This is documentation for the next SDK version. For up-to-date documentation, see the latest version (SDK 55).

Expo 文件系统（旧版）

一个提供访问设备本地文件系统的库。

Android

iOS

tvOS

Included in Expo Go

GitHub

npm

更新日志

重要 FileSystem API 的 legacy 版本包含在 expo-file-system 库中。出于向后兼容的原因，它可以与现代 API 一起使用。

expo-file-system 提供对存储在设备本地的文件系统的访问。它还能够从网络 URL 上传和下载文件。

图示说明 expo-file-system 如何与不同资源交互

在 Expo Go 应用内部，expo-file-system 的工作方式有何不同

在 Expo Go 中，每个项目都有各自独立的文件系统作用域，并且无法访问其他项目的文件系统。

安装

Terminal

- npx expo install expo-file-system

If you are installing this in an existing React Native app, make sure to install expo in your project.

用法

下载文件

Component.js

const callback = downloadProgress => {
  const progress = downloadProgress.totalBytesWritten / downloadProgress.totalBytesExpectedToWrite;
  this.setState({
    downloadProgress: progress,
  });
};

const downloadResumable = FileSystem.createDownloadResumable(
  'https://example.com/videos/small.mp4',
  FileSystem.documentDirectory + 'small.mp4',
  {},
  callback
);

try {
  const { uri } = await downloadResumable.downloadAsync();
  console.log('已完成下载到 ', uri);
} catch (e) {
  console.error(e);
}

try {
  await downloadResumable.pauseAsync();
  console.log('已暂停下载操作，保存以供将来恢复');
  AsyncStorage.setItem('pausedDownload', JSON.stringify(downloadResumable.savable()));
} catch (e) {
  console.error(e);
}

try {
  const { uri } = await downloadResumable.resumeAsync();
  console.log('已完成下载到 ', uri);
} catch (e) {
  console.error(e);
}

//要在应用重启后恢复下载，假设 DownloadResumable.savable() 对象已被存储：
const downloadSnapshotJson = await AsyncStorage.getItem('pausedDownload');
const downloadSnapshot = JSON.parse(downloadSnapshotJson);
const downloadResumable = new FileSystem.DownloadResumable(
  downloadSnapshot.url,
  downloadSnapshot.fileUri,
  downloadSnapshot.options,
  callback,
  downloadSnapshot.resumeData
);

try {
  const { uri } = await downloadResumable.resumeAsync();
  console.log('已完成下载到 ', uri);
} catch (e) {
  console.error(e);
}

管理 Giphy

Giphy 示例

import * as FileSystem from 'expo-file-system/legacy';

const gifDir = FileSystem.cacheDirectory + 'giphy/';
const gifFileUri = (gifId: string) => gifDir + `gif_${gifId}_200.gif`;
const gifUrl = (gifId: string) => `https://media1.giphy.com/media/${gifId}/200.gif`;

// 检查 gif 目录是否存在。如果不存在，则创建它
async function ensureDirExists() {
  const dirInfo = await FileSystem.getInfoAsync(gifDir);
  if (!dirInfo.exists) {
    console.log("Gif 目录不存在，正在创建…");
    await FileSystem.makeDirectoryAsync(gifDir, { intermediates: true });
  }
}

// 下载所有指定为 ID 数组的 gifs
export async function addMultipleGifs(gifIds: string[]) {
  try {
    await ensureDirExists();

    console.log('正在下载', gifIds.length, '个 gif 文件…');
    await Promise.all(gifIds.map(id => FileSystem.downloadAsync(gifUrl(id), gifFileUri(id))));
  } catch (e) {
    console.error("无法下载 gif 文件：", e);
  }
}

// 返回本地 gif 文件的 URI
// 如果本地不存在该 gif，则会下载它
export async function getSingleGif(gifId: string) {
  await ensureDirExists();

  const fileUri = gifFileUri(gifId);
  const fileInfo = await FileSystem.getInfoAsync(fileUri);

  if (!fileInfo.exists) {
    console.log("Gif 未缓存在本地。正在下载…");
    await FileSystem.downloadAsync(gifUrl(gifId), fileUri);
  }

  return fileUri;
}

// 导出可共享的 URI - 它可以在应用外部共享
export async function getGifContentUri(gifId: string) {
  return FileSystem.getContentUriAsync(await getSingleGif(gifId));
}

