1602 lines
60 KiB
Python
1602 lines
60 KiB
Python
from __future__ import annotations
|
||
|
||
import asyncio
|
||
import codecs
|
||
import collections
|
||
import logging
|
||
import random
|
||
import struct
|
||
import uuid
|
||
import warnings
|
||
from typing import (
|
||
Any,
|
||
AsyncIterable,
|
||
AsyncIterator,
|
||
Awaitable,
|
||
Deque,
|
||
Dict,
|
||
Iterable,
|
||
List,
|
||
Mapping,
|
||
Optional,
|
||
Union,
|
||
cast,
|
||
)
|
||
|
||
from ..connection import State
|
||
from ..datastructures import Headers
|
||
from ..exceptions import (
|
||
ConnectionClosed,
|
||
ConnectionClosedError,
|
||
ConnectionClosedOK,
|
||
InvalidState,
|
||
PayloadTooBig,
|
||
ProtocolError,
|
||
)
|
||
from ..extensions import Extension
|
||
from ..frames import (
|
||
OK_CLOSE_CODES,
|
||
OP_BINARY,
|
||
OP_CLOSE,
|
||
OP_CONT,
|
||
OP_PING,
|
||
OP_PONG,
|
||
OP_TEXT,
|
||
Close,
|
||
Opcode,
|
||
prepare_ctrl,
|
||
prepare_data,
|
||
)
|
||
from ..typing import Data, LoggerLike, Subprotocol
|
||
from .compatibility import loop_if_py_lt_38
|
||
from .framing import Frame
|
||
|
||
|
||
__all__ = ["WebSocketCommonProtocol", "broadcast"]
|
||
|
||
|
||
# In order to ensure consistency, the code always checks the current value of
|
||
# WebSocketCommonProtocol.state before assigning a new value and never yields
|
||
# between the check and the assignment.
|
||
|
||
|
||
class WebSocketCommonProtocol(asyncio.Protocol):
|
||
"""
|
||
WebSocket connection.
|
||
|
||
:class:`WebSocketCommonProtocol` provides APIs shared between WebSocket
|
||
servers and clients. You shouldn't use it directly. Instead, use
|
||
:class:`~websockets.client.WebSocketClientProtocol` or
|
||
:class:`~websockets.server.WebSocketServerProtocol`.
|
||
|
||
This documentation focuses on low-level details that aren't covered in the
|
||
documentation of :class:`~websockets.client.WebSocketClientProtocol` and
|
||
:class:`~websockets.server.WebSocketServerProtocol` for the sake of
|
||
simplicity.
|
||
|
||
Once the connection is open, a Ping_ frame is sent every ``ping_interval``
|
||
seconds. This serves as a keepalive. It helps keeping the connection
|
||
open, especially in the presence of proxies with short timeouts on
|
||
inactive connections. Set ``ping_interval`` to :obj:`None` to disable
|
||
this behavior.
|
||
|
||
.. _Ping: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.5.2
|
||
|
||
If the corresponding Pong_ frame isn't received within ``ping_timeout``
|
||
seconds, the connection is considered unusable and is closed with code
|
||
1011. This ensures that the remote endpoint remains responsive. Set
|
||
``ping_timeout`` to :obj:`None` to disable this behavior.
|
||
|
||
.. _Pong: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.5.3
|
||
|
||
The ``close_timeout`` parameter defines a maximum wait time for completing
|
||
the closing handshake and terminating the TCP connection. For legacy
|
||
reasons, :meth:`close` completes in at most ``5 * close_timeout`` seconds
|
||
for clients and ``4 * close_timeout`` for servers.
|
||
|
||
See the discussion of :doc:`timeouts <../topics/timeouts>` for details.
