Issues with MPD protocol

[saintger]

I just made a fresh checkout of libgroove and Groove Basin in order to test compatiblity with MPD clients.

With MPDroid on an Android, everything works except listing Albums, which always return an empty list (listing Artists or Playlist work fine).

With Cantata 1.4.2 on Debian Testing, everything works except the performance at startup. It takes close to 60 seconds before displaying the information (current queue, artists, albums, etc).

Hope that helps,

[mxjeff]

There is also an issue with client to client protocol as used in MPD_sima (auto-queuing MPD client).
I did a quick test on demo.groovebasin.com, the server should list "readmessages", "sendmessage", "subscribe", "unsubscribe" in commands (or notcommands).

http://www.musicpd.org/doc/protocol/client_to_client.html

[andrewrk]

@mxjeff #148
I'll bump the priority on this issue.

[saintger]

I found another significant bug: with MPDroid on Android or MPoD on iOS, the playlist is not correctly refreshed after doing some changes.
For example, if I remove a song from the playlist (directly through the web interface or through the MPD clients), the MPD clients are not correctly updated and there is a mismatch between the real playlist and the one displayed on the MPD clients.

I have no such problems with:

• Groove Basin server with Cantata client
• MPD server with MPDroid or MPoD

I am not sure if this is a problem with Groove Basin or the MPD clients.
Let me know if I can help to debug this further.

Thanks

[saintger]

Hello,

I have just tested again with the following versions:

• groovebasin git master checkout 12/06/2016
• libgroove 4.3.0
• Cantata 1.4.2 on Debian Jessie
• MPoD version 2.1 on iOS.
• MPDroid 1.07.2 on Android.

In parallel I tested with mpd version 0.19.1 instead of groovebasin.

With groovebasin or mpd, Cantata works perfectly.
With mpd, MPDroid and MPoD works perfectly.

With groovebasin and MPDroid:

• cannot see albums list
• queued song from another client or directly from MPDroid don't update the queue list.
• remove song from another client or directly from MPDroid don't update the queue list.

With groovebasin and MPoD:

• queued song from another client or directly from MPoD don't update the queue list.
• remove song from another client or directly from MPoD don't update the queue list.
• display of the song currently playing can be messed up (for instance removing the next track, and before jumping to the next track)

I don't really know how to debug this (I haven't seen anything particular in the log). Could you perhaps tell me how to debug this further ?
Perhaps by using a verbose mode ?

Thanks

[andrewrk]

One way to debug this would be to set up a proxy between the mpd client and the mpd server. The proxy would simply print to stdout commands and responses of the protocol. We could then look at a diff between what groove basin sent and what mpd sent, and hopefully spot the problem.

[saintger]

Could that be of any help:
https://github.com/floriandejonckheere/mpdproxy

[diogocp]

With groovebasin and MPDroid:

• cannot see albums list

Groovebasin debug messages when trying to list albums:

ok mpd command list ["album","group","artist"]
cmd err: list ["album","group","artist"] "group" is not known