web-ext-native-msg

WebExtensions native messaging

Helper modules for WebExtensions native messaging host.

Supported browsers

Browser	Windows	Linux	Mac
Firefox	✓	✓	✓
Thunderbird	✓	✓	✓
Waterfox Current	✓	✓	✓
LibreWolf	✓ *1	✓
Chrome	✓	✓	✓
Chrome Beta	✓ *2	✓	✓
Chrome Canary	✓ *2		✓
Chromium		✓	✓
Brave	✓ *2	✓	✓
Edge	✓	✓	✓
Opera	✓ *2		✓ *2
Vivaldi	✓ *2	✓	✓

*1: Shares host with Firefox. *2: Shares host with Chrome.

Install

npm i web-ext-native-msg

Usage

Class Setup

Creates shell script, application manifest for specified browser.

Sample:

import { Setup } from 'web-ext-native-msg';

const handlerAfterSetup = info => {
  const { configDirPath, shellScriptPath, manifestPath } = info;
  // do something
};

const setup = new Setup({
  hostDescription: 'Description of the host',
  hostName: 'hostname',
  mainScriptFile: 'index.js',
  chromeExtensionIds: ['chrome-extension://xxxxxx'],
  webExtensionIds: ['[e-mail]'],
  callback: handlerAfterSetup
});

setup.run();

Construct:

• new Setup(opt)
  • @param {Object} [opt] - options which contains optional properties below.

Properties:

• browser: {string} - Specify the browser.
• supportedBrowsers: {Array} - List of supported browsers.
• configPath: {string} - Path to save config files.
  • On Windows, config path defaults to C:\Users\[UserName]\AppData\Roaming\[hostName]\config\.
  • On Mac, ~/Library/Application Support/[hostName]/config/.
  • On Linux, ~/.config/[hostName]/config/.
• overwriteConfig: {boolean} - Overwrite config if exists. Defaults to false.
• hostName: {string} - Host name.
• hostDescription: {string} - Host description.
• mainScriptFile: {string} - File name of the main script. Defaults to index.js.
• chromeExtensionIds: {Array} - Array of chrome extension IDs.
• webExtensionIds: {Array} - Array of web extension IDs.
• callback: {Function} - A function that will be called when setup is done.
  • The function will be passed an argument containing information about the paths of the created files.

    {
      configDirPath: {string} - Config dir path.
      shellScriptPath: {string} - Shell script path.
      manifestPath: {string} - Application manifest path.
    }
    

Methods:

• run(): Runs setup script.
  • @returns {?Promise.<void>}

Class Input / Output

Decode / encode native messages exchanged between browser and host.

Sample:

import process from 'node:process';
import { Input, Output } from 'web-ext-native-msg';

const handleReject = e => {
  e = (new Output()).encode(e);
  e && process.stdout.write(e);
  return false;
};

const writeStdout = async msg => {
  msg = await (new Output()).encode(msg);
  return msg && process.stdout.write(msg);
};

const handleMsg = async msg => {
  // do something
};

const input = new Input();

const readStdin = chunk => {
  const arr = input.decode(chunk);
  const func = [];
  Array.isArray(arr) && arr.length && arr.forEach(msg => {
    msg && func.push(handleMsg(msg));
  });
  return Promise.all(func).catch(handleReject);
};

process.stdin.on('data', readStdin);

Construct:

• new Input();
• new Output();

Input method:

• decode(chunk): Decodes message from buffer.
  • @param {string|Buffer} chunk - chunk
  • @returns {?Array} - message array, nullable

Output method:

• encode(msg): Encodes message to buffer.
  • @param {Object} msg - message
  • @returns {?Buffer} - buffered message, nullable

Class ChildProcess / CmdArgs

Spawns child process.

Sample:

import path from 'node:path';
import process from 'node:process';
import { ChildProcess, CmdArgs } from 'web-ext-native-msg';

const arg = '-a -b -c';
const cmdArgs = (new CmdArgs(arg)).toArray();

const app = path.resolve(path.join('path', 'to', 'myApp.exe'));
const file = path.resolve(path.join('path', 'to', 'myFile.txt'));
const opt = {
  cwd: null,
  encoding: 'utf8',
  env: process.env
};

const proc = (new ChildProcess(app, cmdArgs, opt)).spawn(file).catch(e => {
  throw e;
});

Construct:

• new CmdArgs(arg)
  • @param {string|Array} arg - argument input
• new ChildProcess(app, args, opt)
  • @param {string} app - application path
  • @param {string|Array} [args] - command arguments
  • @param {Object} [opt] - options. Defaults to {cwd: null, env: process.env}.

CmdArgs methods:

• toArray(): Arguments to array.
  • @returns {Array} - arguments array or empty array
• toString(): Arguments array to string.
  • @returns {string} - arguments string or empty string

ChildProcess method:

• spawn(file): Spawn child process. Async.
  • @param {string} [file] - file path
  • @returns {Object} - child process

Function convertUriToFilePath(uri)

Converts URI to native file path.

• @param {string} uri - URI
• @returns {?string} - file path, nullable

Function getAbsPath(file)

Get absolute path.

• @param {string} file - file path
• @returns {?string} - absolute file path, nullable

Function getFileNameFromFilePath(file, subst)

Get file name from native file path.

• @param {string} file - file path
• @param {string} [subst] - substitute file name. Defaults to index
• @returns {string} - file name

Function getStat(file)

Get file stat.

• @param {string} file - file path
• @returns {Object} - file stat, nullable

Function removeDir(dir, baseDir)

Remove the directory and it's files. Note: dir should be subdirectory of baseDir.

• @param {string} dir - directory path
• @param {string} baseDir - base directory path
• @returns {void}

Async Function removeDirectory(dir, baseDir)

Remove the directory and it's files. Note: dir should be subdirectory of baseDir.

• @param {string} dir - directory path
• @param {string} baseDir - base directory path
• @returns {void}

Async Function createDirectory(dir, mode)

Create a directory.

• @param {string} dir - directory path to create
• @param {number} [mode] - permission. Defaults to 0o777
• @returns {string} - directory path

Async Function createFile(file, value, opt)

Create a file.

• @param {string} file - file path
• @param {string|Buffer|Uint8Array} value - value to write
• @param {Object} [opt] - options
• @param {string} [opt.encoding] - encoding. Defaults to null
• @param {string} [opt.flag] - flag. Defaults to 'w'
• @param {number|string} [opt.mode] - file permission. Defaults to 0o666
• @returns {string} - file path

Async Function readFile(file, opt)

Read a file.

• @param {string} file - file path
• @param {Object} [opt] - options
• @param {string} [opt.encoding] - encoding. Defaults to null
• @param {string} [opt.flag] - flag. Defaults to 'r'
• @returns {string|Buffer} - file content

Function isDir(dir)

The directory is a directory or not.

• @param {string} dir - directory path
• @returns {boolean} - result

Function isSubDir(dir, baseDir)

The directory is a subdirectory of a certain directory or not.

• @param {string} dir - directory path
• @param {string} baseDir - base directory path
• @returns {boolean} - result

Function isFile(file)

The file is a file or not.

• @param {string} file - file path
• @returns {boolean} - result

Function isExecutable(file, mask)

The file is executable or not.

• @param {string} file - file path
• @param {number} [mask] - mask bit. Defaults to 0o111
• @returns {boolean} - result