo = rootinfos[0];
  let fileInfos = [];
  let isDone = false;
  try {
    let fileIterator = rootInfo.listFile();
    // listFile() with the filter implementation.
    // let fileIterator = rootInfo.listFile(filter);
    if (!fileIterator) {
      console.error("listFile interface returns an undefined object");
      return;
    }
    while (!isDone) {
      let result = fileIterator.next();
      console.log("next result = " + JSON.stringify(result));
      isDone = result.done;
      if (!isDone)
        fileInfos.push(result.value);
    }
  } catch (error) {
    console.error("listFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
  ```

### scanFile

scanFile(filter?: Filter) : FileIterator

Synchronously obtains a **FileIterator** object that recursively retrieves the files matching the conditions of the filter from the device root directory and returns [FileInfo](#fileinfo)using [next()](#next). Currently, this API supports only built-in storage devices.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | -- | -- |
  | filter | [Filter](js-apis-file-fs.md#filter) | No| **Filter** object. |

**Return value**

  | Type| Description|
  | --- | -- |
  | [FileIterator](#fileiterator) | **FileIterator** object obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // Obtain rootInfos by using getRoots().
  // let filter = {suffix : [".txt", ".jpg", ".xlsx"]};
  let rootInfo = rootInfos[0];
  let fileInfos = [];
  let isDone = false;
  try {
    let fileIterator = rootInfo.scanFile();
    // scanFile with the filter implementation.
    // let fileIterator = rootInfo.scanFile(filter);
    if (!fileIterator) {
      console.error("scanFile interface returns undefined object");
      return;
    }
    while (!isDone) {
      let result = fileIterator.next();
      console.log("next result = " + JSON.stringify(result));
      isDone = result.done;
      if (!isDone)
        fileInfos.push(result.value);
    }
  } catch (error) {
    console.error("scanFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  }
  ```

## RootIterator

Provides an iterator object of the device root directory.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

### next

next() : { value: RootInfo, done: boolean }

Obtains the root directory of the next-level device.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Return value**

| Type| Description|
| --- | -- |
| {value: [RootInfo](#rootinfo), done: boolean} | Root directory information obtained. This method traverses the directory until **true** is returned. The **value** field contains the root directory information.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

## FileAccessHelper

Provides a **FileAccessHelper** object.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

### getRoots

getRoots() : Promise&lt;RootIterator&gt;

Obtains information about the device root nodes of the file management service connected to the **Helper** object. This API uses a promise to return a **RootIterator** object,
which returns [RootInfo](#rootinfo) by using [next](#next-1).

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Return value**

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

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  async getRoots() {
    let rootIterator = null;
    let rootinfos = [];
    let isDone = false;
    try {
      // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
      rootIterator = await fileAccessHelper.getRoots();
      if (!rootIterator) {
        console.error("getRoots interface returns an undefined object");
        return;
      }
      while (!isDone) {
        let result = rootIterator.next();
        console.log("next result = " + JSON.stringify(result));
        isDone = result.done;
        if (!isDone)
          rootinfos.push(result.value);
      }
    } catch (error) {
      console.error("getRoots failed, errCode:" + error.code + ", errMessage:" + error.message);
    }
  }
  ```

### getRoots

getRoots(callback:AsyncCallback&lt;RootIterator&gt;) : void

Obtains information about the device root nodes of the file management service connected to the **Helper** object. This API uses an asynchronous callback to return a **RootIterator** object,
which returns [RootInfo](#rootinfo) by using [next](#next-1).

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| callback | AsyncCallback&lt;[RootIterator](#rootiterator)&gt; | Yes| Callback invoked to return the **RootIterator** object obtained.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  async getRoots() {
    let rootinfos = [];
    let isDone = false;
    try {
      // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
      fileAccessHelper.getRoots(function (err, rootIterator) {
        if (err) {
          console.error("Failed to getRoots in async, errCode:" + err.code + ", errMessage:" + err.message);
          return;
        }
        while (!isDone) {
          let result = rootIterator.next();
          console.log("next result = " + JSON.stringify(result));
          isDone = result.done;
          if (!isDone)
            rootinfos.push(result.value);
        }
      });
    } catch (error) {
      console.error("getRoots failed, errCode:" + error.code + ", errMessage:" + error.message);
    }
  }
  ```

