3 * Copyright 2013, Google Inc.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 package org.appspot.apprtc;
30 import android.app.Activity;
31 import android.os.AsyncTask;
32 import android.util.Log;
34 import org.json.JSONArray;
35 import org.json.JSONException;
36 import org.json.JSONObject;
37 import org.webrtc.MediaConstraints;
38 import org.webrtc.PeerConnection;
40 import java.io.IOException;
41 import java.io.InputStream;
42 import java.net.HttpURLConnection;
44 import java.net.URLConnection;
45 import java.util.LinkedList;
46 import java.util.List;
47 import java.util.Scanner;
50 * Negotiates signaling for chatting with apprtc.appspot.com "rooms".
51 * Uses the client<->server specifics of the apprtc AppEngine webapp.
53 * To use: create an instance of this object (registering a message handler) and
54 * call connectToRoom(). Once that's done call sendMessage() and wait for the
55 * registered handler to be called with received messages.
57 public class AppRTCClient {
58 private static final String TAG = "AppRTCClient";
59 private GAEChannelClient channelClient;
60 private final Activity activity;
61 private final GAEChannelClient.MessageHandler gaeHandler;
62 private final IceServersObserver iceServersObserver;
64 // These members are only read/written under sendQueue's lock.
65 private LinkedList<String> sendQueue = new LinkedList<String>();
66 private AppRTCSignalingParameters appRTCSignalingParameters;
69 * Callback fired once the room's signaling parameters specify the set of
72 public static interface IceServersObserver {
73 public void onIceServers(List<PeerConnection.IceServer> iceServers);
77 Activity activity, GAEChannelClient.MessageHandler gaeHandler,
78 IceServersObserver iceServersObserver) {
79 this.activity = activity;
80 this.gaeHandler = gaeHandler;
81 this.iceServersObserver = iceServersObserver;
85 * Asynchronously connect to an AppRTC room URL, e.g.
86 * https://apprtc.appspot.com/?r=NNN and register message-handling callbacks
89 public void connectToRoom(String url) {
90 while (url.indexOf('?') < 0) {
91 // Keep redirecting until we get a room number.
92 (new RedirectResolver()).execute(url);
93 return; // RedirectResolver above calls us back with the next URL.
95 (new RoomParameterGetter()).execute(url);
99 * Disconnect from the GAE Channel.
101 public void disconnect() {
102 if (channelClient != null) {
103 channelClient.close();
104 channelClient = null;
109 * Queue a message for sending to the room's channel and send it if already
110 * connected (other wise queued messages are drained when the channel is
111 eventually established).
113 public synchronized void sendMessage(String msg) {
114 synchronized (sendQueue) {
117 requestQueueDrainInBackground();
120 public boolean isInitiator() {
121 return appRTCSignalingParameters.initiator;
124 public MediaConstraints pcConstraints() {
125 return appRTCSignalingParameters.pcConstraints;
128 public MediaConstraints videoConstraints() {
129 return appRTCSignalingParameters.videoConstraints;
132 public MediaConstraints audioConstraints() {
133 return appRTCSignalingParameters.audioConstraints;
136 // Struct holding the signaling parameters of an AppRTC room.
137 private class AppRTCSignalingParameters {
138 public final List<PeerConnection.IceServer> iceServers;
139 public final String gaeBaseHref;
140 public final String channelToken;
141 public final String postMessageUrl;
142 public final boolean initiator;
143 public final MediaConstraints pcConstraints;
144 public final MediaConstraints videoConstraints;
145 public final MediaConstraints audioConstraints;
147 public AppRTCSignalingParameters(
148 List<PeerConnection.IceServer> iceServers,
149 String gaeBaseHref, String channelToken, String postMessageUrl,
150 boolean initiator, MediaConstraints pcConstraints,
151 MediaConstraints videoConstraints, MediaConstraints audioConstraints) {
152 this.iceServers = iceServers;
153 this.gaeBaseHref = gaeBaseHref;
154 this.channelToken = channelToken;
155 this.postMessageUrl = postMessageUrl;
156 this.initiator = initiator;
157 this.pcConstraints = pcConstraints;
158 this.videoConstraints = videoConstraints;
159 this.audioConstraints = audioConstraints;
163 // Load the given URL and return the value of the Location header of the
164 // resulting 302 response. If the result is not a 302, throws.