|
||
|
||
``close_timeout`` needs to be a parameter of the protocol because
|
||
websockets usually calls :meth:`close` implicitly upon exit:
|
||
|
||
* on the client side, when :func:`~websockets.client.connect` is used as a
|
||
context manager;
|
||
* on the server side, when the connection handler terminates;
|
||
|
||
To apply a timeout to any other API, wrap it in :func:`~asyncio.wait_for`.
|
||
|
||
The ``max_size`` parameter enforces the maximum size for incoming messages
|
||
in bytes. The default value is 1 MiB. If a larger message is received,
|
||
:meth:`recv` will raise :exc:`~websockets.exceptions.ConnectionClosedError`
|
||
and the connection will be closed with code 1009.
|
||
|
||
The ``max_queue`` parameter sets the maximum length of the queue that
|
||
holds incoming messages. The default value is ``32``. Messages are added
|
||
to an in-memory queue when they're received; then :meth:`recv` pops from
|
||
that queue. In order to prevent excessive memory consumption when
|
||
messages are received faster than they can be processed, the queue must
|
||
be bounded. If the queue fills up, the protocol stops processing incoming
|
||
data until :meth:`recv` is called. In this situation, various receive
|
||
buffers (at least in :mod:`asyncio` and in the OS) will fill up, then the
|
||
TCP receive window will shrink, slowing down transmission to avoid packet
|
||
loss.
|
||
|
||
Since Python can use up to 4 bytes of memory to represent a single
|
||
character, each connection may use up to ``4 * max_size * max_queue``
|
||
bytes of memory to store incoming messages. By default, this is 128 MiB.
|
||
You may want to lower the limits, depending on your application's
|
||
requirements.
|
||
|
||
The ``read_limit`` argument sets the high-water limit of the buffer for
|
||
incoming bytes. The low-water limit is half the high-water limit. The
|
||
default value is 64 KiB, half of asyncio's default (based on the current
|
||
implementation of :class:`~asyncio.StreamReader`).
|
||
|
||
The ``write_limit`` argument sets the high-water limit of the buffer for
|
||
outgoing bytes. The low-water limit is a quarter of the high-water limit.
|
||
The default value is 64 KiB, equal to asyncio's default (based on the
|
||
current implementation of ``FlowControlMixin``).
|
||
|
||
See the discussion of :doc:`memory usage <../topics/memory>` for details.
|
||
|
||
Args:
|
||
logger: logger for this connection;
|
||
defaults to ``logging.getLogger("websockets.protocol")``;
|
||
see the :doc:`logging guide <../topics/logging>` for details.
|
||
ping_interval: delay between keepalive pings in seconds;
|
||
:obj:`None` to disable keepalive pings.
|
||
ping_timeout: timeout for keepalive pings in seconds;
|
||
:obj:`None` to disable timeouts.
|
||
close_timeout: timeout for closing the connection in seconds;
|
||
for legacy reasons, the actual timeout is 4 or 5 times larger.
|
||
max_size: maximum size of incoming messages in bytes;
|
||
:obj:`None` to disable the limit.
|
||
max_queue: maximum number of incoming messages in receive buffer;
|
||
:obj:`None` to disable the limit.
|
||
read_limit: high-water mark of read buffer in bytes.
|
||
write_limit: high-water mark of write buffer in bytes.
|
||
|
||
"""
|
||
|
||
# There are only two differences between the client-side and server-side
|
||
# behavior: masking the payload and closing the underlying TCP connection.
|
||
# Set is_client = True/False and side = "client"/"server" to pick a side.
|
||
is_client: bool
|
||
side: str = "undefined"