// 删除整个 giphy 目录及其所有内容
export async function deleteAllGifs() {
  console.log('正在删除所有 GIF 文件…');
  await FileSystem.deleteAsync(gifDir);
}

服务端：处理 multipart 请求

Node.js 中的简单服务器，可以将上传的图片保存到磁盘：

index.js

const express = require('express');
const app = express();
const fs = require('fs');
const multer = require('multer');
const upload = multer({ dest: 'uploads/' });

// 此方法会将请求的二进制内容保存为文件。
app.patch('/binary-upload', (req, res) => {
  req.pipe(fs.createWriteStream('./uploads/image' + Date.now() + '.png'));
  res.end('OK');
});

// 此方法会将请求中的 "photo" 字段保存为文件。
app.patch('/multipart-upload', upload.single('photo'), (req, res) => {
  // 你可以访问其他 HTTP 参数。它们位于 body 对象中。
  console.log(req.body);
  res.end('OK');
});

app.listen(3000, () => {
  console.log('运行在端口 3000');
});

API

import * as FileSystem from 'expo-file-system/legacy';

SAF URI

SAF URI 是与 Storage Access Framework 兼容的 URI。它应当类似于这样：content://com.android.externalstorage.*。获取此类 URI 最简单的方法是通过 requestDirectoryPermissionsAsync 方法。

Constants

`FileSystem Legacy.bundleDirectory`

Android

iOS

tvOS

Type: string | null

URI to the directory where assets bundled with the application are stored.

`FileSystem Legacy.cacheDirectory`

Android

iOS

tvOS

Type: string | null

file:// URI pointing to the directory where temporary files used by this app will be stored. Files stored here may be automatically deleted by the system when low on storage. Example uses are for downloaded or generated files that the app just needs for one-time usage.

`FileSystem Legacy.documentDirectory`

Android

iOS

tvOS

Type: string | null

file:// URI pointing to the directory where user documents for this app will be stored. Files stored here will remain until explicitly deleted by the app. Ends with a trailing /. Example uses are for files the user saves that they expect to see again.

Classes

`DownloadResumable`

Android

iOS

tvOS

Type: Class extends FileSystemCancellableNetworkTask<DownloadProgressData>

DownloadResumable Properties

`fileUri`

Android

iOS

tvOS

Type: string

DownloadResumable Methods

`cancelAsync()`

Android

iOS

tvOS

Returns:

Promise<void>

`downloadAsync()`

Android

iOS

tvOS

Download the contents at a remote URI to a file in the app's file system.

Returns:

Promise<FileSystemDownloadResult | undefined>

Returns a Promise that resolves to FileSystemDownloadResult object, or to undefined when task was cancelled.

`pauseAsync()`

Android

iOS

tvOS

Pause the current download operation. resumeData is added to the DownloadResumable object after a successful pause operation. Returns an object that can be saved with AsyncStorage for future retrieval (the same object that is returned from calling FileSystem.DownloadResumable.savable()).

Returns:

Promise<DownloadPauseState>

Returns a Promise that resolves to DownloadPauseState object.

`resumeAsync()`

Android

iOS

tvOS

Resume a paused download operation.

Returns:

Promise<FileSystemDownloadResult | undefined>

Returns a Promise that resolves to FileSystemDownloadResult object, or to undefined when task was cancelled.

`savable()`

Android

iOS

tvOS

Method to get the object which can be saved with AsyncStorage for future retrieval.

Returns:

DownloadPauseState

Returns object in shape of DownloadPauseState type.

