talk/examples/android/src/org/appspot/apprtc/WebSocketRTCClient.java - platform/external/webrtc - Git at Google

 /*
  * libjingle
  * Copyright 2014, Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
  *     this list of conditions and the following disclaimer in the documentation
  *     and/or other materials provided with the distribution.
  *  3. The name of the author may not be used to endorse or promote products
  *     derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 package org.appspot.apprtc;

 import org.appspot.apprtc.RoomParametersFetcher.RoomParametersFetcherEvents;
 import org.appspot.apprtc.WebSocketChannelClient.WebSocketChannelEvents;
 import org.appspot.apprtc.WebSocketChannelClient.WebSocketConnectionState;
 import org.appspot.apprtc.util.AsyncHttpURLConnection;
 import org.appspot.apprtc.util.AsyncHttpURLConnection.AsyncHttpEvents;
 import org.appspot.apprtc.util.LooperExecutor;

 import android.util.Log;

 import org.json.JSONException;
 import org.json.JSONObject;
 import org.webrtc.IceCandidate;
 import org.webrtc.SessionDescription;

 /**
  * Negotiates signaling for chatting with apprtc.appspot.com "rooms".
  * Uses the client<->server specifics of the apprtc AppEngine webapp.
  *
  * <p>To use: create an instance of this object (registering a message handler) and
  * call connectToRoom().  Once room connection is established
  * onConnectedToRoom() callback with room parameters is invoked.
  * Messages to other party (with local Ice candidates and answer SDP) can
  * be sent after WebSocket connection is established.
  */
 public class WebSocketRTCClient implements AppRTCClient,
     WebSocketChannelEvents {
   private static final String TAG = "WSRTCClient";

   private enum ConnectionState {
     NEW, CONNECTED, CLOSED, ERROR
   };
   private enum MessageType {
     MESSAGE, BYE
   };
   private final LooperExecutor executor;
   private boolean loopback;
   private boolean initiator;
   private SignalingEvents events;
   private WebSocketChannelClient wsClient;
   private ConnectionState roomState;
   private String postMessageUrl;
   private String byeMessageUrl;

   public WebSocketRTCClient(SignalingEvents events) {
     this.events = events;
     executor = new LooperExecutor();
   }

   // --------------------------------------------------------------------
   // AppRTCClient interface implementation.
   // Asynchronously connect to an AppRTC room URL, e.g.
   // https://apprtc.appspot.com/register/<room>, retrieve room parameters
   // and connect to WebSocket server.
   @Override
   public void connectToRoom(final String url, final boolean loopback) {
     executor.requestStart();
     executor.execute(new Runnable() {
       @Override
       public void run() {
         connectToRoomInternal(url, loopback);
       }
     });
   }

   @Override
   public void disconnectFromRoom() {
     executor.execute(new Runnable() {
       @Override
       public void run() {
         disconnectFromRoomInternal();
       }
     });
     executor.requestStop();
   }

   // Connects to room - function runs on a local looper thread.
   private void connectToRoomInternal(String url, boolean loopback) {
     Log.d(TAG, "Connect to room: " + url);
     this.loopback = loopback;
     roomState = ConnectionState.NEW;
     // Create WebSocket client.
     wsClient = new WebSocketChannelClient(executor, this);
     // Get room parameters.
     new RoomParametersFetcher(loopback, url,
       new RoomParametersFetcherEvents() {
         @Override
         public void onSignalingParametersReady(
             final SignalingParameters params) {
           executor.execute(new Runnable() {
             @Override
             public void run() {
               signalingParametersReady(params);
             }
           });
         }

         @Override
         public void onSignalingParametersError(String description) {
           reportError(description);
         }
       }
     );
   }

   // Disconnect from room and send bye messages - runs on a local looper thread.
   private void disconnectFromRoomInternal() {
     Log.d(TAG, "Disconnect. Room state: " + roomState);
     if (roomState == ConnectionState.CONNECTED) {
       Log.d(TAG, "Closing room.");
       sendPostMessage(MessageType.BYE, byeMessageUrl, "");
     }
     roomState = ConnectionState.CLOSED;
     if (wsClient != null) {
       wsClient.disconnect(true);
     }
   }