|
||
|
||
def __init__(
|
||
self,
|
||
*,
|
||
logger: Optional[LoggerLike] = None,
|
||
ping_interval: Optional[float] = 20,
|
||
ping_timeout: Optional[float] = 20,
|
||
close_timeout: Optional[float] = None,
|
||
max_size: Optional[int] = 2**20,
|
||
max_queue: Optional[int] = 2**5,
|
||
read_limit: int = 2**16,
|
||
write_limit: int = 2**16,
|
||
# The following arguments are kept only for backwards compatibility.
|
||
host: Optional[str] = None,
|
||
port: Optional[int] = None,
|
||
secure: Optional[bool] = None,
|
||
legacy_recv: bool = False,
|
||
loop: Optional[asyncio.AbstractEventLoop] = None,
|
||
timeout: Optional[float] = None,
|
||
) -> None:
|
||
if legacy_recv: # pragma: no cover
|
||
warnings.warn("legacy_recv is deprecated", DeprecationWarning)
|
||
|
||
# Backwards compatibility: close_timeout used to be called timeout.
|
||
if timeout is None:
|
||
timeout = 10
|
||
else:
|
||
warnings.warn("rename timeout to close_timeout", DeprecationWarning)
|
||
# If both are specified, timeout is ignored.
|
||
if close_timeout is None:
|
||
close_timeout = timeout
|
||
|
||
# Backwards compatibility: the loop parameter used to be supported.
|
||
if loop is None:
|
||
loop = asyncio.get_event_loop()
|
||
else:
|
||
warnings.warn("remove loop argument", DeprecationWarning)
|
||
|
||
self.ping_interval = ping_interval
|
||
self.ping_timeout = ping_timeout
|
||
self.close_timeout = close_timeout
|
||
self.max_size = max_size
|
||
self.max_queue = max_queue
|
||
self.read_limit = read_limit
|
||
self.write_limit = write_limit
|
||
|
||
# Unique identifier. For logs.
|
||
self.id: uuid.UUID = uuid.uuid4()
|
||
"""Unique identifier of the connection. Useful in logs."""
|
||
|
||
# Logger or LoggerAdapter for this connection.
|
||
if logger is None:
|
||
logger = logging.getLogger("websockets.protocol")
|
||
# https://github.com/python/typeshed/issues/5561
|
||
logger = cast(logging.Logger, logger)
|
||
self.logger: LoggerLike = logging.LoggerAdapter(logger, {"websocket": self})
|
||
"""Logger for this connection."""
|
||
|
||
# Track if DEBUG is enabled. Shortcut logging calls if it isn't.
|
||
self.debug = logger.isEnabledFor(logging.DEBUG)
|
||
|
||
self.loop = loop
|
||
|
||
self._host = host
|
||
self._port = port
|
||
self._secure = secure
|
||
self.legacy_recv = legacy_recv
|
||
|
||
# Configure read buffer limits. The high-water limit is defined by
|
||
# ``self.read_limit``. The ``limit`` argument controls the line length
|
||
# limit and half the buffer limit of :class:`~asyncio.StreamReader`.
|
||
# That's why it must be set to half of ``self.read_limit``.
|
||
self.reader = asyncio.StreamReader(limit=read_limit // 2, loop=loop)
|
||
|
||
# Copied from asyncio.FlowControlMixin
|
||
self._paused = False
|
||
self._drain_waiter: Optional[asyncio.Future[None]] = None
|
||
|
||
self._drain_lock = asyncio.Lock(**loop_if_py_lt_38(loop))
|
||
|
||
# This class implements the data transfer and closing handshake, which
|
||
# are shared between the client-side and the server-side.
|
||
# Subclasses implement the opening handshake and, on success, execute
|
||
# :meth:`connection_open` to change the state to OPEN.
|
||
self.state = State.CONNECTING
|
||
if self.debug:
|
||
self.logger.debug("= connection is CONNECTING")
|
||
|
||
# HTTP protocol parameters.
|
||
self.path: str
|
||
"""Path of the opening handshake request."""
|
||
self.request_headers: Headers
|
||
"""Opening handshake request headers."""
|
||
self.response_headers: Headers
|
||
"""Opening handshake response headers."""