165 private class RedirectResolver extends AsyncTask<String, Void, String> {
167 protected String doInBackground(String... urls) {
168 if (urls.length != 1) {
169 throw new RuntimeException("Must be called with a single URL");
172 return followRedirect(urls[0]);
173 } catch (IOException e) {
174 throw new RuntimeException(e);
179 protected void onPostExecute(String url) {
183 private String followRedirect(String url) throws IOException {
184 HttpURLConnection connection = (HttpURLConnection)
185 new URL(url).openConnection();
186 connection.setInstanceFollowRedirects(false);
187 int code = connection.getResponseCode();
188 if (code != HttpURLConnection.HTTP_MOVED_TEMP) {
189 throw new IOException("Unexpected response: " + code + " for " + url +
190 ", with contents: " + drainStream(connection.getInputStream()));
194 while ((name = connection.getHeaderFieldKey(n)) != null) {
195 value = connection.getHeaderField(n);
196 if (name.equals("Location")) {
201 throw new IOException("Didn't find Location header!");
205 // AsyncTask that converts an AppRTC room URL into the set of signaling
206 // parameters to use with that room.
207 private class RoomParameterGetter
208 extends AsyncTask<String, Void, AppRTCSignalingParameters> {
210 protected AppRTCSignalingParameters doInBackground(String... urls) {
211 if (urls.length != 1) {
212 throw new RuntimeException("Must be called with a single URL");
215 return getParametersForRoomUrl(urls[0]);
216 } catch (JSONException e) {
217 throw new RuntimeException(e);
218 } catch (IOException e) {
219 throw new RuntimeException(e);
224 protected void onPostExecute(AppRTCSignalingParameters params) {
226 new GAEChannelClient(activity, params.channelToken, gaeHandler);
227 synchronized (sendQueue) {
228 appRTCSignalingParameters = params;
230 requestQueueDrainInBackground();
231 iceServersObserver.onIceServers(appRTCSignalingParameters.iceServers);
234 // Fetches |url| and fishes the signaling parameters out of the JSON.
235 private AppRTCSignalingParameters getParametersForRoomUrl(String url)
236 throws IOException, JSONException {
237 url = url + "&t=json";
238 JSONObject roomJson = new JSONObject(
239 drainStream((new URL(url)).openConnection().getInputStream()));
241 if (roomJson.has("error")) {
242 JSONArray errors = roomJson.getJSONArray("error_messages");
243 throw new IOException(errors.toString());
246 String gaeBaseHref = url.substring(0, url.indexOf('?'));
247 String token = roomJson.getString("token");
248 String postMessageUrl = "/message?r=" +
249 roomJson.getString("room_key") + "&u=" +
250 roomJson.getString("me");
251 boolean initiator = roomJson.getInt("initiator") == 1;
252 LinkedList<PeerConnection.IceServer> iceServers =
253 iceServersFromPCConfigJSON(roomJson.getString("pc_config"));
255 boolean isTurnPresent = false;
256 for (PeerConnection.IceServer server : iceServers) {
257 if (server.uri.startsWith("turn:")) {
258 isTurnPresent = true;
262 if (!isTurnPresent) {
263 iceServers.add(requestTurnServer(roomJson.getString("turn_url")));
266 MediaConstraints pcConstraints = constraintsFromJSON(
267 roomJson.getString("pc_constraints"));
268 addDTLSConstraintIfMissing(pcConstraints);
269 Log.d(TAG, "pcConstraints: " + pcConstraints);
270 MediaConstraints videoConstraints = constraintsFromJSON(
271 getAVConstraints("video",
272 roomJson.getString("media_constraints")));
273 Log.d(TAG, "videoConstraints: " + videoConstraints);
274 MediaConstraints audioConstraints = constraintsFromJSON(
275 getAVConstraints("audio",
276 roomJson.getString("media_constraints")));
277 Log.d(TAG, "audioConstraints: " + audioConstraints);
279 return new AppRTCSignalingParameters(
280 iceServers, gaeBaseHref, token, postMessageUrl, initiator,
281 pcConstraints, videoConstraints, audioConstraints);
284 // Mimic Chrome and set DtlsSrtpKeyAgreement to true if not set to false by
286 private void addDTLSConstraintIfMissing(
287 MediaConstraints pcConstraints) {
288 for (MediaConstraints.KeyValuePair pair : pcConstraints.mandatory) {
289 if (pair.getKey().equals("DtlsSrtpKeyAgreement")) {
293 for (MediaConstraints.KeyValuePair pair : pcConstraints.optional) {
294 if (pair.getKey().equals("DtlsSrtpKeyAgreement")) {
298 // DTLS isn't being suppressed (e.g. for debug=loopback calls), so enable
300 pcConstraints.optional.add(
301 new MediaConstraints.KeyValuePair("DtlsSrtpKeyAgreement", "true"));
304 // Return the constraints specified for |type| of "audio" or "video" in
305 // |mediaConstraintsString|.
