Phoenix Browser Virtual File System

The Phoenix Browser Virtual File System (VFS) is a virtualized, Linux-inspired file system directly within your browser. This library brings Node.js fs APIs to the browser.

Phoenix VFS is designed with platform neutrality in mind. This ensures that if you use phoenix vfs as your file system layer, then the code written for browser environments works consistently across popular browsers like Chrome, Edge, Firefox, and Safari, as well as native platforms such as Mac, Windows, and Linux (via Tauri).

The fs lib is available across all browser contexts: the main browser window, web workers, shared workers, and service workers.

The library supports file read and write in all encodings(Eg. utf8, utf16, latin1, ...) supported by iconv library.

File System Structure & Organization

Here's a closer look at the Phoenix VFS organization:

• Root File System (/): At its core, the root file system is backed by IndexedDB. Additional paths, such as those from Tauri or fs access, will be automatically mounted to this root when detected.

• Fs Access APIs (/mnt): If your environment supports fs access APIs, you'll find them conveniently mounted under the /mnt path. use fs.mountNativeFolder API to add more platform folders.

• Tauri APIs Integration:

  • When Tauri APIs are active, you gain direct access to your local machine's file system through the /tauri/ path.
  • Windows Example: /tauri/c/Program Files/ could represent the C drive's "Program Files" directory.
  • Linux/macOS Example: /tauri/usr/bin/ might be an accessible directory, akin to native paths you'd expect on these platforms.

• Node Websocket Connector Integration:

  • The /tauri/ paths can be accessed via websockets. This integration is much more performant than Tauri's fs rust APIs(generally 4x faster and 10x faster for large files).
  • As we use websockets to connection to a node process that executes the actual fs operations, the ws backed /tauri/ apis are available in all web/shared/service workers.
  • This is recommended to use in main browser window as well, as this will relieve the main thread of tauri fs access apis that typically leads to blocking/freezing js window on large file access.
  • Supports filesystem watcher APIs that behaves consistently across all platforms.

By adopting Phoenix VFS, you're not just leveraging a file system; you're integrating a dynamic, adaptable layer that bridges the web and native worlds, making your web applications more powerful and reduces development time and costs.

• Phoenix Browser Virtual File System
  • File System Structure & Organization
  • Installation
    • Getting the code locally
    • Usage in browser
    • Usage in web-worker in browser
    • Usage in Tauri
  • Usage in Tauri with Node Websocket Connector
    • Example: Setting Up Your Own phoenix-fs Server in Node.js
  • Development
  • Tests in Browser
    • Debug Symbols in tests.
  • Tests in tauri
    • Publishing to npm
• API Docs
  • Error Codes
  • Supported file encodings
  • fs.utils
    • Usage of encoding in fs.readFile API
    • Use fs.BYTE_ARRAY_ENCODING for binary files
  • fs.Buffer
    • Buffer Encodings support
  • EventEmitter
  • fs.mountNativeFolder(optionalDirHandle?, callback) Function
    • Parameters:
    • Example Usage:
      • 1. Using the Directory Picker:
      • 2. Using a Provided Directory Handle:
  • fs.openTauriFilePickerAsync(options?) Function
    • Parameters:
    • Returns:
    • Example Usage:
  • fs.openTauriFileSaveDialogueAsync(options?) Function
    • Parameters:
    • Returns:
    • Example Usage:
  • fs.showSaveDialog Function
  • fs.getTauriPlatformPath(phoenixFSPath) function
    • Parameters
    • Returns
    • Throws
    • Examples
  • fs.getTauriVirtualPath(platformPath) function
    • Parameters
    • Returns
    • Throws
    • Example
  • fs.mkdir(path, mode?, callback?) function
  • fs.mkdirs(path, mode?, recursive?, callback?) function
  • fs.readdir(path, options?, callback) function
    • Parameters
    • Examples
  • fs.rename(oldPath, newPath, callback) function
  • fs.copy(src, dst, callback) function
  • fs.SUPPORTED_ENCODINGS Property
  • fs.isEncodingSupported(encodingStr) function
  • fs.stat(path, callback)
    • Parameters
    • Stat Object
    • Example
  • fs.readFile(path, options?, callback) Function
  • fs.writeFile(path, data, options?, callback) Function
    • Parameters:
    • Example:
  • fs.setNodeWSEndpoint(websocketEndpoint)
  • fs.forceUseNodeWSEndpoint(use)
  • fs.preferNodeWSEndpoint(use)
  • fs.watchAsync(pathToWatch, gitIgnorePaths)
    • Parameters
    • Returns
    • Example
  • fs.unwatchAsync(eventEmitter)

Installation

The library can be either installed using npm or using the CDN link (See usage in browser below ).

