Re: Twitch.tv plugin (some help needed)

[Mattias Bengtsson <mattias jc bengtsson gmail com>]

On mån, 2015-01-05 at 10:42 +0100, Bastien Nocera wrote:
> Hey Mattias!
>
> On Mon, 2015-01-05 at 06:25 +0100, Mattias Bengtsson wrote:
> [...]
> >  – The twitch API uses the following flow to get the video stream URI's:
> >    1) GET https://api.twitch.tv/api/channels/:channel/access_token
> >    2) Unpack the JSON payload and extract the sig and token fields
> >    3) The stream is now:
> > http://199.9.251.155/api/channel/hls/:channel.m3u8?token=:token&sig=:sig
> >
> >    Is it possible to let my lua-script return a function for 
> >    retrieving the sig and token values?
>
> Did you mean to ask how you could cache them, so you only need to query
> it once? FWIW, all the HTTP fetches in the Lua sources are async, so
> you'd need to queue the "actual" call.
>
> You'd use global variables for that. grl-pluzz.lua in the
> grilo-lua-sources repo on github has an example of a cache.

Nah, I basically had no idea at all how grilo works, I think I do might
now though. 

> >  I'm fairly sure I'm not supposed
> >    to find these values before I request the stream (running n HTTP-
> >    requests whenever I load a list of streams seems bad, plus I know
> >    from experience that the token can get outdated).
> >
> >  – I would like to be able to browse Twitch like this:
> >    /Top Channels/{stream}
> >    /Games/{game}/{stream}
> >
> >    That is with "sub-folders" at least three deep.
> >    Is this possible in a Lua-plugin? I see that the Rai.tv does it, but
> >    that's also implemented in C.
>
> There's nothing in grilo that cares about depth levels in folders. The
> plugin is the one constructing the "ID" for a folder (a box in grilo
> parlance). When browsing inside that box, you're given the media ID.
> Just make sure you know how to deconstruct the unique ID you've given
> for that box item.
>
> Is that clear?

Maybe. Let's see if I understand.

So for the "top-level" box of my plugin I'd get some media_id sent to
grl_source_browse that I'd match on and I'd return two media-objects: 
- id="top_channels" 
- id="games".

Then when I click on top_channels I'd get a call to grl_source_browse()
with media_id set to "top_channels", I'd pattern match on that and then
return a list of media-objects with id="game/{name_of_game}". 

Rinse and repeat 'til I have covered all of twitch.

This is basically me guessing wildy instead of reading code. :) 
So have I understood it correctly?

If so then the first question above would be solved by returning a media
object with id="stream/{twitch_user}" and when that one is passed to
grl_source_browse() I'd do the lookup of the sig and token then.

I'm quite sure that the reason Twitch does this is to prevent people
from hot-linking and I believe it is frowned upon and also not really
possible to cache these tokens, they need to be retrieved pretty much
immediately before accessing the stream.

> >  – How do I ship an icon with my plugin?
>
> Putting a .gresource file of the same name as the script in the same
> directory.
>
> And then: "source-icon" = "resource:///org/gnome/grilo/twitch.svg"
> in the source itself.

Ah thx!

Regards,
Mattias