106 lines
3.4 KiB
JavaScript
106 lines
3.4 KiB
JavaScript
import bencode from 'bencode'
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/*
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Taken from parse-torrent
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*/
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/**
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* Parse a torrent. Throws an exception if the torrent is missing required fields.
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* @param {Buffer|Object} torrent
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* @return {Object} parsed torrent
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*/
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export function decodeTorrentFile (torrent) {
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if (Buffer.isBuffer(torrent)) {
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torrent = bencode.decode(torrent)
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}
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// sanity check
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ensure(torrent.info, 'info')
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ensure(torrent.info['name.utf-8'] || torrent.info.name, 'info.name')
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ensure(torrent.info['piece length'], 'info[\'piece length\']')
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ensure(torrent.info.pieces, 'info.pieces')
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if (torrent.info.files) {
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torrent.info.files.forEach(file => {
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ensure(typeof file.length === 'number', 'info.files[0].length')
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ensure(file['path.utf-8'] || file.path, 'info.files[0].path')
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})
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} else {
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ensure(typeof torrent.info.length === 'number', 'info.length')
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}
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const result = {
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info: torrent.info,
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infoBuffer: bencode.encode(torrent.info),
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name: (torrent.info['name.utf-8'] || torrent.info.name).toString(),
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announce: []
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}
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result.infoHash = sha1.sync(result.infoBuffer)
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result.infoHashBuffer = Buffer.from(result.infoHash, 'hex')
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if (torrent.info.private !== undefined) result.private = !!torrent.info.private
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if (torrent['creation date']) result.created = new Date(torrent['creation date'] * 1000)
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if (torrent['created by']) result.createdBy = torrent['created by'].toString()
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if (Buffer.isBuffer(torrent.comment)) result.comment = torrent.comment.toString()
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// announce and announce-list will be missing if metadata fetched via ut_metadata
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if (Array.isArray(torrent['announce-list']) && torrent['announce-list'].length > 0) {
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torrent['announce-list'].forEach(urls => {
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urls.forEach(url => {
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result.announce.push(url.toString())
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})
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})
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} else if (torrent.announce) {
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result.announce.push(torrent.announce.toString())
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}
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// handle url-list (BEP19 / web seeding)
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if (Buffer.isBuffer(torrent['url-list'])) {
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// some clients set url-list to empty string
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torrent['url-list'] = torrent['url-list'].length > 0
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? [torrent['url-list']]
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: []
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}
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result.urlList = (torrent['url-list'] || []).map(url => url.toString())
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// remove duplicates by converting to Set and back
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result.announce = Array.from(new Set(result.announce))
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result.urlList = Array.from(new Set(result.urlList))
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const files = torrent.info.files || [torrent.info]
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result.files = files.map((file, i) => {
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const parts = [].concat(result.name, file['path.utf-8'] || file.path || []).map(p => p.toString())
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return {
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path: path.join.apply(null, [path.sep].concat(parts)).slice(1),
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name: parts[parts.length - 1],
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length: file.length,
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offset: files.slice(0, i).reduce(sumLength, 0)
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}
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})
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result.length = files.reduce(sumLength, 0)
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const lastFile = result.files[result.files.length - 1]
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result.pieceLength = torrent.info['piece length']
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result.lastPieceLength = ((lastFile.offset + lastFile.length) % result.pieceLength) || result.pieceLength
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result.pieces = splitPieces(torrent.info.pieces)
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return result
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}
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function splitPieces (buf) {
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const pieces = []
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for (let i = 0; i < buf.length; i += 20) {
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pieces.push(buf.slice(i, i + 20).toString('hex'))
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}
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return pieces
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}
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function ensure (bool, fieldName) {
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if (!bool) throw new Error(`Torrent is missing required field: ${fieldName}`)
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}
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