Update 2025-04-13_16:26:34

venv/lib/python3.11/site-packages/h11/__init__.py

@@ -0,0 +1,62 @@
+# A highish-level implementation of the HTTP/1.1 wire protocol (RFC 7230),
+# containing no networking code at all, loosely modelled on hyper-h2's generic
+# implementation of HTTP/2 (and in particular the h2.connection.H2Connection
+# class). There's still a bunch of subtle details you need to get right if you
+# want to make this actually useful, because it doesn't implement all the
+# semantics to check that what you're asking to write to the wire is sensible,
+# but at least it gets you out of dealing with the wire itself.
+
+from h11._connection import Connection, NEED_DATA, PAUSED
+from h11._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from h11._state import (
+    CLIENT,
+    CLOSED,
+    DONE,
+    ERROR,
+    IDLE,
+    MIGHT_SWITCH_PROTOCOL,
+    MUST_CLOSE,
+    SEND_BODY,
+    SEND_RESPONSE,
+    SERVER,
+    SWITCHED_PROTOCOL,
+)
+from h11._util import LocalProtocolError, ProtocolError, RemoteProtocolError
+from h11._version import __version__
+
+PRODUCT_ID = "python-h11/" + __version__
+
+
+__all__ = (
+    "Connection",
+    "NEED_DATA",
+    "PAUSED",
+    "ConnectionClosed",
+    "Data",
+    "EndOfMessage",
+    "Event",
+    "InformationalResponse",
+    "Request",
+    "Response",
+    "CLIENT",
+    "CLOSED",
+    "DONE",
+    "ERROR",
+    "IDLE",
+    "MUST_CLOSE",
+    "SEND_BODY",
+    "SEND_RESPONSE",
+    "SERVER",
+    "SWITCHED_PROTOCOL",
+    "ProtocolError",
+    "LocalProtocolError",
+    "RemoteProtocolError",
+)

venv/lib/python3.11/site-packages/h11/_abnf.py

@@ -0,0 +1,132 @@
+# We use native strings for all the re patterns, to take advantage of string
+# formatting, and then convert to bytestrings when compiling the final re
+# objects.
+
+# https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#whitespace
+#  OWS            = *( SP / HTAB )
+#                 ; optional whitespace
+OWS = r"[ \t]*"
+
+# https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#rule.token.separators
+#   token          = 1*tchar
+#
+#   tchar          = "!" / "#" / "$" / "%" / "&" / "'" / "*"
+#                  / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
+#                  / DIGIT / ALPHA
+#                  ; any VCHAR, except delimiters
+token = r"[-!#$%&'*+.^_`|~0-9a-zA-Z]+"
+
+# https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#header.fields
+#  field-name     = token
+field_name = token
+
+# The standard says:
+#
+#  field-value    = *( field-content / obs-fold )
+#  field-content  = field-vchar [ 1*( SP / HTAB ) field-vchar ]
+#  field-vchar    = VCHAR / obs-text
+#  obs-fold       = CRLF 1*( SP / HTAB )
+#                 ; obsolete line folding
+#                 ; see Section 3.2.4
+#
+# https://tools.ietf.org/html/rfc5234#appendix-B.1
+#
+#   VCHAR          =  %x21-7E
+#                  ; visible (printing) characters
+#
+# https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#rule.quoted-string
+#   obs-text       = %x80-FF
+#
+# However, the standard definition of field-content is WRONG! It disallows
+# fields containing a single visible character surrounded by whitespace,
+# e.g. "foo a bar".
+#
+# See: https://www.rfc-editor.org/errata_search.php?rfc=7230&eid=4189
+#
+# So our definition of field_content attempts to fix it up...
+#
+# Also, we allow lots of control characters, because apparently people assume
+# that they're legal in practice (e.g., google analytics makes cookies with
+# \x01 in them!):
+#   https://github.com/python-hyper/h11/issues/57
+# We still don't allow NUL or whitespace, because those are often treated as
+# meta-characters and letting them through can lead to nasty issues like SSRF.
+vchar = r"[\x21-\x7e]"
+vchar_or_obs_text = r"[^\x00\s]"
+field_vchar = vchar_or_obs_text
+field_content = r"{field_vchar}+(?:[ \t]+{field_vchar}+)*".format(**globals())
+
+# We handle obs-fold at a different level, and our fixed-up field_content
+# already grows to swallow the whole value, so ? instead of *
+field_value = r"({field_content})?".format(**globals())
+
+#  header-field   = field-name ":" OWS field-value OWS
+header_field = (
+    r"(?P<field_name>{field_name})"
+    r":"
+    r"{OWS}"
+    r"(?P<field_value>{field_value})"
+    r"{OWS}".format(**globals())
+)
+
+# https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#request.line
+#
+#   request-line   = method SP request-target SP HTTP-version CRLF
+#   method         = token
+#   HTTP-version   = HTTP-name "/" DIGIT "." DIGIT
+#   HTTP-name      = %x48.54.54.50 ; "HTTP", case-sensitive
+#
+# request-target is complicated (see RFC 7230 sec 5.3) -- could be path, full
+# URL, host+port (for connect), or even "*", but in any case we are guaranteed
+# that it contists of the visible printing characters.
+method = token
+request_target = r"{vchar}+".format(**globals())
+http_version = r"HTTP/(?P<http_version>[0-9]\.[0-9])"
+request_line = (
+    r"(?P<method>{method})"
+    r" "
+    r"(?P<target>{request_target})"
+    r" "
+    r"{http_version}".format(**globals())
+)
+
+# https://svn.tools.ietf.org/svn/wg/httpbis/specs/rfc7230.html#status.line
+#
+#   status-line = HTTP-version SP status-code SP reason-phrase CRLF
+#   status-code    = 3DIGIT
+#   reason-phrase  = *( HTAB / SP / VCHAR / obs-text )
+status_code = r"[0-9]{3}"
+reason_phrase = r"([ \t]|{vchar_or_obs_text})*".format(**globals())
+status_line = (
+    r"{http_version}"
+    r" "
+    r"(?P<status_code>{status_code})"
+    # However, there are apparently a few too many servers out there that just
+    # leave out the reason phrase:
+    #   https://github.com/scrapy/scrapy/issues/345#issuecomment-281756036
+    #   https://github.com/seanmonstar/httparse/issues/29
+    # so make it optional. ?: is a non-capturing group.
+    r"(?: (?P<reason>{reason_phrase}))?".format(**globals())
+)
+
+HEXDIG = r"[0-9A-Fa-f]"
+# Actually
+#
+#      chunk-size     = 1*HEXDIG
+#
+# but we impose an upper-limit to avoid ridiculosity. len(str(2**64)) == 20
+chunk_size = r"({HEXDIG}){{1,20}}".format(**globals())
+# Actually
+#
+#     chunk-ext      = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
+#
+# but we aren't parsing the things so we don't really care.
+chunk_ext = r";.*"
+chunk_header = (
+    r"(?P<chunk_size>{chunk_size})"
+    r"(?P<chunk_ext>{chunk_ext})?"
+    r"{OWS}\r\n".format(
+        **globals()
+    )  # Even though the specification does not allow for extra whitespaces,
+    # we are lenient with trailing whitespaces because some servers on the wild use it.
+)