`FileSystemCancellableNetworkTask`

Android

iOS

tvOS

FileSystemCancellableNetworkTask Methods

`cancelAsync()`

Android

iOS

tvOS

Returns:

Promise<void>

`UploadTask`

Android

iOS

tvOS

Type: Class extends FileSystemCancellableNetworkTask<UploadProgressData>

UploadTask Methods

`cancelAsync()`

Android

iOS

tvOS

Returns:

Promise<void>

`uploadAsync()`

Android

iOS

tvOS

Returns:

Promise<FileSystemUploadResult | null | undefined>

Methods

`FileSystem Legacy.copyAsync(options)`

Android

iOS

tvOS

Parameter	Type	Description
options	`RelocatingOptions`	A map of move options represented by `RelocatingOptions` type.

Create a copy of a file or directory. Directories are recursively copied with all of their contents. It can be also used to copy content shared by other apps to local filesystem.

Returns:

Promise<void>

`FileSystem Legacy.createDownloadResumable(uri, fileUri, options, callback, resumeData)`

Android

iOS

tvOS

Parameter	Type	Description
uri	`string`	The remote URI to download from.
fileUri	`string`	The local URI of the file to download to. If there is no file at this URI, a new one is created. If there is a file at this URI, its contents are replaced. The directory for the file must exist.
options(optional)	`DownloadOptions`	A map of download options represented by `DownloadOptions` type.
callback(optional)	`FileSystemNetworkTaskProgressCallback<DownloadProgressData>`	This function is called on each data write to update the download progress. Note: When the app has been moved to the background, this callback won't be fired until it's moved to the foreground.
resumeData(optional)	`string`	The string which allows the api to resume a paused download. This is set on the `DownloadResumable` object automatically when a download is paused. When initializing a new `DownloadResumable` this should be `null`.

Create a DownloadResumable object which can start, pause, and resume a download of contents at a remote URI to a file in the app's file system.

Note: You need to call downloadAsync(), on a DownloadResumable instance to initiate the download. The DownloadResumable object has a callback that provides download progress updates. Downloads can be resumed across app restarts by using AsyncStorage to store the DownloadResumable.savable() object for later retrieval. The savable object contains the arguments required to initialize a new DownloadResumable object to resume the download after an app restart. The directory for a local file uri must exist prior to calling this function.

Returns:

DownloadResumable

`FileSystem Legacy.createUploadTask(url, fileUri, options, callback)`

Android

iOS

tvOS

Parameter	Type
url	`string`
fileUri	`string`
options(optional)	`FileSystemUploadOptions`
callback(optional)	`FileSystemNetworkTaskProgressCallback<UploadProgressData>`

Returns:

UploadTask

`FileSystem Legacy.deleteAsync(fileUri, options)`

Android

iOS

tvOS

Parameter	Type	Description
fileUri	`string`	`file://` or SAF URI to the file or directory.
options(optional)	`DeletingOptions`	A map of write options represented by `DeletingOptions` type. Default:`{}`

Delete a file or directory. If the URI points to a directory, the directory and all its contents are recursively deleted.

Returns:

Promise<void>

`FileSystem Legacy.deleteLegacyDocumentDirectoryAndroid()`

Android

iOS

tvOS

Returns:

Promise<void>

`FileSystem Legacy.downloadAsync(uri, fileUri, options)`

Android

iOS

tvOS

Parameter	Type	Description
uri	`string`	The remote URI to download from.
fileUri	`string`	The local URI of the file to download to. If there is no file at this URI, a new one is created. If there is a file at this URI, its contents are replaced. The directory for the file must exist.
options(optional)	`DownloadOptions`	A map of download options represented by `DownloadOptions` type. Default:`{}`

Download the contents at a remote URI to a file in the app's file system. The directory for a local file uri must exist prior to calling this function.

Returns:

Promise<FileSystemDownloadResult>

Returns a Promise that resolves to a FileSystemDownloadResult object.

Example

FileSystem.downloadAsync(
  'http://techslides.com/demos/sample-videos/small.mp4',
  FileSystem.documentDirectory + 'small.mp4'
)
  .then(({ uri }) => {
    console.log('Finished downloading to ', uri);
  })
  .catch(error => {
    console.error(error);
  });

`FileSystem Legacy.getContentUriAsync(fileUri)`

Android

Parameter	Type	Description
fileUri	`string`	The local URI of the file. If there is no file at this URI, an exception will be thrown.