### createFile

createFile(uri: string, displayName: string) : Promise&lt;string&gt;

Creates a file in a directory. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the destination directory for the file to create.|
| displayName | string | Yes| Name of the file to create. By default, the name of a local file must contain the file name extension.|

**Return value**

| Type| Description|
| --- | -- |
| Promise&lt;string&gt; | Promise used to return the URI of the file created.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceUri = "datashare:///media/file/6";
  let displayName = "file1"
  let fileUri = null;
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileUri = await fileAccessHelper.createFile(sourceUri, displayName)
    if (!fileUri) {
      console.error("createFile return undefined object");
      return;
    }
    console.log("createFile sucess, fileUri: " + JSON.stringify(fileUri));
  } catch (error) {
    console.error("createFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### createFile

createFile(uri: string, displayName: string, callback: AsyncCallback&lt;string&gt;) : void

Creates a file in a directory. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the destination directory for the file to create.|
| displayName | string | Yes| Name of the file to create. By default, the name of a local file must contain the file name extension.|
| callback | AsyncCallback&lt;string&gt; | Yes| Callback invoked to return the URI of the file created.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceUri = "datashare:///media/file/6";
  let displayName = "file1"
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.createFile(sourceUri, displayName, function (err, fileUri) {
      if (err) {
        console.error("Failed to createFile in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("createFile sucess, fileUri: " + JSON.stringify(fileUri));
    });
  } catch (error) {
    console.error("createFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### mkDir

mkDir(parentUri: string, displayName: string) : Promise&lt;string&gt;

Creates a directory. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| parentUri | string | Yes| URI of the destination directory for the directory to create.|
| displayName | string | Yes| Name of the directory to create.|

**Return value**

| Type| Description|
| --- | -- |
| Promise&lt;string&gt; | Promise used to return the URI of the directory created.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceUri = "datashare:///media/file/6";
  let dirName = "dirTest"
  let dirUri = null;
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    dirUri = await fileAccessHelper.mkDir(sourceUri, dirName)
    if (!dirUri) {
      console.error("mkDir return undefined object");
      return;
    }
    console.log("mkDir sucess, dirUri: " + JSON.stringify(dirUri));
  } catch (error) {
    console.error("mkDir failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### mkDir

mkDir(parentUri: string, displayName: string, callback: AsyncCallback&lt;string&gt;) : void

Creates a directory. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| parentUri | string | Yes| URI of the destination directory for the directory to create.|
| displayName | string | Yes| Name of the directory to create.|
| callback | AsyncCallback&lt;string&gt; | Yes| Callback invoked to return the URI of the directory created.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceUri = "datashare:///media/file/6";
  let dirName = "dirTest"
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.mkDir(sourceUri, dirName, function (err, dirUri) {
      if (err) {
        console.error("Failed to mkDir in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("mkDir sucess, dirUri: " + JSON.stringify(dirUri));
    });
  } catch (error) {
    console.error("mkDir failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### openFile

openFile(uri: string, flags: OPENFLAGS) : Promise&lt;number&gt;

Opens a file. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the file to open.|
| flags | [OPENFLAGS](#openflags) | Yes| File open mode.|

**Return value**

| Type| Description|
| --- | -- |
| Promise&lt;number&gt; | Promise used to return the file descriptor (FD) of the file opened.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let targetUri  = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fd = await fileAccessHelper.openFile(targetUri, fileAccess.OPENFLAGS.READ);
  } catch (error) {
    console.error("openFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### openFile

openFile(uri: string, flags: OPENFLAGS, callback: AsyncCallback&lt;number&gt;) : void