venv/lib/python3.11/site-packages/h11/_connection.py

@@ -0,0 +1,633 @@
+# This contains the main Connection class. Everything in h11 revolves around
+# this.
+from typing import Any, Callable, cast, Dict, List, Optional, Tuple, Type, Union
+
+from ._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from ._headers import get_comma_header, has_expect_100_continue, set_comma_header
+from ._readers import READERS, ReadersType
+from ._receivebuffer import ReceiveBuffer
+from ._state import (
+    _SWITCH_CONNECT,
+    _SWITCH_UPGRADE,
+    CLIENT,
+    ConnectionState,
+    DONE,
+    ERROR,
+    MIGHT_SWITCH_PROTOCOL,
+    SEND_BODY,
+    SERVER,
+    SWITCHED_PROTOCOL,
+)
+from ._util import (  # Import the internal things we need
+    LocalProtocolError,
+    RemoteProtocolError,
+    Sentinel,
+)
+from ._writers import WRITERS, WritersType
+
+# Everything in __all__ gets re-exported as part of the h11 public API.
+__all__ = ["Connection", "NEED_DATA", "PAUSED"]
+
+
+class NEED_DATA(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class PAUSED(Sentinel, metaclass=Sentinel):
+    pass
+
+
+# If we ever have this much buffered without it making a complete parseable
+# event, we error out. The only time we really buffer is when reading the
+# request/response line + headers together, so this is effectively the limit on
+# the size of that.
+#
+# Some precedents for defaults:
+# - node.js: 80 * 1024
+# - tomcat: 8 * 1024
+# - IIS: 16 * 1024
+# - Apache: <8 KiB per line>
+DEFAULT_MAX_INCOMPLETE_EVENT_SIZE = 16 * 1024
+
+# RFC 7230's rules for connection lifecycles:
+# - If either side says they want to close the connection, then the connection
+#   must close.
+# - HTTP/1.1 defaults to keep-alive unless someone says Connection: close
+# - HTTP/1.0 defaults to close unless both sides say Connection: keep-alive
+#   (and even this is a mess -- e.g. if you're implementing a proxy then
+#   sending Connection: keep-alive is forbidden).
+#
+# We simplify life by simply not supporting keep-alive with HTTP/1.0 peers. So
+# our rule is:
+# - If someone says Connection: close, we will close
+# - If someone uses HTTP/1.0, we will close.
+def _keep_alive(event: Union[Request, Response]) -> bool:
+    connection = get_comma_header(event.headers, b"connection")
+    if b"close" in connection:
+        return False
+    if getattr(event, "http_version", b"1.1") < b"1.1":
+        return False
+    return True
+
+
+def _body_framing(
+    request_method: bytes, event: Union[Request, Response]
+) -> Tuple[str, Union[Tuple[()], Tuple[int]]]:
+    # Called when we enter SEND_BODY to figure out framing information for
+    # this body.
+    #
+    # These are the only two events that can trigger a SEND_BODY state:
+    assert type(event) in (Request, Response)
+    # Returns one of:
+    #
+    #    ("content-length", count)
+    #    ("chunked", ())
+    #    ("http/1.0", ())
+    #
+    # which are (lookup key, *args) for constructing body reader/writer
+    # objects.
+    #
+    # Reference: https://tools.ietf.org/html/rfc7230#section-3.3.3
+    #
+    # Step 1: some responses always have an empty body, regardless of what the
+    # headers say.
+    if type(event) is Response:
+        if (
+            event.status_code in (204, 304)
+            or request_method == b"HEAD"
+            or (request_method == b"CONNECT" and 200 <= event.status_code < 300)
+        ):
+            return ("content-length", (0,))
+        # Section 3.3.3 also lists another case -- responses with status_code
+        # < 200. For us these are InformationalResponses, not Responses, so
+        # they can't get into this function in the first place.
+        assert event.status_code >= 200
+
+    # Step 2: check for Transfer-Encoding (T-E beats C-L):
+    transfer_encodings = get_comma_header(event.headers, b"transfer-encoding")
+    if transfer_encodings:
+        assert transfer_encodings == [b"chunked"]
+        return ("chunked", ())
+
+    # Step 3: check for Content-Length
+    content_lengths = get_comma_header(event.headers, b"content-length")
+    if content_lengths:
+        return ("content-length", (int(content_lengths[0]),))
+
+    # Step 4: no applicable headers; fallback/default depends on type
+    if type(event) is Request:
+        return ("content-length", (0,))
+    else:
+        return ("http/1.0", ())
+
+
+################################################################
+#
+# The main Connection class
+#
+################################################################
+
+
+class Connection:
+    """An object encapsulating the state of an HTTP connection.
+
+    Args:
+        our_role: If you're implementing a client, pass :data:`h11.CLIENT`. If
+            you're implementing a server, pass :data:`h11.SERVER`.
+
+        max_incomplete_event_size (int):
+            The maximum number of bytes we're willing to buffer of an
+            incomplete event. In practice this mostly sets a limit on the
+            maximum size of the request/response line + headers. If this is
+            exceeded, then :meth:`next_event` will raise
+            :exc:`RemoteProtocolError`.
+
+    """
+
+    def __init__(
+        self,
+        our_role: Type[Sentinel],
+        max_incomplete_event_size: int = DEFAULT_MAX_INCOMPLETE_EVENT_SIZE,
+    ) -> None:
+        self._max_incomplete_event_size = max_incomplete_event_size
+        # State and role tracking
+        if our_role not in (CLIENT, SERVER):
+            raise ValueError("expected CLIENT or SERVER, not {!r}".format(our_role))
+        self.our_role = our_role
+        self.their_role: Type[Sentinel]
+        if our_role is CLIENT:
+            self.their_role = SERVER
+        else:
+            self.their_role = CLIENT
+        self._cstate = ConnectionState()
+
+        # Callables for converting data->events or vice-versa given the
+        # current state
+        self._writer = self._get_io_object(self.our_role, None, WRITERS)
+        self._reader = self._get_io_object(self.their_role, None, READERS)
+
+        # Holds any unprocessed received data
+        self._receive_buffer = ReceiveBuffer()
+        # If this is true, then it indicates that the incoming connection was
+        # closed *after* the end of whatever's in self._receive_buffer:
+        self._receive_buffer_closed = False
+
+        # Extra bits of state that don't fit into the state machine.
+        #
+        # These two are only used to interpret framing headers for figuring
+        # out how to read/write response bodies. their_http_version is also
+        # made available as a convenient public API.
+        self.their_http_version: Optional[bytes] = None
+        self._request_method: Optional[bytes] = None
+        # This is pure flow-control and doesn't at all affect the set of legal
+        # transitions, so no need to bother ConnectionState with it:
+        self.client_is_waiting_for_100_continue = False
+
+    @property
+    def states(self) -> Dict[Type[Sentinel], Type[Sentinel]]:
+        """A dictionary like::
+
+           {CLIENT: <client state>, SERVER: <server state>}
+
+        See :ref:`state-machine` for details.
+
+        """
+        return dict(self._cstate.states)
+
+    @property
+    def our_state(self) -> Type[Sentinel]:
+        """The current state of whichever role we are playing. See
+        :ref:`state-machine` for details.
+        """
+        return self._cstate.states[self.our_role]
+
+    @property
+    def their_state(self) -> Type[Sentinel]:
+        """The current state of whichever role we are NOT playing. See
+        :ref:`state-machine` for details.
+        """
+        return self._cstate.states[self.their_role]
+
+    @property
+    def they_are_waiting_for_100_continue(self) -> bool:
+        return self.their_role is CLIENT and self.client_is_waiting_for_100_continue
+
+    def start_next_cycle(self) -> None:
+        """Attempt to reset our connection state for a new request/response
+        cycle.
+
+        If both client and server are in :data:`DONE` state, then resets them
+        both to :data:`IDLE` state in preparation for a new request/response
+        cycle on this same connection. Otherwise, raises a
+        :exc:`LocalProtocolError`.
+
+        See :ref:`keepalive-and-pipelining`.
+
+        """
+        old_states = dict(self._cstate.states)
+        self._cstate.start_next_cycle()
+        self._request_method = None
+        # self.their_http_version gets left alone, since it presumably lasts
+        # beyond a single request/response cycle
+        assert not self.client_is_waiting_for_100_continue
+        self._respond_to_state_changes(old_states)
+
+    def _process_error(self, role: Type[Sentinel]) -> None:
+        old_states = dict(self._cstate.states)
+        self._cstate.process_error(role)
+        self._respond_to_state_changes(old_states)
+
+    def _server_switch_event(self, event: Event) -> Optional[Type[Sentinel]]:
+        if type(event) is InformationalResponse and event.status_code == 101:
+            return _SWITCH_UPGRADE
+        if type(event) is Response:
+            if (
+                _SWITCH_CONNECT in self._cstate.pending_switch_proposals
+                and 200 <= event.status_code < 300
+            ):
+                return _SWITCH_CONNECT
+        return None
+
+    # All events go through here
+    def _process_event(self, role: Type[Sentinel], event: Event) -> None:
+        # First, pass the event through the state machine to make sure it
+        # succeeds.
+        old_states = dict(self._cstate.states)
+        if role is CLIENT and type(event) is Request:
+            if event.method == b"CONNECT":
+                self._cstate.process_client_switch_proposal(_SWITCH_CONNECT)
+            if get_comma_header(event.headers, b"upgrade"):
+                self._cstate.process_client_switch_proposal(_SWITCH_UPGRADE)
+        server_switch_event = None
+        if role is SERVER:
+            server_switch_event = self._server_switch_event(event)
+        self._cstate.process_event(role, type(event), server_switch_event)
+
+        # Then perform the updates triggered by it.
+
+        if type(event) is Request:
+            self._request_method = event.method
+
+        if role is self.their_role and type(event) in (
+            Request,
+            Response,
+            InformationalResponse,
+        ):
+            event = cast(Union[Request, Response, InformationalResponse], event)
+            self.their_http_version = event.http_version
+
+        # Keep alive handling
+        #
+        # RFC 7230 doesn't really say what one should do if Connection: close
+        # shows up on a 1xx InformationalResponse. I think the idea is that
+        # this is not supposed to happen. In any case, if it does happen, we
+        # ignore it.
+        if type(event) in (Request, Response) and not _keep_alive(
+            cast(Union[Request, Response], event)
+        ):
+            self._cstate.process_keep_alive_disabled()
+
+        # 100-continue
+        if type(event) is Request and has_expect_100_continue(event):
+            self.client_is_waiting_for_100_continue = True
+        if type(event) in (InformationalResponse, Response):
+            self.client_is_waiting_for_100_continue = False
+        if role is CLIENT and type(event) in (Data, EndOfMessage):
+            self.client_is_waiting_for_100_continue = False
+
+        self._respond_to_state_changes(old_states, event)
+
+    def _get_io_object(
+        self,
+        role: Type[Sentinel],
+        event: Optional[Event],
+        io_dict: Union[ReadersType, WritersType],
+    ) -> Optional[Callable[..., Any]]:
+        # event may be None; it's only used when entering SEND_BODY
+        state = self._cstate.states[role]
+        if state is SEND_BODY:
+            # Special case: the io_dict has a dict of reader/writer factories
+            # that depend on the request/response framing.
+            framing_type, args = _body_framing(
+                cast(bytes, self._request_method), cast(Union[Request, Response], event)
+            )
+            return io_dict[SEND_BODY][framing_type](*args)  # type: ignore[index]
+        else:
+            # General case: the io_dict just has the appropriate reader/writer
+            # for this state
+            return io_dict.get((role, state))  # type: ignore[return-value]
+
+    # This must be called after any action that might have caused
+    # self._cstate.states to change.
+    def _respond_to_state_changes(
+        self,
+        old_states: Dict[Type[Sentinel], Type[Sentinel]],
+        event: Optional[Event] = None,
+    ) -> None:
+        # Update reader/writer
+        if self.our_state != old_states[self.our_role]:
+            self._writer = self._get_io_object(self.our_role, event, WRITERS)
+        if self.their_state != old_states[self.their_role]:
+            self._reader = self._get_io_object(self.their_role, event, READERS)
+
+    @property
+    def trailing_data(self) -> Tuple[bytes, bool]:
+        """Data that has been received, but not yet processed, represented as
+        a tuple with two elements, where the first is a byte-string containing
+        the unprocessed data itself, and the second is a bool that is True if
+        the receive connection was closed.
+
+        See :ref:`switching-protocols` for discussion of why you'd want this.
+        """
+        return (bytes(self._receive_buffer), self._receive_buffer_closed)
+
+    def receive_data(self, data: bytes) -> None:
+        """Add data to our internal receive buffer.
+
+        This does not actually do any processing on the data, just stores
+        it. To trigger processing, you have to call :meth:`next_event`.
+
+        Args:
+            data (:term:`bytes-like object`):
+                The new data that was just received.
+
+                Special case: If *data* is an empty byte-string like ``b""``,
+                then this indicates that the remote side has closed the
+                connection (end of file). Normally this is convenient, because
+                standard Python APIs like :meth:`file.read` or
+                :meth:`socket.recv` use ``b""`` to indicate end-of-file, while
+                other failures to read are indicated using other mechanisms
+                like raising :exc:`TimeoutError`. When using such an API you
+                can just blindly pass through whatever you get from ``read``
+                to :meth:`receive_data`, and everything will work.
+
+                But, if you have an API where reading an empty string is a
+                valid non-EOF condition, then you need to be aware of this and
+                make sure to check for such strings and avoid passing them to
+                :meth:`receive_data`.
+
+        Returns:
+            Nothing, but after calling this you should call :meth:`next_event`
+            to parse the newly received data.
+
+        Raises:
+            RuntimeError:
+                Raised if you pass an empty *data*, indicating EOF, and then
+                pass a non-empty *data*, indicating more data that somehow
+                arrived after the EOF.
+
+                (Calling ``receive_data(b"")`` multiple times is fine,
+                and equivalent to calling it once.)
+
+        """
+        if data:
+            if self._receive_buffer_closed:
+                raise RuntimeError("received close, then received more data?")
+            self._receive_buffer += data
+        else:
+            self._receive_buffer_closed = True
+
+    def _extract_next_receive_event(
+        self,
+    ) -> Union[Event, Type[NEED_DATA], Type[PAUSED]]:
+        state = self.their_state
+        # We don't pause immediately when they enter DONE, because even in
+        # DONE state we can still process a ConnectionClosed() event. But
+        # if we have data in our buffer, then we definitely aren't getting
+        # a ConnectionClosed() immediately and we need to pause.
+        if state is DONE and self._receive_buffer:
+            return PAUSED
+        if state is MIGHT_SWITCH_PROTOCOL or state is SWITCHED_PROTOCOL:
+            return PAUSED
+        assert self._reader is not None
+        event = self._reader(self._receive_buffer)
+        if event is None:
+            if not self._receive_buffer and self._receive_buffer_closed:
+                # In some unusual cases (basically just HTTP/1.0 bodies), EOF
+                # triggers an actual protocol event; in that case, we want to
+                # return that event, and then the state will change and we'll
+                # get called again to generate the actual ConnectionClosed().
+                if hasattr(self._reader, "read_eof"):
+                    event = self._reader.read_eof()  # type: ignore[attr-defined]
+                else:
+                    event = ConnectionClosed()
+        if event is None:
+            event = NEED_DATA
+        return event  # type: ignore[no-any-return]
+
+    def next_event(self) -> Union[Event, Type[NEED_DATA], Type[PAUSED]]:
+        """Parse the next event out of our receive buffer, update our internal
+        state, and return it.
+
+        This is a mutating operation -- think of it like calling :func:`next`
+        on an iterator.
+
+        Returns:
+            : One of three things:
+
+            1) An event object -- see :ref:`events`.
+
+            2) The special constant :data:`NEED_DATA`, which indicates that
+               you need to read more data from your socket and pass it to
+               :meth:`receive_data` before this method will be able to return
+               any more events.
+
+            3) The special constant :data:`PAUSED`, which indicates that we
+               are not in a state where we can process incoming data (usually
+               because the peer has finished their part of the current
+               request/response cycle, and you have not yet called
+               :meth:`start_next_cycle`). See :ref:`flow-control` for details.
+
+        Raises:
+            RemoteProtocolError:
+                The peer has misbehaved. You should close the connection
+                (possibly after sending some kind of 4xx response).
+
+        Once this method returns :class:`ConnectionClosed` once, then all
+        subsequent calls will also return :class:`ConnectionClosed`.
+
+        If this method raises any exception besides :exc:`RemoteProtocolError`
+        then that's a bug -- if it happens please file a bug report!
+
+        If this method raises any exception then it also sets
+        :attr:`Connection.their_state` to :data:`ERROR` -- see
+        :ref:`error-handling` for discussion.
+
+        """
+
+        if self.their_state is ERROR:
+            raise RemoteProtocolError("Can't receive data when peer state is ERROR")
+        try:
+            event = self._extract_next_receive_event()
+            if event not in [NEED_DATA, PAUSED]:
+                self._process_event(self.their_role, cast(Event, event))
+            if event is NEED_DATA:
+                if len(self._receive_buffer) > self._max_incomplete_event_size:
+                    # 431 is "Request header fields too large" which is pretty
+                    # much the only situation where we can get here
+                    raise RemoteProtocolError(
+                        "Receive buffer too long", error_status_hint=431
+                    )
+                if self._receive_buffer_closed:
+                    # We're still trying to complete some event, but that's
+                    # never going to happen because no more data is coming
+                    raise RemoteProtocolError("peer unexpectedly closed connection")
+            return event
+        except BaseException as exc:
+            self._process_error(self.their_role)
+            if isinstance(exc, LocalProtocolError):
+                exc._reraise_as_remote_protocol_error()
+            else:
+                raise
+
+    def send(self, event: Event) -> Optional[bytes]:
+        """Convert a high-level event into bytes that can be sent to the peer,
+        while updating our internal state machine.
+
+        Args:
+            event: The :ref:`event <events>` to send.
+
+        Returns:
+            If ``type(event) is ConnectionClosed``, then returns
+            ``None``. Otherwise, returns a :term:`bytes-like object`.
+
+        Raises:
+            LocalProtocolError:
+                Sending this event at this time would violate our
+                understanding of the HTTP/1.1 protocol.
+
+        If this method raises any exception then it also sets
+        :attr:`Connection.our_state` to :data:`ERROR` -- see
+        :ref:`error-handling` for discussion.
+
+        """
+        data_list = self.send_with_data_passthrough(event)
+        if data_list is None:
+            return None
+        else:
+            return b"".join(data_list)
+
+    def send_with_data_passthrough(self, event: Event) -> Optional[List[bytes]]:
+        """Identical to :meth:`send`, except that in situations where
+        :meth:`send` returns a single :term:`bytes-like object`, this instead
+        returns a list of them -- and when sending a :class:`Data` event, this
+        list is guaranteed to contain the exact object you passed in as
+        :attr:`Data.data`. See :ref:`sendfile` for discussion.
+
+        """
+        if self.our_state is ERROR:
+            raise LocalProtocolError("Can't send data when our state is ERROR")
+        try:
+            if type(event) is Response:
+                event = self._clean_up_response_headers_for_sending(event)
+            # We want to call _process_event before calling the writer,
+            # because if someone tries to do something invalid then this will
+            # give a sensible error message, while our writers all just assume
+            # they will only receive valid events. But, _process_event might
+            # change self._writer. So we have to do a little dance:
+            writer = self._writer
+            self._process_event(self.our_role, event)
+            if type(event) is ConnectionClosed:
+                return None
+            else:
+                # In any situation where writer is None, process_event should
+                # have raised ProtocolError
+                assert writer is not None
+                data_list: List[bytes] = []
+                writer(event, data_list.append)
+                return data_list
+        except:
+            self._process_error(self.our_role)
+            raise
+
+    def send_failed(self) -> None:
+        """Notify the state machine that we failed to send the data it gave
+        us.
+
+        This causes :attr:`Connection.our_state` to immediately become
+        :data:`ERROR` -- see :ref:`error-handling` for discussion.
+
+        """
+        self._process_error(self.our_role)
+
+    # When sending a Response, we take responsibility for a few things:
+    #
+    # - Sometimes you MUST set Connection: close. We take care of those
+    #   times. (You can also set it yourself if you want, and if you do then
+    #   we'll respect that and close the connection at the right time. But you
+    #   don't have to worry about that unless you want to.)
+    #
+    # - The user has to set Content-Length if they want it. Otherwise, for
+    #   responses that have bodies (e.g. not HEAD), then we will automatically
+    #   select the right mechanism for streaming a body of unknown length,
+    #   which depends on depending on the peer's HTTP version.
+    #
+    # This function's *only* responsibility is making sure headers are set up
+    # right -- everything downstream just looks at the headers. There are no
+    # side channels.
+    def _clean_up_response_headers_for_sending(self, response: Response) -> Response:
+        assert type(response) is Response
+
+        headers = response.headers
+        need_close = False
+
+        # HEAD requests need some special handling: they always act like they
+        # have Content-Length: 0, and that's how _body_framing treats
+        # them. But their headers are supposed to match what we would send if
+        # the request was a GET. (Technically there is one deviation allowed:
+        # we're allowed to leave out the framing headers -- see
+        # https://tools.ietf.org/html/rfc7231#section-4.3.2 . But it's just as
+        # easy to get them right.)
+        method_for_choosing_headers = cast(bytes, self._request_method)
+        if method_for_choosing_headers == b"HEAD":
+            method_for_choosing_headers = b"GET"
+        framing_type, _ = _body_framing(method_for_choosing_headers, response)
+        if framing_type in ("chunked", "http/1.0"):
+            # This response has a body of unknown length.
+            # If our peer is HTTP/1.1, we use Transfer-Encoding: chunked
+            # If our peer is HTTP/1.0, we use no framing headers, and close the
+            # connection afterwards.
+            #
+            # Make sure to clear Content-Length (in principle user could have
+            # set both and then we ignored Content-Length b/c
+            # Transfer-Encoding overwrote it -- this would be naughty of them,
+            # but the HTTP spec says that if our peer does this then we have
+            # to fix it instead of erroring out, so we'll accord the user the
+            # same respect).
+            headers = set_comma_header(headers, b"content-length", [])
+            if self.their_http_version is None or self.their_http_version < b"1.1":
+                # Either we never got a valid request and are sending back an
+                # error (their_http_version is None), so we assume the worst;
+                # or else we did get a valid HTTP/1.0 request, so we know that
+                # they don't understand chunked encoding.
+                headers = set_comma_header(headers, b"transfer-encoding", [])
+                # This is actually redundant ATM, since currently we
+                # unconditionally disable keep-alive when talking to HTTP/1.0
+                # peers. But let's be defensive just in case we add
+                # Connection: keep-alive support later:
+                if self._request_method != b"HEAD":
+                    need_close = True
+            else:
+                headers = set_comma_header(headers, b"transfer-encoding", [b"chunked"])
+
+        if not self._cstate.keep_alive or need_close:
+            # Make sure Connection: close is set
+            connection = set(get_comma_header(headers, b"connection"))
+            connection.discard(b"keep-alive")
+            connection.add(b"close")
+            headers = set_comma_header(headers, b"connection", sorted(connection))
+
+        return Response(
+            headers=headers,
+            status_code=response.status_code,
+            http_version=response.http_version,
+            reason=response.reason,
+        )