|
||
|
||
# WebSocket protocol parameters.
|
||
self.extensions: List[Extension] = []
|
||
self.subprotocol: Optional[Subprotocol] = None
|
||
"""Subprotocol, if one was negotiated."""
|
||
|
||
# Close code and reason, set when a close frame is sent or received.
|
||
self.close_rcvd: Optional[Close] = None
|
||
self.close_sent: Optional[Close] = None
|
||
self.close_rcvd_then_sent: Optional[bool] = None
|
||
|
||
# Completed when the connection state becomes CLOSED. Translates the
|
||
# :meth:`connection_lost` callback to a :class:`~asyncio.Future`
|
||
# that can be awaited. (Other :class:`~asyncio.Protocol` callbacks are
|
||
# translated by ``self.stream_reader``).
|
||
self.connection_lost_waiter: asyncio.Future[None] = loop.create_future()
|
||
|
||
# Queue of received messages.
|
||
self.messages: Deque[Data] = collections.deque()
|
||
self._pop_message_waiter: Optional[asyncio.Future[None]] = None
|
||
self._put_message_waiter: Optional[asyncio.Future[None]] = None
|
||
|
||
# Protect sending fragmented messages.
|
||
self._fragmented_message_waiter: Optional[asyncio.Future[None]] = None
|
||
|
||
# Mapping of ping IDs to pong waiters, in chronological order.
|
||
self.pings: Dict[bytes, asyncio.Future[None]] = {}
|
||
|
||
# Task running the data transfer.
|
||
self.transfer_data_task: asyncio.Task[None]
|
||
|
||
# Exception that occurred during data transfer, if any.
|
||
self.transfer_data_exc: Optional[BaseException] = None
|
||
|
||
# Task sending keepalive pings.
|
||
self.keepalive_ping_task: asyncio.Task[None]
|
||
|
||
# Task closing the TCP connection.
|
||
self.close_connection_task: asyncio.Task[None]
|
||
|
||
# Copied from asyncio.FlowControlMixin
|
||
async def _drain_helper(self) -> None: # pragma: no cover
|
||
if self.connection_lost_waiter.done():
|
||
raise ConnectionResetError("Connection lost")
|
||
if not self._paused:
|
||
return
|
||
waiter = self._drain_waiter
|
||
assert waiter is None or waiter.cancelled()
|
||
waiter = self.loop.create_future()
|
||
self._drain_waiter = waiter
|
||
await waiter
|
||
|
||
# Copied from asyncio.StreamWriter
|
||
async def _drain(self) -> None: # pragma: no cover
|
||
if self.reader is not None:
|
||
exc = self.reader.exception()
|
||
if exc is not None:
|
||
raise exc
|
||
if self.transport is not None:
|
||
if self.transport.is_closing():
|
||
# Yield to the event loop so connection_lost() may be
|
||
# called. Without this, _drain_helper() would return
|
||
# immediately, and code that calls
|
||
# write(...); yield from drain()
|
||
# in a loop would never call connection_lost(), so it
|
||
# would not see an error when the socket is closed.
|
||
await asyncio.sleep(0, **loop_if_py_lt_38(self.loop))
|
||
await self._drain_helper()
|
||
|
||
def connection_open(self) -> None:
|
||
"""
|
||
Callback when the WebSocket opening handshake completes.
|
||
|
||
Enter the OPEN state and start the data transfer phase.
|
||
|
||
"""
|
||
# 4.1. The WebSocket Connection is Established.
|
||
assert self.state is State.CONNECTING
|
||
self.state = State.OPEN
|
||
if self.debug:
|
||
self.logger.debug("= connection is OPEN")
|
||
# Start the task that receives incoming WebSocket messages.
|
||
self.transfer_data_task = self.loop.create_task(self.transfer_data())
|
||
# Start the task that sends pings at regular intervals.
|
||
self.keepalive_ping_task = self.loop.create_task(self.keepalive_ping())
