Password problem when reusing MPD protocol module

[nathanharper]

I've been working on an extension that was basically meant to override and "enhance" the basic MPD frontend, giving the ability to configure what actions users can perform on a playlist, how many requests can be sent from a particular IP, etc. As a proof of concept I made an extension that just overrides the base mpd module, and it worked perfectly except for a problem I ran into with this line:

https://github.com/mopidy/mopidy/blob/develop/mopidy/mpd/protocol/connection.py#L42

I had disabled the mpd module, but wanted to reuse the protocol, and mopidy.mpd.protocol was still referencing the mpd configuration in just that one instance. I was able to get around this by writing a special case to override that particular handler method, but it felt a bit dirty.

My question is: would it make sense to abstract the protocol module a bit more to make it more reusable? Or am I approaching this whole thing the wrong way?

[adamcik]

Hmm, as I'm sure you've noticed this code was never written with this type of use in mind :-)

Immediate ideas that come to mind is:

• the option to unregister handlers, or at least register a new one over an existing one. That way you could replace the one in question.
• if this is the only place we use the config in the protocol module via context we could move the password to Context(config['mpd']['password']) which would allow you to break that dependence I believe.
• Our dispatcher code currently has a chain of things to do. Which combined with our recent registry work could mean that we could add hooks to install something in that chain. Essentially equivalent to a WSGI middleware just for our MPD request handling.

#591 might also play in to this as we would likely end up with tokenizing the requests instead of regexp mathcing them, making some of these ideas easier to achieve.

[adamcik]

Not sure which one I prefer yet, so last comment is really just thinking aloud to see what might work :-)

[nathanharper]

Cool, thanks for the response! For what it's worth, I poked around the module and I think that was the only usage of config, so option 2 might be pretty easy.

[txomon]

@nathanharper I have done so by using stickers in the mpd frontend, and creating Metadata Provider feature in the core.

The usage would be to use sticker set song service:user:txomon and so. Maybe you are interested on that branch https://github.com/txomon/mopidy/tree/feature/metadata-provider

[nathanharper]

Thanks, @txomon . I'm not even familiar with stickers really, but I'll check it out!

[adamcik]

Is this solved give the merging of #659?

[nathanharper]

Yep! Thanks. I'm closing it.