com.elasticrtc.tutorial.loopback.ws.LoopbackSessionHandler.java Source code

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Here is the source code for com.elasticrtc.tutorial.loopback.ws.LoopbackSessionHandler.java

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/*
 * (C) Copyright 2016 elasticRTC (https://www.elasticRTC.com/)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.elasticrtc.tutorial.loopback.ws;

import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;

import org.kurento.client.EventListener;
import org.kurento.client.IceCandidate;
import org.kurento.client.IceCandidateFoundEvent;
import org.kurento.client.KurentoClient;
import org.kurento.client.MediaPipeline;
import org.kurento.client.WebRtcEndpoint;
import org.kurento.jsonrpc.JsonUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonObject;

/**
 * Hello World handler (application and media logic).
 *
 * @author Boni Garcia (bgarcia@gsyc.es)
 * @author David Fernandez (d.fernandezlop@gmail.com)
 * @author Ivan Gracia (igracia@kurento.org)
 * @since 1.0.0
 */
public class LoopbackSessionHandler extends TextWebSocketHandler {

    private static final Gson gson = new GsonBuilder().create();
    private final Logger log = LoggerFactory.getLogger(LoopbackSessionHandler.class);

    @Autowired
    private KurentoClient kurento;

    private final ConcurrentHashMap<String, ClientSession> users = new ConcurrentHashMap<>();

    @Override
    public void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        JsonObject jsonMessage = gson.fromJson(message.getPayload(), JsonObject.class);

        log.debug("Incoming message: {}", jsonMessage);

        switch (jsonMessage.get("id").getAsString()) {
        case "start":
            start(session, jsonMessage);
            break;
        case "stop": {
            ClientSession user = users.remove(session.getId());
            if (user != null) {
                user.release();
            }
            break;
        }
        case "onIceCandidate": {
            JsonObject jsonCandidate = jsonMessage.get("candidate").getAsJsonObject();

            ClientSession user = users.get(session.getId());
            if (user != null) {
                IceCandidate candidate = new IceCandidate(jsonCandidate.get("candidate").getAsString(),
                        jsonCandidate.get("sdpMid").getAsString(), jsonCandidate.get("sdpMLineIndex").getAsInt());
                user.addCandidate(candidate);
            }
            break;
        }
        default:
            sendError(session, "Invalid message with id " + jsonMessage.get("id").getAsString());
            break;
        }
    }

    private void start(final WebSocketSession session, JsonObject jsonMessage) {
        try {
            // 1. Media logic (webRtcEndpoint in loopback)
            MediaPipeline pipeline = kurento.createMediaPipeline();
            WebRtcEndpoint webRtcEndpoint = new WebRtcEndpoint.Builder(pipeline).build();
            webRtcEndpoint.connect(webRtcEndpoint);

            // 2. Store user session
            ClientSession user = new ClientSession();
            user.setMediaPipeline(pipeline);
            user.setWebRtcEndpoint(webRtcEndpoint);
            users.put(session.getId(), user);

            // 3. SDP negotiation
            String sdpOffer = jsonMessage.get("sdpOffer").getAsString();
            String sdpAnswer = webRtcEndpoint.processOffer(sdpOffer);

            JsonObject response = new JsonObject();
            response.addProperty("id", "startResponse");
            response.addProperty("sdpAnswer", sdpAnswer);

            synchronized (session) {
                session.sendMessage(new TextMessage(response.toString()));
            }

            // 4. Gather ICE candidates
            webRtcEndpoint.addIceCandidateFoundListener(new EventListener<IceCandidateFoundEvent>() {
                @Override
                public void onEvent(IceCandidateFoundEvent event) {
                    JsonObject response = new JsonObject();
                    response.addProperty("id", "iceCandidate");
                    response.add("candidate", JsonUtils.toJsonObject(event.getCandidate()));
                    try {
                        synchronized (session) {
                            session.sendMessage(new TextMessage(response.toString()));
                        }
                    } catch (IOException e) {
                        log.error(e.getMessage());
                    }
                }
            });
            webRtcEndpoint.gatherCandidates();

        } catch (Throwable t) {
            sendError(session, t.getMessage());
        }
    }

    private void sendError(WebSocketSession session, String message) {
        try {
            JsonObject response = new JsonObject();
            response.addProperty("id", "error");
            response.addProperty("message", message);
            session.sendMessage(new TextMessage(response.toString()));
        } catch (IOException e) {
            log.error("Exception sending message", e);
        }
    }
}