venv/lib/python3.11/site-packages/h11/_events.py

@@ -0,0 +1,369 @@
+# 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

venv/lib/python3.11/site-packages/h11/_headers.py

@@ -0,0 +1,278 @@
+import re
+from typing import AnyStr, cast, List, overload, Sequence, Tuple, TYPE_CHECKING, Union
+
+from ._abnf import field_name, field_value
+from ._util import bytesify, LocalProtocolError, validate
+
+if TYPE_CHECKING:
+    from ._events import Request
+
+try:
+    from typing import Literal
+except ImportError:
+    from typing_extensions import Literal  # type: ignore
+
+
+# Facts
+# -----
+#
+# Headers are:
+#   keys: case-insensitive ascii
+#   values: mixture of ascii and raw bytes
+#
+# "Historically, HTTP has allowed field content with text in the ISO-8859-1
+# charset [ISO-8859-1], supporting other charsets only through use of
+# [RFC2047] encoding.  In practice, most HTTP header field values use only a
+# subset of the US-ASCII charset [USASCII]. Newly defined header fields SHOULD
+# limit their field values to US-ASCII octets.  A recipient SHOULD treat other
+# octets in field content (obs-text) as opaque data."
+# And it deprecates all non-ascii values
+#
+# Leading/trailing whitespace in header names is forbidden
+#
+# Values get leading/trailing whitespace stripped
+#
+# Content-Disposition actually needs to contain unicode semantically; to
+# accomplish this it has a terrifically weird way of encoding the filename
+# itself as ascii (and even this still has lots of cross-browser
+# incompatibilities)
+#
+# Order is important:
+# "a proxy MUST NOT change the order of these field values when forwarding a
+# message"
+# (and there are several headers where the order indicates a preference)
+#
+# Multiple occurences of the same header:
+# "A sender MUST NOT generate multiple header fields with the same field name
+# in a message unless either the entire field value for that header field is
+# defined as a comma-separated list [or the header is Set-Cookie which gets a
+# special exception]" - RFC 7230. (cookies are in RFC 6265)
+#
+# So every header aside from Set-Cookie can be merged by b", ".join if it
+# occurs repeatedly. But, of course, they can't necessarily be split by
+# .split(b","), because quoting.
+#
+# Given all this mess (case insensitive, duplicates allowed, order is
+# important, ...), there doesn't appear to be any standard way to handle
+# headers in Python -- they're almost like dicts, but... actually just
+# aren't. For now we punt and just use a super simple representation: headers
+# are a list of pairs
+#
+#   [(name1, value1), (name2, value2), ...]
+#
+# where all entries are bytestrings, names are lowercase and have no
+# leading/trailing whitespace, and values are bytestrings with no
+# leading/trailing whitespace. Searching and updating are done via naive O(n)
+# methods.
+#
+# Maybe a dict-of-lists would be better?
+
+_content_length_re = re.compile(rb"[0-9]+")
+_field_name_re = re.compile(field_name.encode("ascii"))
+_field_value_re = re.compile(field_value.encode("ascii"))
+
+
+class Headers(Sequence[Tuple[bytes, bytes]]):
+    """
+    A list-like interface that allows iterating over headers as byte-pairs
+    of (lowercased-name, value).
+
+    Internally we actually store the representation as three-tuples,
+    including both the raw original casing, in order to preserve casing
+    over-the-wire, and the lowercased name, for case-insensitive comparisions.
+
+    r = Request(
+        method="GET",
+        target="/",
+        headers=[("Host", "example.org"), ("Connection", "keep-alive")],
+        http_version="1.1",
+    )
+    assert r.headers == [
+        (b"host", b"example.org"),
+        (b"connection", b"keep-alive")
+    ]
+    assert r.headers.raw_items() == [
+        (b"Host", b"example.org"),
+        (b"Connection", b"keep-alive")
+    ]
+    """
+
+    __slots__ = "_full_items"
+
+    def __init__(self, full_items: List[Tuple[bytes, bytes, bytes]]) -> None:
+        self._full_items = full_items
+
+    def __bool__(self) -> bool:
+        return bool(self._full_items)
+
+    def __eq__(self, other: object) -> bool:
+        return list(self) == list(other)  # type: ignore
+
+    def __len__(self) -> int:
+        return len(self._full_items)
+
+    def __repr__(self) -> str:
+        return "<Headers(%s)>" % repr(list(self))
+
+    def __getitem__(self, idx: int) -> Tuple[bytes, bytes]:  # type: ignore[override]
+        _, name, value = self._full_items[idx]
+        return (name, value)
+
+    def raw_items(self) -> List[Tuple[bytes, bytes]]:
+        return [(raw_name, value) for raw_name, _, value in self._full_items]
+
+
+HeaderTypes = Union[
+    List[Tuple[bytes, bytes]],
+    List[Tuple[bytes, str]],
+    List[Tuple[str, bytes]],
+    List[Tuple[str, str]],
+]
+
+
+@overload
+def normalize_and_validate(headers: Headers, _parsed: Literal[True]) -> Headers:
+    ...
+
+
+@overload
+def normalize_and_validate(headers: HeaderTypes, _parsed: Literal[False]) -> Headers:
+    ...
+
+
+@overload
+def normalize_and_validate(
+    headers: Union[Headers, HeaderTypes], _parsed: bool = False
+) -> Headers:
+    ...
+
+
+def normalize_and_validate(
+    headers: Union[Headers, HeaderTypes], _parsed: bool = False
+) -> Headers:
+    new_headers = []
+    seen_content_length = None
+    saw_transfer_encoding = False
+    for name, value in headers:
+        # For headers coming out of the parser, we can safely skip some steps,
+        # because it always returns bytes and has already run these regexes
+        # over the data:
+        if not _parsed:
+            name = bytesify(name)
+            value = bytesify(value)
+            validate(_field_name_re, name, "Illegal header name {!r}", name)
+            validate(_field_value_re, value, "Illegal header value {!r}", value)
+        assert isinstance(name, bytes)
+        assert isinstance(value, bytes)
+
+        raw_name = name
+        name = name.lower()
+        if name == b"content-length":
+            lengths = {length.strip() for length in value.split(b",")}
+            if len(lengths) != 1:
+                raise LocalProtocolError("conflicting Content-Length headers")
+            value = lengths.pop()
+            validate(_content_length_re, value, "bad Content-Length")
+            if seen_content_length is None:
+                seen_content_length = value
+                new_headers.append((raw_name, name, value))
+            elif seen_content_length != value:
+                raise LocalProtocolError("conflicting Content-Length headers")
+        elif name == b"transfer-encoding":
+            # "A server that receives a request message with a transfer coding
+            # it does not understand SHOULD respond with 501 (Not
+            # Implemented)."
+            # https://tools.ietf.org/html/rfc7230#section-3.3.1
+            if saw_transfer_encoding:
+                raise LocalProtocolError(
+                    "multiple Transfer-Encoding headers", error_status_hint=501
+                )
+            # "All transfer-coding names are case-insensitive"
+            # -- https://tools.ietf.org/html/rfc7230#section-4
+            value = value.lower()
+            if value != b"chunked":
+                raise LocalProtocolError(
+                    "Only Transfer-Encoding: chunked is supported",
+                    error_status_hint=501,
+                )
+            saw_transfer_encoding = True
+            new_headers.append((raw_name, name, value))
+        else:
+            new_headers.append((raw_name, name, value))
+    return Headers(new_headers)
+
+
+def get_comma_header(headers: Headers, name: bytes) -> List[bytes]:
+    # Should only be used for headers whose value is a list of
+    # comma-separated, case-insensitive values.
+    #
+    # The header name `name` is expected to be lower-case bytes.
+    #
+    # Connection: meets these criteria (including cast insensitivity).
+    #
+    # Content-Length: technically is just a single value (1*DIGIT), but the
+    # standard makes reference to implementations that do multiple values, and
+    # using this doesn't hurt. Ditto, case insensitivity doesn't things either
+    # way.
+    #
+    # Transfer-Encoding: is more complex (allows for quoted strings), so
+    # splitting on , is actually wrong. For example, this is legal:
+    #
+    #    Transfer-Encoding: foo; options="1,2", chunked
+    #
+    # and should be parsed as
+    #
+    #    foo; options="1,2"
+    #    chunked
+    #
+    # but this naive function will parse it as
+    #
+    #    foo; options="1
+    #    2"
+    #    chunked
+    #
+    # However, this is okay because the only thing we are going to do with
+    # any Transfer-Encoding is reject ones that aren't just "chunked", so
+    # both of these will be treated the same anyway.
+    #
+    # Expect: the only legal value is the literal string
+    # "100-continue". Splitting on commas is harmless. Case insensitive.
+    #
+    out: List[bytes] = []
+    for _, found_name, found_raw_value in headers._full_items:
+        if found_name == name:
+            found_raw_value = found_raw_value.lower()
+            for found_split_value in found_raw_value.split(b","):
+                found_split_value = found_split_value.strip()
+                if found_split_value:
+                    out.append(found_split_value)
+    return out
+
+
+def set_comma_header(headers: Headers, name: bytes, new_values: List[bytes]) -> Headers:
+    # The header name `name` is expected to be lower-case bytes.
+    #
+    # Note that when we store the header we use title casing for the header
+    # names, in order to match the conventional HTTP header style.
+    #
+    # Simply calling `.title()` is a blunt approach, but it's correct
+    # here given the cases where we're using `set_comma_header`...
+    #
+    # Connection, Content-Length, Transfer-Encoding.
+    new_headers: List[Tuple[bytes, bytes]] = []
+    for found_raw_name, found_name, found_raw_value in headers._full_items:
+        if found_name != name:
+            new_headers.append((found_raw_name, found_raw_value))
+    for new_value in new_values:
+        new_headers.append((name.title(), new_value))
+    return normalize_and_validate(new_headers)
+
+
+def has_expect_100_continue(request: "Request") -> bool:
+    # https://tools.ietf.org/html/rfc7231#section-5.1.1
+    # "A server that receives a 100-continue expectation in an HTTP/1.0 request
+    # MUST ignore that expectation."
+    if request.http_version < b"1.1":
+        return False
+    expect = get_comma_header(request.headers, b"expect")
+    return b"100-continue" in expect

venv/lib/python3.11/site-packages/h11/_readers.py

@@ -0,0 +1,247 @@
+# Code to read HTTP data
+#
+# Strategy: each reader is a callable which takes a ReceiveBuffer object, and
+# either:
+# 1) consumes some of it and returns an Event
+# 2) raises a LocalProtocolError (for consistency -- e.g. we call validate()
+#    and it might raise a LocalProtocolError, so simpler just to always use
+#    this)
+# 3) returns None, meaning "I need more data"
+#
+# If they have a .read_eof attribute, then this will be called if an EOF is
+# received -- but this is optional. Either way, the actual ConnectionClosed
+# event will be generated afterwards.
+#
+# READERS is a dict describing how to pick a reader. It maps states to either:
+# - a reader
+# - or, for body readers, a dict of per-framing reader factories
+
+import re
+from typing import Any, Callable, Dict, Iterable, NoReturn, Optional, Tuple, Type, Union
+
+from ._abnf import chunk_header, header_field, request_line, status_line
+from ._events import Data, EndOfMessage, InformationalResponse, Request, Response
+from ._receivebuffer import ReceiveBuffer
+from ._state import (
+    CLIENT,
+    CLOSED,
+    DONE,
+    IDLE,
+    MUST_CLOSE,
+    SEND_BODY,
+    SEND_RESPONSE,
+    SERVER,
+)
+from ._util import LocalProtocolError, RemoteProtocolError, Sentinel, validate
+
+__all__ = ["READERS"]
+
+header_field_re = re.compile(header_field.encode("ascii"))
+obs_fold_re = re.compile(rb"[ \t]+")
+
+
+def _obsolete_line_fold(lines: Iterable[bytes]) -> Iterable[bytes]:
+    it = iter(lines)
+    last: Optional[bytes] = None
+    for line in it:
+        match = obs_fold_re.match(line)
+        if match:
+            if last is None:
+                raise LocalProtocolError("continuation line at start of headers")
+            if not isinstance(last, bytearray):
+                # Cast to a mutable type, avoiding copy on append to ensure O(n) time
+                last = bytearray(last)
+            last += b" "
+            last += line[match.end() :]
+        else:
+            if last is not None:
+                yield last
+            last = line
+    if last is not None:
+        yield last
+
+
+def _decode_header_lines(
+    lines: Iterable[bytes],
+) -> Iterable[Tuple[bytes, bytes]]:
+    for line in _obsolete_line_fold(lines):
+        matches = validate(header_field_re, line, "illegal header line: {!r}", line)
+        yield (matches["field_name"], matches["field_value"])
+
+
+request_line_re = re.compile(request_line.encode("ascii"))
+
+
+def maybe_read_from_IDLE_client(buf: ReceiveBuffer) -> Optional[Request]:
+    lines = buf.maybe_extract_lines()
+    if lines is None:
+        if buf.is_next_line_obviously_invalid_request_line():
+            raise LocalProtocolError("illegal request line")
+        return None
+    if not lines:
+        raise LocalProtocolError("no request line received")
+    matches = validate(
+        request_line_re, lines[0], "illegal request line: {!r}", lines[0]
+    )
+    return Request(
+        headers=list(_decode_header_lines(lines[1:])), _parsed=True, **matches
+    )
+
+
+status_line_re = re.compile(status_line.encode("ascii"))
+
+
+def maybe_read_from_SEND_RESPONSE_server(
+    buf: ReceiveBuffer,
+) -> Union[InformationalResponse, Response, None]:
+    lines = buf.maybe_extract_lines()
+    if lines is None:
+        if buf.is_next_line_obviously_invalid_request_line():
+            raise LocalProtocolError("illegal request line")
+        return None
+    if not lines:
+        raise LocalProtocolError("no response line received")
+    matches = validate(status_line_re, lines[0], "illegal status line: {!r}", lines[0])
+    http_version = (
+        b"1.1" if matches["http_version"] is None else matches["http_version"]
+    )
+    reason = b"" if matches["reason"] is None else matches["reason"]
+    status_code = int(matches["status_code"])
+    class_: Union[Type[InformationalResponse], Type[Response]] = (
+        InformationalResponse if status_code < 200 else Response
+    )
+    return class_(
+        headers=list(_decode_header_lines(lines[1:])),
+        _parsed=True,
+        status_code=status_code,
+        reason=reason,
+        http_version=http_version,
+    )
+
+
+class ContentLengthReader:
+    def __init__(self, length: int) -> None:
+        self._length = length
+        self._remaining = length
+
+    def __call__(self, buf: ReceiveBuffer) -> Union[Data, EndOfMessage, None]:
+        if self._remaining == 0:
+            return EndOfMessage()
+        data = buf.maybe_extract_at_most(self._remaining)
+        if data is None:
+            return None
+        self._remaining -= len(data)
+        return Data(data=data)
+
+    def read_eof(self) -> NoReturn:
+        raise RemoteProtocolError(
+            "peer closed connection without sending complete message body "
+            "(received {} bytes, expected {})".format(
+                self._length - self._remaining, self._length
+            )
+        )
+
+
+chunk_header_re = re.compile(chunk_header.encode("ascii"))
+
+
+class ChunkedReader:
+    def __init__(self) -> None:
+        self._bytes_in_chunk = 0
+        # After reading a chunk, we have to throw away the trailing \r\n; if
+        # this is >0 then we discard that many bytes before resuming regular
+        # de-chunkification.
+        self._bytes_to_discard = 0
+        self._reading_trailer = False
+
+    def __call__(self, buf: ReceiveBuffer) -> Union[Data, EndOfMessage, None]:
+        if self._reading_trailer:
+            lines = buf.maybe_extract_lines()
+            if lines is None:
+                return None
+            return EndOfMessage(headers=list(_decode_header_lines(lines)))
+        if self._bytes_to_discard > 0:
+            data = buf.maybe_extract_at_most(self._bytes_to_discard)
+            if data is None:
+                return None
+            self._bytes_to_discard -= len(data)
+            if self._bytes_to_discard > 0:
+                return None
+            # else, fall through and read some more
+        assert self._bytes_to_discard == 0
+        if self._bytes_in_chunk == 0:
+            # We need to refill our chunk count
+            chunk_header = buf.maybe_extract_next_line()
+            if chunk_header is None:
+                return None
+            matches = validate(
+                chunk_header_re,
+                chunk_header,
+                "illegal chunk header: {!r}",
+                chunk_header,
+            )
+            # XX FIXME: we discard chunk extensions. Does anyone care?
+            self._bytes_in_chunk = int(matches["chunk_size"], base=16)
+            if self._bytes_in_chunk == 0:
+                self._reading_trailer = True
+                return self(buf)
+            chunk_start = True
+        else:
+            chunk_start = False
+        assert self._bytes_in_chunk > 0
+        data = buf.maybe_extract_at_most(self._bytes_in_chunk)
+        if data is None:
+            return None
+        self._bytes_in_chunk -= len(data)
+        if self._bytes_in_chunk == 0:
+            self._bytes_to_discard = 2
+            chunk_end = True
+        else:
+            chunk_end = False
+        return Data(data=data, chunk_start=chunk_start, chunk_end=chunk_end)
+
+    def read_eof(self) -> NoReturn:
+        raise RemoteProtocolError(
+            "peer closed connection without sending complete message body "
+            "(incomplete chunked read)"
+        )
+
+
+class Http10Reader:
+    def __call__(self, buf: ReceiveBuffer) -> Optional[Data]:
+        data = buf.maybe_extract_at_most(999999999)
+        if data is None:
+            return None
+        return Data(data=data)
+
+    def read_eof(self) -> EndOfMessage:
+        return EndOfMessage()
+
+
+def expect_nothing(buf: ReceiveBuffer) -> None:
+    if buf:
+        raise LocalProtocolError("Got data when expecting EOF")
+    return None
+
+
+ReadersType = Dict[
+    Union[Type[Sentinel], Tuple[Type[Sentinel], Type[Sentinel]]],
+    Union[Callable[..., Any], Dict[str, Callable[..., Any]]],
+]
+
+READERS: ReadersType = {
+    (CLIENT, IDLE): maybe_read_from_IDLE_client,
+    (SERVER, IDLE): maybe_read_from_SEND_RESPONSE_server,
+    (SERVER, SEND_RESPONSE): maybe_read_from_SEND_RESPONSE_server,
+    (CLIENT, DONE): expect_nothing,
+    (CLIENT, MUST_CLOSE): expect_nothing,
+    (CLIENT, CLOSED): expect_nothing,
+    (SERVER, DONE): expect_nothing,
+    (SERVER, MUST_CLOSE): expect_nothing,
+    (SERVER, CLOSED): expect_nothing,
+    SEND_BODY: {
+        "chunked": ChunkedReader,
+        "content-length": ContentLengthReader,
+        "http/1.0": Http10Reader,
+    },
+}