Takes a file:// URI and converts it into content URI (content://) so that it can be accessed by other applications outside of Expo.

Returns:

Promise<string>

Returns a Promise that resolves to a string containing a content:// URI pointing to the file. The URI is the same as the fileUri input parameter but in a different format.

Example

FileSystem.getContentUriAsync(uri).then(cUri => {
  console.log(cUri);
  IntentLauncher.startActivityAsync('android.intent.action.VIEW', {
    data: cUri,
    flags: 1,
  });
});

`FileSystem Legacy.getFreeDiskStorageAsync()`

Android

iOS

tvOS

Gets the available internal disk storage size, in bytes. This returns the free space on the data partition that hosts all of the internal storage for all apps on the device.

Returns:

Promise<number>

Returns a Promise that resolves to the number of bytes available on the internal disk.

`FileSystem Legacy.getInfoAsync(fileUri, options)`

Android

iOS

tvOS

Parameter	Type	Description
fileUri	`string`	URI to the file or directory. See supported URI schemes.
options(optional)	`InfoOptions`	A map of options represented by `InfoOptions` type. Default:`{}`

Get metadata information about a file, directory or external content/asset.

Returns:

Promise<FileInfo>

A Promise that resolves to a FileInfo object. If no item exists at this URI, the returned Promise resolves to FileInfo object in form of { exists: false, isDirectory: false }.

`FileSystem Legacy.getTotalDiskCapacityAsync()`

Android

iOS

tvOS

Gets total internal disk storage size, in bytes. This is the total capacity of the data partition that hosts all the internal storage for all apps on the device.

Returns:

Promise<number>

Returns a Promise that resolves to a number that specifies the total internal disk storage capacity in bytes.

`FileSystem Legacy.makeDirectoryAsync(fileUri, options)`

Android

iOS

tvOS

Parameter	Type	Description
fileUri	`string`	`file://` URI to the new directory to create.
options(optional)	`MakeDirectoryOptions`	A map of create directory options represented by `MakeDirectoryOptions` type. Default:`{}`

Create a new empty directory.

Returns:

Promise<void>

`FileSystem Legacy.moveAsync(options)`

Android

iOS

tvOS

Parameter	Type	Description
options	`RelocatingOptions`	A map of move options represented by `RelocatingOptions` type.

Move a file or directory to a new location.

Returns:

Promise<void>

`FileSystem Legacy.readAsStringAsync(fileUri, options)`

Android

iOS

tvOS

Parameter	Type	Description
fileUri	`string`	`file://` or SAF URI to the file or directory.
options(optional)	`ReadingOptions`	A map of read options represented by `ReadingOptions` type. Default:`{}`

Read the entire contents of a file as a string. Binary will be returned in raw format, you will need to append data:image/png;base64, to use it as Base64.

Returns:

Promise<string>

A Promise that resolves to a string containing the entire contents of the file.

`FileSystem Legacy.readDirectoryAsync(fileUri)`

Android

iOS

tvOS

Parameter	Type	Description
fileUri	`string`	`file://` URI to the directory.

Enumerate the contents of a directory.

Returns:

Promise<string[]>

A Promise that resolves to an array of strings, each containing the name of a file or directory contained in the directory at fileUri.

`FileSystem Legacy.uploadAsync(url, fileUri, options)`

Android

iOS

tvOS

Parameter	Type	Description
url	`string`	The remote URL, where the file will be sent.
fileUri	`string`	The local URI of the file to send. The file must exist.
options(optional)	`FileSystemUploadOptions`	A map of download options represented by `FileSystemUploadOptions` type. Default:`{}`

Upload the contents of the file pointed by fileUri to the remote url.

Returns:

Promise<FileSystemUploadResult>

Returns a Promise that resolves to FileSystemUploadResult object.

