Source code for h11._events

# High level events that make up HTTP/1.1 conversations. Loosely inspired by
# the corresponding events in hyper-h2:
#
#     http://python-hyper.org/h2/en/stable/api.html#events
#
# Don't subclass these. Stuff will break.

import re
from abc import ABC
from dataclasses import dataclass, field
from typing import Any, cast, Dict, List, Tuple, Union

from ._abnf import method, request_target
from ._headers import Headers, normalize_and_validate
from ._util import bytesify, LocalProtocolError, validate

# Everything in __all__ gets re-exported as part of the h11 public API.
__all__ = [
    "Event",
    "Request",
    "InformationalResponse",
    "Response",
    "Data",
    "EndOfMessage",
    "ConnectionClosed",
]

method_re = re.compile(method.encode("ascii"))
request_target_re = re.compile(request_target.encode("ascii"))


class Event(ABC):
    """
    Base class for h11 events.
    """

    __slots__ = ()


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