Getting the code locally

Install the library can be downloaded locally with the following command:

npm install @phcode/fs

Once installed, the virtualfs.js lib will be present in the following location

<project_root>/node_modules/@phcode/fs/dist/virtualfs.js

Usage in browser

Put the below script tag in your html file. A Global fs object will be created with the necessary fs APIs.

• The fs apis have compatibility with nodejs like fs APIs. See filer docs for API docs: https://filer.js.org/

<!--// using CDN link in your html file-->
<script src="https://unpkg.com/@phcode/fs@latest/dist/virtualfs.js"/>

<!--// using CDN link in your html file if you want to debug the file system internals-->
<script src="https://unpkg.com/@phcode/fs@latest/dist/virtualfs-debug.js"/>

<!--// OR to get a particular version, change latest to the version you need:-->
<script src="https://unpkg.com/@phcode/[email protected]/dist/virtualfs.js"/>

<!--// OR if you did npm install-->
<script src="<project_root>/node_modules/@phcode/fs/dist/virtualfs.js"/>

<!--// OR if you did npm install and want to debug the file system internals-->
<script src="<project_root>/node_modules/@phcode/fs/dist/virtualfs-debug.js"/>

<!--If you want to enable debug mode add this before the import script line-->
<script type="text/javascript">
    window.debugMode = true; // if you want to enable debug mode
    // alternatively set your URL query string parameter, https://yoursite?debugMode=true
</script>

Usage in web-worker in browser

Inside your web-worker, import the library as below. There are some limitations for web workers with native fs mount points to keep in mind:

1. Native fs aceess based APIs are only available in chrome. This is a platform limitation and firefox have not started supporting the API yet.
2. Use fs.mountNativeFolder to mount a local directory.
3. After mounting, access the files using the mountPath returned

importScripts('<project_root>/node_modules/@phcode/fs/dist/virtualfs.js');
// OR from CDN directly as
importScripts('https://unpkg.com/@phcode/fs@latest/dist/virtualfs.js');

fs.mountNativeFolder((err, mountPathArray)=>{
    console.log(err, mountPathArray);
});

Usage in Tauri

Make sure to use tauri with withglobaltauri option set in tauri config. Install the required Tauri plugin by adding the following to your Cargo.toml file:

[dependencies]
winapi = { version = "0.3", features = ["fileapi"] }
tauri-plugin-fs-extra = { git = "https://github.com/tauri-apps/plugins-workspace", branch = "v1" }
serde = "1.0"
serde_json = "1.0"

Then:

1. Copy src-tauri/src/platform.rs to the same folder of your tauri main file.
2. Copy all #[tauri::command] from src-tauri/src/main.rs to your tauri main file.
3. Update your tauri::Builder::default() section in your tauri main fn()

Usage in Tauri with Node Websocket Connector

Tauri APIs are accessible exclusively from the main thread. As a workaround, we provide a unique connector that facilitates communication with Node.js through websockets directly from the browser, granting access to the file system from webWorkers. This setup ensures flexibility, enabling the utilization of this library from both the primary browser tab and any worker threads.

For a detailed Node.js implementation, refer to this repository. If the requirement arises to bundle your Node binary, the tauri sidecar feature can be used to bundle node with your tauri app.

Example: Setting Up Your Own phoenix-fs Server in Node.js

Below is a quick guide to get your Phoenix-FS server up and running.

// If you're using CommonJS syntax:
const { CreatePhoenixFsServer , setDebugMode} = require('@phcode/fs/dist/phoenix-fs');

// If you prefer ES6 module syntax, use the import statement instead:
// import { CreatePhoenixFsServer } from '@phcode/fs/dist/phoenix-fs';

// Initialize an HTTP server
const server = http.createServer((req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.end('WebSocket server is operational');
});

// set debug mode to true if you want to see more logs
setDebugMode(true); // remove this in production!
// Attach the Phoenix websocket server to the HTTP server. 
// By default, the WebSocket server endpoint will be `ws://localhost:3000/phoenixFS`
CreatePhoenixFsServer(server);

// If you wish to use a custom path, pass it as the second argument:
// CreatePhoenixFsServer(server, "/yourCustomPath");

// Activate the HTTP server on port 3000
const port = 3000;
server.listen(port, () => {
  console.log(`Server is live on http://localhost:${port}`);
});

Save the code above in a file, run it, and you'll have both an HTTP server and WebSocket server running concurrently.