Example

Client

import * as FileSystem from 'expo-file-system/legacy';

try {
  const response = await FileSystem.uploadAsync(`http://192.168.0.1:1234/binary-upload`, fileUri, {
    fieldName: 'file',
    httpMethod: 'PATCH',
    uploadType: FileSystem.FileSystemUploadType.BINARY_CONTENT,
  });
  console.log(JSON.stringify(response, null, 4));
} catch (error) {
  console.log(error);
}

Server

Refer to the "Server: Handling multipart requests" example - there is code for a simple Node.js server.

`FileSystem Legacy.writeAsStringAsync(fileUri, contents, options)`

Android

iOS

tvOS

Parameter	Type	Description
fileUri	`string`	`file://` or SAF URI to the file or directory. Note: when you're using SAF URI the file needs to exist. You can't create a new file.
contents	`string`	The string to replace the contents of the file with.
options(optional)	`WritingOptions`	A map of write options represented by `WritingOptions` type. Default:`{}`

Write the entire contents of a file as a string.

Returns:

Promise<void>

Namespaces

`StorageAccessFramework`

Android

The StorageAccessFramework is a namespace inside of the expo-file-system module, which encapsulates all functions which can be used with SAF URIs. You can read more about SAF in the Android documentation.

Example

Basic Usage

import { StorageAccessFramework } from 'expo-file-system';

// Requests permissions for external directory
const permissions = await StorageAccessFramework.requestDirectoryPermissionsAsync();

if (permissions.granted) {
  // Gets SAF URI from response
  const uri = permissions.directoryUri;

  // Gets all files inside of selected directory
  const files = await StorageAccessFramework.readDirectoryAsync(uri);
  alert(`Files inside ${uri}:\n\n${JSON.stringify(files)}`);
}

Migrating an album

import * as MediaLibrary from 'expo-media-library';
import * as FileSystem from 'expo-file-system/legacy';
const { StorageAccessFramework } = FileSystem;

async function migrateAlbum(albumName: string) {
  // Gets SAF URI to the album
  const albumUri = StorageAccessFramework.getUriForDirectoryInRoot(albumName);

  // Requests permissions
  const permissions = await StorageAccessFramework.requestDirectoryPermissionsAsync(albumUri);
  if (!permissions.granted) {
    return;
  }

  const permittedUri = permissions.directoryUri;
  // Checks if users selected the correct folder
  if (!permittedUri.includes(albumName)) {
    return;
  }

  const mediaLibraryPermissions = await MediaLibrary.requestPermissionsAsync();
  if (!mediaLibraryPermissions.granted) {
    return;
  }

  // Moves files from external storage to internal storage
  await StorageAccessFramework.moveAsync({
    from: permittedUri,
    to: FileSystem.documentDirectory!,
  });

  const outputDir = FileSystem.documentDirectory! + albumName;
  const migratedFiles = await FileSystem.readDirectoryAsync(outputDir);

  // Creates assets from local files
  const [newAlbumCreator, ...assets] = await Promise.all(
    migratedFiles.map<Promise<MediaLibrary.Asset>>(
      async fileName => await MediaLibrary.createAssetAsync(outputDir + '/' + fileName)
    )
  );

  // Album was empty
  if (!newAlbumCreator) {
    return;
  }

  // Creates a new album in the scoped directory
  const newAlbum = await MediaLibrary.createAlbumAsync(albumName, newAlbumCreator, false);
  if (assets.length) {
    await MediaLibrary.addAssetsToAlbumAsync(assets, newAlbum, false);
  }
}

StorageAccessFramework Methods

`createFileAsync(parentUri, fileName, mimeType)`

Android

Parameter	Type	Description
parentUri	`string`	The SAF URI to the parent directory.
fileName	`string`	The name of new file without the extension.
mimeType	`string`	The MIME type of new file.

Creates a new empty file.

Returns:

Promise<string>

A Promise that resolves to a SAF URI to the created file.

`getUriForDirectoryInRoot(folderName)`

Android

Parameter	Type	Description
folderName	`string`	The name of the folder which is located in the Android root directory.

Gets a SAF URI pointing to a folder in the Android root directory. You can use this function to get URI for StorageAccessFramework.requestDirectoryPermissionsAsync() when you trying to migrate an album. In that case, the name of the album is the folder name.

