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370 lines
12 KiB
Python
370 lines
12 KiB
Python
2 years ago
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# High level events that make up HTTP/1.1 conversations. Loosely inspired by
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# the corresponding events in hyper-h2:
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#
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# http://python-hyper.org/h2/en/stable/api.html#events
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#
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# Don't subclass these. Stuff will break.
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import re
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from abc import ABC
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from dataclasses import dataclass, field
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from typing import Any, cast, Dict, List, Tuple, Union
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from ._abnf import method, request_target
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from ._headers import Headers, normalize_and_validate
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from ._util import bytesify, LocalProtocolError, validate
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# Everything in __all__ gets re-exported as part of the h11 public API.
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__all__ = [
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"Event",
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"Request",
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"InformationalResponse",
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"Response",
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"Data",
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"EndOfMessage",
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"ConnectionClosed",
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]
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method_re = re.compile(method.encode("ascii"))
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request_target_re = re.compile(request_target.encode("ascii"))
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class Event(ABC):
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"""
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Base class for h11 events.
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"""
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__slots__ = ()
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@dataclass(init=False, frozen=True)
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class Request(Event):
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"""The beginning of an HTTP request.
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Fields:
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.. attribute:: method
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An HTTP method, e.g. ``b"GET"`` or ``b"POST"``. Always a byte
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string. :term:`Bytes-like objects <bytes-like object>` and native
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strings containing only ascii characters will be automatically
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converted to byte strings.
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.. attribute:: target
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The target of an HTTP request, e.g. ``b"/index.html"``, or one of the
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more exotic formats described in `RFC 7320, section 5.3
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<https://tools.ietf.org/html/rfc7230#section-5.3>`_. Always a byte
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string. :term:`Bytes-like objects <bytes-like object>` and native
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strings containing only ascii characters will be automatically
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converted to byte strings.
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.. attribute:: headers
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Request headers, represented as a list of (name, value) pairs. See
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:ref:`the header normalization rules <headers-format>` for details.
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.. attribute:: http_version
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The HTTP protocol version, represented as a byte string like
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``b"1.1"``. See :ref:`the HTTP version normalization rules
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<http_version-format>` for details.
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"""
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__slots__ = ("method", "headers", "target", "http_version")
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method: bytes
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headers: Headers
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target: bytes
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http_version: bytes
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def __init__(
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self,
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*,
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method: Union[bytes, str],
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headers: Union[Headers, List[Tuple[bytes, bytes]], List[Tuple[str, str]]],
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target: Union[bytes, str],
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http_version: Union[bytes, str] = b"1.1",
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_parsed: bool = False,
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) -> None:
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super().__init__()
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if isinstance(headers, Headers):
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object.__setattr__(self, "headers", headers)
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else:
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object.__setattr__(
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self, "headers", normalize_and_validate(headers, _parsed=_parsed)
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)
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if not _parsed:
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object.__setattr__(self, "method", bytesify(method))
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object.__setattr__(self, "target", bytesify(target))
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object.__setattr__(self, "http_version", bytesify(http_version))
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else:
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object.__setattr__(self, "method", method)
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object.__setattr__(self, "target", target)
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object.__setattr__(self, "http_version", http_version)
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# "A server MUST respond with a 400 (Bad Request) status code to any
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# HTTP/1.1 request message that lacks a Host header field and to any
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# request message that contains more than one Host header field or a
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# Host header field with an invalid field-value."
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# -- https://tools.ietf.org/html/rfc7230#section-5.4
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host_count = 0
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for name, value in self.headers:
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if name == b"host":
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host_count += 1
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if self.http_version == b"1.1" and host_count == 0:
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raise LocalProtocolError("Missing mandatory Host: header")
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if host_count > 1:
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raise LocalProtocolError("Found multiple Host: headers")
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validate(method_re, self.method, "Illegal method characters")
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validate(request_target_re, self.target, "Illegal target characters")
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# This is an unhashable type.
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__hash__ = None # type: ignore
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@dataclass(init=False, frozen=True)
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class _ResponseBase(Event):
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__slots__ = ("headers", "http_version", "reason", "status_code")
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headers: Headers
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http_version: bytes
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reason: bytes
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status_code: int
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def __init__(
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self,
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*,
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headers: Union[Headers, List[Tuple[bytes, bytes]], List[Tuple[str, str]]],
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status_code: int,
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http_version: Union[bytes, str] = b"1.1",
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reason: Union[bytes, str] = b"",
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_parsed: bool = False,
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) -> None:
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super().__init__()
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if isinstance(headers, Headers):
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object.__setattr__(self, "headers", headers)
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else:
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object.__setattr__(
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self, "headers", normalize_and_validate(headers, _parsed=_parsed)
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)
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if not _parsed:
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object.__setattr__(self, "reason", bytesify(reason))
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object.__setattr__(self, "http_version", bytesify(http_version))
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if not isinstance(status_code, int):
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raise LocalProtocolError("status code must be integer")
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# Because IntEnum objects are instances of int, but aren't
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# duck-compatible (sigh), see gh-72.
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object.__setattr__(self, "status_code", int(status_code))
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else:
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object.__setattr__(self, "reason", reason)
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object.__setattr__(self, "http_version", http_version)
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object.__setattr__(self, "status_code", status_code)
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self.__post_init__()
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def __post_init__(self) -> None:
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pass
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# This is an unhashable type.
