lagarde.py

   1 #!/usr/bin/python3
   2
   3 import argparse
   4 import asyncio
   5 import json
   6 import logging
   7 import ssl
   8 import queue
   9 from typing import Optional, List
  10
  11 import gi
  12 import websockets
  13
  14 gi.require_version('Gst', '1.0')
  15 from gi.repository import Gst
  16
  17 gi.require_version('GstWebRTC', '1.0')
  18 from gi.repository import GstWebRTC
  19
  20 gi.require_version('GstSdp', '1.0')
  21 from gi.repository import GstSdp
  22
  23 log = logging.getLogger(__name__)
  24
  25
  26 class Lagarde:
  27     def __init__(self):
  28         self.sdp_offer: Optional[str] = None
  29         self.websocket: Optional[websockets.client.WebSocketClientProtocol] = None
  30         self.session_id = None
  31         self.received_ice_candidates = queue.Queue()
  32         self.generated_ice_candidates = queue.Queue()
  33         self.user_fragments: Optional[List] = None
  34         self.mids: Optional[List] = None
  35         self.pipe = None
  36         self.webrtcbin = None
  37
  38     def on_negotiation_needed(self, element):
  39         log.debug('on_negotiation_needed')
  40
  41     def on_ice_candidate(self, element, mlineindex, candidate):
  42         log.debug('on_ice_candidate')
  43         self.generated_ice_candidates.put_nowait((mlineindex, candidate))
  44
  45     def webrtcbin_pad_added(self, element, pad):
  46         log.debug('webrtcbin_pad_added')
  47         if pad.direction != Gst.PadDirection.SRC:
  48             return
  49         decodebin = Gst.ElementFactory.make('decodebin')
  50         decodebin.connect('pad-added', self.decodebin_pad_added)
  51         self.pipe.add(decodebin)
  52         decodebin.sync_state_with_parent()
  53         self.webrtcbin.link(decodebin)
  54
  55     def decodebin_pad_added(self, element, pad):
  56         log.debug('decodebin_pad_added')
  57         if not pad.has_current_caps():
  58             log.debug(pad, 'has no caps, ignoring')
  59             return
  60
  61         caps = pad.get_current_caps()
  62         padsize = caps.get_size()
  63         for i in range(padsize):
  64             s = caps.get_structure(i) # Gst.Structure
  65             name = s.get_name()
  66             if name.startswith('video'):
  67                 q = Gst.ElementFactory.make('queue')
  68                 conv = Gst.ElementFactory.make('videoconvert')
  69                 # sink = Gst.ElementFactory.make('autovideosink') # needs XDG_RUNTIME_DIR
  70                 sink = Gst.ElementFactory.make('xvimagesink')
  71                 self.pipe.add(q)
  72                 self.pipe.add(conv)
  73                 self.pipe.add(sink)
  74                 self.pipe.sync_children_states()
  75                 pad.link(q.get_static_pad('sink'))
  76                 q.link(conv)
  77                 conv.link(sink)
  78             elif name.startswith('audio'):
  79                 q = Gst.ElementFactory.make('queue')
  80                 conv = Gst.ElementFactory.make('audioconvert')
  81                 resample = Gst.ElementFactory.make('audioresample')
  82                 sink = Gst.ElementFactory.make('autoaudiosink')
  83                 self.pipe.add(q)
  84                 self.pipe.add(conv)
  85                 self.pipe.add(resample)
  86                 self.pipe.add(sink)
  87                 self.pipe.sync_children_states()
  88                 pad.link(q.get_static_pad('sink'))
  89                 q.link(conv)
  90                 conv.link(resample)
  91                 resample.link(sink)
  92
  93     async def listen_to_gstreamer_bus(self):
  94         Gst.init(None)
  95         self.webrtcbin = Gst.ElementFactory.make('webrtcbin', 'laplace')
  96         self.pipe = Gst.Pipeline.new("pipeline")
  97         Gst.Bin.do_add_element(self.pipe, self.webrtcbin)
  98         bus = Gst.Pipeline.get_bus(self.pipe)
  99         self.webrtcbin.connect('on-negotiation-needed', self.on_negotiation_needed)
 100         self.webrtcbin.connect('on-ice-candidate', self.on_ice_candidate)
 101         self.webrtcbin.connect('pad-added', self.webrtcbin_pad_added)
 102         self.pipe.set_state(Gst.State.PLAYING)
 103         try:
 104             while True:
 105                 if bus.have_pending():
 106                     msg = bus.pop()
 107                     if msg.type == Gst.MessageType.ERROR:
 108                         log.error(f'Error from gstreamer message bus: {msg.get_structure()}')
 109                         return
 110                     elif msg.type == Gst.MessageType.EOS:  # end of stream
 111                         log.info(f'Gstreamer message bus reports end of stream')
 112                         return
 113                 elif self.sdp_offer is not None:
 114                     res, sm = GstSdp.SDPMessage.new()
 115                     assert res == GstSdp.SDPResult.OK
 116                     GstSdp.sdp_message_parse_buffer(bytes(self.sdp_offer.encode()), sm)
 117                     # the three lines above can also be done this way in new versions of GStreamer:
 118                     # sm = GstSdp.SDPMessage.new_from_text(sdp_offer)
 119                     rd = GstWebRTC.WebRTCSessionDescription.new(GstWebRTC.WebRTCSDPType.OFFER, sm)
 120                     gst_promise = Gst.Promise.new()
 121                     self.webrtcbin.emit('set-remote-description', rd, gst_promise)
 122                     await asyncio.get_event_loop().run_in_executor(None, gst_promise.wait)
 123                     self.sdp_offer = None
 124
 125                     gst_promise = Gst.Promise.new()
 126                     self.webrtcbin.emit('create-answer', None, gst_promise)
