Add support for native to web cross-play

[johanhelsing]

There are some small incompatibilities between the native and wasm implementation that makes connections fail.

The native version implements ICE candidate trickling, while the wasm version does not. (#16)

[rozgo]

One of our projects needs this to work. I'll look into this and report back.

[johanhelsing]

@rozgo How did it go?

[rozgo]

I've got it in a state where it should be working, but its not. So far, I'm getting ICE candidates, sending them to connected peers, with ICE trickling enabled. But still works among native or WASM, but not both. I had to pause this last week, but will look into it again on Monday.

Minor changes:

    let ice_server_config_list = [ice_server_config];
    peer_config.ice_servers(&serde_wasm_bindgen::to_value(&ice_server_config_list).unwrap());
    peer_config.ice_transport_policy(RtcIceTransportPolicy::Relay);
    RtcPeerConnection::new_with_configuration(&peer_config).unwrap();

Listening for OnIceCandidates:

    let signal_peer_ice = signal_peer.clone();
    let onicecandidate: Box<dyn FnMut(JsValue)> = Box::new(move |event| {
        let event = Reflect::get(&event, &JsValue::from_str("candidate")).efix();
        if let Ok(event) = event {
            if let Ok(candidate) = event.dyn_into::<RtcIceCandidate>() {
                info!("ICE candidate: {:?}", candidate);
                signal_peer_ice.send(PeerSignal::IceCandidate(candidate.candidate()));
            }
        }
    });
    let onicecandidate = Closure::wrap(onicecandidate);
    conn.set_onicecandidate(Some(onicecandidate.as_ref().unchecked_ref()));

Handling the new candidate with existing message:

            PeerSignal::IceCandidate(candidate) => {
                // Add ice candidate
                info!("ICE CANDIDATE ADDING: {:?}", candidate);
                candidates.push(candidate);
            }

NOTE: I noticed right before I had to move on, that the signaling server was not properly handling Native and WASM, at least it the minimal demo Im using. So it might be something simple, and things might work after that.

[rozgo]

Ok, I got back into this. Made some progress and got WASM communicating to Native but breaks in the other direction. I think I understand the ICE back and forth chatter requirements for trickling now. Should have more info by EOD.

Basically, I'm selecting for receiving ICE candidates and checking if data channel is ready, all while sending ICE candidates to remote peers.

    loop {
        select! {
            _ = channel_ready_rx.next() => {
                debug!("channel ready");
                break;
            }
            msg = signal_receiver.next() => {
                if let Some(PeerSignal::IceCandidate(candidate)) = msg {
                    debug!("got an IceCandidate signal! {}", candidate);
                    let mut ice_candidate: RtcIceCandidateInit = RtcIceCandidateInit::new(&candidate);
                    ice_candidate.sdp_m_line_index(Some(0));
                    JsFuture::from(
                        conn.add_ice_candidate_with_opt_rtc_ice_candidate_init(Some(&ice_candidate)),
                    )
                    .await
                    .efix()?;
                }
            }
        };
    }

    let signal_peer_ice = signal_peer.clone();
    let onicecandidate: Box<dyn FnMut(JsValue)> = Box::new(move |event| {
        let event = Reflect::get(&event, &JsValue::from_str("candidate")).efix();
        if let Ok(event) = event {
            if let Ok(candidate) = event.dyn_into::<RtcIceCandidate>() {
                debug!("sending IceCandidate signal {}", candidate.candidate());
                signal_peer_ice.send(PeerSignal::IceCandidate(candidate.candidate()));
            }
        }
    });
    let onicecandidate = Closure::wrap(onicecandidate);
    conn.set_onicecandidate(Some(onicecandidate.as_ref().unchecked_ref()));

[rozgo]

Ok, it works. will clean up the code and submit a PR tonight.

[johanhelsing]

Awesome! I'll have some time today and tomorrow to review it

[johanhelsing]

Done in #54 🎉