My internet radio station datafruits.fm needed metadata in its audio stream.
I wanted to make a cool hack to set metadata using liquidsoap. This would solve 2 problems:
dj’s are unable to set metadata with their clients, so I’ll do it for them when they authenticate.
the <audio> tag is unable to read the metadata from the stream. I’ll have to get it some other way.
I’ll have liquidsoap call a ruby script when the metadata in the stream changes, using on_meta. We’ll store
the metadata in redis, using pub-sub. Then I’ll set up a controller to relay this metadata.
As a bonus I now effectively have an api for getting the current song that I can
use in my mobile apps for this radio.
I wanted to use streaming in Sinatra to update the metadata quickly, instead of polling.
This was a little bit more difficult to manage than I expected. It was working
sporadically, and it turns out you need to manage all the connections by hand,
you can’t just code one connection and expect it to work.
So I decidedly to go with the certainly not as cool solution of using polling.
However I think its a perfectly fine solution for this situation. Polling is
simple, fairly cheap, and as far as this situation goes, truly ‘live’ updating
of the metadata is not really necessary.
So I ended up just using a regular redis key.
We can just set up a normal get route to get the key.
A simple set setInterval will work for polling and updating the html.
While not as cool, this is a lot easier to work with at the moment. Perhaps I
can think of other radio data I could store in redis and attach an API to from my app.
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