Development

This segment is dedicated to those contributing or modifying the codebase of this repository. If you are just using this as a library, please skip this section.

To build it:

npm install
npm run build

The npm run build command will create two files dist/virtualfs.js and dist/virtualfs-debug.js. Use dist/virtualfs-debug.js if you want to debug the phoenix filesystem lib itself.

Tests in Browser

While developing, use test script to open browser tests.

• Test runs tests against the built artifacts in dist folder.
• You should npm run build if any changes were made to the src folder

npm run build
npm run test-browser

NOTE: you can also use npm run serve to also start a web server for development.

Debug Symbols in tests.

By default, tests are run against the release build test/virtualfs.js. As it is heavily optimized it might be hard to debug with the release lib.

If you want to debug the tests with more debug symbols, search for <script src="virtualfs-debug.js"></script> in file test/index.html and follow steps there.

Tests in tauri

Again, Test runs tests against the built artifacts in dist folder. To develop tests in tauri, run the following commands:

1. First, build the artifacts in the dist folder by running:

npm run build

2. Next, initiate the tests by executing:

npm run test-tauri

This command will build the Tauri app and run the tests against the built artifacts.

While developing tests, keep the following points in mind:

• After making changes to the files in the test folder, press the F5 key to reload and apply the changes to the tests.
• If you modify any files in the src folder, generate the virtualfs.js dist files by running npm run build, and then press F5 to reload the changes for testing.
• For debugging purposes, you can open the developer tools by pressing F12, Ctrl-Shift-i, or Cmd-Shift-i, depending on your operating system.

Publishing to npm

Inorder to publish the package to npm, do the following

1. run npm run relese and push changes to main branch.
2. raise a pull request from main branch to npm branch. Once the pull request is merged and the code pushed to npm branch, GitHub actions will automatically publish the library to npm.

API Docs

Error Codes

The fs.ERR_CODES object has all the stantard error codes used by the APIs. Here is a list:

[
    "ENOENT",
    "EOF",
    "EACCES",
    "EAGAIN",
    "EBADF",
    "EBUSY",
    "EINVAL",
    "EMFILE",
    "ENFILE",
    "ENOBUFS",
    "ENOTDIR",
    "EISDIR",
    "ENOSYS",
    "ECHARSET",
    "EEXIST",
    "ENAMETOOLONG",
    "EPERM",
    "ELOOP",
    "EXDEV",
    "ENOTEMPTY",
    "ENOSPC",
    "EIO",
    "EROFS",
    "ESPIPE",
    "ECANCELED"
]

You can use for example fs.ERR_CODES.EIO to compare the error code you got from any of the below APIs if there are some errors.

Supported file encodings

When using file read and write apis, use fs.SUPPORTED_ENCODINGS.* to get a supported encoding.

The iconv library can also be directly accessed under fs.utils.iconv variable for advanced uses.

// Examples:
// Convert from an encoded buffer to a js string.
str = fs.utils.iconv.decode(Buffer.from([0x68, 0x65, 0x6c, 0x6c, 0x6f]), 'win1251');

// Convert from a js string to an encoded buffer.
buf = fs.utils.iconv.encode("Sample input string", 'win1251');

// Check if encoding is supported
fs.utils.iconv.encodingExists("us-ascii")

fs.utils

fs.utils houses several file related utilities.

1. fs.utils.iconv - iconv-lite: Pure JS character encoding conversion library. See API docs here: https://www.npmjs.com/package/iconv-lite
2. fs.utils.picomatch - Javascript module to match a string against a regular expression, glob, string, or function that takes the string as an argument and returns a truthy or falsy value. https://www.npmjs.com/package/picomatch
3. fs.utils.ignore - To filter filenames according to a .gitignore file. https://www.npmjs.com/package/ignore

Usage of encoding in fs.readFile API

// here you can use `utf16` encoding with `readFile` API to read a UTF16 file.
fs.readFile("/tauri/path/utf16.txt",
        "utf16", (e,contentStr)=>{console.log(contentStr);})
fs.readFile("/tauri/path/utf16.txt",
        fs.SUPPORTED_ENCODINGS.UTF16, (e,contentStr)=>{console.log(contentStr);})

Use fs.BYTE_ARRAY_ENCODING for binary files

When working with binary files in the fs.readFile and fs.writeFile APIs, you can utilize the fs.BYTE_ARRAY_ENCODING encoding. Using this encoding yields an ArrayBuffer, which is a native browser structure. Using this approach offers enhanced performance compared to the polyfilled Buffer object yielded when using just the binary encoding.