Opens a file. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the file to open.|
| flags | [OPENFLAGS](#openflags) | Yes| File open mode.|
| callback | AsyncCallback&lt;number&gt; | Yes| Callback invoked to return the FD of the file opened.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let targetUri  = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.openFile(targetUri, fileAccess.OPENFLAGS.READ, function (err, fd) {
      if (err) {
        console.error("Failed to openFile in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("openFile sucess, fd: " + fd);
    });
  } catch (error) {
    console.error("openFile failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### delete

delete(uri: string) : Promise&lt;number&gt;

Deletes a file or directory. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the file or directory to delete.|

**Return value**

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

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let targetUri = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let code = await fileAccessHelper.delete(targetUri);
    if (code != 0)
      console.error("delete failed, code " + code);
  } catch (error) {
    console.error("delete failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### delete

delete(uri: string, callback: AsyncCallback&lt;number&gt;) : void

Deletes a file or directory. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the file or directory to delete.|
| callback | AsyncCallback&lt;number&gt; | Yes| Callback invoked to return the result.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, targetUri indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let targetUri = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.delete(targetUri, function (err, code) {
      if (err) {
        console.error("Failed to delete in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("delete sucess, code: " + code);
    });
  } catch (error) {
    console.error("delete failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### move

move(sourceFile: string, destFile: string) : Promise&lt;string&gt;

Moves a file or directory. This API uses a promise to return the result. Currently, this API does not support move of files or directories across devices.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| sourceFile | string | Yes| URI of the file or directory to move.|
| destFile | string | Yes| URI of the destination directory, to which the file or directory will be moved.|

**Return value**

| Type| Description|
| ----- | ------ |
| Promise&lt;string&gt; | Promise used to return the URI of the file or directory in the destination directory.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceFile destFile indicates the file or directory in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceFile = "datashare:///media/file/102";
  let destFile = "datashare:///media/file/101";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileUri = await fileAccessHelper.move(sourceFile, destFile);
    console.log("move sucess, fileUri: " + JSON.stringify(fileUri));
  } catch (error) {
    console.error("move failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### move

move(sourceFile: string, destFile: string, callback: AsyncCallback&lt;string&gt;) : void

Moves a file or directory. This API uses an asynchronous callback to return the result. Currently, this API does not support move of files or directories across devices.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| sourceFile | string | Yes| URI of the file or directory to move.|
| destFile | string | Yes| URI of the destination directory, to which the file or directory will be moved.|
| callback | AsyncCallback&lt;string&gt; | Yes| Callback invoked to return the URI of the file or directory in the destination directory.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceFile destFile indicates the file or directory in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceFile = "datashare:///media/file/102";
  let destFile = "datashare:///media/file/101";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.move(sourceFile, destFile, function (err, fileUri) {
      if (err) {
        console.error("Failed to move in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("move sucess, fileUri: " + JSON.stringify(fileUri));
    });
  } catch (error) {
    console.error("move failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### rename

rename(uri: string, displayName: string) : Promise&lt;string&gt;

Renames a file or directory. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the file or directory to rename.|
| displayName | string | Yes| New name of the file or directory, which can contain the file name extension.|

**Return value**

| Type| Description|
| --- | -- |
| Promise&lt;string&gt; | Promise used to return the URI of the renamed file or directory.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceDir indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceDir = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let DestDir = await fileAccessHelper.rename(sourceDir, "testDir");
    console.log("rename sucess, DestDir: " + JSON.stringify(DestDir));
  } catch (error) {
    console.error("rename failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### rename

rename(uri: string, displayName: string, callback: AsyncCallback&lt;string&gt;) : void