306 private String getAVConstraints(
307 String type, String mediaConstraintsString) {
309 JSONObject json = new JSONObject(mediaConstraintsString);
310 // Tricksy handling of values that are allowed to be (boolean or
311 // MediaTrackConstraints) by the getUserMedia() spec. There are three
313 if (!json.has(type) || !json.optBoolean(type, true)) {
314 // Case 1: "audio"/"video" is not present, or is an explicit "false"
318 if (json.optBoolean(type, false)) {
319 // Case 2: "audio"/"video" is an explicit "true" boolean.
320 return "{\"mandatory\": {}, \"optional\": []}";
322 // Case 3: "audio"/"video" is an object.
323 return json.getJSONObject(type).toString();
324 } catch (JSONException e) {
325 throw new RuntimeException(e);
329 private MediaConstraints constraintsFromJSON(String jsonString) {
330 if (jsonString == null) {
334 MediaConstraints constraints = new MediaConstraints();
335 JSONObject json = new JSONObject(jsonString);
336 JSONObject mandatoryJSON = json.optJSONObject("mandatory");
337 if (mandatoryJSON != null) {
338 JSONArray mandatoryKeys = mandatoryJSON.names();
339 if (mandatoryKeys != null) {
340 for (int i = 0; i < mandatoryKeys.length(); ++i) {
341 String key = mandatoryKeys.getString(i);
342 String value = mandatoryJSON.getString(key);
343 constraints.mandatory.add(
344 new MediaConstraints.KeyValuePair(key, value));
348 JSONArray optionalJSON = json.optJSONArray("optional");
349 if (optionalJSON != null) {
350 for (int i = 0; i < optionalJSON.length(); ++i) {
351 JSONObject keyValueDict = optionalJSON.getJSONObject(i);
352 String key = keyValueDict.names().getString(0);
353 String value = keyValueDict.getString(key);
354 constraints.optional.add(
355 new MediaConstraints.KeyValuePair(key, value));
359 } catch (JSONException e) {
360 throw new RuntimeException(e);
364 // Requests & returns a TURN ICE Server based on a request URL. Must be run
365 // off the main thread!
366 private PeerConnection.IceServer requestTurnServer(String url) {
368 URLConnection connection = (new URL(url)).openConnection();
369 connection.addRequestProperty("user-agent", "Mozilla/5.0");
370 connection.addRequestProperty("origin", "https://apprtc.appspot.com");
371 String response = drainStream(connection.getInputStream());
372 JSONObject responseJSON = new JSONObject(response);
373 String uri = responseJSON.getJSONArray("uris").getString(0);
374 String username = responseJSON.getString("username");
375 String password = responseJSON.getString("password");
376 return new PeerConnection.IceServer(uri, username, password);
377 } catch (JSONException e) {
378 throw new RuntimeException(e);
379 } catch (IOException e) {
380 throw new RuntimeException(e);
385 // Return the list of ICE servers described by a WebRTCPeerConnection
386 // configuration string.
387 private LinkedList<PeerConnection.IceServer> iceServersFromPCConfigJSON(
390 JSONObject json = new JSONObject(pcConfig);
391 JSONArray servers = json.getJSONArray("iceServers");
392 LinkedList<PeerConnection.IceServer> ret =
393 new LinkedList<PeerConnection.IceServer>();
394 for (int i = 0; i < servers.length(); ++i) {
395 JSONObject server = servers.getJSONObject(i);
396 String url = server.getString("urls");
398 server.has("credential") ? server.getString("credential") : "";
399 ret.add(new PeerConnection.IceServer(url, "", credential));
402 } catch (JSONException e) {
403 throw new RuntimeException(e);
407 // Request an attempt to drain the send queue, on a background thread.
408 private void requestQueueDrainInBackground() {
409 (new AsyncTask<Void, Void, Void>() {
410 public Void doInBackground(Void... unused) {
417 // Send all queued messages if connected to the room.
418 private void maybeDrainQueue() {
419 synchronized (sendQueue) {
420 if (appRTCSignalingParameters == null) {
424 for (String msg : sendQueue) {
425 URLConnection connection = new URL(
426 appRTCSignalingParameters.gaeBaseHref +
427 appRTCSignalingParameters.postMessageUrl).openConnection();
428 connection.setDoOutput(true);
429 connection.getOutputStream().write(msg.getBytes("UTF-8"));
430 if (!connection.getHeaderField(null).startsWith("HTTP/1.1 200 ")) {
431 throw new IOException(
432 "Non-200 response to POST: " + connection.getHeaderField(null) +
436 } catch (IOException e) {
437 throw new RuntimeException(e);
443 // Return the contents of an InputStream as a String.
444 private static String drainStream(InputStream in) {
445 Scanner s = new Scanner(in).useDelimiter("\\A");
446 return s.hasNext() ? s.next() : "";