   // Callback issued when room parameters are extracted. Runs on local
   // looper thread.
   private void signalingParametersReady(final SignalingParameters params) {
     Log.d(TAG, "Room connection completed.");
     if (loopback && (!params.initiator || params.offerSdp != null)) {
       reportError("Loopback room is busy.");
       return;
     }
     if (!loopback && !params.initiator && params.offerSdp == null) {
       Log.w(TAG, "No offer SDP in room response.");
     }
     initiator = params.initiator;
     postMessageUrl = params.roomUrl + "/message/"
       + params.roomId + "/" + params.clientId;
     byeMessageUrl = params.roomUrl + "/bye/"
       + params.roomId + "/" + params.clientId;
     roomState = ConnectionState.CONNECTED;

     // Fire connection and signaling parameters events.
     events.onConnectedToRoom(params);

     // Connect to WebSocket server.
     wsClient.connect(
         params.wssUrl, params.wssPostUrl, params.roomId, params.clientId);

     // For call receiver get sdp offer and ice candidates
     // from room parameters and fire corresponding events.
     if (!params.initiator) {
       if (params.offerSdp != null) {
         events.onRemoteDescription(params.offerSdp);
       }
       if (params.iceCandidates != null) {
         for (IceCandidate iceCandidate : params.iceCandidates) {
           events.onRemoteIceCandidate(iceCandidate);
         }
       }
     }
   }

   // Send local offer SDP to the other participant.
   @Override
   public void sendOfferSdp(final SessionDescription sdp) {
     executor.execute(new Runnable() {
       @Override
       public void run() {
         if (roomState != ConnectionState.CONNECTED) {
           reportError("Sending offer SDP in non connected state.");
           return;
         }
         JSONObject json = new JSONObject();
         jsonPut(json, "sdp", sdp.description);
         jsonPut(json, "type", "offer");
         sendPostMessage(MessageType.MESSAGE, postMessageUrl, json.toString());
         if (loopback) {
           // In loopback mode rename this offer to answer and route it back.
           SessionDescription sdpAnswer = new SessionDescription(
               SessionDescription.Type.fromCanonicalForm("answer"),
               sdp.description);
           events.onRemoteDescription(sdpAnswer);
         }
       }
     });
   }

   // Send local answer SDP to the other participant.
   @Override
   public void sendAnswerSdp(final SessionDescription sdp) {
     executor.execute(new Runnable() {
       @Override
       public void run() {
         if (loopback) {
           Log.e(TAG, "Sending answer in loopback mode.");
           return;
         }
         if (wsClient.getState() != WebSocketConnectionState.REGISTERED) {
           reportError("Sending answer SDP in non registered state.");
           return;
         }
         JSONObject json = new JSONObject();
         jsonPut(json, "sdp", sdp.description);
         jsonPut(json, "type", "answer");
         wsClient.send(json.toString());
       }
     });
   }

   // Send Ice candidate to the other participant.
   @Override
   public void sendLocalIceCandidate(final IceCandidate candidate) {
     executor.execute(new Runnable() {
       @Override
       public void run() {
         JSONObject json = new JSONObject();
         jsonPut(json, "type", "candidate");
         jsonPut(json, "label", candidate.sdpMLineIndex);
         jsonPut(json, "id", candidate.sdpMid);
         jsonPut(json, "candidate", candidate.sdp);
         if (initiator) {
           // Call initiator sends ice candidates to GAE server.
           if (roomState != ConnectionState.CONNECTED) {
             reportError("Sending ICE candidate in non connected state.");
             return;
           }
           sendPostMessage(MessageType.MESSAGE, postMessageUrl, json.toString());
           if (loopback) {
             events.onRemoteIceCandidate(candidate);
           }
         } else {
           // Call receiver sends ice candidates to websocket server.
           if (wsClient.getState() != WebSocketConnectionState.REGISTERED) {
             reportError("Sending ICE candidate in non registered state.");
             return;
           }
           wsClient.send(json.toString());
         }
       }
     });
   }

