Re: Questions about using rygel with a DBus data source

[Mark <mark d ryan linux intel com>]

Hi Dominic,

I can answer some of your questions.

>
> - Rygel allows me to separate out the (difficult) boilerplate
> nitty-gritty of doing all the UPNP/DLNA/SSDP, etc, from the (easier)
> generation and transmission of media metadata;

Exactly

> - All I have to do is to write a separate out-of-process "metadata
> server" which registers itself using DBus and which serves up
> information about the available media;

This is one option.  However, there is another way you can achieve the 
same effect which may turn out to be more efficient and less work.  In 
short you can create a new Rygel DMS server plugin in C or Vala.  This 
plugin will implement a few classes that provide Rygel with a way to 
extract data from your media database, and optionally to update it. 
There are some examples of how to do this on the Rygel web site:

http://developer.gnome.org/librygel-server/unstable/implementing-server-plugins.html#implementing-server-plugins-overview

I believe these plugins can be compiled outside the Rygel source tree so 
you can keep your code completely separate from Rygel if you like.

BTW., Rygel ships with two DMS plugins, one which uses tracker to 
discover media and a second, mediaexport, which publishes media found in 
a number of standard folders, e.g/. ~/Pictures, ~/Music.  Internally, 
MediaExport uses an sqlite database to store the meta data it needs for 
the files it publishes.  You may find these plugins helpful if you chose 
to implement your own plugin.


> - This "metadata server" is language-independent, as long as it "talks" DBus;

Yes

> - The "heavy lifting" (e.g. streaming) of the media itself to the
> client is taken care of by Rygel;

Yes.

> - I can have several such "metadata servers" simultaneously connected
> over DBus (all of which presumably identify themselves uniquely), and
> only need a single Rygel server to make the media available;

Yes, but if I understand correctly, each meta server will appear as a 
separate DMS on the network.


I'm afraid I don't know enough about the d-bus interface to answer your 
remaining questions.

Best Regards,

Mark