// here you can use `utf16` encoding with `readFile` API to read a UTF16 file.
fs.readFile("/tauri/path/utf16.txt",
        fs.BYTE_ARRAY_ENCODING, (e,contentStr)=>{console.log(contentStr);})

fs.Buffer

This is similar to nodejs buffer APIs implemented in the browser to work with binary files. It is available both in the global scope as Buffer or fs.Buffer. See Examples:

// see more APIs in https://nodejs.org/dist/latest-v6.x/docs/api/buffer.html#buffer_class_buffer
const buf = fs.Buffer.from([0x62, 0x75, 0x66, 0x66, 0x65, 0x72]);

Buffer Encodings support

fs.Buffer.from and fs.Buffer.toString APIs do not support all the encodings. So it is recommended to use iconv to work with custom file encodings and then use the buffer.

// to get a buffer from string, instead of doing Buffer.from, use iconv.encode 
buf = Buffer.from("Sample input string", 'win1251'); // not supported/recommended and wont work even if it works for some cases
buf = fs.utils.iconv.encode("Sample input string", 'win1251'); // recommended way to create buffer for encoding

// to convert buffer to string, use iconv as well
str = buf.toString('win1251'); // not supported/recommended and wont work even if it works for some cases
str = fs.utils.iconv.decode(buf, 'win1251'); // recommended way

EventEmitter

This library provides a global utility, EventEmitter, which is accessible via window.EventEmitter, self.EventEmitter, or simply EventEmitter, depending on the context. This utility replicates the functionality of the Node.js event emitter API, offering a handy tool for incorporating familiar Node.js-style event handling in your browser environment.

For a quick introduction on using the event emitter, refer to: Node.js EventEmitter Guide.

fs.mountNativeFolder(optionalDirHandle?, callback) Function

Mounts an fs access folder to the /mnt dir, prompting the user with a directory picker.

Parameters:

• optionalDirHandle (Object or null, optional):

  • An optional directory handle to use for mounting. If not provided, the function will prompt the user to select a directory.

• callback (Function):

  • A callback function that will be called once the mounting process completes or fails. The callback will be passed two parameters: an error (or null if no error) and an array containing the mounted path (or null if mounting failed).

Example Usage:

1. Using the Directory Picker:

fs.mountNativeFolder(function(error, [mountPath]) {
    if (error) {
        console.error("Error mounting directory:", error);
    } else {
        console.log("Directory mounted at:", mountPath);
    }
});

2. Using a Provided Directory Handle:

const dirHandle = someHandle;/* ... fs access directory handle https://developer.mozilla.org/en-US/docs/Web/API/FileSystemDirectoryHandle ... */;
fs.mountNativeFolder(dirHandle, function(error, [mountPath]) {
    if (error) {
        console.error("Error mounting directory:", error);
    } else {
        console.log("Directory mounted at:", mountPath);
    }
});

fs.openTauriFilePickerAsync(options?) Function

Opens the Tauri file picker asynchronously with given options. If options aren't provided, defaults to picking a single file. If the defaultPath option isn't provided, it will default to the user's document directory.

Parameters:

• options (Object, optional): Configuration options for the Tauri file picker.
  • directory (boolean, default: false): Whether it is a directory or file to be picked.
  • multiple (boolean, default: false): Whether to allow picking multiple files.
  • defaultPath (string, optional): Default directory to open in the file picker. Defaults to the document directory if not provided.
  • title (string, optional): The title of the dialogue window.
  • filters (Array, optional): Extension filters for the file dialog. Example filter:

    [{
      name: 'Image',
      extensions: ['png', 'jpeg']
    }]

Returns:

• A promise that resolves to:
  • null if the user dismissed the dialogue.
  • a string representing the selected filepath.
  • an Array of strings for multiple selected filepaths.

Example Usage:

1. Default File Picker:

   fs.openTauriFilePickerAsync().then(result => {
     console.log(result);
   });

2. Select Multiple Image Files:

   fs.openTauriFilePickerAsync({
     multiple: true,
     filters: [{
       name: 'Images',
       extensions: ['png', 'jpeg', 'jpg']
     }]
   }).then(files => {
     console.log(files);
   });

3. Select Directory:

   fs.openTauriFilePickerAsync({
     directory: true
   }).then(directory => {
     console.log(directory);
   });

fs.openTauriFileSaveDialogueAsync(options?) Function

Opens the Tauri file save dialogue asynchronously using the provided options. If the defaultPath option isn't provided, it defaults to the user's document directory.

