in progress: move webtorrent into background BrowserWindow

background/capture-video-frame.js

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+module.exports = captureVideoFrame
+
+function captureVideoFrame (video, format) {
+  if (typeof video === 'string') video = document.querySelector(video)
+  if (!video || video.nodeName !== 'VIDEO') {
+    throw new Error('First argument must be a <video> element or selector')
+  }
+  if (format == null) format = 'png'
+  if (format !== 'png' && format !== 'jpg' && format !== 'webp') {
+    throw new Error('Second argument must be one of "png", "jpg", or "webp"')
+  }
+
+  var canvas = document.createElement('canvas')
+  canvas.width = video.videoWidth
+  canvas.height = video.videoHeight
+
+  canvas.getContext('2d').drawImage(video, 0, 0)
+
+  var dataUri = canvas.toDataURL('image/' + format)
+  var data = dataUri.split(',')[1]
+
+  return new Buffer(data, 'base64')
+}

background/index.js

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+var createTorrent = require('create-torrent')
+var electron = require('electron')
+var path = require('path')
+var prettyBytes = require('pretty-bytes')
+var throttle = require('throttleit')
+var thunky = require('thunky')
+var torrentPoster = require('./torrent-poster')
+var WebTorrent = require('webtorrent')
+var xhr = require('xhr')
+
+var ipc = electron.ipcRenderer
+
+global.WEBTORRENT_ANNOUNCE = createTorrent.announceList
+  .map(function (arr) {
+    return arr[0]
+  })
+  .filter(function (url) {
+    return url.indexOf('wss://') === 0 || url.indexOf('ws://') === 0
+  })
+
+var getClient = thunky(function (cb) {
+  getRtcConfig('https://instant.io/rtcConfig', function (err, rtcConfig) {
+    if (err) onError(err)
+    var client = window.client = new WebTorrent({
+      rtcConfig: rtcConfig
+    })
+    client.on('warning', onWarning)
+    client.on('error', onError)
+    cb(null, client)
+  })
+})
+
+function getRtcConfig (url, cb) {
+  xhr(url, function (err, res) {
+    if (err || res.statusCode !== 200) {
+      cb(new Error('Could not get WebRTC config from server. Using default (without TURN).'))
+    } else {
+      var rtcConfig
+      try {
+        rtcConfig = JSON.parse(res.body)
+      } catch (err) {
+        return cb(
+          new Error('Got invalid WebRTC config from server: ' + res.body)
+        )
+      }
+      console.log('got rtc config: %o', rtcConfig)
+      cb(null, rtcConfig)
+    }
+  })
+}
+
+// For performance, create the client immediately
+getClient(function () {})
+
+ipc.on('action', function (event, action, ...args) {
+  console.log('action %s', action)
+  if (action === 'addTorrent') {
+    downloadTorrent(args[0])
+  } else {
+    throw new Error('unrecognized action ' + action)
+  }
+})
+
+function downloadTorrent (torrentId) {
+  console.log('Downloading torrent from %s', torrentId)
+  getClient(function (err, client) {
+    if (err) return onError(err)
+    client.add(torrentId, onTorrent)
+  })
+}
+
+function downloadTorrentFile (file) {
+  console.log('Downloading torrent from <strong>' + file.name + '</strong>')
+  getClient(function (err, client) {
+    if (err) return onError(err)
+    client.add(file, onTorrent)
+  })
+}
+
+function seed (files) {
+  if (files.length === 0) return
+  console.log('Seeding ' + files.length + ' files')
+
+  // Seed from WebTorrent
+  getClient(function (err, client) {
+    if (err) return onError(err)
+    client.seed(files, onTorrent)
+  })
+}
+
+function onTorrent (torrent) {
+  console.log('done?', torrent.done)
+  var torrentFileName = path.basename(torrent.name, path.extname(torrent.name)) + '.torrent'
+
+  console.log('"' + torrentFileName + '" contains ' + torrent.files.length + ' files:')
+  torrent.files.forEach(function (file) {
+    console.log('&nbsp;&nbsp;- ' + file.name + ' (' + prettyBytes(file.length) + ')')
+  })
+
+  function updateSpeed () {
+    ipc.send('')
+    var progress = (100 * torrent.progress).toFixed(1)
+    util.updateSpeed(
+      '<b>Peers:</b> ' + torrent.swarm.wires.length + ' ' +
+      '<b>Progress:</b> ' + progress + '% ' +
+      '<b>Download speed:</b> ' + prettyBytes(window.client.downloadSpeed) + '/s ' +
+      '<b>Upload speed:</b> ' + prettyBytes(window.client.uploadSpeed) + '/s'
+    )
+  }
+
+  torrent.on('download', throttle(updateSpeed, 250))
+  torrent.on('upload', throttle(updateSpeed, 250))
+  setInterval(updateSpeed, 5000)
+  updateSpeed()
+
+  // torrentPoster(torrent, function (err, buf) {
+  //   if (err) return onError(err)
+  //   var img = document.createElement('img')
+  //   img.src = URL.createObjectURL(new Blob([ buf ], { type: 'image/png' }))
+  //   document.body.appendChild(img)
+  // })
+}
+
+function onError (err) {
+  console.error(err.stack)
+}
+
+function onWarning (err) {
+  console.log('warning: ' + err.message)
+}

background/torrent-poster.js

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+module.exports = torrentScreenshot
+
+var captureVideoFrame = require('./capture-video-frame')
+
+function torrentScreenshot (torrent, cb) {
+  if (torrent.ready) onReady()
+  else torrent.once('ready', onReady)
+
+  function onReady () {
+    // use largest file
+    var file = torrent.files.reduce(function (a, b) {
+      return a.length > b.length ? a : b
+    })
+    var video = document.createElement('video')
+    file.renderTo(video)
+
+    video.currentTime = 5
+    video.addEventListener('seeked', onSeeked)
+
+    function onSeeked (e) {
+      video.removeEventListener('seeked', onSeeked)
+      var buf = captureVideoFrame(video)
+      cb(null, buf)
+    }
+  }
+}