   // --------------------------------------------------------------------
   // WebSocketChannelEvents interface implementation.
   // All events are called by WebSocketChannelClient on a local looper thread
   // (passed to WebSocket client constructor).
   @Override
   public void onWebSocketOpen() {
     Log.d(TAG, "Websocket connection completed. Registering...");
     wsClient.register();
   }

   @Override
   public void onWebSocketMessage(final String msg) {
     if (wsClient.getState() != WebSocketConnectionState.REGISTERED) {
       Log.e(TAG, "Got WebSocket message in non registered state.");
       return;
     }
     try {
       JSONObject json = new JSONObject(msg);
       String msgText = json.getString("msg");
       String errorText = json.optString("error");
       if (msgText.length() > 0) {
         json = new JSONObject(msgText);
         String type = json.optString("type");
         if (type.equals("candidate")) {
           IceCandidate candidate = new IceCandidate(
               json.getString("id"),
               json.getInt("label"),
               json.getString("candidate"));
           events.onRemoteIceCandidate(candidate);
         } else if (type.equals("answer")) {
           if (initiator) {
             SessionDescription sdp = new SessionDescription(
                 SessionDescription.Type.fromCanonicalForm(type),
                 json.getString("sdp"));
             events.onRemoteDescription(sdp);
           } else {
             reportError("Received answer for call initiator: " + msg);
           }
         } else if (type.equals("offer")) {
           if (!initiator) {
             SessionDescription sdp = new SessionDescription(
                 SessionDescription.Type.fromCanonicalForm(type),
                 json.getString("sdp"));
             events.onRemoteDescription(sdp);
           } else {
             reportError("Received offer for call receiver: " + msg);
           }
         } else if (type.equals("bye")) {
           events.onChannelClose();
         } else {
           reportError("Unexpected WebSocket message: " + msg);
         }
       } else {
         if (errorText != null && errorText.length() > 0) {
           reportError("WebSocket error message: " + errorText);
         } else {
           reportError("Unexpected WebSocket message: " + msg);
         }
       }
     } catch (JSONException e) {
       reportError("WebSocket message JSON parsing error: " + e.toString());
     }
   }

   @Override
   public void onWebSocketClose() {
     events.onChannelClose();
   }

   @Override
   public void onWebSocketError(String description) {
     reportError("WebSocket error: " + description);
   }

   // --------------------------------------------------------------------
   // Helper functions.
   private void reportError(final String errorMessage) {
     Log.e(TAG, errorMessage);
     executor.execute(new Runnable() {
       @Override
       public void run() {
         if (roomState != ConnectionState.ERROR) {
           roomState = ConnectionState.ERROR;
           events.onChannelError(errorMessage);
         }
       }
     });
   }

   // Put a |key|->|value| mapping in |json|.
   private static void jsonPut(JSONObject json, String key, Object value) {
     try {
       json.put(key, value);
     } catch (JSONException e) {
       throw new RuntimeException(e);
     }
   }

   // Send SDP or ICE candidate to a room server.
   private void sendPostMessage(
       final MessageType messageType, final String url, final String message) {
     if (messageType == MessageType.BYE) {
       Log.d(TAG, "C->GAE: " + url);
     } else {
       Log.d(TAG, "C->GAE: " + message);
     }
     AsyncHttpURLConnection httpConnection = new AsyncHttpURLConnection(
       "POST", url, message, new AsyncHttpEvents() {
         @Override
         public void onHttpError(String errorMessage) {
           reportError("GAE POST error: " + errorMessage);
         }