Renames a file or directory. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the file or directory to rename.|
| displayName | string | Yes| New name of the file or directory, which can contain the file name extension.|
| callback | AsyncCallback&lt;string&gt; | Yes| Callback invoked to return the URI of the renamed file or directory.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceDir indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceDir = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.rename(sourceDir, "testDir", function (err, DestDir) {
      if (err) {
        console.error("Failed to rename in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("rename sucess, DestDir: " + JSON.stringify(DestDir));
    });
  } catch (error) {
    console.error("rename failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### access

access(sourceFileUri: string) : Promise&lt;boolean&gt;

Checks whether a file or directory exists. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| sourceFileUri | string | Yes| URI of the file or directory to check.|

**Return value**

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

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceDir indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceDir = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let existJudgment = await fileAccessHelper.access(sourceDir);
    if (existJudgment)
      console.log("sourceDir exists");
    else
      console.log("sourceDir does not exist");
  } catch (error) {
    console.error("access failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### access

access(sourceFileUri: string, callback: AsyncCallback&lt;boolean&gt;) : void

Checks whether a file or directory exists. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| sourceFileUri | string | Yes| URI of the file or directory to check.|
| callback | AsyncCallback&lt;boolean&gt; | Yes| Callback invoked to return the result.|

**Error codes**

For details about error codes, see [File Management Error Codes](../errorcodes/errorcode-filemanagement.md).

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceDir indicates a file in the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceDir = "datashare:///media/file/100";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.access(sourceDir, function (err, existJudgment) {
      if (err) {
        console.error("Failed to access in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      if (existJudgment)
        console.log("sourceDir exists");
      else
        console.log("sourceDir does not exist");
    });
  } catch (error) {
    console.error("access failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### getFileInfoFromUri<sup>10+</sup>

getFileInfoFromUri(uri: string) : Promise\<FileInfo>

Obtains a **FileInfo** object based on the specified URI. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| uri | string | Yes| URI of the file or directory.|

**Return value**

| Type| Description|
| --- | -- |
| Promise\<[FileInfo](#fileinfo)> | Promise used to return the **FileInfo** object obtained.|

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceUri = "datashare:///media/file/6";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileInfo = await fileAccessHelper.getFileInfoFromUri(sourceUri);
  } catch (error) {
    console.error("getFileInfoFromUri failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### getFileInfoFromUri<sup>10+</sup>

getFileInfoFromUri(uri: string, callback: AsyncCallback\<FileInfo>) : void

Obtains a **FileInfo** object based on the specified URI. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

  | Name| Type| Mandatory| Description|
  | --- | --- | --- | -- |
  | uri | string | Yes| URI of the file or directory.|
  | callback | AsyncCallback&lt;[FileInfo](#fileinfo)&gt; | Yes| Callback invoked to return the **FileInfo** object obtained.|

**Example**

  ```js
  // The media library URI is used as an example.
  // In the sample code, sourceUri indicates the Download directory. The URI is the URI in fileInfo.
  // You can use the URI obtained.
  let sourceUri = "datashare:///media/file/6";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.getFileInfoFromUri(sourceUri, function (err, fileInfo) {
      if (err) {
        console.error("Failed to getFileInfoFromUri in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("getFileInfoFromUri success, fileInfo: " + JSON.stringify(fileInfo));
    });
  } catch (error) {
    console.error("getFileInfoFromUri failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```


### getFileInfoFromRelativePath<sup>10+</sup>

getFileInfoFromRelativePath(relativePath: string) : Promise\<FileInfo>

Obtains a **FileInfo** object based on the **relativePath**. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| relativePath | string | Yes| Relative path of the file or directory.|

**Return value**

| Type| Description|
| --- | -- |
| Promise\<[FileInfo](#fileinfo)> | Promise used to return the **FileInfo** object obtained.|

**Example**