Returns:

string

Returns a SAF URI to a folder.

`makeDirectoryAsync(parentUri, dirName)`

Android

Parameter	Type	Description
parentUri	`string`	The SAF URI to the parent directory.
dirName	`string`	The name of new directory.

Creates a new empty directory.

Returns:

Promise<string>

A Promise that resolves to a SAF URI to the created directory.

`readDirectoryAsync(dirUri)`

Android

Parameter	Type	Description
dirUri	`string`	SAF URI to the directory.

Enumerate the contents of a directory.

Returns:

Promise<string[]>

A Promise that resolves to an array of strings, each containing the full SAF URI of a file or directory contained in the directory at fileUri.

`requestDirectoryPermissionsAsync(initialFileUrl)`

Android 11+

Parameter	Type	Description
initialFileUrl(optional)	`string \| null`	The SAF URI of the directory that the file picker should display when it first loads. If URI is incorrect or points to a non-existing folder, it's ignored. Default:`null`

Allows users to select a specific directory, granting your app access to all of the files and sub-directories within that directory.

Returns:

Promise<FileSystemRequestDirectoryPermissionsResult>

Returns a Promise that resolves to FileSystemRequestDirectoryPermissionsResult object.

Types

`DeletingOptions`

Android

iOS

tvOS

Property	Type	Description
idempotent(optional)	`boolean`	If `true`, don't throw an error if there is no file or directory at this URI. Default:`false`

`DownloadOptions`

Android

iOS

tvOS

Property	Type	Description
cache(optional)	`boolean`	-
headers(optional)	`Record<string, string>`	An object containing all the HTTP header fields and their values for the download network request. The keys and values of the object are the header names and values respectively.
md5(optional)	`boolean`	If `true`, include the MD5 hash of the file in the returned object. Provided for convenience since it is common to check the integrity of a file immediately after downloading. Default:`false`
sessionType(optional)	`FileSystemSessionType`	Only for: iOS A session type. Determines if tasks can be handled in the background. On Android, sessions always work in the background and you can't change it. Default:`FileSystemSessionType.BACKGROUND`

`DownloadPauseState`

Android

iOS

tvOS

Property	Type	Description
fileUri	`string`	The local URI of the file to download to. If there is no file at this URI, a new one is created. If there is a file at this URI, its contents are replaced.
options	`DownloadOptions`	Object representing the file download options.
resumeData(optional)	`string`	The string which allows the API to resume a paused download.
url	`string`	The remote URI to download from.

Deprecated: use FileSystemNetworkTaskProgressCallback<DownloadProgressData> instead.

`DownloadProgressCallback`

Android

iOS

tvOS

Type: FileSystemNetworkTaskProgressCallback<DownloadProgressData>

`DownloadProgressData`

Android

iOS

tvOS

Property	Type	Description
totalBytesExpectedToWrite	`number`	The total bytes expected to be written by the download operation. A value of `-1` means that the server did not return the `Content-Length` header and the total size is unknown. Without this header, you won't be able to track the download progress.
totalBytesWritten	`number`	The total bytes written by the download operation.

Deprecated: Use FileSystemDownloadResult instead.

`DownloadResult`

Android

iOS

tvOS

Type: FileSystemDownloadResult

`FileInfo`

Android

iOS

tvOS

Type: object shaped as below:

Property	Type	Description
exists	`true`	Signifies that the requested file exist.
isDirectory	`boolean`	Boolean set to `true` if this is a directory and `false` if it is a file.
md5(optional)	`string`	Present if the `md5` option was truthy. Contains the MD5 hash of the file.
modificationTime	`number`	The last modification time of the file expressed in seconds since epoch.
size	`number`	The size of the file in bytes.
uri	`string`	A URI pointing to the file. This is the same as the `fileUri` input parameter and preserves its scheme (for example, `file://` or `content://`).

