server: refactor out into state machine and add time request

server.py

@@ -9,6 +9,7 @@ from aiortc.contrib.media import MediaBlackhole, MediaPlayer
 import jack as Jack
 import os
 import re
+from datetime import datetime
 
 
 file_contents_ex = re.compile(r"^ws=\d$")
@@ -33,31 +34,37 @@ def write_ob_status(status):
 
 @Jack.set_error_function
 def error(msg):
-    print('Error:', msg)
+    print("Error:", msg)
 
 
 @Jack.set_info_function
 def info(msg):
-    print('Info:', msg)
+    print("Info:", msg)
+
+
+jack = Jack.Client("webstudio")
+out1 = jack.outports.register("out_0")
+out2 = jack.outports.register("out_1")
 
-jack = Jack.Client('webstudio')
-out1 = jack.outports.register('out_0')
-out2 = jack.outports.register('out_1')
 
 def init_buffers():
     global transfer_buffer1, transfer_buffer2
     transfer_buffer1 = Jack.RingBuffer(jack.samplerate * 10)
     transfer_buffer2 = Jack.RingBuffer(jack.samplerate * 10)
+
+
 init_buffers()
 
+
 @jack.set_process_callback
 def process(frames):
     buf1 = out1.get_buffer()
     piece1 = transfer_buffer1.read(len(buf1))
-    buf1[:len(piece1)] = piece1
+    buf1[: len(piece1)] = piece1
     buf2 = out2.get_buffer()
     piece2 = transfer_buffer2.read(len(buf2))
-    buf2[:len(piece2)] = piece2
+    buf2[: len(piece2)] = piece2
+
 
 class JackSender(object):
     def __init__(self, track):
@@ -79,19 +86,24 @@ class JackSender(object):
             # (my testing has shown it to be signed 16-bit)
             # We use PyAV to resample it into the right format
             if self.resampler is None:
-                self.resampler = av.audio.resampler.AudioResampler(format="fltp", layout="stereo", rate=jack.samplerate)
+                self.resampler = av.audio.resampler.AudioResampler(
+                    format="fltp", layout="stereo", rate=jack.samplerate
+                )
             frame.pts = None  # DIRTY HACK
             new_frame = self.resampler.resample(frame)
             transfer_buffer1.write(new_frame.planes[0])
             transfer_buffer2.write(new_frame.planes[1])
 
+
 current_session = None
 
+
 class Session(object):
     def __init__(self):
         self.websocket = None
         self.sender = None
         self.pc = None
+        self.connection_state = None
 
     async def end():
         print(self.connection_id, "going away")
@@ -100,29 +112,24 @@ class Session(object):
         await self.pc.close()
         init_buffers()
         write_ob_status(False)
-        await self.websocket.send(json.dumps({ "kind": "REPLACED" }))
+        await self.websocket.send(json.dumps({"kind": "REPLACED"}))
-
-    async def connect(self, websocket):
-        self.websocket = websocket
-        self.connection_id = uuid.uuid4();
-        print(self.connection_id, "Connected")
-        await websocket.send(json.dumps({"kind": "HELLO", "connectionId": str(self.connection_id)}))
-        sdp_offer = json.loads(await websocket.recv())
-        if sdp_offer["kind"] != "OFFER":
-            await websocket.close(1008)
-            return
-        offer = RTCSessionDescription(sdp=sdp_offer["sdp"], type=sdp_offer["type"])
-        print(self.connection_id, "Received offer")
 
+    def create_peerconnection(self):
         self.pc = RTCPeerConnection()
 
         @self.pc.on("signalingstatechange")
         async def on_signalingstatechange():
-            print(self.connection_id, "Signaling state is {}".format(self.pc.signalingState))
+            print(
+                self.connection_id,
+                "Signaling state is {}".format(self.pc.signalingState),
+            )
 
         @self.pc.on("iceconnectionstatechange")
         async def on_iceconnectionstatechange():
-            print(self.connection_id, "ICE connection state is {}".format(self.pc.iceConnectionState))
+            print(
+                self.connection_id,
+                "ICE connection state is {}".format(self.pc.iceConnectionState),
+            )
             if self.pc.iceConnectionState == "failed":
                 await self.pc.close()
                 self.pc = None
@@ -149,7 +156,11 @@ class Session(object):
                 write_ob_status(True)
                 await self.sender.process()
 
-
+    async def process_ice(self, message):
+        if self.connection_state == "HELLO" and message["kind"] == "OFFER":
+            offer = RTCSessionDescription(sdp=message["sdp"], type=message["type"])
+            print(self.connection_id, "Received offer")
+            self.create_peerconnection()
             await self.pc.setRemoteDescription(offer)
 
             answer = await self.pc.createAnswer()
@@ -164,10 +175,37 @@ class Session(object):
                     }
                 )
             )
+            self.connection_state = "ANSWER"
             print(self.connection_id, "Sent answer")
+        else:
+            print(
+                self.connection_state,
+                "Incorrect kind {} for state {}".format(
+                    message["kind"], self.connection_state
+                ),
+            )
+
+    async def connect(self, websocket):
+        self.websocket = websocket
+        self.connection_id = uuid.uuid4()
+        self.connection_state = "HELLO"
+        print(self.connection_id, "Connected")
+        await websocket.send(
+            json.dumps({"kind": "HELLO", "connectionId": str(self.connection_id)})
+        )
 
         async for msg in websocket:
-            print(self.connection_id, msg)
+            data = json.loads(msg)
+            if data["kind"] == "OFFER":
+                await self.process_ice(data)
+            elif data["kind"] == "TIME":
+                time = datetime.now().time()
+                await websocket.send(json.dumps({"kind": "TIME", "time": str(time)}))
+            else:
+                print(self.connection_id, "Unknown kind {}".format(data["kind"]))
+                await websocket.send(
+                    json.dumps({"kind": "ERROR", "error": "unknown_kind"})
+                )
 
 
 async def serve(websocket, path):