  ```js
  // The relative path of the Media Library is used as an example.
  // In the sample code, relativePath indicates the Download directory, which is the relativePath in fileInfo.
  // You can use the relativePath obtained.
  let relativePath = "Download/";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let fileInfo = await fileAccessHelper.getFileInfoFromRelativePath(relativePath);
  } catch (error) {
    console.error("getFileInfoFromRelativePath failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### getFileInfoFromRelativePath<sup>10+</sup>

getFileInfoFromRelativePath(relativePath: string, callback: AsyncCallback\<FileInfo>) : void

Obtains a **FileInfo** object based on the **relativePath**. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type| Mandatory| Description|
| --- | --- | --- | -- |
| relativePath | string | Yes| Relative path of the file or directory.|
| callback | AsyncCallback&lt;[FileInfo](#fileinfo)&gt; | Yes| Callback invoked to return the **FileInfo** object obtained.|

**Example**

  ```js
  // The relative path of the Media Library is used as an example.
  // In the sample code, relativePath indicates the Download directory, which is the relativePath in fileInfo.
  // You can use the relativePath obtained.
  let relativePath = "Download/";
  try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.getFileInfoFromRelativePath(relativePath, function (err, fileInfo) {
      if (err) {
        console.error("Failed to getFileInfoFromRelativePath in async, errCode:" + err.code + ", errMessage:" + err.message);
        return;
      }
      console.log("getFileInfoFromRelativePath success, fileInfo: " + JSON.stringify(fileInfo));
    });
  } catch (error) {
    console.error("getFileInfoFromRelativePath failed, errCode:" + error.code + ", errMessage:" + error.message);
  };
  ```

### getThumbnail<sup>10+</sup>

getThumbnail(uri: string, size: image.Size) : Promise&lt;image.PixelMap&gt;

Obtains the **Pixelmap** object of a media file based on the specified URI and size. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name| Type                               | Mandatory| Description       |
| ------ | ----------------------------------- | ---- | ----------- |
| uri    | string                              | Yes  | URI of the media file.|
| size   | [image.Size](js-apis-image.md#size) | Yes  | Size of the thumbnail. |

**Return value**

| Type                         | Description              |
| :---------------------------- | :----------------- |
| Promise&lt;[image.PixelMap](js-apis-image.md#pixelmap7)&gt; | Promise used to return the **Pixelmap** object obtained.|

**Example**

```js
// The media library URI is used as an example.
// In the sample code, targetUri indicates a media file (image, audio, or video) in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let targetUri = "datashare:///media/image/100";
let size = { width: 128, height: 128 };
try {
  // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
  let pixelMap = await fileAccessHelper.getThumbnail(targetUri, size);
  let imageInfo = await pixelMap.getImageInfo();    
  console.log("getThumbnail sucess, pixelMap.width: " + imageInfo.size.width);
  console.log("getThumbnail sucess, pixelMap.height: " + imageInfo.size.height);
} catch (error) {
  console.error("getThumbnail failed, errCode:" + error.code + ", errMessage:" + error.message);
};
```

### getThumbnail<sup>10+</sup>

 getThumbnail(uri: string, size: image.Size, callback: AsyncCallback&lt;image.PixelMap&gt;) : void

Obtains the **Pixelmap** object of a media file based on the specified URI and size. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name  | Type                               | Mandatory| Description              |
| -------- | ----------------------------------- | ---- | ------------------ |
| uri      | string                              | Yes  | URI of the media file.       |
| size     | [image.Size](js-apis-image.md#size) | Yes  | Size of the thumbnail.        |
| callback | AsyncCallback&lt;[image.PixelMap](js-apis-image.md#pixelmap7)&gt; | Yes  | Callback invoked to return the **Pixelmap** object obtained.|