venv/lib/python3.11/site-packages/h11/_receivebuffer.py

@@ -0,0 +1,153 @@
+import re
+import sys
+from typing import List, Optional, Union
+
+__all__ = ["ReceiveBuffer"]
+
+
+# Operations we want to support:
+# - find next \r\n or \r\n\r\n (\n or \n\n are also acceptable),
+#   or wait until there is one
+# - read at-most-N bytes
+# Goals:
+# - on average, do this fast
+# - worst case, do this in O(n) where n is the number of bytes processed
+# Plan:
+# - store bytearray, offset, how far we've searched for a separator token
+# - use the how-far-we've-searched data to avoid rescanning
+# - while doing a stream of uninterrupted processing, advance offset instead
+#   of constantly copying
+# WARNING:
+# - I haven't benchmarked or profiled any of this yet.
+#
+# Note that starting in Python 3.4, deleting the initial n bytes from a
+# bytearray is amortized O(n), thanks to some excellent work by Antoine
+# Martin:
+#
+#     https://bugs.python.org/issue19087
+#
+# This means that if we only supported 3.4+, we could get rid of the code here
+# involving self._start and self.compress, because it's doing exactly the same
+# thing that bytearray now does internally.
+#
+# BUT unfortunately, we still support 2.7, and reading short segments out of a
+# long buffer MUST be O(bytes read) to avoid DoS issues, so we can't actually
+# delete this code. Yet:
+#
+#     https://pythonclock.org/
+#
+# (Two things to double-check first though: make sure PyPy also has the
+# optimization, and benchmark to make sure it's a win, since we do have a
+# slightly clever thing where we delay calling compress() until we've
+# processed a whole event, which could in theory be slightly more efficient
+# than the internal bytearray support.)
+blank_line_regex = re.compile(b"\n\r?\n", re.MULTILINE)
+
+
+class ReceiveBuffer:
+    def __init__(self) -> None:
+        self._data = bytearray()
+        self._next_line_search = 0
+        self._multiple_lines_search = 0
+
+    def __iadd__(self, byteslike: Union[bytes, bytearray]) -> "ReceiveBuffer":
+        self._data += byteslike
+        return self
+
+    def __bool__(self) -> bool:
+        return bool(len(self))
+
+    def __len__(self) -> int:
+        return len(self._data)
+
+    # for @property unprocessed_data
+    def __bytes__(self) -> bytes:
+        return bytes(self._data)
+
+    def _extract(self, count: int) -> bytearray:
+        # extracting an initial slice of the data buffer and return it
+        out = self._data[:count]
+        del self._data[:count]
+
+        self._next_line_search = 0
+        self._multiple_lines_search = 0
+
+        return out
+
+    def maybe_extract_at_most(self, count: int) -> Optional[bytearray]:
+        """
+        Extract a fixed number of bytes from the buffer.
+        """
+        out = self._data[:count]
+        if not out:
+            return None
+
+        return self._extract(count)
+
+    def maybe_extract_next_line(self) -> Optional[bytearray]:
+        """
+        Extract the first line, if it is completed in the buffer.
+        """
+        # Only search in buffer space that we've not already looked at.
+        search_start_index = max(0, self._next_line_search - 1)
+        partial_idx = self._data.find(b"\r\n", search_start_index)
+
+        if partial_idx == -1:
+            self._next_line_search = len(self._data)
+            return None
+
+        # + 2 is to compensate len(b"\r\n")
+        idx = partial_idx + 2
+
+        return self._extract(idx)
+
+    def maybe_extract_lines(self) -> Optional[List[bytearray]]:
+        """
+        Extract everything up to the first blank line, and return a list of lines.
+        """
+        # Handle the case where we have an immediate empty line.
+        if self._data[:1] == b"\n":
+            self._extract(1)
+            return []
+
+        if self._data[:2] == b"\r\n":
+            self._extract(2)
+            return []
+
+        # Only search in buffer space that we've not already looked at.
+        match = blank_line_regex.search(self._data, self._multiple_lines_search)
+        if match is None:
+            self._multiple_lines_search = max(0, len(self._data) - 2)
+            return None
+
+        # Truncate the buffer and return it.
+        idx = match.span(0)[-1]
+        out = self._extract(idx)
+        lines = out.split(b"\n")
+
+        for line in lines:
+            if line.endswith(b"\r"):
+                del line[-1]
+
+        assert lines[-2] == lines[-1] == b""
+
+        del lines[-2:]
+
+        return lines
+
+    # In theory we should wait until `\r\n` before starting to validate
+    # incoming data. However it's interesting to detect (very) invalid data
+    # early given they might not even contain `\r\n` at all (hence only
+    # timeout will get rid of them).
+    # This is not a 100% effective detection but more of a cheap sanity check
+    # allowing for early abort in some useful cases.
+    # This is especially interesting when peer is messing up with HTTPS and
+    # sent us a TLS stream where we were expecting plain HTTP given all
+    # versions of TLS so far start handshake with a 0x16 message type code.
+    def is_next_line_obviously_invalid_request_line(self) -> bool:
+        try:
+            # HTTP header line must not contain non-printable characters
+            # and should not start with a space
+            return self._data[0] < 0x21
+        except IndexError:
+            return False

venv/lib/python3.11/site-packages/h11/_state.py

@@ -0,0 +1,367 @@
+################################################################
+# The core state machine
+################################################################
+#
+# Rule 1: everything that affects the state machine and state transitions must
+# live here in this file. As much as possible goes into the table-based
+# representation, but for the bits that don't quite fit, the actual code and
+# state must nonetheless live here.
+#
+# Rule 2: this file does not know about what role we're playing; it only knows
+# about HTTP request/response cycles in the abstract. This ensures that we
+# don't cheat and apply different rules to local and remote parties.
+#
+#
+# Theory of operation
+# ===================
+#
+# Possibly the simplest way to think about this is that we actually have 5
+# different state machines here. Yes, 5. These are:
+#
+# 1) The client state, with its complicated automaton (see the docs)
+# 2) The server state, with its complicated automaton (see the docs)
+# 3) The keep-alive state, with possible states {True, False}
+# 4) The SWITCH_CONNECT state, with possible states {False, True}
+# 5) The SWITCH_UPGRADE state, with possible states {False, True}
+#
+# For (3)-(5), the first state listed is the initial state.
+#
+# (1)-(3) are stored explicitly in member variables. The last
+# two are stored implicitly in the pending_switch_proposals set as:
+#   (state of 4) == (_SWITCH_CONNECT in pending_switch_proposals)
+#   (state of 5) == (_SWITCH_UPGRADE in pending_switch_proposals)
+#
+# And each of these machines has two different kinds of transitions:
+#
+# a) Event-triggered
+# b) State-triggered
+#
+# Event triggered is the obvious thing that you'd think it is: some event
+# happens, and if it's the right event at the right time then a transition
+# happens. But there are somewhat complicated rules for which machines can
+# "see" which events. (As a rule of thumb, if a machine "sees" an event, this
+# means two things: the event can affect the machine, and if the machine is
+# not in a state where it expects that event then it's an error.) These rules
+# are:
+#
+# 1) The client machine sees all h11.events objects emitted by the client.
+#
+# 2) The server machine sees all h11.events objects emitted by the server.
+#
+#    It also sees the client's Request event.
+#
+#    And sometimes, server events are annotated with a _SWITCH_* event. For
+#    example, we can have a (Response, _SWITCH_CONNECT) event, which is
+#    different from a regular Response event.
+#
+# 3) The keep-alive machine sees the process_keep_alive_disabled() event
+#    (which is derived from Request/Response events), and this event
+#    transitions it from True -> False, or from False -> False. There's no way
+#    to transition back.
+#
+# 4&5) The _SWITCH_* machines transition from False->True when we get a
+#    Request that proposes the relevant type of switch (via
+#    process_client_switch_proposals), and they go from True->False when we
+#    get a Response that has no _SWITCH_* annotation.
+#
+# So that's event-triggered transitions.
+#
+# State-triggered transitions are less standard. What they do here is couple
+# the machines together. The way this works is, when certain *joint*
+# configurations of states are achieved, then we automatically transition to a
+# new *joint* state. So, for example, if we're ever in a joint state with
+#
+#   client: DONE
+#   keep-alive: False
+#
+# then the client state immediately transitions to:
+#
+#   client: MUST_CLOSE
+#
+# This is fundamentally different from an event-based transition, because it
+# doesn't matter how we arrived at the {client: DONE, keep-alive: False} state
+# -- maybe the client transitioned SEND_BODY -> DONE, or keep-alive
+# transitioned True -> False. Either way, once this precondition is satisfied,
+# this transition is immediately triggered.
+#
+# What if two conflicting state-based transitions get enabled at the same
+# time?  In practice there's only one case where this arises (client DONE ->
+# MIGHT_SWITCH_PROTOCOL versus DONE -> MUST_CLOSE), and we resolve it by
+# explicitly prioritizing the DONE -> MIGHT_SWITCH_PROTOCOL transition.
+#
+# Implementation
+# --------------
+#
+# The event-triggered transitions for the server and client machines are all
+# stored explicitly in a table. Ditto for the state-triggered transitions that
+# involve just the server and client state.
+#
+# The transitions for the other machines, and the state-triggered transitions
+# that involve the other machines, are written out as explicit Python code.
+#
+# It'd be nice if there were some cleaner way to do all this. This isn't
+# *too* terrible, but I feel like it could probably be better.
+#
+# WARNING
+# -------
+#
+# The script that generates the state machine diagrams for the docs knows how
+# to read out the EVENT_TRIGGERED_TRANSITIONS and STATE_TRIGGERED_TRANSITIONS
+# tables. But it can't automatically read the transitions that are written
+# directly in Python code. So if you touch those, you need to also update the
+# script to keep it in sync!
+from typing import cast, Dict, Optional, Set, Tuple, Type, Union
+
+from ._events import *
+from ._util import LocalProtocolError, Sentinel
+
+# Everything in __all__ gets re-exported as part of the h11 public API.
+__all__ = [
+    "CLIENT",
+    "SERVER",
+    "IDLE",
+    "SEND_RESPONSE",
+    "SEND_BODY",
+    "DONE",
+    "MUST_CLOSE",
+    "CLOSED",
+    "MIGHT_SWITCH_PROTOCOL",
+    "SWITCHED_PROTOCOL",
+    "ERROR",
+]
+
+
+class CLIENT(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class SERVER(Sentinel, metaclass=Sentinel):
+    pass
+
+
+# States
+class IDLE(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class SEND_RESPONSE(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class SEND_BODY(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class DONE(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class MUST_CLOSE(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class CLOSED(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class ERROR(Sentinel, metaclass=Sentinel):
+    pass
+
+
+# Switch types
+class MIGHT_SWITCH_PROTOCOL(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class SWITCHED_PROTOCOL(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class _SWITCH_UPGRADE(Sentinel, metaclass=Sentinel):
+    pass
+
+
+class _SWITCH_CONNECT(Sentinel, metaclass=Sentinel):
+    pass
+
+
+EventTransitionType = Dict[
+    Type[Sentinel],
+    Dict[
+        Type[Sentinel],
+        Dict[Union[Type[Event], Tuple[Type[Event], Type[Sentinel]]], Type[Sentinel]],
+    ],
+]
+
+EVENT_TRIGGERED_TRANSITIONS: EventTransitionType = {
+    CLIENT: {
+        IDLE: {Request: SEND_BODY, ConnectionClosed: CLOSED},
+        SEND_BODY: {Data: SEND_BODY, EndOfMessage: DONE},
+        DONE: {ConnectionClosed: CLOSED},
+        MUST_CLOSE: {ConnectionClosed: CLOSED},
+        CLOSED: {ConnectionClosed: CLOSED},
+        MIGHT_SWITCH_PROTOCOL: {},
+        SWITCHED_PROTOCOL: {},
+        ERROR: {},
+    },
+    SERVER: {
+        IDLE: {
+            ConnectionClosed: CLOSED,
+            Response: SEND_BODY,
+            # Special case: server sees client Request events, in this form
+            (Request, CLIENT): SEND_RESPONSE,
+        },
+        SEND_RESPONSE: {
+            InformationalResponse: SEND_RESPONSE,
+            Response: SEND_BODY,
+            (InformationalResponse, _SWITCH_UPGRADE): SWITCHED_PROTOCOL,
+            (Response, _SWITCH_CONNECT): SWITCHED_PROTOCOL,
+        },
+        SEND_BODY: {Data: SEND_BODY, EndOfMessage: DONE},
+        DONE: {ConnectionClosed: CLOSED},
+        MUST_CLOSE: {ConnectionClosed: CLOSED},
+        CLOSED: {ConnectionClosed: CLOSED},
+        SWITCHED_PROTOCOL: {},
+        ERROR: {},
+    },
+}
+
+StateTransitionType = Dict[
+    Tuple[Type[Sentinel], Type[Sentinel]], Dict[Type[Sentinel], Type[Sentinel]]
+]
+
+# NB: there are also some special-case state-triggered transitions hard-coded
+# into _fire_state_triggered_transitions below.
+STATE_TRIGGERED_TRANSITIONS: StateTransitionType = {
+    # (Client state, Server state) -> new states
+    # Protocol negotiation
+    (MIGHT_SWITCH_PROTOCOL, SWITCHED_PROTOCOL): {CLIENT: SWITCHED_PROTOCOL},
+    # Socket shutdown
+    (CLOSED, DONE): {SERVER: MUST_CLOSE},
+    (CLOSED, IDLE): {SERVER: MUST_CLOSE},
+    (ERROR, DONE): {SERVER: MUST_CLOSE},
+    (DONE, CLOSED): {CLIENT: MUST_CLOSE},
+    (IDLE, CLOSED): {CLIENT: MUST_CLOSE},
+    (DONE, ERROR): {CLIENT: MUST_CLOSE},
+}
+
+
+class ConnectionState:
+    def __init__(self) -> None:
+        # Extra bits of state that don't quite fit into the state model.
+
+        # If this is False then it enables the automatic DONE -> MUST_CLOSE
+        # transition. Don't set this directly; call .keep_alive_disabled()
+        self.keep_alive = True
+
+        # This is a subset of {UPGRADE, CONNECT}, containing the proposals
+        # made by the client for switching protocols.
+        self.pending_switch_proposals: Set[Type[Sentinel]] = set()
+
+        self.states: Dict[Type[Sentinel], Type[Sentinel]] = {CLIENT: IDLE, SERVER: IDLE}
+
+    def process_error(self, role: Type[Sentinel]) -> None:
+        self.states[role] = ERROR
+        self._fire_state_triggered_transitions()
+
+    def process_keep_alive_disabled(self) -> None:
+        self.keep_alive = False
+        self._fire_state_triggered_transitions()
+
+    def process_client_switch_proposal(self, switch_event: Type[Sentinel]) -> None:
+        self.pending_switch_proposals.add(switch_event)
+        self._fire_state_triggered_transitions()
+
+    def process_event(
+        self,
+        role: Type[Sentinel],
+        event_type: Type[Event],
+        server_switch_event: Optional[Type[Sentinel]] = None,
+    ) -> None:
+        _event_type: Union[Type[Event], Tuple[Type[Event], Type[Sentinel]]] = event_type
+        if server_switch_event is not None:
+            assert role is SERVER
+            if server_switch_event not in self.pending_switch_proposals:
+                raise LocalProtocolError(
+                    "Received server {} event without a pending proposal".format(
+                        server_switch_event
+                    )
+                )
+            _event_type = (event_type, server_switch_event)
+        if server_switch_event is None and _event_type is Response:
+            self.pending_switch_proposals = set()
+        self._fire_event_triggered_transitions(role, _event_type)
+        # Special case: the server state does get to see Request
+        # events.
+        if _event_type is Request:
+            assert role is CLIENT
+            self._fire_event_triggered_transitions(SERVER, (Request, CLIENT))
+        self._fire_state_triggered_transitions()
+
+    def _fire_event_triggered_transitions(
+        self,
+        role: Type[Sentinel],
+        event_type: Union[Type[Event], Tuple[Type[Event], Type[Sentinel]]],
+    ) -> None:
+        state = self.states[role]
+        try:
+            new_state = EVENT_TRIGGERED_TRANSITIONS[role][state][event_type]
+        except KeyError:
+            event_type = cast(Type[Event], event_type)
+            raise LocalProtocolError(
+                "can't handle event type {} when role={} and state={}".format(
+                    event_type.__name__, role, self.states[role]
+                )
+            ) from None
+        self.states[role] = new_state
+
+    def _fire_state_triggered_transitions(self) -> None:
+        # We apply these rules repeatedly until converging on a fixed point
+        while True:
+            start_states = dict(self.states)
+
+            # It could happen that both these special-case transitions are
+            # enabled at the same time:
+            #
+            #    DONE -> MIGHT_SWITCH_PROTOCOL
+            #    DONE -> MUST_CLOSE
+            #
+            # For example, this will always be true of a HTTP/1.0 client
+            # requesting CONNECT.  If this happens, the protocol switch takes
+            # priority. From there the client will either go to
+            # SWITCHED_PROTOCOL, in which case it's none of our business when
+            # they close the connection, or else the server will deny the
+            # request, in which case the client will go back to DONE and then
+            # from there to MUST_CLOSE.
+            if self.pending_switch_proposals:
+                if self.states[CLIENT] is DONE:
+                    self.states[CLIENT] = MIGHT_SWITCH_PROTOCOL
+
+            if not self.pending_switch_proposals:
+                if self.states[CLIENT] is MIGHT_SWITCH_PROTOCOL:
+                    self.states[CLIENT] = DONE
+
+            if not self.keep_alive:
+                for role in (CLIENT, SERVER):
+                    if self.states[role] is DONE:
+                        self.states[role] = MUST_CLOSE
+
+            # Tabular state-triggered transitions
+            joint_state = (self.states[CLIENT], self.states[SERVER])
+            changes = STATE_TRIGGERED_TRANSITIONS.get(joint_state, {})
+            self.states.update(changes)
+
+            if self.states == start_states:
+                # Fixed point reached
+                return
+
+    def start_next_cycle(self) -> None:
+        if self.states != {CLIENT: DONE, SERVER: DONE}:
+            raise LocalProtocolError(
+                "not in a reusable state. self.states={}".format(self.states)
+            )
+        # Can't reach DONE/DONE with any of these active, but still, let's be
+        # sure.
+        assert self.keep_alive
+        assert not self.pending_switch_proposals
+        self.states = {CLIENT: IDLE, SERVER: IDLE}

