Server Sent Events - how to handle asking for an event that doesn't exist

[danjenkins]

How do you know what events a WHEP server supports? Is there a discovery path that will list whats supported by the server somewhere?

I don't see anything in the current draft version that says "you asked for layers events but we don't support it... so return a 4xx to the POST request"

WHEP is meant to be generic, so being able to know what events a server may accept programatically is important

[murillo128]

it is in the Link header with the sse url

Link: <https://whep.ietf.org/resource/213786HF/sse>;
      rel="urn:ietf:params:whep:ext:core:server-sent-events"
      events="active,inactive,layers,reconnect,viewercount,scte35"

[danjenkins]

Ah! I'd completely missed that, thanks!

What about what happens when you ask for something sse/events endpoint doesnt support?

[murillo128]

It is up to the server to decide if it rejects the request or ignore the event. Not sure if we need to explicity specify what to do with misbehaving clients

[danjenkins]

@murillo128 I don't understand that, isn't the point of a spec to say "this is how the server should behave" ? If I request something that isn't supported surely it should fail and tell me "you're not going to get that event because we don't support it" ?

[murillo128]

My point of view is, if the client MUST send a subset of the events provided by the server, then this case is outside of the spec, and HTTP directorate has prevented us for redefining http behaviour. That's why I am not sure if we should cover how to handle non-compliant clients or not.

[danjenkins]

So just following on after watching the session online, this needs a PR to add detail on that failure scenario. Is this something you want to add @murillo128 ? Or do you want someone else to do that?