dweb-transports/TransportWEBTORRENT.js

405 lines
17 KiB
JavaScript

/*
This Transport layers builds on WebTorrent
Y Lists have listeners and generate events - see docs at ...
*/
// WebTorrent components
//Require in consumer;
//const WebTorrent = require('webtorrent');
const stream = require('readable-stream');
const Url = require('url');
const path = require('path');
const debug = require('debug')('dweb-transports:webtorrent');
// Other Dweb modules
const errors = require('./Errors'); // Standard Dweb Errors
const Transport = require('./Transport.js'); // Base class for TransportXyz
const Transports = require('./Transports'); // Manage all Transports that are loaded
let defaultoptions = {
};
class TransportWEBTORRENT extends Transport {
/*
WebTorrent specific transport
Fields:
webtorrent: object returned when starting webtorrent
*/
constructor(options) {
super(options);
this.webtorrent = undefined; // Undefined till start WebTorrent
this.options = options; // Dictionary of options
this.name = "WEBTORRENT"; // For console log etc
this.supportURLs = ['magnet'];
this.supportFunctions = ['fetch', 'createReadStream', "seed"];
this.supportFeatures = ['noCache']; // Note doesnt actually support noCache, but immutable is same
this.status = Transport.STATUS_LOADED;
}
p_webtorrentstart() {
/*
Start WebTorrent and wait until for ready.
*/
let self = this;
return new Promise((resolve, reject) => {
this.webtorrent = new WebTorrent(this.options);
this.webtorrent.once("ready", () => {
debug("ready");
resolve();
});
this.webtorrent.once("error", (err) => reject(err));
this.webtorrent.on("warning", (err) => {
console.warn("WebTorrent Torrent WARNING: " + err.message);
});
})
}
//TODO-SPLIT define load()
static setup0(options) {
/*
First part of setup, create obj, add to Transports but dont attempt to connect, typically called instead of p_setup if want to parallelize connections.
*/
let combinedoptions = Transport.mergeoptions(defaultoptions, options.webtorrent);
debug("setup0: options=%o", combinedoptions);
let t = new TransportWEBTORRENT(combinedoptions);
Transports.addtransport(t);
return t;
}
async p_setup1(cb) {
try {
this.status = Transport.STATUS_STARTING;
if (cb) cb(this);
await this.p_webtorrentstart();
await this.p_status();
} catch(err) {
console.error(this.name, "failed to connect", err.message);
this.status = Transport.STATUS_FAILED;
}
if (cb) cb(this);
return this;
}
stop(refreshstatus, cb) {
this.webtorrent.destroy((err) => {
this.status = Transport.STATUS_FAILED;
if (refreshstatus) refreshstatus(this);
if (err) {
debug("Webtorrent error during stopping %o", err);
} else {
debug("Webtorrent stopped");
}
cb(err, this);
});
}
async p_status() {
/*
Return a string for the status of a transport. No particular format, but keep it short as it will probably be in a small area of the screen.
*/
if (this.webtorrent && this.webtorrent.ready) {
this.status = Transport.STATUS_CONNECTED;
} else if (this.webtorrent) {
this.status = Transport.STATUS_STARTING;
} else {
this.status = Transport.STATUS_FAILED;
}
return super.p_status();
}
webtorrentparseurl(url) {
/* Parse a URL
url: URL as string or already parsed into Url - should start magnet: or in future might support dweb:/magnet/; some other formats might be supported
returns: torrentid, path
*/
if (!url) {
throw new errors.CodingError("TransportWEBTORRENT.p_rawfetch: requires url");
}
const urlstring = (typeof url === "string" ? url : url.href);
const index = urlstring.indexOf('/');
if (index === -1) {
throw new errors.CodingError("TransportWEBTORRENT.p_rawfetch: invalid url - missing path component. Should look like magnet:xyzabc/path/to/file");
}
const torrentId = urlstring.slice(0, index);
const path = urlstring.slice(index + 1);
return { torrentId, path }
}
async p_webtorrentadd(torrentId, opts) {
return new Promise((resolve, reject) => {
// Check if this torrentId is already added to the webtorrent client
let torrent = this.webtorrent.get(torrentId);
// If not, then add the torrentId to the torrent client
if (!torrent) {
// This can be added in to rewrite a known torrent for example to test a different tracker.