venv/lib/python3.11/site-packages/h11/_util.py

@@ -0,0 +1,135 @@
+from typing import Any, Dict, NoReturn, Pattern, Tuple, Type, TypeVar, Union
+
+__all__ = [
+    "ProtocolError",
+    "LocalProtocolError",
+    "RemoteProtocolError",
+    "validate",
+    "bytesify",
+]
+
+
+class ProtocolError(Exception):
+    """Exception indicating a violation of the HTTP/1.1 protocol.
+
+    This as an abstract base class, with two concrete base classes:
+    :exc:`LocalProtocolError`, which indicates that you tried to do something
+    that HTTP/1.1 says is illegal, and :exc:`RemoteProtocolError`, which
+    indicates that the remote peer tried to do something that HTTP/1.1 says is
+    illegal. See :ref:`error-handling` for details.
+
+    In addition to the normal :exc:`Exception` features, it has one attribute:
+
+    .. attribute:: error_status_hint
+
+       This gives a suggestion as to what status code a server might use if
+       this error occurred as part of a request.
+
+       For a :exc:`RemoteProtocolError`, this is useful as a suggestion for
+       how you might want to respond to a misbehaving peer, if you're
+       implementing a server.
+
+       For a :exc:`LocalProtocolError`, this can be taken as a suggestion for
+       how your peer might have responded to *you* if h11 had allowed you to
+       continue.
+
+       The default is 400 Bad Request, a generic catch-all for protocol
+       violations.
+
+    """
+
+    def __init__(self, msg: str, error_status_hint: int = 400) -> None:
+        if type(self) is ProtocolError:
+            raise TypeError("tried to directly instantiate ProtocolError")
+        Exception.__init__(self, msg)
+        self.error_status_hint = error_status_hint
+
+
+# Strategy: there are a number of public APIs where a LocalProtocolError can
+# be raised (send(), all the different event constructors, ...), and only one
+# public API where RemoteProtocolError can be raised
+# (receive_data()). Therefore we always raise LocalProtocolError internally,
+# and then receive_data will translate this into a RemoteProtocolError.
+#
+# Internally:
+#   LocalProtocolError is the generic "ProtocolError".
+# Externally:
+#   LocalProtocolError is for local errors and RemoteProtocolError is for
+#   remote errors.
+class LocalProtocolError(ProtocolError):
+    def _reraise_as_remote_protocol_error(self) -> NoReturn:
+        # After catching a LocalProtocolError, use this method to re-raise it
+        # as a RemoteProtocolError. This method must be called from inside an
+        # except: block.
+        #
+        # An easy way to get an equivalent RemoteProtocolError is just to
+        # modify 'self' in place.
+        self.__class__ = RemoteProtocolError  # type: ignore
+        # But the re-raising is somewhat non-trivial -- you might think that
+        # now that we've modified the in-flight exception object, that just
+        # doing 'raise' to re-raise it would be enough. But it turns out that
+        # this doesn't work, because Python tracks the exception type
+        # (exc_info[0]) separately from the exception object (exc_info[1]),
+        # and we only modified the latter. So we really do need to re-raise
+        # the new type explicitly.
+        # On py3, the traceback is part of the exception object, so our
+        # in-place modification preserved it and we can just re-raise:
+        raise self
+
+
+class RemoteProtocolError(ProtocolError):
+    pass
+
+
+def validate(
+    regex: Pattern[bytes], data: bytes, msg: str = "malformed data", *format_args: Any
+) -> Dict[str, bytes]:
+    match = regex.fullmatch(data)
+    if not match:
+        if format_args:
+            msg = msg.format(*format_args)
+        raise LocalProtocolError(msg)
+    return match.groupdict()
+
+
+# Sentinel values
+#
+# - Inherit identity-based comparison and hashing from object
+# - Have a nice repr
+# - Have a *bonus property*: type(sentinel) is sentinel
+#
+# The bonus property is useful if you want to take the return value from
+# next_event() and do some sort of dispatch based on type(event).
+
+_T_Sentinel = TypeVar("_T_Sentinel", bound="Sentinel")
+
+
+class Sentinel(type):
+    def __new__(
+        cls: Type[_T_Sentinel],
+        name: str,
+        bases: Tuple[type, ...],
+        namespace: Dict[str, Any],
+        **kwds: Any
+    ) -> _T_Sentinel:
+        assert bases == (Sentinel,)
+        v = super().__new__(cls, name, bases, namespace, **kwds)
+        v.__class__ = v  # type: ignore
+        return v
+
+    def __repr__(self) -> str:
+        return self.__name__
+
+
+# Used for methods, request targets, HTTP versions, header names, and header
+# values. Accepts ascii-strings, or bytes/bytearray/memoryview/..., and always
+# returns bytes.
+def bytesify(s: Union[bytes, bytearray, memoryview, int, str]) -> bytes:
+    # Fast-path:
+    if type(s) is bytes:
+        return s
+    if isinstance(s, str):
+        s = s.encode("ascii")
+    if isinstance(s, int):
+        raise TypeError("expected bytes-like object, not int")
+    return bytes(s)

venv/lib/python3.11/site-packages/h11/_version.py

@@ -0,0 +1,16 @@
+# This file must be kept very simple, because it is consumed from several
+# places -- it is imported by h11/__init__.py, execfile'd by setup.py, etc.
+
+# We use a simple scheme:
+#   1.0.0 -> 1.0.0+dev -> 1.1.0 -> 1.1.0+dev
+# where the +dev versions are never released into the wild, they're just what
+# we stick into the VCS in between releases.
+#
+# This is compatible with PEP 440:
+#   http://legacy.python.org/dev/peps/pep-0440/
+# via the use of the "local suffix" "+dev", which is disallowed on index
+# servers and causes 1.0.0+dev to sort after plain 1.0.0, which is what we
+# want. (Contrast with the special suffix 1.0.0.dev, which sorts *before*
+# 1.0.0.)
+
+__version__ = "0.14.0"

venv/lib/python3.11/site-packages/h11/_writers.py

@@ -0,0 +1,145 @@
+# Code to read HTTP data
+#
+# Strategy: each writer takes an event + a write-some-bytes function, which is
+# calls.
+#
+# WRITERS is a dict describing how to pick a reader. It maps states to either:
+# - a writer
+# - or, for body writers, a dict of framin-dependent writer factories
+
+from typing import Any, Callable, Dict, List, Tuple, Type, Union
+
+from ._events import Data, EndOfMessage, Event, InformationalResponse, Request, Response
+from ._headers import Headers
+from ._state import CLIENT, IDLE, SEND_BODY, SEND_RESPONSE, SERVER
+from ._util import LocalProtocolError, Sentinel
+
+__all__ = ["WRITERS"]
+
+Writer = Callable[[bytes], Any]
+
+
+def write_headers(headers: Headers, write: Writer) -> None:
+    # "Since the Host field-value is critical information for handling a
+    # request, a user agent SHOULD generate Host as the first header field
+    # following the request-line." - RFC 7230
+    raw_items = headers._full_items
+    for raw_name, name, value in raw_items:
+        if name == b"host":
+            write(b"%s: %s\r\n" % (raw_name, value))
+    for raw_name, name, value in raw_items:
+        if name != b"host":
+            write(b"%s: %s\r\n" % (raw_name, value))
+    write(b"\r\n")
+
+
+def write_request(request: Request, write: Writer) -> None:
+    if request.http_version != b"1.1":
+        raise LocalProtocolError("I only send HTTP/1.1")
+    write(b"%s %s HTTP/1.1\r\n" % (request.method, request.target))
+    write_headers(request.headers, write)
+
+
+# Shared between InformationalResponse and Response
+def write_any_response(
+    response: Union[InformationalResponse, Response], write: Writer
+) -> None:
+    if response.http_version != b"1.1":
+        raise LocalProtocolError("I only send HTTP/1.1")
+    status_bytes = str(response.status_code).encode("ascii")
+    # We don't bother sending ascii status messages like "OK"; they're
+    # optional and ignored by the protocol. (But the space after the numeric
+    # status code is mandatory.)
+    #
+    # XX FIXME: could at least make an effort to pull out the status message
+    # from stdlib's http.HTTPStatus table. Or maybe just steal their enums
+    # (either by import or copy/paste). We already accept them as status codes
+    # since they're of type IntEnum < int.
+    write(b"HTTP/1.1 %s %s\r\n" % (status_bytes, response.reason))
+    write_headers(response.headers, write)
+
+
+class BodyWriter:
+    def __call__(self, event: Event, write: Writer) -> None:
+        if type(event) is Data:
+            self.send_data(event.data, write)
+        elif type(event) is EndOfMessage:
+            self.send_eom(event.headers, write)
+        else:  # pragma: no cover
+            assert False
+
+    def send_data(self, data: bytes, write: Writer) -> None:
+        pass
+
+    def send_eom(self, headers: Headers, write: Writer) -> None:
+        pass
+
+
+#
+# These are all careful not to do anything to 'data' except call len(data) and
+# write(data). This allows us to transparently pass-through funny objects,
+# like placeholder objects referring to files on disk that will be sent via
+# sendfile(2).
+#
+class ContentLengthWriter(BodyWriter):
+    def __init__(self, length: int) -> None:
+        self._length = length
+
+    def send_data(self, data: bytes, write: Writer) -> None:
+        self._length -= len(data)
+        if self._length < 0:
+            raise LocalProtocolError("Too much data for declared Content-Length")
+        write(data)
+
+    def send_eom(self, headers: Headers, write: Writer) -> None:
+        if self._length != 0:
+            raise LocalProtocolError("Too little data for declared Content-Length")
+        if headers:
+            raise LocalProtocolError("Content-Length and trailers don't mix")
+
+
+class ChunkedWriter(BodyWriter):
+    def send_data(self, data: bytes, write: Writer) -> None:
+        # if we encoded 0-length data in the naive way, it would look like an
+        # end-of-message.
+        if not data:
+            return
+        write(b"%x\r\n" % len(data))
+        write(data)
+        write(b"\r\n")
+
+    def send_eom(self, headers: Headers, write: Writer) -> None:
+        write(b"0\r\n")
+        write_headers(headers, write)
+
+
+class Http10Writer(BodyWriter):
+    def send_data(self, data: bytes, write: Writer) -> None:
+        write(data)
+
+    def send_eom(self, headers: Headers, write: Writer) -> None:
+        if headers:
+            raise LocalProtocolError("can't send trailers to HTTP/1.0 client")
+        # no need to close the socket ourselves, that will be taken care of by
+        # Connection: close machinery
+
+
+WritersType = Dict[
+    Union[Tuple[Type[Sentinel], Type[Sentinel]], Type[Sentinel]],
+    Union[
+        Dict[str, Type[BodyWriter]],
+        Callable[[Union[InformationalResponse, Response], Writer], None],
+        Callable[[Request, Writer], None],
+    ],
+]
+
+WRITERS: WritersType = {
+    (CLIENT, IDLE): write_request,
+    (SERVER, IDLE): write_any_response,
+    (SERVER, SEND_RESPONSE): write_any_response,
+    SEND_BODY: {
+        "chunked": ChunkedWriter,
+        "content-length": ContentLengthWriter,
+        "http/1.0": Http10Writer,
+    },
+}

venv/lib/python3.11/site-packages/h11/py.typed

@@ -0,0 +1 @@
+Marker

venv/lib/python3.11/site-packages/h11/tests/data/test-file

@@ -0,0 +1 @@
+92b12bc045050b55b848d37167a1a63947c364579889ce1d39788e45e9fac9e5

venv/lib/python3.11/site-packages/h11/tests/helpers.py

@@ -0,0 +1,101 @@
+from typing import cast, List, Type, Union, ValuesView
+
+from .._connection import Connection, NEED_DATA, PAUSED
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._state import CLIENT, CLOSED, DONE, MUST_CLOSE, SERVER
+from .._util import Sentinel
+
+try:
+    from typing import Literal
+except ImportError:
+    from typing_extensions import Literal  # type: ignore
+
+
+def get_all_events(conn: Connection) -> List[Event]:
+    got_events = []
+    while True:
+        event = conn.next_event()
+        if event in (NEED_DATA, PAUSED):
+            break
+        event = cast(Event, event)
+        got_events.append(event)
+        if type(event) is ConnectionClosed:
+            break
+    return got_events
+
+
+def receive_and_get(conn: Connection, data: bytes) -> List[Event]:
+    conn.receive_data(data)
+    return get_all_events(conn)
+
+
+# Merges adjacent Data events, converts payloads to bytestrings, and removes
+# chunk boundaries.
+def normalize_data_events(in_events: List[Event]) -> List[Event]:
+    out_events: List[Event] = []
+    for event in in_events:
+        if type(event) is Data:
+            event = Data(data=bytes(event.data), chunk_start=False, chunk_end=False)
+        if out_events and type(out_events[-1]) is type(event) is Data:
+            out_events[-1] = Data(
+                data=out_events[-1].data + event.data,
+                chunk_start=out_events[-1].chunk_start,
+                chunk_end=out_events[-1].chunk_end,
+            )
+        else:
+            out_events.append(event)
+    return out_events
+
+
+# Given that we want to write tests that push some events through a Connection
+# and check that its state updates appropriately... we might as make a habit
+# of pushing them through two Connections with a fake network link in
+# between.
+class ConnectionPair:
+    def __init__(self) -> None:
+        self.conn = {CLIENT: Connection(CLIENT), SERVER: Connection(SERVER)}
+        self.other = {CLIENT: SERVER, SERVER: CLIENT}
+
+    @property
+    def conns(self) -> ValuesView[Connection]:
+        return self.conn.values()
+
+    # expect="match" if expect=send_events; expect=[...] to say what expected
+    def send(
+        self,
+        role: Type[Sentinel],
+        send_events: Union[List[Event], Event],
+        expect: Union[List[Event], Event, Literal["match"]] = "match",
+    ) -> bytes:
+        if not isinstance(send_events, list):
+            send_events = [send_events]
+        data = b""
+        closed = False
+        for send_event in send_events:
+            new_data = self.conn[role].send(send_event)
+            if new_data is None:
+                closed = True
+            else:
+                data += new_data
+        # send uses b"" to mean b"", and None to mean closed
+        # receive uses b"" to mean closed, and None to mean "try again"
+        # so we have to translate between the two conventions
+        if data:
+            self.conn[self.other[role]].receive_data(data)
+        if closed:
+            self.conn[self.other[role]].receive_data(b"")
+        got_events = get_all_events(self.conn[self.other[role]])
+        if expect == "match":
+            expect = send_events
+        if not isinstance(expect, list):
+            expect = [expect]
+        assert got_events == expect
+        return data

