Fall back to using track Ref if playlist lookup fails.

Fixes #226.

README.rst

@@ -123,6 +123,7 @@ v2.4.0 (UNRELEASED)
 - Now initializes the GUI properly, even if the user is offline or the Mopidy server cannot be reached.
 - Fixed `Alarm Clock <https://pypi.python.org/pypi/Mopidy-AlarmClock/>`_ detection.
 - When browsing the library using the local 'File' extension, only playable audio files will have context menu icons.
+- Playlists will now list tracks even if they are no longer available in the library. (Fixes: `#226 <https://github.com/pimusicbox/mopidy-musicbox-webclient/issues/226>`_).
 
 v2.3.0 (2016-05-15)
 -------------------

mopidy_musicbox_webclient/static/js/functionsvars.js

@@ -479,9 +479,9 @@ function showOffline (on) {
 }
 
 // from http://dzone.com/snippets/validate-url-regexp
-function validUri (str) {
+function validUri (uri) {
     var regexp = /^(mms|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?/
-    return regexp.test(str)
+    return regexp.test(uri)
 }
 
 function validServiceUri (str) {
@@ -494,7 +494,7 @@ function getScheme (uri) {
 
 function isPlayable (track) {
     if (typeof track.type === 'undefined' || track.type === 'track') {
-        if (getScheme(track.uri) === 'file') {
+        if (track.uri && getScheme(track.uri) === 'file') {
             var ext = track.uri.split('.').pop().toLowerCase()
             if ($.inArray(ext, audioExt) === -1) {
                 // Files must have the correct extension

mopidy_musicbox_webclient/static/js/process_ws.js

@@ -187,9 +187,11 @@ function processPlaylistItems (resultDict) {
     return mopidy.library.lookup({'uris': trackUris}).then(function (tracks) {
         // Transform from dict to list and cache result
         var newplaylisturi = resultDict.uri
+        var track
         playlists[newplaylisturi] = {'uri': newplaylisturi, 'tracks': []}
         for (i = 0; i < trackUris.length; i++) {
-            playlists[newplaylisturi].tracks.push(tracks[trackUris[i]][0])
+            track = tracks[trackUris[i]][0] || resultDict.items[i]  // Fall back to using track Ref if lookup failed.
+            playlists[newplaylisturi].tracks.push(track)
         }
         showLoading(false)
         return playlists[newplaylisturi].tracks

mopidy_musicbox_webclient/static/mb.appcache

@@ -1,6 +1,6 @@
 CACHE MANIFEST
 
-# 2017-01-18:v2
+# 2017-02-04:v1
 
 NETWORK:
 *