f2e-spec Preserve web frontend playlist after Performous disconnects

What does this PR do?

This will attempt to restore the playlist on the web frontend after it disconnects with Performous (for example, when it crashes).

Motivation

When Performous crashes, the current playlist gets lost. This is an intended behavior, but can get cumbersome on the web frontend whenever Performous is used during events where the queue could get quite long. One solution is to make a screenshot before restarting Performous and manually re-add the songs, however, this isn't efficient, and can take up quite some time, even minutes before people can request songs again.

Additional Notes

Some modifications to the original code has been done. I've tried to keep the original code style as much as possible, including using double quotes instead of single quotes. An attempt has been made to keep it ES2015 compatible, however, there might be issues due to that. Eventually it does need to be rewritten to ESNext, but that will take some time.

May 08 '25 00:05 GaryCXJk

Download the artifacts for this pull request:

This service is provided by nightly.link. These artifacts will expire in 90 days and will not be available for download after that time.

May 09 '25 20:05 github-actions[bot]

Quality Gate passed

Issues
10 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.8% Duplication on New Code

See analysis details on SonarQube Cloud

Jun 28 '25 18:06 sonarqubecloud[bot]

Quality Gate passed

Issues
31 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.2% Duplication on New Code

See analysis details on SonarQube Cloud

Aug 24 '25 04:08 sonarqubecloud[bot]

I'll see if i can make some time later today to get this tested as i'd love to use it ~well hopefully i don't need to use it~ for the next event(s) :)

Aug 24 '25 11:08 Baklap4

Tonight i'll do a final test with the huge library. I suspect no further issues and that it can be merged as is :) Thanks for the updates!

Aug 25 '25 05:08 Baklap4

Testing:

Test 1

Start Performous
Add 3 tracks to playlist (but don't play any)
Exit & Restart Performous
Verified that playlist is found, and offered for re-loading. ✅
Clicking [Restore Playlist] re-creates tracks, in previous order ✅

Test2

Start Performous
Add 3 tracks to playlist (but don't play any)
kill -9 Performous & Restart Performous
Verified that playlist is found, and offered for re-loading. ✅
Clicking [Restore Playlist] re-creates tracks, in previous order ✅

Test3

... as per Test1
Observed that Playlist test matches previous selections ✅

Test4

... as per Test1
Download Playlist JSON ✅
Observed that Playlist JSON content matches previous selections ✅

Test5

... as per Test1
Clicked [Remove playlist]
Verified playlist cleared ✅

Test6

... After Test5 is run
Restart Performous
Verified playlist remains cleared ✅

Test7

... as per Test1
Play through first song in playlist
Refresh playlist during playback
Observe first playlist track is played ✅
Observe first playlist track is removed from playlist ✅
Observe the on-screen track during the switch to Playlist Menu is auto-added to playlist ❌
Observe the on-screen track during the switch to Playlist Menu is added twice to playlist ❌

Test8

As per Test7
Wait for playing song to finish, refreshing playlist occasionally
Observe playlist correctness is maintained after track finishes playing ✅

I'll leave it there for the moment.
Failures in Test7 could be operator error - what should happen here?

Sep 27 '25 00:09 kt--

Test7

... as per Test1

Play through first song in playlist

Refresh playlist during playback

Observe first playlist track is played ✅

Observe first playlist track is removed from playlist ✅

Observe the on-screen track during the switch to Playlist Menu is auto-added to playlist ❌

Observe the on-screen track during the switch to Playlist Menu is added twice to playlist ❌

This is the pre-existing behavior, currently playing songs are removed from the playlist. This is something I don't think should be changed, or even has to be. Most crashes happen near the end of the song or in-between songs, rarely in the middle of one, unless the song was corrupted or an unusual bug popped up, in the latter case you can manually queue the song again.

Sep 27 '25 18:09 GaryCXJk

Test 9.

Play playlist right through ✅
Observe Performous plays fine. ✅
Observe Web front-end pop-up a message "A previous playlist has been found", as if Performous has crashed ❌
Observed the playlist contains that last track ??

As an ignorant user I did not expect this behaviour. I expected to see an empty list, or maybe something like "playlist has completed" message.

Sep 27 '25 19:09 kt--

I'm wondering if we shouldn't push a JSON record like {"performous":"playlist-ended"} as a marker that the entire playlist has been consumed, rather than return an empty set from /api/getCurrentPlaylist.json.

Hmmm, now I've written that, it sounds dodgy.

The playlist reloader works well, but it cannot differentiate between a "used up" empty playlist, and "Performous crashed" empty playlist.

Oct 01 '25 05:10 kt--

No, it truly is an oversight. I always look at the http response code to see if the application crashed or not.

Oct 01 '25 12:10 GaryCXJk

Okay, I've been wracking my brains over this, but in search.js, there's a reference to the properties App and AppVersion, which causes the search not to work. It's easy for me to figure out what AppVersion is (it's most likely the version of the timing file, like, for USDX it would be 1.2.0 for the most recent, otherwise it's whatever was decided for the default version). But I'm not entirely sure about App. I want to fix it with this issue before I send it over for approval again, but I do need to be sure I'll fix it correctly. I assume App refers to the application the timing file was originally made for (StepMania, Frets On Fire, UltraStar Deluxe), but I'll have to be certain.

To be extra safe, I'll add the optional chaining operator to these variables, so that at the very least search will continue to work.

https://github.com/performous/performous/blob/d5278e3264e87b4a0d2815e1b67f0fd672e9305c/data/themes/default/www/js/search.js#L90

Nov 19 '25 21:11 GaryCXJk