venv/lib/python3.11/site-packages/h11/tests/test_against_stdlib_http.py

@@ -0,0 +1,115 @@
+import json
+import os.path
+import socket
+import socketserver
+import threading
+from contextlib import closing, contextmanager
+from http.server import SimpleHTTPRequestHandler
+from typing import Callable, Generator
+from urllib.request import urlopen
+
+import h11
+
+
+@contextmanager
+def socket_server(
+    handler: Callable[..., socketserver.BaseRequestHandler]
+) -> Generator[socketserver.TCPServer, None, None]:
+    httpd = socketserver.TCPServer(("127.0.0.1", 0), handler)
+    thread = threading.Thread(
+        target=httpd.serve_forever, kwargs={"poll_interval": 0.01}
+    )
+    thread.daemon = True
+    try:
+        thread.start()
+        yield httpd
+    finally:
+        httpd.shutdown()
+
+
+test_file_path = os.path.join(os.path.dirname(__file__), "data/test-file")
+with open(test_file_path, "rb") as f:
+    test_file_data = f.read()
+
+
+class SingleMindedRequestHandler(SimpleHTTPRequestHandler):
+    def translate_path(self, path: str) -> str:
+        return test_file_path
+
+
+def test_h11_as_client() -> None:
+    with socket_server(SingleMindedRequestHandler) as httpd:
+        with closing(socket.create_connection(httpd.server_address)) as s:
+            c = h11.Connection(h11.CLIENT)
+
+            s.sendall(
+                c.send(  # type: ignore[arg-type]
+                    h11.Request(
+                        method="GET", target="/foo", headers=[("Host", "localhost")]
+                    )
+                )
+            )
+            s.sendall(c.send(h11.EndOfMessage()))  # type: ignore[arg-type]
+
+            data = bytearray()
+            while True:
+                event = c.next_event()
+                print(event)
+                if event is h11.NEED_DATA:
+                    # Use a small read buffer to make things more challenging
+                    # and exercise more paths :-)
+                    c.receive_data(s.recv(10))
+                    continue
+                if type(event) is h11.Response:
+                    assert event.status_code == 200
+                if type(event) is h11.Data:
+                    data += event.data
+                if type(event) is h11.EndOfMessage:
+                    break
+            assert bytes(data) == test_file_data
+
+
+class H11RequestHandler(socketserver.BaseRequestHandler):
+    def handle(self) -> None:
+        with closing(self.request) as s:
+            c = h11.Connection(h11.SERVER)
+            request = None
+            while True:
+                event = c.next_event()
+                if event is h11.NEED_DATA:
+                    # Use a small read buffer to make things more challenging
+                    # and exercise more paths :-)
+                    c.receive_data(s.recv(10))
+                    continue
+                if type(event) is h11.Request:
+                    request = event
+                if type(event) is h11.EndOfMessage:
+                    break
+            assert request is not None
+            info = json.dumps(
+                {
+                    "method": request.method.decode("ascii"),
+                    "target": request.target.decode("ascii"),
+                    "headers": {
+                        name.decode("ascii"): value.decode("ascii")
+                        for (name, value) in request.headers
+                    },
+                }
+            )
+            s.sendall(c.send(h11.Response(status_code=200, headers=[])))  # type: ignore[arg-type]
+            s.sendall(c.send(h11.Data(data=info.encode("ascii"))))
+            s.sendall(c.send(h11.EndOfMessage()))
+
+
+def test_h11_as_server() -> None:
+    with socket_server(H11RequestHandler) as httpd:
+        host, port = httpd.server_address
+        url = "http://{}:{}/some-path".format(host, port)
+        with closing(urlopen(url)) as f:
+            assert f.getcode() == 200
+            data = f.read()
+    info = json.loads(data.decode("ascii"))
+    print(info)
+    assert info["method"] == "GET"
+    assert info["target"] == "/some-path"
+    assert "urllib" in info["headers"]["user-agent"]

venv/lib/python3.11/site-packages/h11/tests/test_events.py

@@ -0,0 +1,150 @@
+from http import HTTPStatus
+
+import pytest
+
+from .. import _events
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._util import LocalProtocolError
+
+
+def test_events() -> None:
+    with pytest.raises(LocalProtocolError):
+        # Missing Host:
+        req = Request(
+            method="GET", target="/", headers=[("a", "b")], http_version="1.1"
+        )
+    # But this is okay (HTTP/1.0)
+    req = Request(method="GET", target="/", headers=[("a", "b")], http_version="1.0")
+    # fields are normalized
+    assert req.method == b"GET"
+    assert req.target == b"/"
+    assert req.headers == [(b"a", b"b")]
+    assert req.http_version == b"1.0"
+
+    # This is also okay -- has a Host (with weird capitalization, which is ok)
+    req = Request(
+        method="GET",
+        target="/",
+        headers=[("a", "b"), ("hOSt", "example.com")],
+        http_version="1.1",
+    )
+    # we normalize header capitalization
+    assert req.headers == [(b"a", b"b"), (b"host", b"example.com")]
+
+    # Multiple host is bad too
+    with pytest.raises(LocalProtocolError):
+        req = Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "a"), ("Host", "a")],
+            http_version="1.1",
+        )
+    # Even for HTTP/1.0
+    with pytest.raises(LocalProtocolError):
+        req = Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "a"), ("Host", "a")],
+            http_version="1.0",
+        )
+
+    # Header values are validated
+    for bad_char in "\x00\r\n\f\v":
+        with pytest.raises(LocalProtocolError):
+            req = Request(
+                method="GET",
+                target="/",
+                headers=[("Host", "a"), ("Foo", "asd" + bad_char)],
+                http_version="1.0",
+            )
+
+    # But for compatibility we allow non-whitespace control characters, even
+    # though they're forbidden by the spec.
+    Request(
+        method="GET",
+        target="/",
+        headers=[("Host", "a"), ("Foo", "asd\x01\x02\x7f")],
+        http_version="1.0",
+    )
+
+    # Request target is validated
+    for bad_byte in b"\x00\x20\x7f\xee":
+        target = bytearray(b"/")
+        target.append(bad_byte)
+        with pytest.raises(LocalProtocolError):
+            Request(
+                method="GET", target=target, headers=[("Host", "a")], http_version="1.1"
+            )
+
+    # Request method is validated
+    with pytest.raises(LocalProtocolError):
+        Request(
+            method="GET / HTTP/1.1",
+            target=target,
+            headers=[("Host", "a")],
+            http_version="1.1",
+        )
+
+    ir = InformationalResponse(status_code=100, headers=[("Host", "a")])
+    assert ir.status_code == 100
+    assert ir.headers == [(b"host", b"a")]
+    assert ir.http_version == b"1.1"
+
+    with pytest.raises(LocalProtocolError):
+        InformationalResponse(status_code=200, headers=[("Host", "a")])
+
+    resp = Response(status_code=204, headers=[], http_version="1.0")  # type: ignore[arg-type]
+    assert resp.status_code == 204
+    assert resp.headers == []
+    assert resp.http_version == b"1.0"
+
+    with pytest.raises(LocalProtocolError):
+        resp = Response(status_code=100, headers=[], http_version="1.0")  # type: ignore[arg-type]
+
+    with pytest.raises(LocalProtocolError):
+        Response(status_code="100", headers=[], http_version="1.0")  # type: ignore[arg-type]
+
+    with pytest.raises(LocalProtocolError):
+        InformationalResponse(status_code=b"100", headers=[], http_version="1.0")  # type: ignore[arg-type]
+
+    d = Data(data=b"asdf")
+    assert d.data == b"asdf"
+
+    eom = EndOfMessage()
+    assert eom.headers == []
+
+    cc = ConnectionClosed()
+    assert repr(cc) == "ConnectionClosed()"
+
+
+def test_intenum_status_code() -> None:
+    # https://github.com/python-hyper/h11/issues/72
+
+    r = Response(status_code=HTTPStatus.OK, headers=[], http_version="1.0")  # type: ignore[arg-type]
+    assert r.status_code == HTTPStatus.OK
+    assert type(r.status_code) is not type(HTTPStatus.OK)
+    assert type(r.status_code) is int
+
+
+def test_header_casing() -> None:
+    r = Request(
+        method="GET",
+        target="/",
+        headers=[("Host", "example.org"), ("Connection", "keep-alive")],
+        http_version="1.1",
+    )
+    assert len(r.headers) == 2
+    assert r.headers[0] == (b"host", b"example.org")
+    assert r.headers == [(b"host", b"example.org"), (b"connection", b"keep-alive")]
+    assert r.headers.raw_items() == [
+        (b"Host", b"example.org"),
+        (b"Connection", b"keep-alive"),
+    ]

venv/lib/python3.11/site-packages/h11/tests/test_headers.py

@@ -0,0 +1,157 @@
+import pytest
+
+from .._events import Request
+from .._headers import (
+    get_comma_header,
+    has_expect_100_continue,
+    Headers,
+    normalize_and_validate,
+    set_comma_header,
+)
+from .._util import LocalProtocolError
+
+
+def test_normalize_and_validate() -> None:
+    assert normalize_and_validate([("foo", "bar")]) == [(b"foo", b"bar")]
+    assert normalize_and_validate([(b"foo", b"bar")]) == [(b"foo", b"bar")]
+
+    # no leading/trailing whitespace in names
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo ", "bar")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b" foo", "bar")])
+
+    # no weird characters in names
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate([(b"foo bar", b"baz")])
+    assert "foo bar" in str(excinfo.value)
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo\x00bar", b"baz")])
+    # Not even 8-bit characters:
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo\xffbar", b"baz")])
+    # And not even the control characters we allow in values:
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([(b"foo\x01bar", b"baz")])
+
+    # no return or NUL characters in values
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate([("foo", "bar\rbaz")])
+    assert "bar\\rbaz" in str(excinfo.value)
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "bar\nbaz")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "bar\x00baz")])
+    # no leading/trailing whitespace
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "barbaz  ")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "  barbaz")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "barbaz\t")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("foo", "\tbarbaz")])
+
+    # content-length
+    assert normalize_and_validate([("Content-Length", "1")]) == [
+        (b"content-length", b"1")
+    ]
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "asdf")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "1x")])
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "1"), ("Content-Length", "2")])
+    assert normalize_and_validate(
+        [("Content-Length", "0"), ("Content-Length", "0")]
+    ) == [(b"content-length", b"0")]
+    assert normalize_and_validate([("Content-Length", "0 , 0")]) == [
+        (b"content-length", b"0")
+    ]
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate(
+            [("Content-Length", "1"), ("Content-Length", "1"), ("Content-Length", "2")]
+        )
+    with pytest.raises(LocalProtocolError):
+        normalize_and_validate([("Content-Length", "1 , 1,2")])
+
+    # transfer-encoding
+    assert normalize_and_validate([("Transfer-Encoding", "chunked")]) == [
+        (b"transfer-encoding", b"chunked")
+    ]
+    assert normalize_and_validate([("Transfer-Encoding", "cHuNkEd")]) == [
+        (b"transfer-encoding", b"chunked")
+    ]
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate([("Transfer-Encoding", "gzip")])
+    assert excinfo.value.error_status_hint == 501  # Not Implemented
+    with pytest.raises(LocalProtocolError) as excinfo:
+        normalize_and_validate(
+            [("Transfer-Encoding", "chunked"), ("Transfer-Encoding", "gzip")]
+        )
+    assert excinfo.value.error_status_hint == 501  # Not Implemented
+
+
+def test_get_set_comma_header() -> None:
+    headers = normalize_and_validate(
+        [
+            ("Connection", "close"),
+            ("whatever", "something"),
+            ("connectiON", "fOo,, , BAR"),
+        ]
+    )
+
+    assert get_comma_header(headers, b"connection") == [b"close", b"foo", b"bar"]
+
+    headers = set_comma_header(headers, b"newthing", ["a", "b"])  # type: ignore
+
+    with pytest.raises(LocalProtocolError):
+        set_comma_header(headers, b"newthing", ["  a", "b"])  # type: ignore
+
+    assert headers == [
+        (b"connection", b"close"),
+        (b"whatever", b"something"),
+        (b"connection", b"fOo,, , BAR"),
+        (b"newthing", b"a"),
+        (b"newthing", b"b"),
+    ]
+
+    headers = set_comma_header(headers, b"whatever", ["different thing"])  # type: ignore
+
+    assert headers == [
+        (b"connection", b"close"),
+        (b"connection", b"fOo,, , BAR"),
+        (b"newthing", b"a"),
+        (b"newthing", b"b"),
+        (b"whatever", b"different thing"),
+    ]
+
+
+def test_has_100_continue() -> None:
+    assert has_expect_100_continue(
+        Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "example.com"), ("Expect", "100-continue")],
+        )
+    )
+    assert not has_expect_100_continue(
+        Request(method="GET", target="/", headers=[("Host", "example.com")])
+    )
+    # Case insensitive
+    assert has_expect_100_continue(
+        Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "example.com"), ("Expect", "100-Continue")],
+        )
+    )
+    # Doesn't work in HTTP/1.0
+    assert not has_expect_100_continue(
+        Request(
+            method="GET",
+            target="/",
+            headers=[("Host", "example.com"), ("Expect", "100-continue")],
+            http_version="1.0",
+        )
+    )

venv/lib/python3.11/site-packages/h11/tests/test_helpers.py

@@ -0,0 +1,32 @@
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .helpers import normalize_data_events
+
+
+def test_normalize_data_events() -> None:
+    assert normalize_data_events(
+        [
+            Data(data=bytearray(b"1")),
+            Data(data=b"2"),
+            Response(status_code=200, headers=[]),  # type: ignore[arg-type]
+            Data(data=b"3"),
+            Data(data=b"4"),
+            EndOfMessage(),
+            Data(data=b"5"),
+            Data(data=b"6"),
+            Data(data=b"7"),
+        ]
+    ) == [
+        Data(data=b"12"),
+        Response(status_code=200, headers=[]),  # type: ignore[arg-type]
+        Data(data=b"34"),
+        EndOfMessage(),
+        Data(data=b"567"),
+    ]

