Method _reader_task

py/private/cdp.py:446–493

Runs in the background and handles incoming messages. Dispatches responses to commands and events to listeners.

(self)

        return session

    async def _reader_task(self):
        """Runs in the background and handles incoming messages.

        Dispatches responses to commands and events to listeners.
        """
        global devtools
        if devtools is None:
            raise RuntimeError("CDP devtools module not loaded. Call import_devtools() first.")
        while True:
            try:
                message = await self.ws.get_message()
            except WsConnectionClosed:
                # If the WebSocket is closed, we don't want to throw an
                # exception from the reader task. Instead we will throw
                # exceptions from the public API methods, and we can quietly
                # exit the reader task here.
                break
            try:
                data = json.loads(message)
            except json.JSONDecodeError:
                raise BrowserError(
                    {
                        "code": -32700,
                        "message": "Client received invalid JSON",
                        "data": message,
                    }
                )
            logger.debug("Received message %r", data)
            if "sessionId" in data:
                session_id = devtools.target.SessionID(data["sessionId"])
                try:
                    session = self.sessions[session_id]
                except KeyError:
                    raise BrowserError(
                        {
                            "code": -32700,
                            "message": "Browser sent a message for an invalid session",
                            "data": f"{session_id!r}",
                        }
                    )
                session._handle_data(data)
            else:
                self._handle_data(data)

        for _, session in self.sessions.items():
            for _, senders in session.channels.items():
                for sender in senders:
                    sender.close()


@asynccontextmanager