Or object shaped as below:

Property	Type	Description
exists	`false`	-
isDirectory	`false`	-
uri	`string`	-

`FileSystemAcceptedUploadHttpMethod`

Android

iOS

tvOS

Literal Type: string

Acceptable values are: 'POST' | 'PUT' | 'PATCH'

`FileSystemDownloadResult`

Android

iOS

tvOS

Type: FileSystemHttpResult extended by:

Property	Type	Description
md5(optional)	`string`	Present if the `md5` option was truthy. Contains the MD5 hash of the file.
uri	`string`	A `file://` URI pointing to the file. This is the same as the `fileUri` input parameter.

`FileSystemHttpResult`

Android

iOS

tvOS

Property	Type	Description
headers	`Record<string, string>`	An object containing all the HTTP response header fields and their values for the download network request. The keys and values of the object are the header names and values respectively.
mimeType	`string \| null`	-
status	`number`	The HTTP response status code for the download network request.

`FileSystemNetworkTaskProgressCallback(data)`

Android

iOS

tvOS

Parameter	Type
data	`T`

Returns:

void

`FileSystemRequestDirectoryPermissionsResult`

Android

iOS

tvOS

Type: object shaped as below:

Property	Type	Description
granted	`false`	-

Or object shaped as below:

Property	Type	Description
directoryUri	`string`	The SAF URI to the user's selected directory. Available only if permissions were granted.
granted	`true`	-

`FileSystemUploadOptions`

Android

iOS

tvOS

Type: UploadOptionsBinary | UploadOptionsMultipart extended by:

Property	Type	Description
headers(optional)	`Record<string, string>`	An object containing all the HTTP header fields and their values for the upload network request. The keys and values of the object are the header names and values respectively.
httpMethod(optional)	`FileSystemAcceptedUploadHttpMethod`	The request method. Default:`FileSystemAcceptedUploadHttpMethod.POST`
sessionType(optional)	`FileSystemSessionType`	Only for: iOS A session type. Determines if tasks can be handled in the background. On Android, sessions always work in the background and you can't change it. Default:`FileSystemSessionType.BACKGROUND`

`FileSystemUploadResult`

Android

iOS

tvOS

Type: FileSystemHttpResult extended by:

Property	Type	Description
body	`string`	The body of the server response.

`InfoOptions`

Android

iOS

tvOS

Property	Type	Description
md5(optional)	`boolean`	Whether to return the MD5 hash of the file. Default:`false`

`MakeDirectoryOptions`

Android

iOS

tvOS

Property	Type	Description
intermediates(optional)	`boolean`	If `true`, don't throw an error if there is no file or directory at this URI. Default:`false`

`ProgressEvent`

Android

iOS

tvOS

Property	Type	Description
data	`T`	-
uuid	`string`	-

`ReadingOptions`

Android

iOS

tvOS

Property	Type	Description
encoding(optional)	`EncodingType \| 'utf8' \| 'base64'`	The encoding format to use when reading the file. Default:`EncodingType.UTF8`
length(optional)	`number`	Optional number of bytes to read. This option is only used when `encoding: FileSystem.EncodingType.Base64` and `position` is defined.
position(optional)	`number`	Optional number of bytes to skip. This option is only used when `encoding: FileSystem.EncodingType.Base64` and `length` is defined.

`RelocatingOptions`

Android

iOS

tvOS

Property	Type	Description
from	`string`	URI or SAF URI to the asset, file, or directory. See supported URI schemes.
to	`string`	`file://` URI to the file or directory which should be its new location.

`UploadOptionsBinary`

Android

iOS

tvOS

Upload options when upload type is set to binary.

Property	Type	Description
uploadType(optional)	`FileSystemUploadType`	Upload type determines how the file will be sent to the server. Value will be `FileSystemUploadType.BINARY_CONTENT`.

`UploadOptionsMultipart`

Android

iOS

tvOS

Upload options when upload type is set to multipart.

Property	Type	Description
fieldName(optional)	`string`	The name of the field which will hold uploaded file. Defaults to the file name without an extension.
mimeType(optional)	`string`	The MIME type of the provided file. If not provided, the module will try to guess it based on the extension.
parameters(optional)	`Record<string, string>`	Additional form properties. They will be located in the request body.
uploadType	`FileSystemUploadType`	Upload type determines how the file will be sent to the server. Value will be `FileSystemUploadType.MULTIPART`.