venv/lib/python3.11/site-packages/h11/tests/test_io.py

@@ -0,0 +1,572 @@
+from typing import Any, Callable, Generator, List
+
+import pytest
+
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._headers import Headers, normalize_and_validate
+from .._readers import (
+    _obsolete_line_fold,
+    ChunkedReader,
+    ContentLengthReader,
+    Http10Reader,
+    READERS,
+)
+from .._receivebuffer import ReceiveBuffer
+from .._state import (
+    CLIENT,
+    CLOSED,
+    DONE,
+    IDLE,
+    MIGHT_SWITCH_PROTOCOL,
+    MUST_CLOSE,
+    SEND_BODY,
+    SEND_RESPONSE,
+    SERVER,
+    SWITCHED_PROTOCOL,
+)
+from .._util import LocalProtocolError
+from .._writers import (
+    ChunkedWriter,
+    ContentLengthWriter,
+    Http10Writer,
+    write_any_response,
+    write_headers,
+    write_request,
+    WRITERS,
+)
+from .helpers import normalize_data_events
+
+SIMPLE_CASES = [
+    (
+        (CLIENT, IDLE),
+        Request(
+            method="GET",
+            target="/a",
+            headers=[("Host", "foo"), ("Connection", "close")],
+        ),
+        b"GET /a HTTP/1.1\r\nHost: foo\r\nConnection: close\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        Response(status_code=200, headers=[("Connection", "close")], reason=b"OK"),
+        b"HTTP/1.1 200 OK\r\nConnection: close\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        Response(status_code=200, headers=[], reason=b"OK"),  # type: ignore[arg-type]
+        b"HTTP/1.1 200 OK\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        InformationalResponse(
+            status_code=101, headers=[("Upgrade", "websocket")], reason=b"Upgrade"
+        ),
+        b"HTTP/1.1 101 Upgrade\r\nUpgrade: websocket\r\n\r\n",
+    ),
+    (
+        (SERVER, SEND_RESPONSE),
+        InformationalResponse(status_code=101, headers=[], reason=b"Upgrade"),  # type: ignore[arg-type]
+        b"HTTP/1.1 101 Upgrade\r\n\r\n",
+    ),
+]
+
+
+def dowrite(writer: Callable[..., None], obj: Any) -> bytes:
+    got_list: List[bytes] = []
+    writer(obj, got_list.append)
+    return b"".join(got_list)
+
+
+def tw(writer: Any, obj: Any, expected: Any) -> None:
+    got = dowrite(writer, obj)
+    assert got == expected
+
+
+def makebuf(data: bytes) -> ReceiveBuffer:
+    buf = ReceiveBuffer()
+    buf += data
+    return buf
+
+
+def tr(reader: Any, data: bytes, expected: Any) -> None:
+    def check(got: Any) -> None:
+        assert got == expected
+        # Headers should always be returned as bytes, not e.g. bytearray
+        # https://github.com/python-hyper/wsproto/pull/54#issuecomment-377709478
+        for name, value in getattr(got, "headers", []):
+            assert type(name) is bytes
+            assert type(value) is bytes
+
+    # Simple: consume whole thing
+    buf = makebuf(data)
+    check(reader(buf))
+    assert not buf
+
+    # Incrementally growing buffer
+    buf = ReceiveBuffer()
+    for i in range(len(data)):
+        assert reader(buf) is None
+        buf += data[i : i + 1]
+    check(reader(buf))
+
+    # Trailing data
+    buf = makebuf(data)
+    buf += b"trailing"
+    check(reader(buf))
+    assert bytes(buf) == b"trailing"
+
+
+def test_writers_simple() -> None:
+    for ((role, state), event, binary) in SIMPLE_CASES:
+        tw(WRITERS[role, state], event, binary)
+
+
+def test_readers_simple() -> None:
+    for ((role, state), event, binary) in SIMPLE_CASES:
+        tr(READERS[role, state], binary, event)
+
+
+def test_writers_unusual() -> None:
+    # Simple test of the write_headers utility routine
+    tw(
+        write_headers,
+        normalize_and_validate([("foo", "bar"), ("baz", "quux")]),
+        b"foo: bar\r\nbaz: quux\r\n\r\n",
+    )
+    tw(write_headers, Headers([]), b"\r\n")
+
+    # We understand HTTP/1.0, but we don't speak it
+    with pytest.raises(LocalProtocolError):
+        tw(
+            write_request,
+            Request(
+                method="GET",
+                target="/",
+                headers=[("Host", "foo"), ("Connection", "close")],
+                http_version="1.0",
+            ),
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tw(
+            write_any_response,
+            Response(
+                status_code=200, headers=[("Connection", "close")], http_version="1.0"
+            ),
+            None,
+        )
+
+
+def test_readers_unusual() -> None:
+    # Reading HTTP/1.0
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.0\r\nSome: header\r\n\r\n",
+        Request(
+            method="HEAD",
+            target="/foo",
+            headers=[("Some", "header")],
+            http_version="1.0",
+        ),
+    )
+
+    # check no-headers, since it's only legal with HTTP/1.0
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.0\r\n\r\n",
+        Request(method="HEAD", target="/foo", headers=[], http_version="1.0"),  # type: ignore[arg-type]
+    )
+
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\nSome: header\r\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("Some", "header")],
+            http_version="1.0",
+            reason=b"OK",
+        ),
+    )
+
+    # single-character header values (actually disallowed by the ABNF in RFC
+    # 7230 -- this is a bug in the standard that we originally copied...)
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\n" b"Foo: a a a a a \r\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("Foo", "a a a a a")],
+            http_version="1.0",
+            reason=b"OK",
+        ),
+    )
+
+    # Empty headers -- also legal
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\n" b"Foo:\r\n\r\n",
+        Response(
+            status_code=200, headers=[("Foo", "")], http_version="1.0", reason=b"OK"
+        ),
+    )
+
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200 OK\r\n" b"Foo: \t \t \r\n\r\n",
+        Response(
+            status_code=200, headers=[("Foo", "")], http_version="1.0", reason=b"OK"
+        ),
+    )
+
+    # Tolerate broken servers that leave off the response code
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.0 200\r\n" b"Foo: bar\r\n\r\n",
+        Response(
+            status_code=200, headers=[("Foo", "bar")], http_version="1.0", reason=b""
+        ),
+    )
+
+    # Tolerate headers line endings (\r\n and \n)
+    #    \n\r\b between headers and body
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.1 200 OK\r\nSomeHeader: val\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("SomeHeader", "val")],
+            http_version="1.1",
+            reason="OK",
+        ),
+    )
+
+    #   delimited only with \n
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.1 200 OK\nSomeHeader1: val1\nSomeHeader2: val2\n\n",
+        Response(
+            status_code=200,
+            headers=[("SomeHeader1", "val1"), ("SomeHeader2", "val2")],
+            http_version="1.1",
+            reason="OK",
+        ),
+    )
+
+    #   mixed \r\n and \n
+    tr(
+        READERS[SERVER, SEND_RESPONSE],
+        b"HTTP/1.1 200 OK\r\nSomeHeader1: val1\nSomeHeader2: val2\n\r\n",
+        Response(
+            status_code=200,
+            headers=[("SomeHeader1", "val1"), ("SomeHeader2", "val2")],
+            http_version="1.1",
+            reason="OK",
+        ),
+    )
+
+    # obsolete line folding
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.1\r\n"
+        b"Host: example.com\r\n"
+        b"Some: multi-line\r\n"
+        b" header\r\n"
+        b"\tnonsense\r\n"
+        b"    \t   \t\tI guess\r\n"
+        b"Connection: close\r\n"
+        b"More-nonsense: in the\r\n"
+        b"    last header  \r\n\r\n",
+        Request(
+            method="HEAD",
+            target="/foo",
+            headers=[
+                ("Host", "example.com"),
+                ("Some", "multi-line header nonsense I guess"),
+                ("Connection", "close"),
+                ("More-nonsense", "in the last header"),
+            ],
+        ),
+    )
+
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"  folded: line\r\n\r\n",
+            None,
+        )
+
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"foo  : line\r\n\r\n",
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"foo\t: line\r\n\r\n",
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"foo\t: line\r\n\r\n",
+            None,
+        )
+    with pytest.raises(LocalProtocolError):
+        tr(READERS[CLIENT, IDLE], b"HEAD /foo HTTP/1.1\r\n" b": line\r\n\r\n", None)
+
+
+def test__obsolete_line_fold_bytes() -> None:
+    # _obsolete_line_fold has a defensive cast to bytearray, which is
+    # necessary to protect against O(n^2) behavior in case anyone ever passes
+    # in regular bytestrings... but right now we never pass in regular
+    # bytestrings. so this test just exists to get some coverage on that
+    # defensive cast.
+    assert list(_obsolete_line_fold([b"aaa", b"bbb", b"  ccc", b"ddd"])) == [
+        b"aaa",
+        bytearray(b"bbb ccc"),
+        b"ddd",
+    ]
+
+
+def _run_reader_iter(
+    reader: Any, buf: bytes, do_eof: bool
+) -> Generator[Any, None, None]:
+    while True:
+        event = reader(buf)
+        if event is None:
+            break
+        yield event
+        # body readers have undefined behavior after returning EndOfMessage,
+        # because this changes the state so they don't get called again
+        if type(event) is EndOfMessage:
+            break
+    if do_eof:
+        assert not buf
+        yield reader.read_eof()
+
+
+def _run_reader(*args: Any) -> List[Event]:
+    events = list(_run_reader_iter(*args))
+    return normalize_data_events(events)
+
+
+def t_body_reader(thunk: Any, data: bytes, expected: Any, do_eof: bool = False) -> None:
+    # Simple: consume whole thing
+    print("Test 1")
+    buf = makebuf(data)
+    assert _run_reader(thunk(), buf, do_eof) == expected
+
+    # Incrementally growing buffer
+    print("Test 2")
+    reader = thunk()
+    buf = ReceiveBuffer()
+    events = []
+    for i in range(len(data)):
+        events += _run_reader(reader, buf, False)
+        buf += data[i : i + 1]
+    events += _run_reader(reader, buf, do_eof)
+    assert normalize_data_events(events) == expected
+
+    is_complete = any(type(event) is EndOfMessage for event in expected)
+    if is_complete and not do_eof:
+        buf = makebuf(data + b"trailing")
+        assert _run_reader(thunk(), buf, False) == expected
+
+
+def test_ContentLengthReader() -> None:
+    t_body_reader(lambda: ContentLengthReader(0), b"", [EndOfMessage()])
+
+    t_body_reader(
+        lambda: ContentLengthReader(10),
+        b"0123456789",
+        [Data(data=b"0123456789"), EndOfMessage()],
+    )
+
+
+def test_Http10Reader() -> None:
+    t_body_reader(Http10Reader, b"", [EndOfMessage()], do_eof=True)
+    t_body_reader(Http10Reader, b"asdf", [Data(data=b"asdf")], do_eof=False)
+    t_body_reader(
+        Http10Reader, b"asdf", [Data(data=b"asdf"), EndOfMessage()], do_eof=True
+    )
+
+
+def test_ChunkedReader() -> None:
+    t_body_reader(ChunkedReader, b"0\r\n\r\n", [EndOfMessage()])
+
+    t_body_reader(
+        ChunkedReader,
+        b"0\r\nSome: header\r\n\r\n",
+        [EndOfMessage(headers=[("Some", "header")])],
+    )
+
+    t_body_reader(
+        ChunkedReader,
+        b"5\r\n01234\r\n"
+        + b"10\r\n0123456789abcdef\r\n"
+        + b"0\r\n"
+        + b"Some: header\r\n\r\n",
+        [
+            Data(data=b"012340123456789abcdef"),
+            EndOfMessage(headers=[("Some", "header")]),
+        ],
+    )
+
+    t_body_reader(
+        ChunkedReader,
+        b"5\r\n01234\r\n" + b"10\r\n0123456789abcdef\r\n" + b"0\r\n\r\n",
+        [Data(data=b"012340123456789abcdef"), EndOfMessage()],
+    )
+
+    # handles upper and lowercase hex
+    t_body_reader(
+        ChunkedReader,
+        b"aA\r\n" + b"x" * 0xAA + b"\r\n" + b"0\r\n\r\n",
+        [Data(data=b"x" * 0xAA), EndOfMessage()],
+    )
+
+    # refuses arbitrarily long chunk integers
+    with pytest.raises(LocalProtocolError):
+        # Technically this is legal HTTP/1.1, but we refuse to process chunk
+        # sizes that don't fit into 20 characters of hex
+        t_body_reader(ChunkedReader, b"9" * 100 + b"\r\nxxx", [Data(data=b"xxx")])
+
+    # refuses garbage in the chunk count
+    with pytest.raises(LocalProtocolError):
+        t_body_reader(ChunkedReader, b"10\x00\r\nxxx", None)
+
+    # handles (and discards) "chunk extensions" omg wtf
+    t_body_reader(
+        ChunkedReader,
+        b"5; hello=there\r\n"
+        + b"xxxxx"
+        + b"\r\n"
+        + b'0; random="junk"; some=more; canbe=lonnnnngg\r\n\r\n',
+        [Data(data=b"xxxxx"), EndOfMessage()],
+    )
+
+    t_body_reader(
+        ChunkedReader,
+        b"5   	 \r\n01234\r\n" + b"0\r\n\r\n",
+        [Data(data=b"01234"), EndOfMessage()],
+    )
+
+
+def test_ContentLengthWriter() -> None:
+    w = ContentLengthWriter(5)
+    assert dowrite(w, Data(data=b"123")) == b"123"
+    assert dowrite(w, Data(data=b"45")) == b"45"
+    assert dowrite(w, EndOfMessage()) == b""
+
+    w = ContentLengthWriter(5)
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, Data(data=b"123456"))
+
+    w = ContentLengthWriter(5)
+    dowrite(w, Data(data=b"123"))
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, Data(data=b"456"))
+
+    w = ContentLengthWriter(5)
+    dowrite(w, Data(data=b"123"))
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, EndOfMessage())
+
+    w = ContentLengthWriter(5)
+    dowrite(w, Data(data=b"123")) == b"123"
+    dowrite(w, Data(data=b"45")) == b"45"
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, EndOfMessage(headers=[("Etag", "asdf")]))
+
+
+def test_ChunkedWriter() -> None:
+    w = ChunkedWriter()
+    assert dowrite(w, Data(data=b"aaa")) == b"3\r\naaa\r\n"
+    assert dowrite(w, Data(data=b"a" * 20)) == b"14\r\n" + b"a" * 20 + b"\r\n"
+
+    assert dowrite(w, Data(data=b"")) == b""
+
+    assert dowrite(w, EndOfMessage()) == b"0\r\n\r\n"
+
+    assert (
+        dowrite(w, EndOfMessage(headers=[("Etag", "asdf"), ("a", "b")]))
+        == b"0\r\nEtag: asdf\r\na: b\r\n\r\n"
+    )
+
+
+def test_Http10Writer() -> None:
+    w = Http10Writer()
+    assert dowrite(w, Data(data=b"1234")) == b"1234"
+    assert dowrite(w, EndOfMessage()) == b""
+
+    with pytest.raises(LocalProtocolError):
+        dowrite(w, EndOfMessage(headers=[("Etag", "asdf")]))
+
+
+def test_reject_garbage_after_request_line() -> None:
+    with pytest.raises(LocalProtocolError):
+        tr(READERS[SERVER, SEND_RESPONSE], b"HTTP/1.0 200 OK\x00xxxx\r\n\r\n", None)
+
+
+def test_reject_garbage_after_response_line() -> None:
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1 xxxxxx\r\n" b"Host: a\r\n\r\n",
+            None,
+        )
+
+
+def test_reject_garbage_in_header_line() -> None:
+    with pytest.raises(LocalProtocolError):
+        tr(
+            READERS[CLIENT, IDLE],
+            b"HEAD /foo HTTP/1.1\r\n" b"Host: foo\x00bar\r\n\r\n",
+            None,
+        )
+
+
+def test_reject_non_vchar_in_path() -> None:
+    for bad_char in b"\x00\x20\x7f\xee":
+        message = bytearray(b"HEAD /")
+        message.append(bad_char)
+        message.extend(b" HTTP/1.1\r\nHost: foobar\r\n\r\n")
+        with pytest.raises(LocalProtocolError):
+            tr(READERS[CLIENT, IDLE], message, None)
+
+
+# https://github.com/python-hyper/h11/issues/57
+def test_allow_some_garbage_in_cookies() -> None:
+    tr(
+        READERS[CLIENT, IDLE],
+        b"HEAD /foo HTTP/1.1\r\n"
+        b"Host: foo\r\n"
+        b"Set-Cookie: ___utmvafIumyLc=kUd\x01UpAt; path=/; Max-Age=900\r\n"
+        b"\r\n",
+        Request(
+            method="HEAD",
+            target="/foo",
+            headers=[
+                ("Host", "foo"),
+                ("Set-Cookie", "___utmvafIumyLc=kUd\x01UpAt; path=/; Max-Age=900"),
+            ],
+        ),
+    )
+
+
+def test_host_comes_first() -> None:
+    tw(
+        write_headers,
+        normalize_and_validate([("foo", "bar"), ("Host", "example.com")]),
+        b"Host: example.com\r\nfoo: bar\r\n\r\n",
+    )

