| #!/usr/bin/python2.4 |
| # |
| # Copyright 2011 Google Inc. All Rights Reserved. |
| |
| """WebRTC Demo |
| |
| This module demonstrates the WebRTC API by implementing a simple video chat app. |
| """ |
| |
| import cgi |
| import logging |
| import os |
| import random |
| import re |
| import json |
| import jinja2 |
| import webapp2 |
| import threading |
| from google.appengine.api import channel |
| from google.appengine.ext import db |
| |
| jinja_environment = jinja2.Environment( |
| loader=jinja2.FileSystemLoader(os.path.dirname(__file__))) |
| |
| # Lock for syncing DB operation in concurrent requests handling. |
| # TODO(brave): keeping working on improving performance with thread syncing. |
| # One possible method for near future is to reduce the message caching. |
| LOCK = threading.RLock() |
| |
| def generate_random(length): |
| word = '' |
| for _ in range(length): |
| word += random.choice('0123456789') |
| return word |
| |
| def sanitize(key): |
| return re.sub('[^a-zA-Z0-9\-]', '-', key) |
| |
| def make_client_id(room, user): |
| return room.key().id_or_name() + '/' + user |
| |
| def get_default_stun_server(user_agent): |
| default_stun_server = 'stun.l.google.com:19302' |
| if 'Firefox' in user_agent: |
| default_stun_server = 'stun.services.mozilla.com' |
| return default_stun_server |
| |
| def get_preferred_audio_receive_codec(): |
| return 'opus/48000' |
| |
| def get_preferred_audio_send_codec(user_agent): |
| # Empty string means no preference. |
| preferred_audio_send_codec = '' |
| # Prefer to send ISAC on Chrome for Android. |
| if 'Android' in user_agent and 'Chrome' in user_agent: |
| preferred_audio_send_codec = 'ISAC/16000' |
| return preferred_audio_send_codec |
| |
| def make_pc_config(stun_server, turn_server, ts_pwd): |
| servers = [] |
| if turn_server: |
| turn_config = 'turn:{}'.format(turn_server) |
| servers.append({'url':turn_config, 'credential':ts_pwd}) |
| if stun_server: |
| stun_config = 'stun:{}'.format(stun_server) |
| servers.append({'url':stun_config}) |
| return {'iceServers':servers} |
| |
| def create_channel(room, user, duration_minutes): |
| client_id = make_client_id(room, user) |
| return channel.create_channel(client_id, duration_minutes) |
| |
| def make_loopback_answer(message): |
| message = message.replace("\"offer\"", "\"answer\"") |
| message = message.replace("a=ice-options:google-ice\\r\\n", "") |
| return message |
| |
| def handle_message(room, user, message): |
| message_obj = json.loads(message) |
| other_user = room.get_other_user(user) |
| room_key = room.key().id_or_name() |
| if message_obj['type'] == 'bye': |
| # This would remove the other_user in loopback test too. |
| # So check its availability before forwarding Bye message. |
| room.remove_user(user) |
| logging.info('User ' + user + ' quit from room ' + room_key) |
| logging.info('Room ' + room_key + ' has state ' + str(room)) |
| if other_user and room.has_user(other_user): |
| if message_obj['type'] == 'offer': |
| # Special case the loopback scenario. |
| if other_user == user: |
| message = make_loopback_answer(message) |
| on_message(room, other_user, message) |
| else: |
| # For unittest |
| on_message(room, user, message) |
| |
| def get_saved_messages(client_id): |
| return Message.gql("WHERE client_id = :id", id=client_id) |
| |
| def delete_saved_messages(client_id): |
| messages = get_saved_messages(client_id) |
| for message in messages: |
| message.delete() |
| logging.info('Deleted the saved message for ' + client_id) |
| |
| def send_saved_messages(client_id): |
| messages = get_saved_messages(client_id) |
| for message in messages: |
| channel.send_message(client_id, message.msg) |
| logging.info('Delivered saved message to ' + client_id) |
| message.delete() |
| |
| def on_message(room, user, message): |
| client_id = make_client_id(room, user) |
| if room.is_connected(user): |
| channel.send_message(client_id, message) |
| logging.info('Delivered message to user ' + user) |
| else: |
| new_message = Message(client_id = client_id, msg = message) |
| new_message.put() |
