Connect to a Janus server

[Charles92011]

Starting with the assumption that the JavaRTC server is going to connect to the Janus server and maintain a client connection to that server:

1. First of all, the Client object is designed to be constructed on an incoming websocket connection. it then: sends the greeting message back to the client software, with the session id.
2. When the client software receives the greeting message it creates a peer connection and sends the offer SDP to the Client object. The Client object sends the answer SDP
3. The client software and the Client object send ICE candidates back and forth until negotiation is complete and the connection is made.

Once connections are made each end responds to receiving tracks.

In order to initiate a connection to a Janus server:

1. a Connection object must be instantiated by some method other than a websocket connection.
2. The Connection object must then connect to the Janus server, and send the "create" request to the Janus server.
3. When Janus responds with success, store the Janus session ID
4. Create an offer using the Peerconnection object member of the Connection object
5. Send that offer to Janus using the "message" message
6. Respond to ICE Candidate messages by sending those candidates to Janus using the "trickle" message.
7. Respond to Janus's "answer" SDP by setting the remote connection on the Peerconnection object
8. Send the "attach" message to Janus, to attach to a Janus plugin, e.g. echotest

[kinsleykajiva]

yes, the order seems to be intact, in the above mention, so for with the library https://github.com/devopvoid/webrtc-java I have faced a problem with steps 4-5 , I seem not to get the ice candidates. hence no media gets sent at all, which I have investigated.

As a side note, I have downloaded the https://github.com/devopvoid/webrtc-java repo to run on my machine,I haven't managed to get the sample or demo to work at , because I cant build the project on my PC, so it has been hard to pinpoint if the library https://github.com/devopvoid/webrtc-java has problems or what?

[Charles92011]

I was never able to get the library to compile either. I don't think it's a problem with the library, it's definitely some holes in my own personal knowledge. But the Maven repo is available, so my project makes use of that. Basically, I'm not as interested in building the library as I am in using it, so using the maven repo work just fine for me.

I haven't yet tried to use the library to establish a connection (e.g. make an offer), so I can't yet say if the onIceCandidate method doesn't fire in that case. I am using it as a server, accepting a an offer and sending an answer, and the onIceCandidate does fire.

Do you have an example application that I can take a look at?

[kinsleykajiva]

here is a sample code of the application that I am testing setting up :

[kinsleykajiva]

ActivtyApp.java is the driver class

[kinsleykajiva]

find code below
SDK/JDK: 17

[kinsleykajiva]

@Charles92011 anything yet your end or update there ?

[Charles92011]

I'm building a test project, I should have some insight later today.

[Charles92011]

@kinsleykajiva I'm not as much interested in connecting with Janus as I am in replacing Janus. So I only took this as far as sending the ICE Candidates. To simplify the code I used the Janus REST API instead of websockets, but I did get it to working just fine.

package main;

import java.util.List;

import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;

import dev.onvoid.webrtc.CreateSessionDescriptionObserver;
import dev.onvoid.webrtc.PeerConnectionFactory;
import dev.onvoid.webrtc.PeerConnectionObserver;
import dev.onvoid.webrtc.RTCConfiguration;
import dev.onvoid.webrtc.RTCIceCandidate;
import dev.onvoid.webrtc.RTCIceServer;
import dev.onvoid.webrtc.RTCOfferOptions;
import dev.onvoid.webrtc.RTCPeerConnection;
import dev.onvoid.webrtc.RTCSessionDescription;
import dev.onvoid.webrtc.SetSessionDescriptionObserver;
import dev.onvoid.webrtc.media.audio.AudioOptions;
import dev.onvoid.webrtc.media.audio.AudioSource;
import dev.onvoid.webrtc.media.audio.AudioTrack;
import utility.HttpExchange;
import utility.Log;
import utility.Properties;

public class Connection implements 
	PeerConnectionObserver, 
	CreateSessionDescriptionObserver, 
	SetSessionDescriptionObserver {

	private final RTCPeerConnection peerConnection;
	private final String janusServer = Properties.getPropertyS("janus");
	private final String apiSecret = Properties.getPropertyS("apiSecret");
	
	private String sessionId;
	private String pluginHandle;
	
	
	public Connection() throws InterruptedException {
		
		Log.log(apiSecret);
		
		RTCConfiguration rtcConfiguration = new RTCConfiguration();

		RTCIceServer stunServer = new RTCIceServer();
		stunServer.urls.add("stun:stun.l.google.com:19302");
		rtcConfiguration.iceServers.add(stunServer);

		PeerConnectionFactory peerConnectionFactory = new PeerConnectionFactory();
		
