Audio caching (ServiceWorker)

[markspolakovs]

WebStudio is currently hosted at /webstudio//webstudio-dev. This poses an issue when we want to intercept NIPSWeb requests, which are to /myradio/NIPSWeb/{secure,managed}_play. To get this to work we have to scope the service worker to / (done in 47b3c7e), which works, but has two problems:

1. we need to send a Service-Worker-Allow: / header, to even let this work
2. The service worker controls all requests on ury.org.uk, which means that if we screw up the config we can break the entire site (I did do this once, by accidentally turning all of ury.org.uk into /webstudio dev - fixed in b11de69 but the point remains)

Consider possible solutions:

• Move all of WebStudio to a subdomain - no
• Make a copy of the MyRadio API on a subdomain - no, because NIPSWeb isn't actually the API (hrrng)
• Proxy something like /webstudio/secure_play -> /myradio/NIPSWeb/secure_play - could work

[mstratford]

This is still borked, it currently overrides the webstudio stateserver API urls, and often with an older cached version too. Given the RAM issues we were having, I don't think doing this is suitable anywho.

[markspolakovs]

urg - I suspect some tweaking to the regex in b11de69 may be needed