         @Override
         public void onHttpComplete(String response) {
           if (messageType == MessageType.MESSAGE) {
             try {
               JSONObject roomJson = new JSONObject(response);
               String result = roomJson.getString("result");
               if (!result.equals("SUCCESS")) {
                 reportError("GAE POST error: " + result);
               }
             } catch (JSONException e) {
               reportError("GAE POST JSON error: " + e.toString());
             }
           }
         }
       });
     httpConnection.send();
   }
 }
	/*
	* libjingle
	* Copyright 2014, Google Inc.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice,
	* this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright notice,
	* this list of conditions and the following disclaimer in the documentation
	* and/or other materials provided with the distribution.
	* 3. The name of the author may not be used to endorse or promote products
	* derived from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
	* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	package org.appspot.apprtc;

	import org.appspot.apprtc.RoomParametersFetcher.RoomParametersFetcherEvents;
	import org.appspot.apprtc.WebSocketChannelClient.WebSocketChannelEvents;
	import org.appspot.apprtc.WebSocketChannelClient.WebSocketConnectionState;
	import org.appspot.apprtc.util.AsyncHttpURLConnection;
	import org.appspot.apprtc.util.AsyncHttpURLConnection.AsyncHttpEvents;
	import org.appspot.apprtc.util.LooperExecutor;

	import android.util.Log;

	import org.json.JSONException;
	import org.json.JSONObject;
	import org.webrtc.IceCandidate;
	import org.webrtc.SessionDescription;

	/**
	* Negotiates signaling for chatting with apprtc.appspot.com "rooms".
	* Uses the client<->server specifics of the apprtc AppEngine webapp.
	*
	* <p>To use: create an instance of this object (registering a message handler) and
	* call connectToRoom(). Once room connection is established
	* onConnectedToRoom() callback with room parameters is invoked.
	* Messages to other party (with local Ice candidates and answer SDP) can
	* be sent after WebSocket connection is established.
	*/
	public class WebSocketRTCClient implements AppRTCClient,
	WebSocketChannelEvents {
	private static final String TAG = "WSRTCClient";

	private enum ConnectionState {
	NEW, CONNECTED, CLOSED, ERROR
	};
	private enum MessageType {
	MESSAGE, BYE
	};
	private final LooperExecutor executor;
	private boolean loopback;
	private boolean initiator;
	private SignalingEvents events;
	private WebSocketChannelClient wsClient;
	private ConnectionState roomState;
	private String postMessageUrl;
	private String byeMessageUrl;

	public WebSocketRTCClient(SignalingEvents events) {
	this.events = events;
	executor = new LooperExecutor();
	}

	// --------------------------------------------------------------------
	// AppRTCClient interface implementation.
	// Asynchronously connect to an AppRTC room URL, e.g.
	// https://apprtc.appspot.com/register/<room>, retrieve room parameters
	// and connect to WebSocket server.
	@Override
	public void connectToRoom(final String url, final boolean loopback) {
	executor.requestStart();
	executor.execute(new Runnable() {
	@Override
	public void run() {
	connectToRoomInternal(url, loopback);
	}
	});
	}

	@Override
	public void disconnectFromRoom() {
	executor.execute(new Runnable() {
	@Override
	public void run() {
	disconnectFromRoomInternal();
	}
	});
	executor.requestStop();
	}

	// Connects to room - function runs on a local looper thread.
	private void connectToRoomInternal(String url, boolean loopback) {
	Log.d(TAG, "Connect to room: " + url);
	this.loopback = loopback;
	roomState = ConnectionState.NEW;
	// Create WebSocket client.
	wsClient = new WebSocketChannelClient(executor, this);
	// Get room parameters.
	new RoomParametersFetcher(loopback, url,
	new RoomParametersFetcherEvents() {
	@Override
	public void onSignalingParametersReady(
	final SignalingParameters params) {
	executor.execute(new Runnable() {
	@Override
	public void run() {
	signalingParametersReady(params);
	}
	});
	}

	@Override
	public void onSignalingParametersError(String description) {
	reportError(description);
	}
	}
	);
	}

	// Disconnect from room and send bye messages - runs on a local looper thread.
	private void disconnectFromRoomInternal() {
	Log.d(TAG, "Disconnect. Room state: " + roomState);
	if (roomState == ConnectionState.CONNECTED) {
	Log.d(TAG, "Closing room.");
	sendPostMessage(MessageType.BYE, byeMessageUrl, "");
	}
	roomState = ConnectionState.CLOSED;
	if (wsClient != null) {
	wsClient.disconnect(true);
	}
	}

