WebTorrent – A Server Side Torrent Downlaoder

Introduction

WebTorrent is a JavaScript library that allows you to download and stream torrent files directly in the browser. Unlike traditional torrent clients that run on the client-side, WebTorrent runs on the server-side, providing a more secure and efficient way to download and stream torrent files. In this tutorial, we will go over the steps to use WebTorrent as a server-side torrent downloader.

Prerequisites

• Node.js (version 14 or higher)
• A modern web browser (e.g. Google Chrome, Mozilla Firefox)
• A torrent file or a magnet link
• Basic understanding of JavaScript and Node.js

Step 1: Install WebTorrent

To start using WebTorrent, you need to install it as a Node.js module. Open your terminal and run the following command:

npm install webtorrent

This will install the WebTorrent library and its dependencies.

Step 2: Create a New Node.js Project

Create a new directory for your project and navigate to it in your terminal. Then, create a new file called index.js and add the following code:

const WebTorrent = require('webtorrent');

const client = new WebTorrent();

client.on('error', (err) => {
  console.error('Error:', err);
});

client.on('torrent', (torrent) => {
  console.log('Torrent loaded:', torrent.infoHash);
});

client.load('magnet:?xt=urn:btih:torrent-file-hash', (torrent) => {
  console.log('Torrent loaded:', torrent.infoHash);
});

This code creates a new WebTorrent client and sets up event listeners for errors and torrent loading.

Step 3: Load a Torrent File or Magnet Link

To load a torrent file or magnet link, replace the magnet:?xt=urn:btih:torrent-file-hash string with the actual URL or magnet link of the torrent you want to download. For example:

client.load('https://example.com/torrent.torrent', (torrent) => {
  console.log('Torrent loaded:', torrent.infoHash);
});

Or:

client.load('magnet:?xt=urn:btih:torrent-file-hash', (torrent) => {
  console.log('Torrent loaded:', torrent.infoHash);
});

Step 4: Start the Torrent Download

Once the torrent is loaded, you can start the download by calling the start() method on the torrent object. For example:

torrent.start((torrent) => {
  console.log('Download started:', torrent.infoHash);
});

This will start the download process, and you can monitor the progress using the torrent.progress property.

Step 5: Stream the Torrent

To stream the torrent, you can use the torrent.getPeers() method to get a list of peers and then use the torrent.getChunk() method to get a chunk of the torrent data. For example:

torrent.getPeers((peers) => {
  console.log('Peers:', peers);
});

torrent.getChunk(0, (chunk) => {
  console.log('Chunk:', chunk);
});

This will give you the first chunk of the torrent data, which you can then stream to the client-side.

Step 6: Serve the Torrent

To serve the torrent to clients, you can use a web server such as Express.js. Here is an example of how to serve the torrent using Express.js:

const express = require('express');
const app = express();

app.use(express.static('public'));

app.get('/torrent', (req, res) => {
  res.sendFile('public/torrent.torrent');
});

app.listen(3000, () => {
  console.log('Server listening on port 3000');
});

This code sets up an Express.js server that serves the torrent file from the public directory.

Conclusion

In this tutorial, we have covered the steps to use WebTorrent as a server-side torrent downloader. We have installed WebTorrent, created a new Node.js project, loaded a torrent file or magnet link, started the download, streamed the torrent, and served the torrent to clients. With WebTorrent, you can easily download and stream torrent files directly in the browser, providing a more secure and efficient way to distribute large files.