**Example**

```js
// The media library URI is used as an example.
// In the sample code, targetUri indicates a media file (image, audio, or video) in the Download directory. The URI is the URI in fileInfo.
// You can use the URI obtained.
let targetUri = "datashare:///media/image/100";
let size = { width: 128, height: 128 };
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.getThumbnail(targetUri, size, async(err, pixelMap) => {
        if (err) {
            console.error("Failed to getThumbnail in async, errCode:" + err.code + ", errMessage:" + err.message);
            return;
        }
        let imageInfo = await pixelMap.getImageInfo();
        console.log("getThumbnail sucess, pixelMap.width: " + imageInfo.size.width);
        console.log("getThumbnail sucess, pixelMap.height: " + imageInfo.size.height);
    });
} catch (error) {
    console.error("getThumbnail failed, errCode:" + error.code + ", errMessage:" + error.message);
};
```

### query<sup>10+</sup>

query(uri:string, metaJson: string) : Promise&lt;string&gt;

Queries the attribute information about a file or directory based on the URI. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name  | Type  | Mandatory| Description                                                |
| -------- | ------ | ---- | ---------------------------------------------------- |
| uri      | string | Yes  | URI of the file or directory (obtained from [FileInfo](#fileinfo)).|
| metaJson | string | Yes  | Attribute [FILEKEY](#filekey10) to query.       |

**Return value**

| Type                 | Description                            |
| :-------------------- | :------------------------------- |
| Promise&lt;string&gt; | Promised used to return the attribute queried and the value obtained.|

**Example**

```js
var imageFileRelativePath = "Download/queryTest/image/01.jpg";
var jsonStrSingleRelativepath = JSON.stringify({ [fileAccess.FileKey.RELATIVE_PATH]: "" });
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    var fileInfo = await fileAccessHelper.getFileInfoFromRelativePath(imageFileRelativePath);
    let queryResult = await fileAccessHelper.query(fileInfo.uri, jsonStrSingleRelativepath);
    console.log("query_file_single faf query, queryResult.relative_path: " + JSON.parse(queryResult).relative_path);
} catch (error) {
     console.error("query_file_single faf query failed, error.code :" + error.code + ", errorMessage :" + error.message);
};
```

### query<sup>10+</sup>

query(uri:string, metaJson: string, callback: AsyncCallback&lt;string&gt;) : void

Queries the attribute information about a file or directory based on the URI. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name  | Type                       | Mandatory| Description                                                |
| -------- | --------------------------- | ---- | ---------------------------------------------------- |
| uri      | string | Yes  | URI of the file or directory (obtained from [FileInfo](#fileinfo)).|
| metaJson | string | Yes  | Attribute [FILEKEY](#filekey10) to query.       |
| callback | AsyncCallback&lt;string&gt; | Yes  | Callback invoked to return the attribute queried and the value obtained.                    |

**Example**

```js
var imageFileRelativePath = "Download/queryTest/image/01.jpg";
var jsonStrSingleRelativepath = JSON.stringify({ [fileAccess.FileKey.RELATIVE_PATH]: "" });
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    var fileInfo = await fileAccessHelper.getFileInfoFromRelativePath(imageFileRelativePath);
    fileAccessHelper.query(fileInfo.uri, jsonStrSingleRelativepath, (err, queryResult)=>{
        if (err) {
            console.log("query_file_single faf query Failed, errCode:" + err.code + ", errMessage:" + err.message);
            return;
        }
        console.log("query_file_single faf query, queryResult.relative_path: " + JSON.parse(queryResult).relative_path);
    })
} catch (error) {
   console.error("query_file_single faf query failed, error.code :" + error.code + ", errorMessage :" + error.message);
};
```

### copy<sup>10+</sup>

copy(sourceUri: string, destUri: string, force?: boolean) : Promise&lt;Array&lt;CopyResult&gt;&gt;

Copies a file or directory. This API uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name   | Type   | Mandatory| Description                                                        |
| --------- | ------- | ---- | ------------------------------------------------------------ |
| sourceUri | string  | Yes  | URI of the file or directory to copy, for example, **datashare:///media/file/102**. |
| destUri   | string  | Yes  | URI of the destination directory, for example, **datashare:///media/file/101**.         |
| force     | boolean | No  | Whether to forcibly overwrite the file with the same name. <br>If **force** is **true**, the file with the same name will be overwritten. If **force** is **false** or not specified, the file with the same name will not be overwritten.|