| logging.info('Saved message for user ' + user) |
| |
| def make_media_track_constraints(constraints_string): |
| if not constraints_string or constraints_string.lower() == 'true': |
| track_constraints = True |
| elif constraints_string.lower() == 'false': |
| track_constraints = False |
| else: |
| track_constraints = {'mandatory': {}, 'optional': []} |
| for constraint_string in constraints_string.split(','): |
| constraint = constraint_string.split('=') |
| if len(constraint) != 2: |
| logging.error('Ignoring malformed constraint: ' + constraint_string) |
| continue |
| if constraint[0].startswith('goog'): |
| track_constraints['optional'].append({constraint[0]: constraint[1]}) |
| else: |
| track_constraints['mandatory'][constraint[0]] = constraint[1] |
| |
| return track_constraints |
| |
| def make_media_stream_constraints(audio, video): |
| stream_constraints = ( |
| {'audio': make_media_track_constraints(audio), |
| 'video': make_media_track_constraints(video)}) |
| logging.info('Applying media constraints: ' + str(stream_constraints)) |
| return stream_constraints |
| |
| def make_pc_constraints(compat, dscp): |
| constraints = { 'optional': [] } |
| # For interop with FireFox. Enable DTLS in peerConnection ctor. |
| if compat.lower() == 'true': |
| constraints['optional'].append({'DtlsSrtpKeyAgreement': True}) |
| # Disable DTLS in peerConnection ctor for loopback call. The value |
| # of compat is false for loopback mode. |
| else: |
| constraints['optional'].append({'DtlsSrtpKeyAgreement': False}) |
| |
| # DSCP for QoS support |
| if dscp.lower() == 'true': |
| constraints['optional'].append({'googDscp': True}) |
| |
| return constraints |
| |
| def make_offer_constraints(): |
| constraints = { 'mandatory': {}, 'optional': [] } |
| return constraints |
| |
| def append_url_arguments(request, link): |
| for argument in request.arguments(): |
| if argument != 'r': |
| link += ('&' + cgi.escape(argument, True) + '=' + |
| cgi.escape(request.get(argument), True)) |
| return link |
| |
| # This database is to store the messages from the sender client when the |
| # receiver client is not ready to receive the messages. |
| # Use TextProperty instead of StringProperty for msg because |
| # the session description can be more than 500 characters. |
| class Message(db.Model): |
| client_id = db.StringProperty() |
| msg = db.TextProperty() |
| |
| class Room(db.Model): |
| """All the data we store for a room""" |
| user1 = db.StringProperty() |
| user2 = db.StringProperty() |
| user1_connected = db.BooleanProperty(default=False) |
| user2_connected = db.BooleanProperty(default=False) |
| |
| def __str__(self): |
| result = '[' |
| if self.user1: |
| result += "%s-%r" % (self.user1, self.user1_connected) |
| if self.user2: |
| result += ", %s-%r" % (self.user2, self.user2_connected) |
| result += ']' |
| return result |
| |
| def get_occupancy(self): |
| occupancy = 0 |
| if self.user1: |
| occupancy += 1 |
| if self.user2: |
| occupancy += 1 |
| return occupancy |
| |
| def get_other_user(self, user): |
| if user == self.user1: |
| return self.user2 |
| elif user == self.user2: |
| return self.user1 |
| else: |
| return None |
| |
| def has_user(self, user): |
| return (user and (user == self.user1 or user == self.user2)) |
| |
| def add_user(self, user): |
| if not self.user1: |
| self.user1 = user |
| elif not self.user2: |
| self.user2 = user |
| else: |
| raise RuntimeError('room is full') |
| self.put() |
| |
| def remove_user(self, user): |
| delete_saved_messages(make_client_id(self, user)) |
| if user == self.user2: |
| self.user2 = None |
| self.user2_connected = False |
| if user == self.user1: |
| if self.user2: |
| self.user1 = self.user2 |
| self.user1_connected = self.user2_connected |
| self.user2 = None |
| self.user2_connected = False |
| else: |
| self.user1 = None |
| self.user1_connected = False |
| if self.get_occupancy() > 0: |
| self.put() |
| else: |
| self.delete() |
| |
| def set_connected(self, user): |
| if user == self.user1: |
| self.user1_connected = True |
| if user == self.user2: |
| self.user2_connected = True |