Parameters:

• options (Object, optional): Configuration options for the Tauri file save dialogue.
  • defaultPath (string, optional): Initial directory or file path. If it's a directory path, the dialog interface will change to that folder. If it's not an existing directory, the file name will be set to the dialog's file name input and the dialog will be set to the parent folder. If not provided, defaults to the user's document directory.
  • title (string, optional): The title of the dialog window.
  • filters (Array<{name: string, extensions: string[]}>, optional): Extension filters for the file dialog. For example:

    filters: [{
      name: 'Image',
      extensions: ['png', 'jpeg']
    }]

Returns:

A promise that resolves to the selected file path if a location was chosen, or null if the dialogue was cancelled.

Example Usage:

fs.openTauriFileSaveDialogueAsync({
    defaultPath: '/path/to/example.txt',
    filters: [{ name: 'Text Files', extensions: ['txt'] }]
}).then(savePath => {
    if (savePath) {
        console.log("File will be saved at:", savePath);
    } else {
        console.log("Save dialogue was cancelled");
    }
});

fs.showSaveDialog Function

Same as fs.openTauriFileSaveDialogueAsync Function if executed in Tauri browser main window. Not supported in Tauri web workers.

Throws not implemented error in non-tauri environments.

fs.getTauriPlatformPath(phoenixFSPath) function

Convert Phoenix virtual file system path to platform-specific paths.

• For Windows, /tauri/c/d/a.txt will correspond to c:\d\a.txt.
• For *nix systems (Linux/Mac/Unix), /tauri/x/y/a.txt will correspond to /x/y/a.txt.

Parameters

• phoenixFSPath (string): The Phoenix virtual file system path to be converted.

Returns

• (string): The platform-specific path.

Throws

• Errors.EINVAL: If the provided path doesn't start with /tauri/ or cannot resolve to system path.

Examples

On a Windows system:

fs.getTauriPlatformPath('/tauri/c/users/user/a.txt');  // Returns: 'c:\users\user\a.txt'

On a *nix system:

fs.getTauriPlatformPath('/tauri/home/user/a.txt');  // Returns: '/home/user/a.txt'

fs.getTauriVirtualPath(platformPath) function

Converts platform-specific Tauri paths to Phoenix virtual file system path.

• For Windows: c:\d\a.txt will be translated to /tauri/c/d/a.txt.
• For *nix systems (Linux/Mac/Unix): /x/y/a.txt will be translated to /tauri/x/y/a.txt.

Parameters

• platformPath (string): The platform-specific path that needs to be converted.

Returns

• string: The corresponding Phoenix virtual file system path.

Throws

• Errors.EINVAL: If the provided path cannot be converted to a Phoenix FS path.

Example

On a Windows system:

fs.getTauriVirtualPath('c:\\users\\user\\a.txt');  
// Returns: '/tauri/c/users/user/a.txt'

On a *nix system:

fs.getTauriVirtualPath('/home/user/a.txt');  
// Returns: '/tauri/home/user/a.txt'

fs.mkdir(path, mode?, callback?) function

Creates a directory at given path. Not that the parent dir should exist for this to work. else use fs.mkdirs.

• Parameters:

  • path (string) - The path where the directory should be created.
  • mode (number|function) (Optional, default: 0o777) - The directory permissions.
  • callback (function) (Optional) - Callback to execute once directory creation is done. Called with an error as the first argument on failure, and null on success.

• Examples:

  // Create directory with default mode, and a callback.
  fs.mkdir("/tauri/some/path", callback);
  
  // Create directory with specified mode and a callback.
  fs.mkdir("/tauri/some/path", 0o755, callback);
    
  // Create directory without mode and without a callback.
  fs.mkdir("/tauri/some/path");

• Returns:

  • void

fs.mkdirs(path, mode?, recursive?, callback?) function

Creates a directory with optional mode and recursion (create all intermediate directories if those don't exist).

• Parameters:

  • path (string) - The path where the directory should be created.
  • mode (number|function) (Optional, default: 0o777) - The directory permissions.
  • recursive (boolean|function) (Optional, default: false) - Whether to create directories recursively.
  • callback (function) (Optional) - Callback to execute once directory creation is done. Called with an error as the first argument on failure, and null on success.

