[AIT-96] feat: add msgpack suppport for websocket transport

ably/realtime/connectionmanager.py

@@ -154,6 +154,9 @@ async def __get_transport_params(self) -> dict:
         params["v"] = protocol_version
         if self.connection_details:
             params["resume"] = self.connection_details.connection_key
+        # RTN2a: Set format to msgpack if use_binary_protocol is enabled
+        if self.options.use_binary_protocol:
+            params["format"] = "msgpack"
         return params
 
     async def close_impl(self) -> None:

ably/realtime/realtime_channel.py

@@ -558,7 +558,8 @@ def _on_message(self, proto_msg: dict) -> None:
         elif action == ProtocolMessageAction.MESSAGE:
             messages = []
             try:
-                messages = Message.from_encoded_array(proto_msg.get('messages'), context=self.__decoding_context)
+                messages = Message.from_encoded_array(proto_msg.get('messages'),
+                                                      cipher=self.cipher, context=self.__decoding_context)
                 self.__decoding_context.last_message_id = messages[-1].id
                 self.__channel_serial = channel_serial
             except AblyException as e:

ably/transport/websockettransport.py

@@ -8,6 +8,8 @@
 from enum import IntEnum
 from typing import TYPE_CHECKING
 
+import msgpack
+
 from ably.http.httputils import HttpUtils
 from ably.types.connectiondetails import ConnectionDetails
 from ably.util.eventemitter import EventEmitter
@@ -71,6 +73,7 @@ def __init__(self, connection_manager: ConnectionManager, host: str, params: dic
         self.is_disposed = False
         self.host = host
         self.params = params
+        self.format = params.get('format', 'json')
         super().__init__()
 
     def connect(self):
@@ -189,12 +192,23 @@ async def ws_read_loop(self):
             raise AblyException('ws_read_loop started with no websocket', 500, 50000)
         try:
             async for raw in self.websocket:
-                msg = json.loads(raw)
-                task = asyncio.create_task(self.on_protocol_message(msg))
-                task.add_done_callback(self.on_protcol_message_handled)
+                # Decode based on format
+                try:
+                    msg = self.decode_raw_websocket_frame(raw)
+                    task = asyncio.create_task(self.on_protocol_message(msg))
+                    task.add_done_callback(self.on_protcol_message_handled)
+                except Exception as e:
+                    log.exception(
+                        f"WebSocketTransport.decode(): Unexpected exception handling channel message: {e}"
+                    )
         except ConnectionClosedOK:
             return
 
+    def decode_raw_websocket_frame(self, raw: str | bytes) -> dict:
+        if self.format == 'msgpack':
+            return msgpack.unpackb(raw, raw=False)
+        return json.loads(raw)
+
     def on_protcol_message_handled(self, task):
         try:
             exception = task.exception()
@@ -231,8 +245,13 @@ async def close(self):
     async def send(self, message: dict):
         if self.websocket is None:
             raise Exception()
-        raw_msg = json.dumps(message)
-        log.info(f'WebSocketTransport.send(): sending {raw_msg}')
+        # Encode based on format
+        if self.format == 'msgpack':
+            raw_msg = msgpack.packb(message, use_bin_type=True)
+            log.info(f'WebSocketTransport.send(): sending msgpack message (length: {len(raw_msg)} bytes)')
+        else:
+            raw_msg = json.dumps(message)
+            log.info(f'WebSocketTransport.send(): sending {raw_msg}')
         await self.websocket.send(raw_msg)
 
     def set_idle_timer(self, timeout: float):