|
||
# Start the task that eventually closes the TCP connection.
|
||
self.close_connection_task = self.loop.create_task(self.close_connection())
|
||
|
||
@property
|
||
def host(self) -> Optional[str]:
|
||
alternative = "remote_address" if self.is_client else "local_address"
|
||
warnings.warn(f"use {alternative}[0] instead of host", DeprecationWarning)
|
||
return self._host
|
||
|
||
@property
|
||
def port(self) -> Optional[int]:
|
||
alternative = "remote_address" if self.is_client else "local_address"
|
||
warnings.warn(f"use {alternative}[1] instead of port", DeprecationWarning)
|
||
return self._port
|
||
|
||
@property
|
||
def secure(self) -> Optional[bool]:
|
||
warnings.warn("don't use secure", DeprecationWarning)
|
||
return self._secure
|
||
|
||
# Public API
|
||
|
||
@property
|
||
def local_address(self) -> Any:
|
||
"""
|
||
Local address of the connection.
|
||
|
||
For IPv4 connections, this is a ``(host, port)`` tuple.
|
||
|
||
The format of the address depends on the address family;
|
||
see :meth:`~socket.socket.getsockname`.
|
||
|
||
:obj:`None` if the TCP connection isn't established yet.
|
||
|
||
"""
|
||
try:
|
||
transport = self.transport
|
||
except AttributeError:
|
||
return None
|
||
else:
|
||
return transport.get_extra_info("sockname")
|
||
|
||
@property
|
||
def remote_address(self) -> Any:
|
||
"""
|
||
Remote address of the connection.
|
||
|
||
For IPv4 connections, this is a ``(host, port)`` tuple.
|
||
|
||
The format of the address depends on the address family;
|
||
see :meth:`~socket.socket.getpeername`.
|
||
|
||
:obj:`None` if the TCP connection isn't established yet.
|
||
|
||
"""
|
||
try:
|
||
transport = self.transport
|
||
except AttributeError:
|
||
return None
|
||
else:
|
||
return transport.get_extra_info("peername")
|
||
|
||
@property
|
||
def open(self) -> bool:
|
||
"""
|
||
:obj:`True` when the connection is open; :obj:`False` otherwise.
|
||
|
||
This attribute may be used to detect disconnections. However, this
|
||
approach is discouraged per the EAFP_ principle. Instead, you should
|
||
handle :exc:`~websockets.exceptions.ConnectionClosed` exceptions.
|
||
|
||
.. _EAFP: https://docs.python.org/3/glossary.html#term-eafp
|
||
|
||
"""
|
||
return self.state is State.OPEN and not self.transfer_data_task.done()
|
||
|
||
@property
|
||
def closed(self) -> bool:
|
||
"""
|
||
:obj:`True` when the connection is closed; :obj:`False` otherwise.
|
||
|
||
Be aware that both :attr:`open` and :attr:`closed` are :obj:`False`
|
||
during the opening and closing sequences.
|
||
|
||
"""
|
||
return self.state is State.CLOSED
|
||
|
||
@property
|
||
def close_code(self) -> Optional[int]:
|
||
"""
|
||
WebSocket close code, defined in `section 7.1.5 of RFC 6455`_.
|
||
|
||
.. _section 7.1.5 of RFC 6455:
|
||
https://www.rfc-editor.org/rfc/rfc6455.html#section-7.1.5
|
||
|
||
:obj:`None` if the connection isn't closed yet.
|
||
|
||
"""
|
||
if self.state is not State.CLOSED:
|
||
return None
|
||
elif self.close_rcvd is None:
|
||
return 1006
|
||
else:
|
||
return self.close_rcvd.code
|
||
|
||
@property
|
||
def close_reason(self) -> Optional[str]:
|
||
"""
|
||
WebSocket close reason, defined in `section 7.1.6 of RFC 6455`_.