//let testid = "magnet:?xt=urn:btih:ELHVM7F4VEOTZQFDHCX7OZXUXKINUIPJ&tr=http%3A%2F%2Fbt1.archive.org%3A6969%2Fannounce&tr=http%3A%2F%2Fbt2.archive.org%3A6969%2Fannounce&tr=wss%3A%2F%2Ftracker.btorrent.xyz&tr=wss%3A%2F%2Ftracker.openwebtorrent.com&tr=wss%3A%2F%2Ftracker.fastcast.nz&ws=https%3A%2F%2Fdweb.me%2Farc%2Farchive.org%2Fdownload%2F&xs=https%3A%2F%2Fdweb.me%2Farc%2Farchive.org%2Ftorrent%2Fcommute";
//let testidnewtrack = "magnet:?xt=urn:btih:ELHVM7F4VEOTZQFDHCX7OZXUXKINUIPJ&tr=http%3A%2F%2Fbt1.archive.org%3A6969%2Fannounce&tr=http%3A%2F%2Fbt2.archive.org%3A6969%2Fannounce&tr=wss%3A%2F%2Fdweb.archive.org:6969&ws=https%3A%2F%2Fdweb.me%2Farc%2Farchive.org%2Fdownload%2F&xs=https%3A%2F%2Fdweb.me%2Farc%2Farchive.org%2Ftorrent%2Fcommute";
//if (torrentId === testid) torrentId = testidnewtrack;
torrent = this.webtorrent.add(torrentId, opts);
torrent.once("error", (err) => {
reject(new errors.TransportError("Torrent encountered a fatal error " + err.message));
});
torrent.on("warning", (err) => {
console.warn("WebTorrent Torrent WARNING: " + err.message + " (" + torrent.name + ")");
});
}
if (torrent.ready) {
resolve(torrent);
} else {
torrent.once("ready", () => {
resolve(torrent);
});
}
});
}
webtorrentfindfile (torrent, path) {
/*
Given a torrent object and a path to a file within the torrent, find the given file.
*/
const filePath = torrent.name + '/' + path;
const file = torrent.files.find(file => {
return file.path === filePath;
});
if (!file) {
//debugger;
throw new errors.TransportError("Requested file (" + path + ") not found within torrent ");
}
return file;
}
p_rawfetch(url) {
/*
Fetch some bytes based on a url of the form:
magnet:xyzabc/path/to/file
(Where xyzabc is the typical magnet uri contents)
No assumption is made about the data in terms of size or structure. Returns a new Promise that resolves to a buffer.
:param string url: URL of object being retrieved
:resolve buffer: Return the object being fetched.
:throws: TransportError if url invalid - note this happens immediately, not as a catch in the promise
*/
return new Promise((resolve, reject) => {
// Logged by Transports
const { torrentId, path } = this.webtorrentparseurl(url);
this.p_webtorrentadd(torrentId)
.then((torrent) => {
torrent.deselect(0, torrent.pieces.length - 1, false); // Dont download entire torrent as will pull just the file we want (warning - may give problems if multiple reads from same webtorrent)
const file = this.webtorrentfindfile(torrent, path);
file.getBuffer((err, buffer) => {
if (err) {
return reject(new errors.TransportError("Torrent encountered a fatal error " + err.message + " (" + torrent.name + ")"));
}
resolve(buffer);
});
})
.catch((err) => reject(err));
});
}
seed({fileRelativePath, directoryPath, torrentRelativePath }, cb) {
/* Add a file to webTorrent - this will be called each time a file is cached and adds the torrent to WT handling so its seeding this (and other) files in directory */
if (!torrentRelativePath) { // If no torrentfile available then just skip WebTorrent, MirrorFS will often seed the file (eg to IPFS) while its fetching the torrent and then seed that.
cb(null);
} else {
const torrentfile = path.join(directoryPath, torrentRelativePath);
this.p_addTorrentFromTorrentFile(torrentfile, directoryPath)
.then(res => { debug("Added %s/%s to webtorrent", directoryPath, fileRelativePath); cb(null)})
.catch(err => {
if (err.message.includes("Cannot add duplicate torrent")) { // Ignore silently if already added
cb(null);
} else {
debug("addWebTorrent failed %s/%s", directoryPath, fileRelativePath); cb(err);
}
});
}
}
async _p_fileTorrentFromUrl(url) {
/*
Then open a webtorrent for the file specified in the path part of the url
url: of form magnet:... or magnet/:...
return: Web Torrent file
*/
try {
const {torrentId, path} = this.webtorrentparseurl(url);
const torrent = await this.p_webtorrentadd(torrentId);
torrent.deselect(0, torrent.pieces.length - 1, false); // Dont download entire torrent as will pull just the file we want (warning - may give problems if multiple reads from same webtorrent)
const file = this.webtorrentfindfile(torrent, path);
if (typeof window !== "undefined") { // Check running in browser
window.WEBTORRENT_TORRENT = torrent;
window.WEBTORRENT_FILE = file;
torrent.once('close', () => {
window.WEBTORRENT_TORRENT = null;
window.WEBTORRENT_FILE = null;
})
}
return file
} catch(err) {
// Logged by Transports
throw(err);
}
}
async p_addTorrentFromTorrentFile(torrentFilePath, filesPath) {
// TODO-API: doc
try {
const opts = { path: filesPath };
const oldTorrent = this.webtorrent.get(torrentFilePath);
if (oldTorrent) {
oldTorrent.rescanFiles();
} else {
const torrent = await this.p_webtorrentadd(torrentFilePath, opts);
torrent.deselect(0, torrent.pieces.length - 1, false); // Dont download entire torrent as will pull just the file we want (warning - may give problems if multiple reads from same webtorrent)
}
} catch(err) {
// Logged by Transports
throw(err);
}
}
async p_f_createReadStream(url, {wanturl=false}={}) {
/*
Fetch bytes progressively, using a node.js readable stream, based on a url of the form:
No assumption is made about the data in terms of size or structure.
