Class ASGIProtocol

gunicorn/asgi/protocol.py:335–1790

HTTP/1.1 protocol handler for ASGI applications. Handles connection lifecycle, request parsing, and ASGI app invocation. Uses callback-based parsing (H1CProtocol/PythonProtocol) for efficient incremental parsing in data_received().

class ASGIProtocol(asyncio.Protocol):
    """HTTP/1.1 protocol handler for ASGI applications.

    Handles connection lifecycle, request parsing, and ASGI app invocation.
    Uses callback-based parsing (H1CProtocol/PythonProtocol) for efficient
    incremental parsing in data_received().
    """

    # Class-level cache for H1CProtocol availability
    _h1c_available = None
    _h1c_protocol_class = None
    _h1c_has_limits = False  # True if >= 0.4.1 (has limit parameters)
    _h1c_limit_request_line = None  # Exception class from gunicorn_h1c >= 0.4.1
    _h1c_limit_request_headers = None  # Exception class from gunicorn_h1c >= 0.4.1
    _h1c_invalid_chunk_extension = None  # Exception class from gunicorn_h1c >= 0.6.3

    def __init__(self, worker):
        self.worker = worker
        self.cfg = worker.cfg
        self.log = worker.log
        self.app = worker.asgi

        self.transport = None
        self.reader = None  # Only used for HTTP/2
        self.writer = None
        self._task = None
        self.req_count = 0

        # Connection state
        self._closed = False
        self._body_receiver = None  # Set per-request for disconnect signaling

        # Response buffering for write batching
        self._response_buffer = None

        # Backpressure control
        self._reading_paused = False
        self._max_buffer_size = 65536 * 4  # 256KB max buffer (HTTP/2 only)

        # Keep-alive timer
        self._keepalive_handle = None

        # Callback parser state
        self._callback_parser = None
        self._request_ready = None  # Event signaling headers complete
        self._current_request = None  # Request built from parser state
        self._is_ssl = False

        # Write flow control
        self._flow_control = None

        # WebSocket protocol (set during upgrade, receives data via callbacks)
        self._websocket = None

    def connection_made(self, transport):
        """Called when a connection is established."""
        self.transport = transport
        self.worker.nr_conns += 1