# Public File Access and Management
>![icon-note.gif](public_sys-resources/icon-note.gif) **NOTE:**
>
>- The initial APIs of this module are supported since API version 8. Newly added APIs will be marked with a superscript to indicate their earliest API version.
>- The APIs of this module are system APIs and cannot be called by third-party applications. Currently, these APIs can be called only by **filepicker**.
## Modules to Import

```js
import filemanager from '@ohos.fileManager';
```

## filemanager.getRoot

getRoot(options? : {dev? : DevInfo}) : Promise<FileInfo[]>

Obtains information about the files in the first-level directory in asynchronous mode. This method uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.FileManagerService

- Parameters
  | Name| Type| Mandatory| Description|
  | --- | --- | --- | -- |
  | dev | [DevInfo](#devinfo) | No| Device name. The default value is **local**, which is the only value supported.|

- Return value

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

- Example

```js
filemanager.getRoot().then((fileInfo) => {
    if(Array.isArray(fileInfo)) {
        for (var i = 0; i < fileInfo.length; i++) {
            console.log(JSON.Stringify(fileInfo))
        }
    }
}).catch((err) => {
    console.log(err)
});
```

## filemanager.getRoot

getRoot(options? : {dev? : DevInfo}, callback : AsyncCallback&lt;FileInfo[]&gt;) : void

Obtains information about the files in the first-level directory in asynchronous mode. This method uses a callback to return the result.

**System capability**: SystemCapability.FileManagement.FileManagerService

- Parameters

  | Name  | Type                     | Mandatory| Description                         |
  | -------- | ------------------------- | ---- | ----------------------------- |
  | dev      | [DevInfo](#devinfo)              | No  | Device name. The default value is **local**, which is the only value supported.|
  | callback | AsyncCallback&lt;[FileInfo](#fileinfo)[]&gt; | Yes  | Callback invoked to return the file information obtained. |

- Example

```js
filemanager.getRoot((err, fileInfo) => {
    if(Array.isArray(fileInfo)) {
        for (var i = 0; i < fileInfo.length; i++) {
            console.log(JSON.Stringify(fileInfo))
        }
    }
})
```

## filemanager.listFile

listFile(path : string, type : string, options? : {dev? : DevInfo, offset? : number, count? : number}) : Promise&lt;FileInfo[]&gt;

Obtains information about the files in the second-level directory in asynchronous mode. This method uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.FileManagerService

- Parameters
  | Name| Type| Mandatory| Description|
  | --- | --- | --- | -- |
  | type | string | Yes| Type of the files to query. The file type can be **file**, **image**, **audio**, or **video**.|
  | path | string | Yes| URI of the directory to query.|
  | dev | [DevInfo](#devinfo) | Yes| Device name. The default value is **local**, which is the only value supported.|
  | offset | number | No| Start position from which the files are to query.|
  | count | number | No| Number of files to query.|

- Return value

  | Type| Description|
  | --- | -- |
  | Promise&lt;FileInfo[]&gt; | Promise used to return the file information obtained.|

- Error
  | Error Info| Error Code|Description|
  | --       | ---    | -- |
  |No such file or directory | 2      | The directory or file of the specified URI does not exist.|
  |No such process | 3 | Failed to obtain the FMS service.|
  |Not a directory | 20 | The object specified by the URI is not a directory.|

```js
// Obtain all files in the directory.
// Call listFile() and getRoot() to obtain file URIs.
let media_path = file.uri
filemanager.listFile(media_path, "file")
.then((fileInfo) => {
    if(Array.isArray(fileInfo)) {
        for (var i = 0; i < fileInfo.length; i++) {
            console.log(JSON.Stringify(fileInfo))
        }
    }
}).catch((err) => {
    console.log(err)
})
```
## filemanager.listFile

listFile(path : string, type : string, options? : {dev? : DevInfo, offset? : number, count? : number}, callback : AsyncCallback&lt;FileInfo[]&gt;) : void

Obtains information about the files in the second-level directory in asynchronous mode. This method uses a callback to return the result.

