Unify stun and turn server urls

[danxuliu]

Requires #5491 and #5503

This is a breaking change for Talk 12. The settings endpoint version was initially just bumped, but then the old API versions were dropped.

The format resembles the RTCIceServer format, so the returned values can be directly used by the WebUI like done until now. Mobile clients will need to be adjusted, though.

Important: The RTCIceServer MDN page states that Avoid specifying an unnecessarily large number of URLs in the urls property; the startup time for your connection will go up substantially. Every server in the list will be contacted and tried out before one is selected to be used for negotiation. It should be verified whether that applies too when using trickle ICE or not; if it does then it might be needed to rethink the format before merging this.

• Update: I have not been able to reproduce the described behaviour (although I have not done any fancy test like delaying packets for a specific server or something like that; I just used real servers, real servers unreachable by a specific protocol and wrong addresses). Even with several servers the connection could be established before the gathering of candidates finished.

  Internally both Firefox and Chromium just iterate through all the urls and add a separate server for each of them; in practice it seems that it does not make any difference to provide four server elements each with a single url or a single server element with four urls.

  So I guess that the statement above refers only to systems where trickle ICE is not being used 🤷

Before

stunservers: [
  [
    url: "stunServer1"
  ],
  [
    url: "stunServer2"
  ],
  [
    url: "stunServer3"
  ]
],
turnservers: [
  [
    url: [ "turnServer1-1" ],
    urls: [ "turnServer1-1" ],
    username: "user1"
    credentials: "credentials1"
  ],
  [
    url: [ "turnServer1-2" ],
    urls: [ "turnServer1-2" ],
    username: "user1"
    credentials: "credentials1"
  ],
  [
    url: [ "turnServer2" ],
    urls: [ "turnServer2" ],
    username: "user2"
    credentials: "credentials2"
  ],
]

After

stunservers: [
  [
    urls: [ "stunServer1", "stunServer2", "stunServer3" ]
  ],
],
turnservers: [
  [
    urls: [ "turnServer1-1", "turnServer1-2" ],
    username: "user1"
    credentials: "credentials1"
  ],
  [
    urls: [ "turnServer2" ],
    username: "user2"
    credentials: "credentials2"
  ],
]

[danxuliu]

Rebased on master and bumped API version instead of modifying the previous one.

Tested with Firefox and Chromium; it should work with Safari too... but tests are welcome ;-)

[Ivansss]

Could we add the capability "signaling-v3" here? :)

[nickvergessen]

Yes we should add that capability and at the same time (as said in the other PR) we can drop v1+v2 at the same time as all clients for nextcloud22 need to be updated for conversation-v4 already and there is no fallback possible.

[danxuliu]

But if v1+v2 are dropped (I guess by replacing v(1|2|3) with v3 in routes.php) then there is no need to have different arrays, or there is? 🤔

[nickvergessen]

Exactly that was the plan? Make everything simple as you don't need to support the other things.

[danxuliu]

But then what did you mean by create different arrays based on the already available $apiVersion??

[nickvergessen]

Hmm maybe too many context switches 🤔

[danxuliu]

Hmm maybe too many context switches 🤔

Try setting event loops :-P

Capability added and previous endpoint versions dropped.

[nickvergessen]

please update all signaling urls to v3

[nickvergessen]

Fixed with a fixup commit

[nickvergessen]

Rebased after #5465 and did the fixups

[danxuliu]

Fixed a bug with the stunservers array (it was an object rather than an array, I had fixed it already but it seems that I failed to push 🤦), moved dropping all the endpoints to the third commit rather than the second one, and removed some unneeded code now that the previous versions are not supported.

Edit: oh, and tested and works 👍