|
||
|
||
.. _section 7.1.6 of RFC 6455:
|
||
https://www.rfc-editor.org/rfc/rfc6455.html#section-7.1.6
|
||
|
||
:obj:`None` if the connection isn't closed yet.
|
||
|
||
"""
|
||
if self.state is not State.CLOSED:
|
||
return None
|
||
elif self.close_rcvd is None:
|
||
return ""
|
||
else:
|
||
return self.close_rcvd.reason
|
||
|
||
async def __aiter__(self) -> AsyncIterator[Data]:
|
||
"""
|
||
Iterate on incoming messages.
|
||
|
||
The iterator exits normally when the connection is closed with the
|
||
close code 1000 (OK) or 1001(going away). It raises
|
||
a :exc:`~websockets.exceptions.ConnectionClosedError` exception when
|
||
the connection is closed with any other code.
|
||
|
||
"""
|
||
try:
|
||
while True:
|
||
yield await self.recv()
|
||
except ConnectionClosedOK:
|
||
return
|
||
|
||
async def recv(self) -> Data:
|
||
"""
|
||
Receive the next message.
|
||
|
||
When the connection is closed, :meth:`recv` raises
|
||
:exc:`~websockets.exceptions.ConnectionClosed`. Specifically, it
|
||
raises :exc:`~websockets.exceptions.ConnectionClosedOK` after a normal
|
||
connection closure and
|
||
:exc:`~websockets.exceptions.ConnectionClosedError` after a protocol
|
||
error or a network failure. This is how you detect the end of the
|
||
message stream.
|
||
|
||
Canceling :meth:`recv` is safe. There's no risk of losing the next
|
||
message. The next invocation of :meth:`recv` will return it.
|
||
|
||
This makes it possible to enforce a timeout by wrapping :meth:`recv`
|
||
in :func:`~asyncio.wait_for`.
|
||
|
||
Returns:
|
||
Data: A string (:class:`str`) for a Text_ frame. A bytestring
|
||
(:class:`bytes`) for a Binary_ frame.
|
||
|
||
.. _Text: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.6
|
||
.. _Binary: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.6
|
||
|
||
Raises:
|
||
ConnectionClosed: when the connection is closed.
|
||
RuntimeError: if two coroutines call :meth:`recv` concurrently.
|
||
|
||
"""
|
||
if self._pop_message_waiter is not None:
|
||
raise RuntimeError(
|
||
"cannot call recv while another coroutine "
|
||
"is already waiting for the next message"
|
||
)
|
||
|
||
# Don't await self.ensure_open() here:
|
||
# - messages could be available in the queue even if the connection
|
||
# is closed;
|
||
# - messages could be received before the closing frame even if the
|
||
# connection is closing.
|
||
|
||
# Wait until there's a message in the queue (if necessary) or the
|
||
# connection is closed.
|
||
while len(self.messages) <= 0:
|
||
pop_message_waiter: asyncio.Future[None] = self.loop.create_future()
|
||
self._pop_message_waiter = pop_message_waiter
|
||
try:
|
||
# If asyncio.wait() is canceled, it doesn't cancel
|
||
# pop_message_waiter and self.transfer_data_task.
|
||
await asyncio.wait(
|
||
[pop_message_waiter, self.transfer_data_task],
|
||
return_when=asyncio.FIRST_COMPLETED,
|
||
**loop_if_py_lt_38(self.loop),
|
||
)
|
||
finally:
|
||
self._pop_message_waiter = None
|
||
|
||
# If asyncio.wait(...) exited because self.transfer_data_task
|
||
# completed before receiving a new message, raise a suitable
|
||
# exception (or return None if legacy_recv is enabled).
|
||
if not pop_message_waiter.done():
|
||
if self.legacy_recv:
|
||
return None # type: ignore
|
||
else:
|
||
# Wait until the connection is closed to raise
|
||
# ConnectionClosed with the correct code and reason.
|
||
await self.ensure_open()
|
||
|
||
# Pop a message from the queue.
|
||
message = self.messages.popleft()
|
||
|
||
# Notify transfer_data().
|
||
if self._put_message_waiter is not None:
|
||
self._put_message_waiter.set_result(None)
|
||
self._put_message_waiter = None
|
||
|
||
return message
|
||
|
||
async def send(
|
||
self,
|
||
message: Union[Data, Iterable[Data], AsyncIterable[Data]],
|
||
) -> None:
|
||
"""
|
||
Send a message.