**System capability**: SystemCapability.FileManagement.FileManagerService

- Parameters

  | Name  | Type                     | Mandatory| Description                                                        |
  | -------- | ------------------------- | ---- | ------------------------------------------------------------ |
  | type     | string                    | Yes  | Type of the files to query. The file type can be **file**, **image**, **audio**, or **video**.|
  | path     | string                    | Yes  | URI of the directory to query.                                               |
  | dev | [DevInfo](#devinfo) | No| Device name. The default value is **local**, which is the only value supported.|
  | offset | number | No| Start position from which the files are to query.|
  | count | number | No| Number of files to query.|
  | callback | AsyncCallback&lt;[FileInfo](#fileinfo)[]&gt; | Yes  | Callback invoked to return the file information obtained.                                |
- Error

  | Error Info                 | Error Code| Description                     |
  | ------------------------- | ------ | ------------------------- |
  |No such file or directory  | 2      | The directory or file of the specified URI does not exist.|
  |No such process            | 3      | Failed to obtain the FMS service.          |
  |Not a directory            | 20     | The object specified by the URI is not a directory.|

```js
// Call listFile() and getRoot() to obtain the file URIs.
let media_path = file.uri
filemanager.listFile(media_path, "file", (err, fileInfo) => {
    if(Array.isArray(fileInfo)) {
        for (var i = 0; i < fileInfo.length; i++) {
            console.log(JSON.Stringify(fileInfo))
        }
    }
})
```

## filemanager.createFile

filemanager.createFile(path : string, filename : string, options? : {dev? : DevInfo})  :   promise&lt;string&gt;

Creates a file in the specified path in asynchronous mode. This method uses a promise to return the result.

**System capability**: SystemCapability.FileManagement.FileManagerService

- Parameters
  | Name| Type| Mandatory| Description|
  | --- | --- | --- | -- |
  | filename | string | Yes| Name of the file to create.|
  | path | string | Yes| URI of the file to create.|
  | dev | [DevInfo](#devinfo) | No| Device name. The default value is **local**, which is the only value supported.|

- Return value

  | Type| Description|
  | --- | -- |
  | promise<string>| Promise used to return the URI of the file created.|

- Error
  | Error Info| Error Code|Description|
  | -- | --- | -- |
  | Operation not permitted | 1 | A file with the same name already exists.|
  | No such file or directory | 2 | The directory or file of the specified URI does not exist.|
  | No such process | 3 | Failed to obtain the FMS service.|
  | Not a directory | 20 | The object specified by the URI is not a directory.|

```js
// Create a file.
let media_path = file.uri // Obtain the file URI using listFile() and getRoot().
let name = "xxx.jpg" // File to be saved.
filemanager.createFile(media_path, name)
.then((uri) => {
// The URI of the file created is returned.
})
.catch((err) => {
    console.log(err)
})
```

## filemanager.createFile

createFile(path : string, filename: string, options? : {dev? : DevInfo}, callback : AsyncCallback&lt;string&gt;) : void

Creates a file in the specified path in asynchronous mode. This method uses a callback to return the result.

**System capability**: SystemCapability.FileManagement.FileManagerService

- Parameters

  | Name  | Type                     | Mandatory| Description                         |
  | -------- | ------------------------- | ---- | ----------------------------- |
  | filename | string                    | Yes  | Name of the file to create.               |
  | path     | string                    | Yes  | URI of the file to create.            |
  | dev | [DevInfo](#devinfo) | No| Device name. The default value is **local**, which is the only value supported.|
  | callback | AsyncCallback&lt;[FileInfo](#fileinfo)[]&gt; | Yes  | Callback invoked to return the file information obtained. |

- Error

  | Error Info                 | Error Code| Description                     |
  | ------------------------- | ------ | ------------------------- |
  | Operation not permitted   | 1      | A file with the same name already exists.             |
  | No such file or directory | 2      | The directory or file of the specified URI does not exist.|
  | No such process           | 3      | Failed to obtain the FMS service.          |
  | Not a directory           | 20     | The object specified by the URI is not a directory.|

```js
// Create a file.
// Call listFile() and getRoot() to obtain the file URI.
let media_path = file.uri
// File to be saved.
let name = "xxx.jpg"
filemanager.createFile(media_path, name, (err, uri) => {
// The URI of the file created is returned.
})
```

## FileInfo
Defines the file information returned by **getRoot()** or **listFile()**.

**System capability**: SystemCapability.FileManagement.FileManagerService

### Attributes

| Name| Type| Readable| Writable| Description|
| --- | -- | -- | -- | -- |
| name | string | Yes| No| File name.|
| path | string | Yes| No| URI of the file.|
| type | string | Yes| No| File type.|
| size | number | Yes| No| File size.|
| addedTime | number | Yes| No| Time when the file was scanned to the database.|
| modifiedTime | number | Yes| No| Time when the file was modified.|

## DevInfo
Defines the device type.

**System capability**: SystemCapability.FileManagement.FileManagerService

### Attributes

  | Name| Type| Readable| Writable| Description|
  | --- | -- | -- | -- | -- |
  | name | string | Yes| Yes| Device name.|