WIP: Stop sniffing mimetype on playlists and don't use playlist.once anymore

[hairmare]

This replaces the mime type sniffing that we are doing when loading a playlist with a hardcoded mime type. We can always assume that the generated m3u files have a text/plain mime type. With this assumption liquidsoap won't log Wrong mime type application/octet-stream for playlist! if the file is empty.

We need to switch to not using playlist.once anymore since it is deprecated nowadays: savonet/liquidsoap#1015. I think we don't need to use reload_mode="once" but can stick to reload_mode=watch since the prio file is handled in a way that watching it leads to the behaviour we want.

• deactivate mime type sniffing
• refactor so we don't use playlist.once anymore
• test if this works with all the liquidsoap versions we are supporting (currently 1.3.2 with the possibilty to upgrade to 1.3.7 which has already been built, 1.4 support depends on us rolling out CentOS 8)

[spameier]

Maybe we should use application/x-mpegURL.
I just noticed the following lines in the logs:

2020/05/01 17:05:43 [classics:3] Playlist treated as format application/x-mpegURL

Not entirely sure though. 😕

[hairmare]

Maybe we should use application/x-mpegURL.

I changed it to audio/x-mpegurl after referencing the docs.

[codecov-commenter]

Codecov Report

Merging #48 into master will decrease coverage by 0.88%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #48      +/-   ##
==========================================
- Coverage   78.90%   78.01%   -0.89%     
==========================================
  Files           1        1              
  Lines         602      605       +3     
  Branches      141      141              
==========================================
- Hits          475      472       -3     
- Misses        110      114       +4     
- Partials       17       19       +2     

Impacted Files	Coverage Δ
klangbecken.py	78.01% <0.00%> (-0.89%)	⬇️

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[smlz]

What is the reason for removing .once for the prio playlist?

The rest looks good.

[smlz]

You should leave the .once, to double ensure that the prio playlist never loops.

[hairmare]

playlist.once is deprecated in new versions of liquidsoap and it is recommended to replace it with reload_mode=once. Since we are already using reload_mode=watch and the prio.m3u file gets changed when it is used anyway I think that keeping the reload_mode as is makes sense. See my initial comment for a link to the liquidsoap PR that deprecates playlist.once.

[smlz]

My bad. Thanks for the hint.

I think making sure that we never ever end up in a endless loop would be wise, especially when I'm looking at my hacky prio playlist code. I would suggest, that we add two more options to the playlist call: mode="normal" and loop=false. Better be safe than sorry.

This might also allow us to implement a priority queue with more than one entry in the future.

[hairmare]

I added mode=normal but didn't add loop=false since loop only seems to be implemented in dev according to the docs.

[smlz]

I think we can close this one. Right?

[hairmare]

I think we can close this one. Right?

At a glance, I don't think so... IMO we should still circumvent mimetype sniffing and get rid of playlist.once.

[smlz]

playlist.once is gone in the new code.

As far as mime type sniffing goes, I tried this out some time ago with strange results. Manually setting the mime type makes check_next always fail, and thus sends the player into an endless loop. 😰