		Log.log("creating peer connection");
		
		peerConnection = peerConnectionFactory.createPeerConnection(rtcConfiguration, this);
		
		// need to give it some media or Janus complains
		AudioOptions audioOptions = new AudioOptions();
        AudioSource audioSource = peerConnectionFactory.createAudioSource(audioOptions);
        AudioTrack audioTrack = peerConnectionFactory.createAudioTrack("audioTrack", audioSource);
		
        peerConnection.addTrack(audioTrack, List.of("stream"));

	}
	
	public void go() {

		final String payload = String.format("{\"janus\":\"create\",\"transaction\":\"1234\",\"apisecret\":\"%s\"}", apiSecret);

		try (HttpExchange httpExchange = new HttpExchange(janusServer)) {

			Log.log("sending: %s", payload);
			
			String response = httpExchange
				.setRequestBody(payload)
				.post()
				.getResponse();
			
			Log.log(response);
			

			final JSONParser jsonParser = new JSONParser();
			JSONObject jResponse = (JSONObject)jsonParser.parse(response);
			JSONObject jData = (JSONObject)jResponse.get("data");
			sessionId = jData.get("id").toString();
			
			Log.log("janus session = %s", sessionId);
			
			attachPlugin();
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	
	private void attachPlugin() {
		
		final String payload = String.format("{\"janus\":\"attach\",\"transaction\":\"1234\",\"apisecret\":\"%s\",\"plugin\":\"janus.plugin.echotest\"}", apiSecret);
		String url = String.format("%s%s/", janusServer, sessionId);
		
		try (HttpExchange httpExchange = new HttpExchange(url)) {

			Log.log("sending: %s", payload);
			
			String response = httpExchange
				.setRequestBody(payload)
				.post()
				.getResponse();
			
			Log.log(response);
			
			final JSONParser jsonParser = new JSONParser();
			JSONObject jResponse = (JSONObject)jsonParser.parse(response);
			JSONObject jData = (JSONObject)jResponse.get("data");
			pluginHandle = jData.get("id").toString();
			
			Log.log("janus plugin handle = %s", pluginHandle);

			RTCOfferOptions options = new RTCOfferOptions();
			peerConnection.createOffer(options, this);
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	
	@Override
	public void onSuccess(RTCSessionDescription description) {
		
		peerConnection.setLocalDescription(description, this);
		
		String payload = String.format("{\"janus\" : \"message\", \"transaction\" : \"1234\", \"apisecret\":\"%s\", \"body\" : {\"audio\" : false, \"video\" : false}, \"jsep\" : {\"type\" : \"%s\", \"sdp\" : \"%s\"}}", 
				apiSecret,
				description.sdpType.toString(),
				description.sdp.toString().trim().replace("\r\n", "\\n"));

		String url = String.format("%s%s/%s/", janusServer, sessionId, pluginHandle);
		
		try (HttpExchange httpExchange = new HttpExchange(url)) {

			Log.log("sending: %s", payload);
			
			String response = httpExchange
				.setRequestBody(payload)
				.post()
				.getResponse();
			
			Log.log(response);
			

			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	
	}
	

	@Override
	public void onSuccess() {
		Log.log("On Success");
		
	}

	@Override
	public void onIceCandidate(RTCIceCandidate candidate) {
		// TODO Auto-generated method stub
		
		Log.log("On Ice Candidate");

		String payload = String.format("{\"janus\" : \"trickle\", \"transaction\" : \"1234\", \"apisecret\":\"%s\", \"candidate\" : {\"sdpMid\" : \"%s\", \"sdpMLineIndex\" : %d, \"candidate\" : \"%s\"}}", 
				apiSecret,
				candidate.sdpMid,
				candidate.sdpMLineIndex,
				candidate.sdp.toString().trim().replace("\r\n", "\\n"));

		String url = String.format("%s%s/%s/", janusServer, sessionId, pluginHandle);
		
		try (HttpExchange httpExchange = new HttpExchange(url)) {

			Log.log("sending: %s", payload);
			
			String response = httpExchange
				.setRequestBody(payload)
				.post()
				.getResponse();
			
			Log.log(response);
			
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	
	}



	@Override
	public void onFailure(String error) {
		// TODO Auto-generated method stub
		
	}

	
}

[kinsleykajiva]

hi, this is working as much, the method gets invoked, thanks for the effort.

[kinsleykajiva]

if you dont minds me asking please tell me why are you replacing Janus and with what are replacing with ?

[Charles92011]

I'm planning to replace it with Java RTC, because I want specific control over connections that are harder to do in Janus than in a custom application.