Correctly fix the webtorrent redundancy bug

server/helpers/webtorrent.ts

@@ -1,41 +1,54 @@
 import { logger } from './logger'
+import { generateVideoTmpPath } from './utils'
 import * as WebTorrent from 'webtorrent'
-import { remove } from 'fs-extra'
+import { createWriteStream, ensureDir, remove } from 'fs-extra'
 import { CONFIG } from '../initializers'
 import { join } from 'path'
 
-function downloadWebTorrentVideo (target: { magnetUri: string, torrentName?: string }, timeout?: number) {
+async function downloadWebTorrentVideo (target: { magnetUri: string, torrentName?: string }, timeout?: number) {
   const id = target.magnetUri || target.torrentName
   let timer
 
+  const path = generateVideoTmpPath(id)
   logger.info('Importing torrent video %s', id)
 
+  const directoryPath = join(CONFIG.STORAGE.VIDEOS_DIR, 'import')
+  await ensureDir(directoryPath)
+
   return new Promise<string>((res, rej) => {
     const webtorrent = new WebTorrent()
     let file: WebTorrent.TorrentFile
 
     const torrentId = target.magnetUri || join(CONFIG.STORAGE.TORRENTS_DIR, target.torrentName)
 
-    const options = { path: CONFIG.STORAGE.VIDEOS_DIR }
+    const options = { path: directoryPath }
     const torrent = webtorrent.add(torrentId, options, torrent => {
       if (torrent.files.length !== 1) {
         if (timer) clearTimeout(timer)
 
-        return safeWebtorrentDestroy(webtorrent, torrentId, file.name, target.torrentName)
+        return safeWebtorrentDestroy(webtorrent, torrentId, join(directoryPath, file.name), target.torrentName)
           .then(() => rej(new Error('Cannot import torrent ' + torrentId + ': there are multiple files in it')))
       }
 
-      torrent.on('done', () => {
+      file = torrent.files[ 0 ]
-        // FIXME: Dirty fix, we need to wait the FS sync but webtorrent does not provide such method
+
-        setTimeout(() => res(join(CONFIG.STORAGE.VIDEOS_DIR, torrent.files[ 0 ].name)), 1000)
+      // FIXME: avoid creating another stream when https://github.com/webtorrent/webtorrent/issues/1517 is fixed
+      const writeStream = createWriteStream(path)
+      writeStream.on('finish', () => {
+        if (timer) clearTimeout(timer)
+
+        return safeWebtorrentDestroy(webtorrent, torrentId, join(directoryPath, file.name), target.torrentName)
+          .then(() => res(path))
       })
+
+      file.createReadStream().pipe(writeStream)
     })
 
     torrent.on('error', err => rej(err))
 
     if (timeout) {
       timer = setTimeout(async () => {
-        return safeWebtorrentDestroy(webtorrent, torrentId, file ? file.name : undefined, target.torrentName)
+        return safeWebtorrentDestroy(webtorrent, torrentId, file ? join(directoryPath, file.name) : undefined, target.torrentName)
           .then(() => rej(new Error('Webtorrent download timeout.')))
       }, timeout)
     }
@@ -50,7 +63,7 @@ export {
 
 // ---------------------------------------------------------------------------
 
-function safeWebtorrentDestroy (webtorrent: WebTorrent.Instance, torrentId: string, filename?: string, torrentName?: string) {
+function safeWebtorrentDestroy (webtorrent: WebTorrent.Instance, torrentId: string, filepath?: string, torrentName?: string) {
   return new Promise(res => {
     webtorrent.destroy(err => {
       // Delete torrent file
@@ -60,9 +73,9 @@ function safeWebtorrentDestroy (webtorrent: WebTorrent.Instance, torrentId: stri
       }
 
       // Delete downloaded file
-      if (filename) {
+      if (filepath) {
-        remove(join(CONFIG.STORAGE.VIDEOS_DIR, filename))
+        remove(filepath)
-          .catch(err => logger.error('Cannot remove torrent file %s in webtorrent download.', filename, { err }))
+          .catch(err => logger.error('Cannot remove torrent file %s in webtorrent download.', filepath, { err }))
       }
 
       if (err) {