| self.put() |
| |
| def is_connected(self, user): |
| if user == self.user1: |
| return self.user1_connected |
| if user == self.user2: |
| return self.user2_connected |
| |
| @db.transactional |
| def connect_user_to_room(room_key, user): |
| room = Room.get_by_key_name(room_key) |
| # Check if room has user in case that disconnect message comes before |
| # connect message with unknown reason, observed with local AppEngine SDK. |
| if room and room.has_user(user): |
| room.set_connected(user) |
| logging.info('User ' + user + ' connected to room ' + room_key) |
| logging.info('Room ' + room_key + ' has state ' + str(room)) |
| else: |
| logging.warning('Unexpected Connect Message to room ' + room_key) |
| return room |
| |
| class ConnectPage(webapp2.RequestHandler): |
| def post(self): |
| key = self.request.get('from') |
| room_key, user = key.split('/') |
| with LOCK: |
| room = connect_user_to_room(room_key, user) |
| if room and room.has_user(user): |
| send_saved_messages(make_client_id(room, user)) |
| |
| class DisconnectPage(webapp2.RequestHandler): |
| def post(self): |
| key = self.request.get('from') |
| room_key, user = key.split('/') |
| with LOCK: |
| room = Room.get_by_key_name(room_key) |
| if room and room.has_user(user): |
| other_user = room.get_other_user(user) |
| room.remove_user(user) |
| logging.info('User ' + user + ' removed from room ' + room_key) |
| logging.info('Room ' + room_key + ' has state ' + str(room)) |
| if other_user and other_user != user: |
| channel.send_message(make_client_id(room, other_user), |
| '{"type":"bye"}') |
| logging.info('Sent BYE to ' + other_user) |
| logging.warning('User ' + user + ' disconnected from room ' + room_key) |
| |
| |
| class MessagePage(webapp2.RequestHandler): |
| def post(self): |
| message = self.request.body |
| room_key = self.request.get('r') |
| user = self.request.get('u') |
| with LOCK: |
| room = Room.get_by_key_name(room_key) |
| if room: |
| handle_message(room, user, message) |
| else: |
| logging.warning('Unknown room ' + room_key) |
| |
| class MainPage(webapp2.RequestHandler): |
| """The main UI page, renders the 'index.html' template.""" |
| def get(self): |
| """Renders the main page. When this page is shown, we create a new |
| channel to push asynchronous updates to the client.""" |
| |
| # Append strings to this list to have them thrown up in message boxes. This |
| # will also cause the app to fail. |
| error_messages = [] |
| # Get the base url without arguments. |
| base_url = self.request.path_url |
| user_agent = self.request.headers['User-Agent'] |
| room_key = sanitize(self.request.get('r')) |
| stun_server = self.request.get('ss') |
| if not stun_server: |
| stun_server = get_default_stun_server(user_agent) |
| turn_server = self.request.get('ts') |
| |
| ts_pwd = self.request.get('tp') |
| |
| # Use "audio" and "video" to set the media stream constraints. Defined here: |
| # http://goo.gl/V7cZg |
| # |
| # "true" and "false" are recognized and interpreted as bools, for example: |
| # "?audio=true&video=false" (Start an audio-only call.) |
| # "?audio=false" (Start a video-only call.) |
| # If unspecified, the stream constraint defaults to True. |
| # |
| # To specify media track constraints, pass in a comma-separated list of |
| # key/value pairs, separated by a "=". Examples: |
| # "?audio=googEchoCancellation=false,googAutoGainControl=true" |
| # (Disable echo cancellation and enable gain control.) |
| # |
| # "?video=minWidth=1280,minHeight=720,googNoiseReduction=true" |
| # (Set the minimum resolution to 1280x720 and enable noise reduction.) |
| # |
| # Keys starting with "goog" will be added to the "optional" key; all others |
| # will be added to the "mandatory" key. |
| # |
| # The audio keys are defined here: talk/app/webrtc/localaudiosource.cc |
| # The video keys are defined here: talk/app/webrtc/videosource.cc |
| audio = self.request.get('audio') |
| video = self.request.get('video') |
| |
| if self.request.get('hd').lower() == 'true': |
| if video: |
| message = 'The "hd" parameter has overridden video=' + str(video) |