 127                     result = await asyncio.get_event_loop().run_in_executor(None, gst_promise.wait)
 128                     assert result == Gst.PromiseResult.REPLIED
 129                     reply = gst_promise.get_reply()
 130                     answer = reply.get_value('answer')
 131                     sdp_message = answer.sdp
 132                     self.user_fragments = [sdp_message.get_media(i).get_attribute_val('ice-ufrag')
 133                                           for i in range(sdp_message.medias_len())]
 134                     self.mids = [sdp_message.get_media(i).get_attribute_val('mid')
 135                                           for i in range(sdp_message.medias_len())]
 136                     sdp_answer = sdp_message.as_text()
 137                     log.info(f'Send SDP answer:\n{sdp_answer}')
 138                     sdp_answer_msg = json.dumps({
 139                         'SessionID': self.session_id,
 140                         'Type': "gotAnswer",
 141                         'Value': json.dumps({
 142                             'type': 'answer',
 143                             'sdp': sdp_answer
 144                         })
 145                     })
 146                     gst_promise = Gst.Promise.new()
 147                     self.webrtcbin.emit('set-local-description', answer, gst_promise)
 148                     await asyncio.get_event_loop().run_in_executor(None, gst_promise.wait)
 149                     gst_promise.get_reply()
 150                     await self.websocket.send(sdp_answer_msg)
 151
 152                 elif self.received_ice_candidates.qsize() > 0:
 153                     ic = self.received_ice_candidates.get_nowait()
 154                     if ic['candidate'] != '':
 155                         self.webrtcbin.emit('add-ice-candidate', ic['sdpMLineIndex'], ic['candidate'])
 156
 157                 elif self.generated_ice_candidates.qsize() > 0:
 158                     mlineindex, candidate = self.generated_ice_candidates.get_nowait()
 159                     icemsg_value = json.dumps({
 160                         "candidate": candidate,
 161                         "sdpMid": self.mids[mlineindex],
 162                         "sdpMLineIndex": mlineindex,
 163                         "usernameFragment": self.user_fragments[mlineindex],
 164                     })
 165                     icemsg = json.dumps({
 166                         'SessionID': self.session_id,
 167                         'Type': 'addCalleeIceCandidate',
 168                         'Value': icemsg_value,
 169                     })
 170                     log.info(f'Send ICE candidate: {icemsg_value}')
 171                     await self.websocket.send(icemsg)
 172
 173                 else:
 174                     await asyncio.sleep(0.1)
 175         finally:
 176             self.pipe.set_state(Gst.State.NULL)
 177
 178     async def talk_to_websocket(self, uri):
 179         async for msg in self.websocket:
 180             msg_json = json.loads(msg)
 181             msg_type = msg_json['Type']
 182             msg_value = msg_json['Value']
 183             assert self.session_id is None or self.session_id == msg_json['SessionID']
 184             if msg_type == 'newSession':
 185                 self.session_id = msg_json['SessionID']
 186                 log.info(f"New session {self.session_id}")
 187             elif msg_type == 'gotOffer':
 188                 value_json = json.loads(msg_value)
 189                 sdp = value_json['sdp']
 190                 log.info(f'Got SDP offer:\n{sdp}')
 191                 self.sdp_offer = sdp
 192             elif msg_type == 'addCallerIceCandidate':
 193                 value_json = json.loads(msg_value)
 194                 log.info(f'Got ICE candidate: {value_json}')
 195                 self.received_ice_candidates.put_nowait(value_json)
 196             elif msg_type == 'roomNotFound':
 197                 log.error(f'The room was not found: {uri}')
 198                 return
 199             elif msg_type == 'roomClosed':
 200                 log.info(f'Oh noes, the room went away (session {self.session_id})!')
 201                 self.session_id = None
 202                 return
 203             else:
 204                 log.error(f'Unknown message type {msg_type}')
 205
 206     async def run(self, uri):
 207         ssl_context = ssl.SSLContext()
 208         ssl_context.check_hostname = False
 209         ssl_context.verify_mode = ssl.CERT_NONE
 210         try:
 211             async with websockets.connect(uri, ssl=ssl_context) as self.websocket:
 212                 talk_to_websocket_task = asyncio.Task(self.talk_to_websocket(uri))
 213                 listen_to_gstreamer_bus_task = asyncio.Task(self.listen_to_gstreamer_bus())
 214                 done, pending = await asyncio.wait(
 215                     [talk_to_websocket_task, listen_to_gstreamer_bus_task],
 216                     return_when=asyncio.FIRST_COMPLETED)
 217                 for d in done:
 218                     d.result()
 219                 for p in pending:
 220                     p.cancel()
 221         except OSError as e:
 222             print(e)
 223
 224
 225 def main():
 226     logging.basicConfig(level=logging.INFO, format='%(asctime)-15s %(message)s')
 227     parser = argparse.ArgumentParser()
 228     parser.add_argument('--uri', default='wss://localhost:1234/ws_connect?id=cug',
 229                         help='Signalling server URI')
 230     args = parser.parse_args()
 231     lagarde = Lagarde()
 232     asyncio.run(lagarde.run(args.uri), debug=True)
 233
 234
 235 if __name__ == '__main__':
 236     main()