|
||
|
||
A string (:class:`str`) is sent as a Text_ frame. A bytestring or
|
||
bytes-like object (:class:`bytes`, :class:`bytearray`, or
|
||
:class:`memoryview`) is sent as a Binary_ frame.
|
||
|
||
.. _Text: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.6
|
||
.. _Binary: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.6
|
||
|
||
:meth:`send` also accepts an iterable or an asynchronous iterable of
|
||
strings, bytestrings, or bytes-like objects to enable fragmentation_.
|
||
Each item is treated as a message fragment and sent in its own frame.
|
||
All items must be of the same type, or else :meth:`send` will raise a
|
||
:exc:`TypeError` and the connection will be closed.
|
||
|
||
.. _fragmentation: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.4
|
||
|
||
:meth:`send` rejects dict-like objects because this is often an error.
|
||
(If you want to send the keys of a dict-like object as fragments, call
|
||
its :meth:`~dict.keys` method and pass the result to :meth:`send`.)
|
||
|
||
Canceling :meth:`send` is discouraged. Instead, you should close the
|
||
connection with :meth:`close`. Indeed, there are only two situations
|
||
where :meth:`send` may yield control to the event loop and then get
|
||
canceled; in both cases, :meth:`close` has the same effect and is
|
||
more clear:
|
||
|
||
1. The write buffer is full. If you don't want to wait until enough
|
||
data is sent, your only alternative is to close the connection.
|
||
:meth:`close` will likely time out then abort the TCP connection.
|
||
2. ``message`` is an asynchronous iterator that yields control.
|
||
Stopping in the middle of a fragmented message will cause a
|
||
protocol error and the connection will be closed.
|
||
|
||
When the connection is closed, :meth:`send` raises
|
||
:exc:`~websockets.exceptions.ConnectionClosed`. Specifically, it
|
||
raises :exc:`~websockets.exceptions.ConnectionClosedOK` after a normal
|
||
connection closure and
|
||
:exc:`~websockets.exceptions.ConnectionClosedError` after a protocol
|
||
error or a network failure.
|
||
|
||
Args:
|
||
message (Union[Data, Iterable[Data], AsyncIterable[Data]): message
|
||
to send.
|
||
|
||
Raises:
|
||
ConnectionClosed: when the connection is closed.
|
||
TypeError: if ``message`` doesn't have a supported type.
|
||
|
||
"""
|
||
await self.ensure_open()
|
||
|
||
# While sending a fragmented message, prevent sending other messages
|
||
# until all fragments are sent.
|
||
while self._fragmented_message_waiter is not None:
|
||
await asyncio.shield(self._fragmented_message_waiter)
|
||
|
||
# Unfragmented message -- this case must be handled first because
|
||
# strings and bytes-like objects are iterable.
|
||
|
||
if isinstance(message, (str, bytes, bytearray, memoryview)):
|
||
opcode, data = prepare_data(message)
|
||
await self.write_frame(True, opcode, data)
|
||
|
||
# Catch a common mistake -- passing a dict to send().
|
||
|
||
elif isinstance(message, Mapping):
|
||
raise TypeError("data is a dict-like object")