`UploadProgressData`

Android

iOS

tvOS

Property	Type	Description
totalBytesExpectedToSend	`number`	The total bytes expected to be sent by the upload operation.
totalBytesSent	`number`	The total bytes sent by the upload operation.

`WritingOptions`

Android

iOS

tvOS

Property	Type	Description
append(optional)	`boolean`	Whether to append the contents to the end of the file or overwrite the existing file. Default:`false`
encoding(optional)	`EncodingType \| 'utf8' \| 'base64'`	The encoding format to use when writing the file. Default:`FileSystem.EncodingType.UTF8`

Enums

`EncodingType`

Android

iOS

tvOS

These values can be used to define how file system data is read / written.

`Base64`

EncodingType.Base64 ＝ "base64"

Binary, radix-64 representation.

`UTF8`

EncodingType.UTF8 ＝ "utf8"

Standard encoding format.

`FileSystemSessionType`

iOS

These values can be used to define how sessions work on iOS.

`BACKGROUND`

FileSystemSessionType.BACKGROUND ＝ 0

Using this mode means that the downloading/uploading session on the native side will work even if the application is moved to background. If the task completes while the application is in background, the Promise will be either resolved immediately or (if the application execution has already been stopped) once the app is moved to foreground again.

Note: The background session doesn't fail if the server or your connection is down. Rather, it continues retrying until the task succeeds or is canceled manually.

`FOREGROUND`

FileSystemSessionType.FOREGROUND ＝ 1

Using this mode means that downloading/uploading session on the native side will be terminated once the application becomes inactive (e.g. when it goes to background). Bringing the application to foreground again would trigger Promise rejection.

`FileSystemUploadType`

Android

iOS

tvOS

`BINARY_CONTENT`

FileSystemUploadType.BINARY_CONTENT ＝ 0

The file will be sent as a request's body. The request can't contain additional data.

`MULTIPART`

FileSystemUploadType.MULTIPART ＝ 1

An RFC 2387-compliant request body. The provided file will be encoded into HTTP request. This request can contain additional data represented by UploadOptionsMultipart type.

支持的 URI scheme

在此表中，你可以看到每种方法可以处理哪种类型的 URI。例如，如果你有一个以 content:// 开头的 URI，就不能使用 FileSystem.readAsStringAsync()，但可以使用支持该 scheme 的 FileSystem.copyAsync()。

方法名称	Android	iOS
`getInfoAsync`	`file:///`, `content://`, `asset://`, 无 scheme	`file://`, `ph://`, `assets-library://`
`readAsStringAsync`	`file:///`, `asset://`, SAF URI	`file://`
`writeAsStringAsync`	`file:///`, SAF URI	`file://`
`deleteAsync`	`file:///`, SAF URI	`file://`
`moveAsync`	来源： `file:///`, SAF URI 目标： `file://`	来源： `file://` 目标： `file://`
`copyAsync`	来源： `file:///`, `content://`, `asset://`, SAF URI, 无 scheme 目标： `file://`	来源： `file://`, `ph://`, `assets-library://` 目标： `file://`
`makeDirectoryAsync`	`file:///`	`file://`
`readDirectoryAsync`	`file:///`	`file://`
`downloadAsync`	来源： `http://`, `https://` 目标： `file:///`	来源： `http://`, `https://` 目标： `file://`
`uploadAsync`	来源： `file:///` 目标： `http://` `https://`	来源： `file://` 目标： `http://` `https://`
`createDownloadResumable`	来源： `http://`, `https://` 目标： `file:///`	来源： `http://`, `https://` 目标： `file://`

在 Android 上，无 scheme 默认表示一个捆绑资源。

权限

Android

以下权限会通过此库的 AndroidManifest.xml 自动添加。

Android Permission	Description
`READ_EXTERNAL_STORAGE`	Allows an application to read from external storage.
`WRITE_EXTERNAL_STORAGE`	Allows an application to write to external storage.
`INTERNET`	Allows applications to open network sockets.

iOS

不需要权限。