• Examples:

  // Create directory without recursion and with default mode, and a callback.
  fs.mkdirs("/tauri/some/path", callback);
  
  // Create directory with specified mode, without recursion, and a callback.
  fs.mkdirs("/tauri/some/path", 0o755, callback);
  
  // Create directory with specified mode, with recursion, and a callback.
  fs.mkdirs("/tauri/some/path", 0o755, true, callback);
  
  // Create directory without recursion, without mode, and without a callback.
  fs.mkdirs("/tauri/some/path");

• Returns:

  • void

fs.readdir(path, options?, callback) function

Reads the contents of a directory. This method will list all the entries of a directory as an array of strings (filenames, directory names, or symbolic link names). If the withFileTypes option is set to true, it will return file stat objects array instead of strings.

Parameters

• path (string): The path to the directory that needs to be read.
• options (Object, optional): Options for reading the directory.
  • withFileTypes (boolean, default: false): Set to true to return stats of each content file/dir.
• callback (function): A callback function to execute once the directory is read. This function gets two arguments: (err, entries). err will be set if an error occurred during reading. entries is an array of file names or fs stat objects.

Examples

Using withFileTypes option:

fs.readdir("/tauri/some/path", { withFileTypes: true }, function(err, entries) {
  if (err) throw err;
  console.log(entries); // Outputs file stats
});

Without specifying withFileTypes option:

fs.readdir("/tauri/some/path", function(err, entries) {
  if (err) throw err;
  console.log(entries); // Outputs an array of file/dir names
});

fs.rename(oldPath, newPath, callback) function

Renames (or moves) a file or directory. If the destination already exists, the operation will fail.

Parameters:

• oldPath (string): The current path of the file or directory.
• newPath (string): The new path to rename the file or directory to.
• callback (function): A callback function to be executed once the rename operation is complete. This function receives a single argument:
  • err: An error which will be set if an error occurred during the rename.

Example:

fs.rename("/tauri/some/path", "/tauri/new/path", function(err) {
  if (err) throw err;
  console.log('Rename complete');
});

Returns: void

fs.copy(src, dst, callback) function

Asynchronously copies a source file or directory to a destination.

• If the source is a file, it will be copied to the specified destination (the destination file doesn't exist).
• If the source is a directory, the directory will be copied recursively to the destination.

Parameters:

• src (string): The path to the source file or directory.

• dst (string): The path to the destination.

  • If the source is a file, this should be the full path to the destination file.
  • If the source is a directory, this should be the destination directory where the source directory's contents should be copied.
  • If the destination directory exists, the source folder will be copied as a child of the destination folder.

• callback (function): Callback function called once the copy operation completes.

  • The first argument is an error if any occurred during the copy operation or null if the copy was successful.
  • The second argument is the path to the copied file or directory if the copy was successful.

Exceptions:

• Throws Errors.ENOENT When the source doesn't exist.
• Throws Errors.EIO For I/O related errors.
• Throws Errors.EEXIST When the destination file or directory already exists.

Example:

fs.copy('/path/to/src', '/path/to/dest', (err, copiedPath) => {
  if (err) {
    console.error('Copy failed:', err);
  } else {
    console.log('Copy succeeded:', copiedPath);
  }
});

Returns: void

fs.SUPPORTED_ENCODINGS Property

Description:
This property holds an array of encodings that are compatible with the fs.readFile and fs.readDir APIs.

Note:
The encodings within this list are in lowercase. If you need to verify the support for an encoding irrespective of its case (e.g., both utf8 and UTF8), utilize the fs.isEncodingSupported method.

fs.isEncodingSupported(encodingStr) function

Description:
Determines if a given encoding is supported.

Parameters:

• encoding (string): The encoding format to check.

Returns:
A boolean value. Returns true if the encoding is supported, otherwise returns false.

Examples:

if (fs.isEncodingSupported('utf8')) {
   // perform operation with utf8 encoding
}

const supported = fs.isEncodingSupported('LATIN1');  // returns true
const notSupported = fs.isEncodingSupported('oopshehe');  // returns false

fs.stat(path, callback)

Retrieves the status of a file or directory. Once the operation is complete, the result will be an object with detailed information. The provided callback function is executed with the status details.

Parameters

• path: string

  • The path to the file or directory to retrieve the status for.

• callback: function

  • The callback function executed when the operation is complete.
  • Receives two arguments:
    1. An error object if an error occurred, otherwise null.
    2. The stat object containing the details about the file or directory.