This is the initialisation step, which returns a function suitable for <VIDEO>
Returns a new Promise that resolves to function for a node.js readable stream.
Node.js readable stream docs: https://nodejs.org/api/stream.html#stream_readable_streams
:param string url: URL of object being retrieved of form magnet:xyzabc/path/to/file (Where xyzabc is the typical magnet uri contents)
:param boolean wanturl True if want the URL of the stream (for service workers)
:resolves to: f({start, end}) => stream (The readable stream.)
:throws: TransportError if url invalid - note this happens immediately, not as a catch in the promise
*/
// Logged by Transports
try {
let filet = await this._p_fileTorrentFromUrl(url);
let self = this;
if (wanturl) {
return url;
} else {
return function (opts) { return self.createReadStream(filet, opts); };
}
} catch(err) {
// Logged by Transports
throw(err);
}
}
createReadStream(file, opts) {
/*
The function, encapsulated and inside another function by p_f_createReadStream (see docs)
:param file: Webtorrent "file" as returned by webtorrentfindfile
:param opts: { start: byte to start from; end: optional end byte }
:returns stream: The readable stream.
*/
debug("reading from stream %s %o", file.name, opts);
let through;
try {
through = new stream.PassThrough();
const fileStream = file.createReadStream(opts);
fileStream.pipe(through);
return through;
} catch(err) {
debug("createReadStream error %s", err);
if (typeof through.destroy === 'function')
through.destroy(err);
else through.emit('error', err)
}
}
async p_createReadableStream(url, opts) {
//Return a readable stream (suitable for a HTTP response) from a node type stream from webtorrent.
// This is used by dweb-serviceworker for WebTorrent only
let filet = await this._p_fileTorrentFromUrl(url);
return new ReadableStream({
start (controller) {
debug("start %s %o", url, opts);
// Create a webtorrent file stream
const filestream = filet.createReadStream(opts);
// When data comes out of webtorrent node.js style stream, put it into the WHATWG stream
filestream.on('data', value => {
controller.enqueue(value)
});
filestream.on('end', () => {
controller.close()
})
},
cancel (reason) {
throw new errors.TransportError(`cancelled ${url}, ${opts} ${reason}`);
}
});
}
static async p_test(opts) {
try {
let transport = await this.p_setup(opts); // Assumes IPFS already setup
console.log(transport.name, "p_test setup", opts, "complete");
let res = await transport.p_status();
console.assert(res === Transport.STATUS_CONNECTED);
// Creative commons torrent, copied from https://webtorrent.io/free-torrents
let bigBuckBunny = 'magnet:?xt=urn:btih:dd8255ecdc7ca55fb0bbf81323d87062db1f6d1c&dn=Big+Buck+Bunny&tr=udp%3A%2F%2Fexplodie.org%3A6969&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969&tr=udp%3A%2F%2Ftracker.empire-js.us%3A1337&tr=udp%3A%2F%2Ftracker.leechers-paradise.org%3A6969&tr=udp%3A%2F%2Ftracker.opentrackr.org%3A1337&tr=wss%3A%2F%2Ftracker.btorrent.xyz&tr=wss%3A%2F%2Ftracker.fastcast.nz&tr=wss%3A%2F%2Ftracker.openwebtorrent.com&ws=https%3A%2F%2Fwebtorrent.io%2Ftorrents%2F&xs=https%3A%2F%2Fwebtorrent.io%2Ftorrents%2Fbig-buck-bunny.torrent/Big Buck Bunny.en.srt';
let data1 = await transport.p_rawfetch(bigBuckBunny);
data1 = data1.toString();
assertData(data1);
const stream = await transport.createReadStream(bigBuckBunny);
const chunks = [];
stream.on("data", (chunk) => {
chunks.push(chunk);
});
stream.on("end", () => {
const data2 = Buffer.concat(chunks).toString();
assertData(data2);
});
function assertData(data) {
// Test for a string that is contained within the file
let expectedWithinData = "00:00:02,000 --> 00:00:05,000";
console.assert(data.indexOf(expectedWithinData) !== -1, "Should fetch 'Big Buck Bunny.en.srt' from the torrent");
// Test that the length is what we expect
console.assert(data.length, 129, "'Big Buck Bunny.en.srt' was " + data.length);
}
} catch (err) {
console.log("Exception thrown in", transport.name, "p_test():", err.message);
throw err;
}
}
}
Transports._transportclasses["WEBTORRENT"] = TransportWEBTORRENT;
TransportWEBTORRENT.scripts = ['webtorrent@latest/webtorrent.min.js'];
TransportWEBTORRENT.requires = ['webtorrent'];
exports = module.exports = TransportWEBTORRENT;