303 lines
9.6 KiB
Python
303 lines
9.6 KiB
Python
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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 . import _headers
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from ._abnf import request_target
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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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"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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request_target_re = re.compile(request_target.encode("ascii"))
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class _EventBundle:
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_fields = []
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_defaults = {}
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def __init__(self, **kwargs):
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_parsed = kwargs.pop("_parsed", False)
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allowed = set(self._fields)
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for kwarg in kwargs:
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if kwarg not in allowed:
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raise TypeError(
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"unrecognized kwarg {} for {}".format(
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kwarg, self.__class__.__name__
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)
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)
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required = allowed.difference(self._defaults)
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for field in required:
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if field not in kwargs:
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raise TypeError(
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"missing required kwarg {} for {}".format(
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field, self.__class__.__name__
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)
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)
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self.__dict__.update(self._defaults)
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self.__dict__.update(kwargs)
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# Special handling for some fields
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if "headers" in self.__dict__:
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self.headers = _headers.normalize_and_validate(
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self.headers, _parsed=_parsed
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)
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if not _parsed:
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for field in ["method", "target", "http_version", "reason"]:
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if field in self.__dict__:
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self.__dict__[field] = bytesify(self.__dict__[field])
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if "status_code" in self.__dict__:
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if not isinstance(self.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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self.status_code = int(self.status_code)
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self._validate()
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def _validate(self):
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pass
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def __repr__(self):
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name = self.__class__.__name__
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kwarg_strs = [
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"{}={}".format(field, self.__dict__[field]) for field in self._fields
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]
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kwarg_str = ", ".join(kwarg_strs)
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return "{}({})".format(name, kwarg_str)
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# Useful for tests
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def __eq__(self, other):
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return self.__class__ == other.__class__ and self.__dict__ == other.__dict__
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# This is an unhashable type.
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__hash__ = None
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class Request(_EventBundle):
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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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_fields = ["method", "target", "headers", "http_version"]
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_defaults = {"http_version": b"1.1"}
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def _validate(self):
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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(request_target_re, self.target, "Illegal target characters")
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class _ResponseBase(_EventBundle):
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_fields = ["status_code", "headers", "http_version", "reason"]
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_defaults = {"http_version": b"1.1", "reason": b""}
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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 _validate(self):
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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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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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600).
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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 _validate(self):
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if not (200 <= self.status_code < 600):
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raise LocalProtocolError(
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"Response status_code should be in range [200, 600), not {}".format(
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self.status_code
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)
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)
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class Data(_EventBundle):
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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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_fields = ["data", "chunk_start", "chunk_end"]
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_defaults = {"chunk_start": False, "chunk_end": False}
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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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class EndOfMessage(_EventBundle):
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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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_fields = ["headers"]
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_defaults = {"headers": []}
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class ConnectionClosed(_EventBundle):
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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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