Stat Object

The returned stat object contains the following properties:

• name: The base name of the file or directory.
• isFile(), isDirectory(), and isSymbolicLink(): Functions to determine the type of the node.
• type: Indicates the type of the node, which can be a string indicating directory, file, or symbolic link. Prefer above isFile() type check over this.
• size: The size of the file in bytes.
• mode: The file's mode (integer representing the file's permission mode).
• readonly: Boolean value indicating if the file is read-only.
• ctime: Time the file was created (milliseconds since the POSIX Epoch).
• atime: Time the file was last accessed (milliseconds since the POSIX Epoch).
• mtime: Time the file was last modified (milliseconds since the POSIX Epoch).
• nlinks: The number of hard links.

Example

fs.stat("/tauri/some/path", function(err, statObj) {
  if (err) throw err;
  console.log(statObj);
});

fs.readFile(path, options?, callback) Function

Description:
Reads the contents of a file.

Parameters:

• path (string):
  The path of the file to read.

• options (Object|string):
  This can either be a string representing the encoding or an object with more specific options.

  • If provided as a string, it determines the encoding. The default encoding is 'binary', which returns a 'Buffer'. To obtain content as a UTF8 string, specify it as utf8. A list of all supported encodings can be found in 'fs.SUPPORTED_ENCODINGS'.

    Note: When reading binary files from paths like /tauri/ or using fsAccess from /mnt/, it's advisable to use 'fs.BYTE_ARRAY_ENCODING' instead of the 'binary' encoding. This ensures improved performance during binary reads. The result would be an ArrayBuffer native to the browser rather than using the 'Buffer' polyfill.

  • If provided as an object, it can have the following keys:

    • encoding (string): The type of encoding. Default is 'binary'. Supported encodings can be seen in 'fs.SUPPORTED_ENCODINGS'.
    • flag (string): The file system flag. Default is 'r'.

• callback (function):
  The callback function to execute once the file read operation concludes.

  • This callback receives two arguments:
    1. An error object (or null if there were no errors).
    2. The data read from the file (its type is based on the encoding option).

Example:

fs.readFile("/path/to/file", { encoding: 'utf8' }, function(err, data) {
   if (err) throw err;
   console.log(data);
});
// or
fs.readFile("/path/to/file", 'utf8', function(err, data) {
  if (err) throw err;
  console.log(data);
});

Returns:
void (This function does not return anything)

fs.writeFile(path, data, options?, callback) Function

Writes data to a file, replacing the file if it already exists.

Parameters:

• path: (string)

  • The path of the file where data should be written.

• data: (ArrayBuffer|Buffer|string|number)

  • The data to write. This can be an ArrayBuffer, Buffer, string, or number.

• options: (Object|string) [Optional]

  • If provided as a string, it determines the encoding. Default is 'binary', which writes the buffer as is. Retrieve the list of all supported encodings from 'fs.SUPPORTED_ENCODINGS'. If writing binary files from within /tauri/ or fsAccess(/mnt/) paths, then instead of 'binary' encoding, prefer 'fs.BYTE_ARRAY_ENCODING' with ArrayBuffer data.
  • If provided as an object, it can have the following properties:
    • encoding (string): The type of encoding. Default is 'binary'.
    • flag (string): The file system flag. Default is 'w'.
    • mode (number): (Optional, default: 0o666) - The permissions.

• callback: (function)

  • The callback function executed once the file write operation concludes.
    • Receives one argument: An error object (or null if there were no errors).

Example:

fs.writeFile("/path/to/file", "Hello World", { encoding: 'utf8' }, function(err) {
   if (err) throw err;
   console.log("File written successfully!");
});
// or
fs.writeFile("/path/to/file", "Hello World", 'utf8', function(err) {
  if (err) throw err;
  console.log("File written successfully!");
});

fs.setNodeWSEndpoint(websocketEndpoint)

Sets the websocket endpoint and returns a promise that resolves when the tauri node fs connection is open. It ensures the socket remains open across failures and automatically reconnects as necessary.

• Parameters:

  • websocketEndpoint : string. Eg.: ws://localhost:3000/phoenixFS

• Returns:

  • Promise

fs.forceUseNodeWSEndpoint(use)

Forces the usage of the Node WebSocket endpoint. Throws an error if the Node WebSocket endpoint is not set.

• Parameters

  • use: Boolean
    • If true, forces the use of the Node WebSocket endpoint.