	// Callback issued when room parameters are extracted. Runs on local
	// looper thread.
	private void signalingParametersReady(final SignalingParameters params) {
	Log.d(TAG, "Room connection completed.");
	if (loopback && (!params.initiator \|\| params.offerSdp != null)) {
	reportError("Loopback room is busy.");
	return;
	}
	if (!loopback && !params.initiator && params.offerSdp == null) {
	Log.w(TAG, "No offer SDP in room response.");
	}
	initiator = params.initiator;
	postMessageUrl = params.roomUrl + "/message/"
	+ params.roomId + "/" + params.clientId;
	byeMessageUrl = params.roomUrl + "/bye/"
	+ params.roomId + "/" + params.clientId;
	roomState = ConnectionState.CONNECTED;

	// Fire connection and signaling parameters events.
	events.onConnectedToRoom(params);

	// Connect to WebSocket server.
	wsClient.connect(
	params.wssUrl, params.wssPostUrl, params.roomId, params.clientId);

	// For call receiver get sdp offer and ice candidates
	// from room parameters and fire corresponding events.
	if (!params.initiator) {
	if (params.offerSdp != null) {
	events.onRemoteDescription(params.offerSdp);
	}
	if (params.iceCandidates != null) {
	for (IceCandidate iceCandidate : params.iceCandidates) {
	events.onRemoteIceCandidate(iceCandidate);
	}
	}
	}
	}

	// Send local offer SDP to the other participant.
	@Override
	public void sendOfferSdp(final SessionDescription sdp) {
	executor.execute(new Runnable() {
	@Override
	public void run() {
	if (roomState != ConnectionState.CONNECTED) {
	reportError("Sending offer SDP in non connected state.");
	return;
	}
	JSONObject json = new JSONObject();
	jsonPut(json, "sdp", sdp.description);
	jsonPut(json, "type", "offer");
	sendPostMessage(MessageType.MESSAGE, postMessageUrl, json.toString());
	if (loopback) {
	// In loopback mode rename this offer to answer and route it back.
	SessionDescription sdpAnswer = new SessionDescription(
	SessionDescription.Type.fromCanonicalForm("answer"),
	sdp.description);
	events.onRemoteDescription(sdpAnswer);
	}
	}
	});
	}

	// Send local answer SDP to the other participant.
	@Override
	public void sendAnswerSdp(final SessionDescription sdp) {
	executor.execute(new Runnable() {
	@Override
	public void run() {
	if (loopback) {
	Log.e(TAG, "Sending answer in loopback mode.");
	return;
	}
	if (wsClient.getState() != WebSocketConnectionState.REGISTERED) {
	reportError("Sending answer SDP in non registered state.");
	return;
	}
	JSONObject json = new JSONObject();
	jsonPut(json, "sdp", sdp.description);
	jsonPut(json, "type", "answer");
	wsClient.send(json.toString());
	}
	});
	}

	// Send Ice candidate to the other participant.
	@Override
	public void sendLocalIceCandidate(final IceCandidate candidate) {
	executor.execute(new Runnable() {
	@Override
	public void run() {
	JSONObject json = new JSONObject();
	jsonPut(json, "type", "candidate");
	jsonPut(json, "label", candidate.sdpMLineIndex);
	jsonPut(json, "id", candidate.sdpMid);
	jsonPut(json, "candidate", candidate.sdp);
	if (initiator) {
	// Call initiator sends ice candidates to GAE server.
	if (roomState != ConnectionState.CONNECTED) {
	reportError("Sending ICE candidate in non connected state.");
	return;
	}
	sendPostMessage(MessageType.MESSAGE, postMessageUrl, json.toString());
	if (loopback) {
	events.onRemoteIceCandidate(candidate);
	}
	} else {
	// Call receiver sends ice candidates to websocket server.
	if (wsClient.getState() != WebSocketConnectionState.REGISTERED) {
	reportError("Sending ICE candidate in non registered state.");
	return;
	}
	wsClient.send(json.toString());
	}
	}
	});
	}

