WebTorrent

The streaming torrent client. For node.js and the web.

WebTorrent is a streaming torrent client for node.js and the browser. YEP, THAT'S RIGHT. THE BROWSER. It's written completely in JavaScript – the language of the web – so the same code works in both runtimes.

In node.js, this module is a simple torrent client, using TCP and UDP to talk to other torrent clients.

In the browser, WebTorrent uses WebRTC (data channels) for peer-to-peer transport. It can be used without browser plugins, extensions, or installations. It's Just JavaScript™. Note: WebTorrent does not support UDP/TCP peers in browser.

Simply include the webtorrent.min.js script on your page to start fetching files over WebRTC using the BitTorrent protocol, or require('webtorrent') with browserify. See demo apps and code examples below.

To make BitTorrent work over WebRTC (which is the only P2P transport that works on the web) we made some protocol changes. Therefore, a browser-based WebTorrent client or "web peer" can only connect to other clients that support WebTorrent/WebRTC.

To seed files to web peers, use a client that supports WebTorrent, e.g. WebTorrent Desktop, a desktop client with a familiar UI that can connect to web peers, webtorrent-hybrid, a command line program, or Instant.io, a website. Established torrent clients like Vuze have already added WebTorrent support so they can connect to both normal and web peers. We hope other clients will follow.

Features

• Torrent client for node.js & the browser (same npm package!)
• Insanely fast
• Download multiple torrents simultaneously, efficiently
• Pure Javascript (no native dependencies)
• Exposes files as streams
  • Fetches pieces from the network on-demand so seeking is supported (even before torrent is finished)
  • Seamlessly switches between sequential and rarest-first piece selection strategy
• Supports advanced torrent client features
  • magnet uri support via ut_metadata
  • peer discovery via dht, tracker, and ut_pex
  • protocol extension api for adding new extensions
• Comprehensive test suite (runs completely offline, so it's reliable and fast)

Browser/WebRTC environment features

• WebRTC data channels for lightweight peer-to-peer communication with no plugins
• No silos. WebTorrent is a P2P network for the entire web. WebTorrent clients running on one domain can connect to clients on any other domain.
• Stream video torrents into a <video> tag (webm (vp8, vp9) or mp4 (h.264))
• Supports Chrome, Firefox, and Opera.

Install

To install WebTorrent for use in node or the browser with require('webtorrent'), run:

npm install webtorrent

To install a webtorrent command line program, run:

npm install webtorrent-cli -g

To install a WebTorrent desktop appliation for Mac, Windows, or Linux, see WebTorrent Desktop.

Ways to help

• Join us in Gitter or on freenode at #webtorrent to help with development or to hang out with some mad science hackers :)
• Create a new issue to report bugs
• Fix an issue. WebTorrent is an OPEN Open Source Project!

Who is using WebTorrent today?

Lots of folks!

WebTorrent API Documentation

Read the full API Documentation.

Usage

WebTorrent is the first BitTorrent client that works in the browser, using open web standards (no plugins, just HTML5 and WebRTC)! It's easy to get started!

In the browser

Downloading a file is simple:

var WebTorrent = require('webtorrent')

var client = new WebTorrent()
var magnetURI = '...'

client.add(magnetURI, function (torrent) {
  // Got torrent metadata!
  console.log('Client is downloading:', torrent.infoHash)

  torrent.files.forEach(function (file) {
    // Display the file by appending it to the DOM. Supports video, audio, images, and
    // more. Specify a container element (CSS selector or reference to DOM node).
    file.appendTo('body')
  })
})

Seeding a file is simple, too:

var dragDrop = require('drag-drop')
var WebTorrent = require('webtorrent')

var client = new WebTorrent()

// When user drops files on the browser, create a new torrent and start seeding it!
dragDrop('body', function (files) {
  client.seed(files, function (torrent) {
    console.log('Client is seeding:', torrent.infoHash)
  })
})

There are more examples in docs/get-started.md.

Browserify

WebTorrent works great with browserify, an npm package that let's you use node-style require() to organize your browser code and load modules installed by npm (as seen in the previous examples).

Webpack

WebTorrent also works with webpack, a module bundler similar to browserify. However, webpack requires the following extra configuration:

{
  target: 'web',
  node: {
    fs: 'empty'
  },
  module: {
    loaders: [
      // make sure to install the 'json-loader' package: npm install json-loader
      {
        test: /\.json$/,
        loader: 'json'
      }
    ]
  }
}

Otherwise you could also directly use the pre-built version via require('webtorrent/webtorrent.min').

Script tag

WebTorrent is also available as a standalone script (webtorrent.min.js) which exposes WebTorrent on the window object, so it can be used with just a script tag:

<script src="webtorrent.min.js"></script>

The WebTorrent script is also hosted on fast, reliable CDN infrastructure (Cloudflare and MaxCDN) for easy inclusion on your site:

<script src="https://cdn.jsdelivr.net/webtorrent/latest/webtorrent.min.js"></script>

In Node.js

WebTorrent also works in node.js, using the same npm package! It's mad science!

NOTE: To connect to "web peers" (browsers) in addition to normal BitTorrent peers, use webtorrent-hybrid which includes WebRTC support for node.

As a command line app

WebTorrent is also available as a command line app. Here's how to use it:

$ npm install webtorrent-cli -g
$ webtorrent --help

To download a torrent:

$ webtorrent magnet_uri

To stream a torrent to a device like AirPlay or Chromecast, just pass a flag:

$ webtorrent magnet_uri --airplay

There are many supported streaming options:

--airplay               Apple TV
--chromecast            Chromecast
--mplayer               MPlayer
--mpv                   MPV
--omx [jack]            omx [default: hdmi]
--vlc                   VLC
--xbmc                  XBMC
--stdout                standard out [implies --quiet]

In addition to magnet uris, webtorrent supports many ways to specify a torrent.

Modules

Most of the active development is happening inside of small npm packages which are used by WebTorrent.

The Node Way™

"When applications are done well, they are just the really application-specific, brackish residue that can't be so easily abstracted away. All the nice, reusable components sublimate away onto github and npm where everybody can collaborate to advance the commons." — substack from "how I write modules"

Modules

These are the main modules that make up WebTorrent:

module	tests	version	description
webtorrent			torrent client (this module)
bittorrent-dht			distributed hash table client
bittorrent-peerid			identify client name/version
bittorrent-protocol			bittorrent protocol stream
bittorrent-tracker			bittorrent tracker server/client
create-torrent			create .torrent files
magnet-uri			parse magnet uris
parse-torrent			parse torrent identifiers
render-media			intelligently render media files
torrent-discovery			find peers via dht and tracker
ut_metadata			metadata for magnet uris (protocol extension)
ut_pex			peer discovery (protocol extension)

Enable debug logs

In node, enable debug logs by setting the DEBUG environment variable to the name of the module you want to debug (e.g. bittorrent-protocol, or * to print all logs).

DEBUG=* webtorrent

In the browser, enable debug logs by running this in the developer console:

localStorage.debug = '*'

Disable by running this:

localStorage.removeItem('debug')

Talks about WebTorrent

• May 2015 (Data Terra Nemo) - WebTorrent: Mother of all demos
• Nov 2014 (JSConf Asia) - How WebTorrent Works
• Sep 2014 (NodeConf EU) – WebTorrent Mad Science (first working WebTorrent demo)
• May 2014 (JS.LA) – How I Built a BitTorrent Client in the Browser (progress update; node client working)
• Oct 2013 (RealtimeConf) – WebRTC Black Magic (first mention of idea for WebTorrent)

License

MIT. Copyright (c) WebTorrent, LLC.