• Throws

  • Throws an error if the Node WebSocket endpoint has not been set.
  • Call fs.setNodeWSEndpoint(websocketEndpoint) before calling this API.

fs.preferNodeWSEndpoint(use)

Sets the preference to use the Node WebSocket endpoint if available. Throws an error if the Node WebSocket endpoint is not set. If a Node connection is not available, it falls back to Tauri. To always force the library to use the Node WebSocket endpoint for all FS APIs, use fs.forceUseNodeWSEndpoint.

• Parameters

  • use: Boolean
    • If true, prefers the use of the Node WebSocket endpoint when available.

• Throws

  • Throws an error if the Node WebSocket endpoint has not been set.
  • Call fs.setNodeWSEndpoint(websocketEndpoint) before calling this this API.

fs.watchAsync(pathToWatch, gitIgnorePaths)

Watch a specific path asynchronously for filesystem changes.

This function returns a promise that resolves an EventEmitter that will emit the following events:

• fs.WATCH_EVENTS.ADD_FILE: When a file is created.
• fs.WATCH_EVENTS.ADD_DIR: When a directory is created.
• fs.WATCH_EVENTS.UNLINK_FILE: When a file is deleted.
• fs.WATCH_EVENTS.UNLINK_DIR: When a directory is deleted.
• fs.WATCH_EVENTS.CHANGE: When a file is changed.

The watcher will ignore all files matching patterns in the provided gitignore.

NOTE: Behavior differs between paths within /tauri/ and other paths. Within Tauri, every file and folder modification is emitted as a distinct event. However, for other paths, the events are aggregated to the nearest discernible parent directory. Examples:

1. Within Tauri Paths: If you rename a parent directory named parentDir to newDir containing two files (file1.txt and file2.txt), you will receive six separate events:

• 2 Events for UNLINK_DIR parentDir and ADD_DIR newDir
• 2 Event for the UNLINK_FILE parentDir/file1.txt and parentDir/file2.txt due to its parent's renaming.
• 2 Event for the ADD_FILE newDir/file1.txt and newDir/file2.txt due to its parent's renaming.

2. Other Paths: Using the same scenario as above (renaming parentDir with two files inside), you will receive just two event(UNLINK_DIR and ADD_DIR) indicating the change in the parentDir. The individual changes to file1.txt and file2.txt are aggregated under the parent directory's event.

This means developers working with Tauri paths should design their event handlers to accommodate individual events for each file and directory change.

Parameters

• pathToWatch (string): The path to watch for filesystem changes.

• gitIgnorePaths (string or Array, optional, default=""): The patterns to ignore, either provided as a string (representing the content of a .gitignore file) or an array of individual patterns. The watcher will adhere to the standard .gitignore specification as detailed at git-scm. It's important to note that if a parent directory is excluded from watching, its child directories will also be excluded, regardless of any un-ignore patterns in git ignore file (e.g., !node_modules/dont_ignore_dir).

Returns

• EventEmitter: The event emitter that will notify of filesystem changes.

Example

// In the below watcher, we provide a gitignore formatted text to ignore 'node_modules' folder
// See https://git-scm.com/docs/gitignore for details.
const watcher = await fs.watchAsync('/path/to/watch', 'node_modules');

watcher.on(Constants.WATCH_EVENTS.ADD_FILE, (event) => {
  console.log(`File created: ${event.path}`);
});

watcher.on(Constants.WATCH_EVENTS.UNLINK_DIR, (event) => {
  console.log(`Directory deleted: ${event.path}`);
});

fs.unwatchAsync(eventEmitter)

Stops watching for filesystem changes on a previously set path.

Once you've stopped watching using unwatchAsync, any further operations on the event emitter will throw an error. If you wish to start watching again, you will need to call fs.watchAsync.

• Parameters
  • eventEmitter - The event emitter returned by fs.watchAsync that you wish to stop watching.
• Throws
  • Throws an error (Errors.EINVAL) if the watcher is already closed or if operations are attempted after closing.

Example:

const watcher = await fs.watchAsync('/path/to/watch', 'node_modules');

// Listen to an event.
watcher.on(fs.WATCH_EVENTS.ADD_FILE, (event) => {
  console.log(`File created: ${event.path}`);
});

// ... After some time, stop watching.
await unwatchAsync(watcher);

// Throws error since the watcher is closed.
watcher.on(fs.WATCH_EVENTS.ADD_FILE, (event) => {
  console.log(`File created: ${event.path}`);
});