	// --------------------------------------------------------------------
	// WebSocketChannelEvents interface implementation.
	// All events are called by WebSocketChannelClient on a local looper thread
	// (passed to WebSocket client constructor).
	@Override
	public void onWebSocketOpen() {
	Log.d(TAG, "Websocket connection completed. Registering...");
	wsClient.register();
	}

	@Override
	public void onWebSocketMessage(final String msg) {
	if (wsClient.getState() != WebSocketConnectionState.REGISTERED) {
	Log.e(TAG, "Got WebSocket message in non registered state.");
	return;
	}
	try {
	JSONObject json = new JSONObject(msg);
	String msgText = json.getString("msg");
	String errorText = json.optString("error");
	if (msgText.length() > 0) {
	json = new JSONObject(msgText);
	String type = json.optString("type");
	if (type.equals("candidate")) {
	IceCandidate candidate = new IceCandidate(
	json.getString("id"),
	json.getInt("label"),
	json.getString("candidate"));
	events.onRemoteIceCandidate(candidate);
	} else if (type.equals("answer")) {
	if (initiator) {
	SessionDescription sdp = new SessionDescription(
	SessionDescription.Type.fromCanonicalForm(type),
	json.getString("sdp"));
	events.onRemoteDescription(sdp);
	} else {
	reportError("Received answer for call initiator: " + msg);
	}
	} else if (type.equals("offer")) {
	if (!initiator) {
	SessionDescription sdp = new SessionDescription(
	SessionDescription.Type.fromCanonicalForm(type),
	json.getString("sdp"));
	events.onRemoteDescription(sdp);
	} else {
	reportError("Received offer for call receiver: " + msg);
	}
	} else if (type.equals("bye")) {
	events.onChannelClose();
	} else {
	reportError("Unexpected WebSocket message: " + msg);
	}
	} else {
	if (errorText != null && errorText.length() > 0) {
	reportError("WebSocket error message: " + errorText);
	} else {
	reportError("Unexpected WebSocket message: " + msg);
	}
	}
	} catch (JSONException e) {
	reportError("WebSocket message JSON parsing error: " + e.toString());
	}
	}

	@Override
	public void onWebSocketClose() {
	events.onChannelClose();
	}

	@Override
	public void onWebSocketError(String description) {
	reportError("WebSocket error: " + description);
	}

	// --------------------------------------------------------------------
	// Helper functions.
	private void reportError(final String errorMessage) {
	Log.e(TAG, errorMessage);
	executor.execute(new Runnable() {
	@Override
	public void run() {
	if (roomState != ConnectionState.ERROR) {
	roomState = ConnectionState.ERROR;
	events.onChannelError(errorMessage);
	}
	}
	});
	}

	// Put a \|key\|->\|value\| mapping in \|json\|.
	private static void jsonPut(JSONObject json, String key, Object value) {
	try {
	json.put(key, value);
	} catch (JSONException e) {
	throw new RuntimeException(e);
	}
	}

	// Send SDP or ICE candidate to a room server.
	private void sendPostMessage(
	final MessageType messageType, final String url, final String message) {
	if (messageType == MessageType.BYE) {
	Log.d(TAG, "C->GAE: " + url);
	} else {
	Log.d(TAG, "C->GAE: " + message);
	}
	AsyncHttpURLConnection httpConnection = new AsyncHttpURLConnection(
	"POST", url, message, new AsyncHttpEvents() {
	@Override
	public void onHttpError(String errorMessage) {
	reportError("GAE POST error: " + errorMessage);
	}

	@Override
	public void onHttpComplete(String response) {
	if (messageType == MessageType.MESSAGE) {
	try {
	JSONObject roomJson = new JSONObject(response);
	String result = roomJson.getString("result");
	if (!result.equals("SUCCESS")) {
	reportError("GAE POST error: " + result);
	}
	} catch (JSONException e) {
	reportError("GAE POST JSON error: " + e.toString());
	}
	}
	}
	});
	httpConnection.send();
	}
	}