| logging.error(message) |
| error_messages.append(message) |
| video = 'minWidth=1280,minHeight=720' |
| |
| if self.request.get('minre') or self.request.get('maxre'): |
| message = ('The "minre" and "maxre" parameters are no longer supported. ' |
| 'Use "video" instead.') |
| logging.error(message) |
| error_messages.append(message) |
| |
| audio_send_codec = self.request.get('asc') |
| if not audio_send_codec: |
| audio_send_codec = get_preferred_audio_send_codec(user_agent) |
| |
| audio_receive_codec = self.request.get('arc') |
| if not audio_receive_codec: |
| audio_receive_codec = get_preferred_audio_receive_codec() |
| |
| # Set stereo to false by default. |
| stereo = 'false' |
| if self.request.get('stereo'): |
| stereo = self.request.get('stereo') |
| |
| # Set compat to true by default. |
| compat = 'true' |
| if self.request.get('compat'): |
| compat = self.request.get('compat') |
| |
| debug = self.request.get('debug') |
| if debug == 'loopback': |
| # Set compat to false as DTLS does not work for loopback. |
| compat = 'false' |
| |
| # Set DSCP for QoS support in WebRTC |
| dscp = self.request.get('dscp') |
| |
| # token_timeout for channel creation, default 30min, max 2 days, min 3min. |
| token_timeout = self.request.get_range('tt', |
| min_value = 3, |
| max_value = 3000, |
| default = 30) |
| |
| unittest = self.request.get('unittest') |
| if unittest: |
| # Always create a new room for the unit tests. |
| room_key = generate_random(8) |
| |
| if not room_key: |
| room_key = generate_random(8) |
| redirect = '/?r=' + room_key |
| redirect = append_url_arguments(self.request, redirect) |
| self.redirect(redirect) |
| logging.info('Redirecting visitor to base URL to ' + redirect) |
| return |
| |
| user = None |
| initiator = 0 |
| with LOCK: |
| room = Room.get_by_key_name(room_key) |
| if not room and debug != "full": |
| # New room. |
| user = generate_random(8) |
| room = Room(key_name = room_key) |
| room.add_user(user) |
| if debug != 'loopback': |
| initiator = 0 |
| else: |
| room.add_user(user) |
| initiator = 1 |
| elif room and room.get_occupancy() == 1 and debug != 'full': |
| # 1 occupant. |
| user = generate_random(8) |
| room.add_user(user) |
| initiator = 1 |
| else: |
| # 2 occupants (full). |
| template = jinja_environment.get_template('full.html') |
| self.response.out.write(template.render({ 'room_key': room_key })) |
| logging.info('Room ' + room_key + ' is full') |
| return |
| |
| room_link = base_url + '?r=' + room_key |
| room_link = append_url_arguments(self.request, room_link) |
| turn_url = 'https://computeengineondemand.appspot.com/' |
| turn_url = turn_url + 'turn?' + 'username=' + user + '&key=4080218913' |
| token = create_channel(room, user, token_timeout) |
| pc_config = make_pc_config(stun_server, turn_server, ts_pwd) |
| pc_constraints = make_pc_constraints(compat, dscp) |
| offer_constraints = make_offer_constraints() |
| media_constraints = make_media_stream_constraints(audio, video) |
| template_values = {'error_messages': error_messages, |
| 'token': token, |
| 'me': user, |
| 'room_key': room_key, |
| 'room_link': room_link, |
| 'initiator': initiator, |
| 'pc_config': json.dumps(pc_config), |
| 'pc_constraints': json.dumps(pc_constraints), |
| 'offer_constraints': json.dumps(offer_constraints), |
| 'media_constraints': json.dumps(media_constraints), |
| 'turn_url': turn_url, |
| 'stereo': stereo, |
| 'audio_send_codec': audio_send_codec, |
| 'audio_receive_codec': audio_receive_codec |
| } |
| if unittest: |
| target_page = 'test/test_' + unittest + '.html' |
| else: |
| target_page = 'index.html' |
| |
| template = jinja_environment.get_template(target_page) |
| self.response.out.write(template.render(template_values)) |
| logging.info('User ' + user + ' added to room ' + room_key) |
| logging.info('Room ' + room_key + ' has state ' + str(room)) |
| |
| |
| app = webapp2.WSGIApplication([ |
| ('/', MainPage), |
| ('/message', MessagePage), |
| ('/_ah/channel/connected/', ConnectPage), |
| ('/_ah/channel/disconnected/', DisconnectPage) |
| ], debug=True) |