**Return value**

| Type                                                   | Description                                                        |
| :------------------------------------------------------ | :----------------------------------------------------------- |
| Promise&lt;Array&lt;[CopyResult](#copyresult10)&gt;&gt; | Promise used to return the result. If the file or directory is copied successfully, no information is returned. If the file copy fails, **copyResult** is returned.|

Example 1: Copy a file with **force** unspecified.

```js
// The media library URI is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
let sourceFile = "datashare:///media/file/102";
let destFile = "datashare:///media/file/101";
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let copyResult = await fileAccessHelper.copy(sourceFile, destFile);
    if (copyResult.length === 0) {
        console.log("copy success");
    } else {
        for (let i = 0; i < copyResult.length; i++) {
            console.error("errCode" + copyResult[i].errCode);
            console.error("errMsg" + copyResult[i].errMsg);
            console.error("sourceUri" + copyResult[i].sourceUri);
            console.error("destUri" + copyResult[i].destUri);
        }
    }
} catch (error) {
    console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
}
```

Example 2: Copy a file or directory when **force** set to **true**.

```js
// The media library URI is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
let sourceFile = "datashare:///media/file/102";
let destFile = "datashare:///media/file/101";
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    let copyResult = await fileAccessHelper.copy(sourceFile, destFile, true);
    if (copyResult.length === 0) {
        console.log("copy success");
    } else {
        for (let i = 0; i < copyResult.length; i++) {
            console.error("errCode" + copyResult[i].errCode);
            console.error("errMsg" + copyResult[i].errMsg);
            console.error("sourceUri" + copyResult[i].sourceUri);
            console.error("destUri" + copyResult[i].destUri);
        }
    }
} catch (error) {
    console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
}
```

### copy<sup>10+</sup>

copy(sourceUri: string, destUri: string, callback: AsyncCallback&lt;Array&lt;CopyResult&gt;&gt;) : void

Copies a file or directory. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name   | Type                                            | Mandatory| Description                                                        |
| --------- | ------------------------------------------------ | ---- | ------------------------------------------------------------ |
| sourceUri | string                                           | Yes  | URI of the file or directory to copy, for example, **datashare:///media/file/102**. |
| destUri   | string                                           | Yes  | URI of the destination directory, for example, **datashare:///media/file/101**.         |
| callback  | AsyncCallback&lt;Array&lt;[CopyResult](#copyresult10)&gt;&gt; | Yes  | Callback invoked to return the result. If the file or directory is copied successfully, no information is returned. If the file copy fails, **copyResult** is returned.|

**Example**

```js
// The media library URI is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
let sourceFile = "datashare:///media/file/102";
let destFile = "datashare:///media/file/101";
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.copy(sourceFile, destFile, async (err, copyResult) => {
        if (err) {
            console.error("copy failed, errCode:" + err.code + ", errMessage:" + err.message);
            return;
        }
        if (copyResult.length === 0) {
            console.log("copy success");
        } else {
            for (let i = 0; i < copyResult.length; i++) {
                console.error("errCode" + copyResult[i].errCode);
                console.error("errMsg" + copyResult[i].errMsg);
                console.error("sourceUri" + copyResult[i].sourceUri);
                console.error("destUri" + copyResult[i].destUri);
            }
        }
    });
} catch (error) {
    console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
}
```

### copy<sup>10+</sup>

copy(sourceUri: string, destUri: string, force: boolean, callback: AsyncCallback&lt;Array&lt;CopyResult&gt;&gt;) : void

Copies a file or directory. This API uses an asynchronous callback to return the result.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

