# 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__ = ()
@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
@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
@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
@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 :-/
@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
@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