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__hash__ = None # type: ignore
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@dataclass(init=False, frozen=True)
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class InformationalResponse(_ResponseBase):
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"""An HTTP informational response.
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Fields:
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.. attribute:: status_code
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The status code of this response, as an integer. For an
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:class:`InformationalResponse`, this is always in the range [100,
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200).
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.. attribute:: headers
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Request headers, represented as a list of (name, value) pairs. See
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:ref:`the header normalization rules <headers-format>` for
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details.
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.. attribute:: http_version
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The HTTP protocol version, represented as a byte string like
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``b"1.1"``. See :ref:`the HTTP version normalization rules
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<http_version-format>` for details.
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.. attribute:: reason
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The reason phrase of this response, as a byte string. For example:
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``b"OK"``, or ``b"Not Found"``.
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"""
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def __post_init__(self) -> None:
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if not (100 <= self.status_code < 200):
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raise LocalProtocolError(
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"InformationalResponse status_code should be in range "
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"[100, 200), not {}".format(self.status_code)
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)
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# This is an unhashable type.
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__hash__ = None # type: ignore
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@dataclass(init=False, frozen=True)
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class Response(_ResponseBase):
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"""The beginning of an HTTP response.
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Fields:
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.. attribute:: status_code
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The status code of this response, as an integer. For an
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:class:`Response`, this is always in the range [200,
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1000).
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.. attribute:: headers
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Request headers, represented as a list of (name, value) pairs. See
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:ref:`the header normalization rules <headers-format>` for details.
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.. attribute:: http_version
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The HTTP protocol version, represented as a byte string like
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``b"1.1"``. See :ref:`the HTTP version normalization rules
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<http_version-format>` for details.
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.. attribute:: reason
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The reason phrase of this response, as a byte string. For example:
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``b"OK"``, or ``b"Not Found"``.
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"""
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def __post_init__(self) -> None:
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if not (200 <= self.status_code < 1000):
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raise LocalProtocolError(
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"Response status_code should be in range [200, 1000), not {}".format(
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self.status_code
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)
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)
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# This is an unhashable type.
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__hash__ = None # type: ignore
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@dataclass(init=False, frozen=True)
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class Data(Event):
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"""Part of an HTTP message body.
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Fields:
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.. attribute:: data
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A :term:`bytes-like object` containing part of a message body. Or, if
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using the ``combine=False`` argument to :meth:`Connection.send`, then
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any object that your socket writing code knows what to do with, and for
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which calling :func:`len` returns the number of bytes that will be
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written -- see :ref:`sendfile` for details.
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.. attribute:: chunk_start
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A marker that indicates whether this data object is from the start of a
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chunked transfer encoding chunk. This field is ignored when when a Data
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event is provided to :meth:`Connection.send`: it is only valid on
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events emitted from :meth:`Connection.next_event`. You probably
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shouldn't use this attribute at all; see
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:ref:`chunk-delimiters-are-bad` for details.
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.. attribute:: chunk_end
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A marker that indicates whether this data object is the last for a
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given chunked transfer encoding chunk. This field is ignored when when
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a Data event is provided to :meth:`Connection.send`: it is only valid
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on events emitted from :meth:`Connection.next_event`. You probably
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shouldn't use this attribute at all; see
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:ref:`chunk-delimiters-are-bad` for details.
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"""
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__slots__ = ("data", "chunk_start", "chunk_end")
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data: bytes
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chunk_start: bool
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chunk_end: bool
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def __init__(
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self, data: bytes, chunk_start: bool = False, chunk_end: bool = False
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) -> None:
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object.__setattr__(self, "data", data)
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object.__setattr__(self, "chunk_start", chunk_start)
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object.__setattr__(self, "chunk_end", chunk_end)
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# This is an unhashable type.
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__hash__ = None # type: ignore
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# XX FIXME: "A recipient MUST ignore (or consider as an error) any fields that
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# are forbidden to be sent in a trailer, since processing them as if they were
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# present in the header section might bypass external security filters."
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# https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#chunked.trailer.part
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# Unfortunately, the list of forbidden fields is long and vague :-/
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@dataclass(init=False, frozen=True)
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class EndOfMessage(Event):
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"""The end of an HTTP message.
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Fields:
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.. attribute:: headers
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Default value: ``[]``
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Any trailing headers attached to this message, represented as a list of
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(name, value) pairs. See :ref:`the header normalization rules
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<headers-format>` for details.
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Must be empty unless ``Transfer-Encoding: chunked`` is in use.
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"""
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__slots__ = ("headers",)
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headers: Headers
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def __init__(
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self,
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*,
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headers: Union[
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Headers, List[Tuple[bytes, bytes]], List[Tuple[str, str]], None
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] = None,
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_parsed: bool = False,
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) -> None:
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super().__init__()
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if headers is None:
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headers = Headers([])
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elif not isinstance(headers, Headers):
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headers = normalize_and_validate(headers, _parsed=_parsed)
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object.__setattr__(self, "headers", headers)
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# This is an unhashable type.
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__hash__ = None # type: ignore
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@dataclass(frozen=True)
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class ConnectionClosed(Event):
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"""This event indicates that the sender has closed their outgoing
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connection.
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Note that this does not necessarily mean that they can't *receive* further
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data, because TCP connections are composed to two one-way channels which
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can be closed independently. See :ref:`closing` for details.
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No fields.
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"""
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pass
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