**Parameters**

| Name   | Type                                            | Mandatory| Description                                                        |
| --------- | ------------------------------------------------ | ---- | ------------------------------------------------------------ |
| sourceUri | string                                           | Yes  | URI of the file or directory to copy, for example, **datashare:///media/file/102**. |
| destUri   | string                                           | Yes  | URI of the destination directory, for example, **datashare:///media/file/101**.         |
| force     | boolean                                          | Yes  | Whether to forcibly overwrite the file with the same name. <br>If **force** is **true**, the file with the same name will be overwritten. If **force** is **false** or not specified, the file with the same name will not be overwritten.|
| callback  | AsyncCallback&lt;Array&lt;[CopyResult](#copyresult10)&gt;&gt; | Yes  | Callback invoked to return the result. If the file or directory is copied successfully, no information is returned. If the file copy fails, **copyResult** is returned.|

**Example**

```js
// The media library URI is used as an example.
// In the sample code, sourceFile indicates the file (directory) in the Download directory to copy, destFile indicates the destination directory in the Download directory, and uri is to URI in fileInfo.
// You can use the URI obtained.
let sourceFile = "datashare:///media/file/102";
let destFile = "datashare:///media/file/101";
try {
    // Obtain fileAccessHelper by referring to the sample code of fileAccess.createFileAccessHelper.
    fileAccessHelper.copy(sourceFile, destFile, true, async (err, copyResult) => {
        if (err) {
            console.error("copy failed, errCode:" + err.code + ", errMessage:" + err.message);
            return;
        }
        if (copyResult.length === 0) {
            console.log("copy success");
        } else {
            for (let i = 0; i < copyResult.length; i++) {
                console.error("errCode" + copyResult[i].errCode);
                console.error("errMsg" + copyResult[i].errMsg);
                console.error("sourceUri" + copyResult[i].sourceUri);
                console.error("destUri" + copyResult[i].destUri);
            }
        }
    });
} catch (error) {
    console.error("copy failed, errCode:" + error.code + ", errMessage:" + error.message);
}
```

## CopyResult<sup>10+</sup>

Defines the information returned when the file copy operation fails. If the copy operation is successful, no information is returned.

**System capability**: SystemCapability.FileManagement.UserFileService

**Required permissions**: ohos.permission.FILE_ACCESS_MANAGER

| Name     | Type  | Readable| Writable| Description               |
| --------- | ------ | ---- | ---- | ----------------- |
| sourceUri | string | Yes  | No  | URI of the source file or directory.                                        |
| destUri   | string | Yes  | No  | URI of the conflict file. If the error is not caused by a conflict, **destUri** is empty.|
| errCode   | number | Yes  | No  | Error code.                                                |
| errMsg    | string | Yes  | No  | Error information.                                              |

## OPENFLAGS

Enumerates the file open modes.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

| Name| Value| Description|
| ----- | ------ | ------ |
| READ | 0o0 | Read mode.|
| WRITE | 0o1 | Write mode.|
| WRITE_READ | 0o2 | Read/Write mode.|

## FILEKEY<sup>10+</sup>

Enumerates the keys of the file attributes to query.

**Model restriction**: This API can be used only in the stage model.

**System capability**: SystemCapability.FileManagement.UserFileService

| Name         | Value           | Description                               |
| ------------- | ------------- | ----------------------------------- |
| DISPLAY_NAME  | 'display_name'  | Name of the file.                             |
| DATE_ADDED    | 'date_added'   | Date when the file was created, for example, **1501925454**.     |
| DATE_MODIFIED | 'date_modified' | Date when a file was modified, for example, **1665310670**.     |
| RELATIVE_PATH | 'relative_path' | Relative path of the file, for example, **Pictures/Screenshots/**.|
| FILE_SIZE     | 'size'          | Size of a file, in bytes.       |
| WIDTH         | 'width'         | Width of the image file, in pixels.       |
| HEIGHT        | 'height'        | Height of the image file, in pixels.       |
| DURATION      | 'duration'      | Duration of the audio or video file, in milliseconds. |