venv

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diff --git a/venv/lib/python3.11/site-packages/h11/_connection.py b/venv/lib/python3.11/site-packages/h11/_connection.py
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+# 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,
+        )