Asynchronous music-metadata updates while streaming (#1449)

* Ensure that default file/protocol handlers are re-installed after updating.

Previously, they were only installed when the preference was changed.
This caused the handlers to point to non-existing files after updates
occurred and older versions were removed by Squirrel.

Closes #791, #911.

* webtorrent/webtorrent-desktop#1340: Switch to async metadata updates.

* Use fat arrow

* Fix issue track number not displayed if total number of tracks is not defined (common.track.of === null).

* Add disk number in addition to track number.

* Update order of audio properties from: album, track, disk, format to track, disk, album, format

* #1340 Update music-metadata to 2.5.0, enabling async 'per' tag updates
#1452 Fix for playing some '.m4b' files

* #1340 Commented out the metadata event debug output.

* #1340 Remove line comment to get rid of max line length lint error

* Update music-metadata 2.6.0 to fix some async events are getting triggered.

* Return JSX block.

* Get rid of third parameter which is replaced by CSS capitalize

* Fixed error when value is undefined.

* Update music-metadata dependency to 2.6.1.

* fix(package): update music-metadata to version 3.1.0

Closes #1478

* Revert "Ensure that default file/protocol handlers are re-installed after updating."

This reverts commit 39145b2366.

package.json

@@ -32,7 +32,7 @@
     "location-history": "^1.0.0",
     "material-ui": "^0.17.0",
     "mkdirp": "^0.5.1",
-    "music-metadata": "^2.4.2",
+    "music-metadata": "^3.1.0",
     "network-address": "^1.1.0",
     "parse-torrent": "^6.0.1",
     "prettier-bytes": "^1.0.1",

src/renderer/pages/player-page.js

@@ -238,9 +238,7 @@ function renderAudioMetadata (state) {
   const elems = []
 
   // Audio metadata: artist(s)
-  const artist = common.albumartist || common.artist ||
+  const artist = common.artist || common.albumartist
-    (common.artists && common.artists.filter(function (a) { return a }).join(', ')) ||
-    '(Unknown Artist)'
   if (artist) {
     elems.push((
       <div key='artist' className='audio-artist'>

src/renderer/webtorrent.js

@@ -345,7 +345,12 @@ function getAudioMetadata (infoHash, index) {
   const metadata = { title: file.name }
   ipc.send('wt-audio-metadata', infoHash, index, metadata)
 
-  const options = { native: false, skipCovers: true, fileSize: file.length }
+  const options = { native: false,
+    skipCovers: true,
+    fileSize: file.length,
+    observer: event => {
+      ipc.send('wt-audio-metadata', infoHash, index, event.metadata)
+    } }
   const onMetaData = file.done
     // If completed; use direct file access
     ? mm.parseFile(path.join(torrent.path, file.path), options)
@@ -353,9 +358,8 @@ function getAudioMetadata (infoHash, index) {
     : mm.parseStream(file.createReadStream(), file.name, options)
 
   onMetaData
-    .then(function (metadata) {
+    .then(() => {
-      console.log('got audio metadata for %s (length=%s): %o', file.name, file.length, metadata)
+      console.log(`metadata for file='${file.name}' completed.`)
-      ipc.send('wt-audio-metadata', infoHash, index, metadata)
     }).catch(function (err) {
       return console.log('error getting audio metadata for ' + infoHash + ':' + index, err)
     })