Method _setup_callback_parser

gunicorn/asgi/protocol.py:452–532

Create callback parser based on http_parser setting. Parser selection: - auto: Use H1CProtocol if available (>= 0.4.1) and no incompatible flags, else PythonProtocol - fast: Require H1CProtocol >= 0.4.1 (error if unavailable or incompatible flags) - python: Use Pytho

(self)

    )

    def _setup_callback_parser(self):
        """Create callback parser based on http_parser setting.

        Parser selection:
        - auto: Use H1CProtocol if available (>= 0.4.1) and no incompatible flags, else PythonProtocol
        - fast: Require H1CProtocol >= 0.4.1 (error if unavailable or incompatible flags)
        - python: Use PythonProtocol only
        """
        parser_setting = getattr(self.cfg, 'http_parser', 'auto')

        # Check for incompatible compatibility flags
        incompatible = []
        for flag in self._FAST_PARSER_INCOMPATIBLE_FLAGS:
            if getattr(self.cfg, flag, False):
                incompatible.append(flag)
        # PROXY protocol framing is implemented only in PythonProtocol; the C parser
        # has no proxy_protocol kwarg and would silently drop the framing.
        if getattr(self.cfg, 'proxy_protocol', 'off') != 'off':
            incompatible.append('proxy_protocol')

        if parser_setting == 'python':
            parser_class = PythonProtocol
        elif parser_setting == 'fast':
            if not self._check_h1c_protocol_available():
                raise RuntimeError("gunicorn_h1c required for http_parser='fast'")
            if not ASGIProtocol._h1c_has_limits:
                raise RuntimeError(
                    "gunicorn_h1c >= 0.4.1 required for http_parser='fast'. "
                    "Please upgrade: pip install --upgrade gunicorn_h1c"
                )
            if incompatible:
                raise RuntimeError(
                    "http_parser='fast' is incompatible with compatibility flags: %s. "
                    "Use http_parser='python' or disable these flags."
                    % ', '.join(incompatible)
                )
            parser_class = ASGIProtocol._h1c_protocol_class
        else:  # auto
            if (self._check_h1c_protocol_available() and
                    ASGIProtocol._h1c_has_limits and not incompatible):
                parser_class = ASGIProtocol._h1c_protocol_class
            else:
                parser_class = PythonProtocol

        # Handle limit_request_line=0 (unlimited per documentation)
        # PythonProtocol handles 0 correctly, but C parser needs a large value
        limit_request_line = self.cfg.limit_request_line
        if limit_request_line == 0 and parser_class != PythonProtocol:
            limit_request_line = 1024 * 1024  # 1MB for C parser

        # Create parser with callbacks and limit parameters (both parsers support them).
        # Only the Python parser implements PROXY protocol framing; pass the option there.
        parser_kwargs = {
            'on_headers_complete': self._on_headers_complete,
            'on_body': self._on_body,
            'on_message_complete': self._on_message_complete,
            'limit_request_line': limit_request_line,
            'limit_request_fields': self.cfg.limit_request_fields,