venv/lib/python3.11/site-packages/h11/tests/test_receivebuffer.py

@@ -0,0 +1,135 @@
+import re
+from typing import Tuple
+
+import pytest
+
+from .._receivebuffer import ReceiveBuffer
+
+
+def test_receivebuffer() -> None:
+    b = ReceiveBuffer()
+    assert not b
+    assert len(b) == 0
+    assert bytes(b) == b""
+
+    b += b"123"
+    assert b
+    assert len(b) == 3
+    assert bytes(b) == b"123"
+
+    assert bytes(b) == b"123"
+
+    assert b.maybe_extract_at_most(2) == b"12"
+    assert b
+    assert len(b) == 1
+    assert bytes(b) == b"3"
+
+    assert bytes(b) == b"3"
+
+    assert b.maybe_extract_at_most(10) == b"3"
+    assert bytes(b) == b""
+
+    assert b.maybe_extract_at_most(10) is None
+    assert not b
+
+    ################################################################
+    # maybe_extract_until_next
+    ################################################################
+
+    b += b"123\n456\r\n789\r\n"
+
+    assert b.maybe_extract_next_line() == b"123\n456\r\n"
+    assert bytes(b) == b"789\r\n"
+
+    assert b.maybe_extract_next_line() == b"789\r\n"
+    assert bytes(b) == b""
+
+    b += b"12\r"
+    assert b.maybe_extract_next_line() is None
+    assert bytes(b) == b"12\r"
+
+    b += b"345\n\r"
+    assert b.maybe_extract_next_line() is None
+    assert bytes(b) == b"12\r345\n\r"
+
+    # here we stopped at the middle of b"\r\n" delimiter
+
+    b += b"\n6789aaa123\r\n"
+    assert b.maybe_extract_next_line() == b"12\r345\n\r\n"
+    assert b.maybe_extract_next_line() == b"6789aaa123\r\n"
+    assert b.maybe_extract_next_line() is None
+    assert bytes(b) == b""
+
+    ################################################################
+    # maybe_extract_lines
+    ################################################################
+
+    b += b"123\r\na: b\r\nfoo:bar\r\n\r\ntrailing"
+    lines = b.maybe_extract_lines()
+    assert lines == [b"123", b"a: b", b"foo:bar"]
+    assert bytes(b) == b"trailing"
+
+    assert b.maybe_extract_lines() is None
+
+    b += b"\r\n\r"
+    assert b.maybe_extract_lines() is None
+
+    assert b.maybe_extract_at_most(100) == b"trailing\r\n\r"
+    assert not b
+
+    # Empty body case (as happens at the end of chunked encoding if there are
+    # no trailing headers, e.g.)
+    b += b"\r\ntrailing"
+    assert b.maybe_extract_lines() == []
+    assert bytes(b) == b"trailing"
+
+
+@pytest.mark.parametrize(
+    "data",
+    [
+        pytest.param(
+            (
+                b"HTTP/1.1 200 OK\r\n",
+                b"Content-type: text/plain\r\n",
+                b"Connection: close\r\n",
+                b"\r\n",
+                b"Some body",
+            ),
+            id="with_crlf_delimiter",
+        ),
+        pytest.param(
+            (
+                b"HTTP/1.1 200 OK\n",
+                b"Content-type: text/plain\n",
+                b"Connection: close\n",
+                b"\n",
+                b"Some body",
+            ),
+            id="with_lf_only_delimiter",
+        ),
+        pytest.param(
+            (
+                b"HTTP/1.1 200 OK\n",
+                b"Content-type: text/plain\r\n",
+                b"Connection: close\n",
+                b"\n",
+                b"Some body",
+            ),
+            id="with_mixed_crlf_and_lf",
+        ),
+    ],
+)
+def test_receivebuffer_for_invalid_delimiter(data: Tuple[bytes]) -> None:
+    b = ReceiveBuffer()
+
+    for line in data:
+        b += line
+
+    lines = b.maybe_extract_lines()
+
+    assert lines == [
+        b"HTTP/1.1 200 OK",
+        b"Content-type: text/plain",
+        b"Connection: close",
+    ]
+    assert bytes(b) == b"Some body"

venv/lib/python3.11/site-packages/h11/tests/test_state.py

@@ -0,0 +1,271 @@
+import pytest
+
+from .._events import (
+    ConnectionClosed,
+    Data,
+    EndOfMessage,
+    Event,
+    InformationalResponse,
+    Request,
+    Response,
+)
+from .._state import (
+    _SWITCH_CONNECT,
+    _SWITCH_UPGRADE,
+    CLIENT,
+    CLOSED,
+    ConnectionState,
+    DONE,
+    IDLE,
+    MIGHT_SWITCH_PROTOCOL,
+    MUST_CLOSE,
+    SEND_BODY,
+    SEND_RESPONSE,
+    SERVER,
+    SWITCHED_PROTOCOL,
+)
+from .._util import LocalProtocolError
+
+
+def test_ConnectionState() -> None:
+    cs = ConnectionState()
+
+    # Basic event-triggered transitions
+
+    assert cs.states == {CLIENT: IDLE, SERVER: IDLE}
+
+    cs.process_event(CLIENT, Request)
+    # The SERVER-Request special case:
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    # Illegal transitions raise an error and nothing happens
+    with pytest.raises(LocalProtocolError):
+        cs.process_event(CLIENT, Request)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    cs.process_event(SERVER, InformationalResponse)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    cs.process_event(SERVER, Response)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_BODY}
+
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, EndOfMessage)
+    assert cs.states == {CLIENT: DONE, SERVER: DONE}
+
+    # State-triggered transition
+
+    cs.process_event(SERVER, ConnectionClosed)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: CLOSED}
+
+
+def test_ConnectionState_keep_alive() -> None:
+    # keep_alive = False
+    cs = ConnectionState()
+    cs.process_event(CLIENT, Request)
+    cs.process_keep_alive_disabled()
+    cs.process_event(CLIENT, EndOfMessage)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: SEND_RESPONSE}
+
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: MUST_CLOSE}
+
+
+def test_ConnectionState_keep_alive_in_DONE() -> None:
+    # Check that if keep_alive is disabled when the CLIENT is already in DONE,
+    # then this is sufficient to immediately trigger the DONE -> MUST_CLOSE
+    # transition
+    cs = ConnectionState()
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    assert cs.states[CLIENT] is DONE
+    cs.process_keep_alive_disabled()
+    assert cs.states[CLIENT] is MUST_CLOSE
+
+
+def test_ConnectionState_switch_denied() -> None:
+    for switch_type in (_SWITCH_CONNECT, _SWITCH_UPGRADE):
+        for deny_early in (True, False):
+            cs = ConnectionState()
+            cs.process_client_switch_proposal(switch_type)
+            cs.process_event(CLIENT, Request)
+            cs.process_event(CLIENT, Data)
+            assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+            assert switch_type in cs.pending_switch_proposals
+
+            if deny_early:
+                # before client reaches DONE
+                cs.process_event(SERVER, Response)
+                assert not cs.pending_switch_proposals
+
+            cs.process_event(CLIENT, EndOfMessage)
+
+            if deny_early:
+                assert cs.states == {CLIENT: DONE, SERVER: SEND_BODY}
+            else:
+                assert cs.states == {
+                    CLIENT: MIGHT_SWITCH_PROTOCOL,
+                    SERVER: SEND_RESPONSE,
+                }
+
+                cs.process_event(SERVER, InformationalResponse)
+                assert cs.states == {
+                    CLIENT: MIGHT_SWITCH_PROTOCOL,
+                    SERVER: SEND_RESPONSE,
+                }
+
+                cs.process_event(SERVER, Response)
+                assert cs.states == {CLIENT: DONE, SERVER: SEND_BODY}
+                assert not cs.pending_switch_proposals
+
+
+_response_type_for_switch = {
+    _SWITCH_UPGRADE: InformationalResponse,
+    _SWITCH_CONNECT: Response,
+    None: Response,
+}
+
+
+def test_ConnectionState_protocol_switch_accepted() -> None:
+    for switch_event in [_SWITCH_UPGRADE, _SWITCH_CONNECT]:
+        cs = ConnectionState()
+        cs.process_client_switch_proposal(switch_event)
+        cs.process_event(CLIENT, Request)
+        cs.process_event(CLIENT, Data)
+        assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+        cs.process_event(CLIENT, EndOfMessage)
+        assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+
+        cs.process_event(SERVER, InformationalResponse)
+        assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+
+        cs.process_event(SERVER, _response_type_for_switch[switch_event], switch_event)
+        assert cs.states == {CLIENT: SWITCHED_PROTOCOL, SERVER: SWITCHED_PROTOCOL}
+
+
+def test_ConnectionState_double_protocol_switch() -> None:
+    # CONNECT + Upgrade is legal! Very silly, but legal. So we support
+    # it. Because sometimes doing the silly thing is easier than not.
+    for server_switch in [None, _SWITCH_UPGRADE, _SWITCH_CONNECT]:
+        cs = ConnectionState()
+        cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+        cs.process_client_switch_proposal(_SWITCH_CONNECT)
+        cs.process_event(CLIENT, Request)
+        cs.process_event(CLIENT, EndOfMessage)
+        assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+        cs.process_event(
+            SERVER, _response_type_for_switch[server_switch], server_switch
+        )
+        if server_switch is None:
+            assert cs.states == {CLIENT: DONE, SERVER: SEND_BODY}
+        else:
+            assert cs.states == {CLIENT: SWITCHED_PROTOCOL, SERVER: SWITCHED_PROTOCOL}
+
+
+def test_ConnectionState_inconsistent_protocol_switch() -> None:
+    for client_switches, server_switch in [
+        ([], _SWITCH_CONNECT),
+        ([], _SWITCH_UPGRADE),
+        ([_SWITCH_UPGRADE], _SWITCH_CONNECT),
+        ([_SWITCH_CONNECT], _SWITCH_UPGRADE),
+    ]:
+        cs = ConnectionState()
+        for client_switch in client_switches:  # type: ignore[attr-defined]
+            cs.process_client_switch_proposal(client_switch)
+        cs.process_event(CLIENT, Request)
+        with pytest.raises(LocalProtocolError):
+            cs.process_event(SERVER, Response, server_switch)
+
+
+def test_ConnectionState_keepalive_protocol_switch_interaction() -> None:
+    # keep_alive=False + pending_switch_proposals
+    cs = ConnectionState()
+    cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+    cs.process_event(CLIENT, Request)
+    cs.process_keep_alive_disabled()
+    cs.process_event(CLIENT, Data)
+    assert cs.states == {CLIENT: SEND_BODY, SERVER: SEND_RESPONSE}
+
+    # the protocol switch "wins"
+    cs.process_event(CLIENT, EndOfMessage)
+    assert cs.states == {CLIENT: MIGHT_SWITCH_PROTOCOL, SERVER: SEND_RESPONSE}
+
+    # but when the server denies the request, keep_alive comes back into play
+    cs.process_event(SERVER, Response)
+    assert cs.states == {CLIENT: MUST_CLOSE, SERVER: SEND_BODY}
+
+
+def test_ConnectionState_reuse() -> None:
+    cs = ConnectionState()
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    cs.start_next_cycle()
+    assert cs.states == {CLIENT: IDLE, SERVER: IDLE}
+
+    # No keepalive
+
+    cs.process_event(CLIENT, Request)
+    cs.process_keep_alive_disabled()
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    # One side closed
+
+    cs = ConnectionState()
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(CLIENT, ConnectionClosed)
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    # Succesful protocol switch
+
+    cs = ConnectionState()
+    cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, InformationalResponse, _SWITCH_UPGRADE)
+
+    with pytest.raises(LocalProtocolError):
+        cs.start_next_cycle()
+
+    # Failed protocol switch
+
+    cs = ConnectionState()
+    cs.process_client_switch_proposal(_SWITCH_UPGRADE)
+    cs.process_event(CLIENT, Request)
+    cs.process_event(CLIENT, EndOfMessage)
+    cs.process_event(SERVER, Response)
+    cs.process_event(SERVER, EndOfMessage)
+
+    cs.start_next_cycle()
+    assert cs.states == {CLIENT: IDLE, SERVER: IDLE}
+
+
+def test_server_request_is_illegal() -> None:
+    # There used to be a bug in how we handled the Request special case that
+    # made this allowed...
+    cs = ConnectionState()
+    with pytest.raises(LocalProtocolError):
+        cs.process_event(SERVER, Request)

venv/lib/python3.11/site-packages/h11/tests/test_util.py

@@ -0,0 +1,112 @@
+import re
+import sys
+import traceback
+from typing import NoReturn
+
+import pytest
+
+from .._util import (
+    bytesify,
+    LocalProtocolError,
+    ProtocolError,
+    RemoteProtocolError,
+    Sentinel,
+    validate,
+)
+
+
+def test_ProtocolError() -> None:
+    with pytest.raises(TypeError):
+        ProtocolError("abstract base class")
+
+
+def test_LocalProtocolError() -> None:
+    try:
+        raise LocalProtocolError("foo")
+    except LocalProtocolError as e:
+        assert str(e) == "foo"
+        assert e.error_status_hint == 400
+
+    try:
+        raise LocalProtocolError("foo", error_status_hint=418)
+    except LocalProtocolError as e:
+        assert str(e) == "foo"
+        assert e.error_status_hint == 418
+
+    def thunk() -> NoReturn:
+        raise LocalProtocolError("a", error_status_hint=420)
+
+    try:
+        try:
+            thunk()
+        except LocalProtocolError as exc1:
+            orig_traceback = "".join(traceback.format_tb(sys.exc_info()[2]))
+            exc1._reraise_as_remote_protocol_error()
+    except RemoteProtocolError as exc2:
+        assert type(exc2) is RemoteProtocolError
+        assert exc2.args == ("a",)
+        assert exc2.error_status_hint == 420
+        new_traceback = "".join(traceback.format_tb(sys.exc_info()[2]))
+        assert new_traceback.endswith(orig_traceback)
+
+
+def test_validate() -> None:
+    my_re = re.compile(rb"(?P<group1>[0-9]+)\.(?P<group2>[0-9]+)")
+    with pytest.raises(LocalProtocolError):
+        validate(my_re, b"0.")
+
+    groups = validate(my_re, b"0.1")
+    assert groups == {"group1": b"0", "group2": b"1"}
+
+    # successful partial matches are an error - must match whole string
+    with pytest.raises(LocalProtocolError):
+        validate(my_re, b"0.1xx")
+    with pytest.raises(LocalProtocolError):
+        validate(my_re, b"0.1\n")
+
+
+def test_validate_formatting() -> None:
+    my_re = re.compile(rb"foo")
+
+    with pytest.raises(LocalProtocolError) as excinfo:
+        validate(my_re, b"", "oops")
+    assert "oops" in str(excinfo.value)
+
+    with pytest.raises(LocalProtocolError) as excinfo:
+        validate(my_re, b"", "oops {}")
+    assert "oops {}" in str(excinfo.value)
+
+    with pytest.raises(LocalProtocolError) as excinfo:
+        validate(my_re, b"", "oops {} xx", 10)
+    assert "oops 10 xx" in str(excinfo.value)
+
+
+def test_make_sentinel() -> None:
+    class S(Sentinel, metaclass=Sentinel):
+        pass
+
+    assert repr(S) == "S"
+    assert S == S
+    assert type(S).__name__ == "S"
+    assert S in {S}
+    assert type(S) is S
+
+    class S2(Sentinel, metaclass=Sentinel):
+        pass
+
+    assert repr(S2) == "S2"
+    assert S != S2
+    assert S not in {S2}
+    assert type(S) is not type(S2)
+
+
+def test_bytesify() -> None:
+    assert bytesify(b"123") == b"123"
+    assert bytesify(bytearray(b"123")) == b"123"
+    assert bytesify("123") == b"123"
+
+    with pytest.raises(UnicodeEncodeError):
+        bytesify("\u1234")
+
+    with pytest.raises(TypeError):
+        bytesify(10)