|
||
|
||
# Fragmented message -- regular iterator.
|
||
|
||
elif isinstance(message, Iterable):
|
||
|
||
# Work around https://github.com/python/mypy/issues/6227
|
||
message = cast(Iterable[Data], message)
|
||
|
||
iter_message = iter(message)
|
||
try:
|
||
message_chunk = next(iter_message)
|
||
except StopIteration:
|
||
return
|
||
opcode, data = prepare_data(message_chunk)
|
||
|
||
self._fragmented_message_waiter = asyncio.Future()
|
||
try:
|
||
# First fragment.
|
||
await self.write_frame(False, opcode, data)
|
||
|
||
# Other fragments.
|
||
for message_chunk in iter_message:
|
||
confirm_opcode, data = prepare_data(message_chunk)
|
||
if confirm_opcode != opcode:
|
||
raise TypeError("data contains inconsistent types")
|
||
await self.write_frame(False, OP_CONT, data)
|
||
|
||
# Final fragment.
|
||
await self.write_frame(True, OP_CONT, b"")
|
||
|
||
except (Exception, asyncio.CancelledError):
|
||
# We're half-way through a fragmented message and we can't
|
||
# complete it. This makes the connection unusable.
|
||
self.fail_connection(1011)
|
||
raise
|
||
|
||
finally:
|
||
self._fragmented_message_waiter.set_result(None)
|
||
self._fragmented_message_waiter = None
|
||
|
||
# Fragmented message -- asynchronous iterator
|
||
|
||
elif isinstance(message, AsyncIterable):
|
||
# aiter_message = aiter(message) without aiter
|
||
# https://github.com/python/mypy/issues/5738
|
||
aiter_message = type(message).__aiter__(message) # type: ignore
|
||
try:
|
||
# message_chunk = anext(aiter_message) without anext
|
||
# https://github.com/python/mypy/issues/5738
|
||
message_chunk = await type(aiter_message).__anext__( # type: ignore
|
||
aiter_message
|
||
)
|
||
except StopAsyncIteration:
|
||
return
|
||
opcode, data = prepare_data(message_chunk)
|
||
|
||
self._fragmented_message_waiter = asyncio.Future()
|
||
try:
|
||
# First fragment.
|
||
await self.write_frame(False, opcode, data)
|
||
|
||
# Other fragments.
|
||
# https://github.com/python/mypy/issues/5738
|
||
# coverage reports this code as not covered, but it is
|
||
# exercised by tests - changing it breaks the tests!
|
||
async for message_chunk in aiter_message: # type: ignore # pragma: no cover # noqa
|
||
confirm_opcode, data = prepare_data(message_chunk)
|
||
if confirm_opcode != opcode:
|
||
raise TypeError("data contains inconsistent types")
|
||
await self.write_frame(False, OP_CONT, data)
|
||
|
||
# Final fragment.
|
||
await self.write_frame(True, OP_CONT, b"")
|
||
|
||
except (Exception, asyncio.CancelledError):
|
||
# We're half-way through a fragmented message and we can't
|
||
# complete it. This makes the connection unusable.
|
||
self.fail_connection(1011)
|
||
raise
|
||
|
||
finally:
|
||
self._fragmented_message_waiter.set_result(None)
|
||
self._fragmented_message_waiter = None
|
||
|
||
else:
|
||
raise TypeError("data must be str, bytes-like, or iterable")
|
||
|
||
async def close(self, code: int = 1000, reason: str = "") -> None:
|
||
"""
|
||
Perform the closing handshake.
|
||
|
||
:meth:`close` waits for the other end to complete the handshake and
|
||
for the TCP connection to terminate. As a consequence, there's no need
|
||
to await :meth:`wait_closed` after :meth:`close`.
|
||
|
||
:meth:`close` is idempotent: it doesn't do anything once the
|
||
connection is closed.
|
||
|
||
Wrapping :func:`close` in :func:`~asyncio.create_task` is safe, given
|
||
that errors during connection termination aren't particularly useful.
|
||
|
||
Canceling :meth:`close` is discouraged. If it takes too long, you can
|
||
set a shorter ``close_timeout``. If you don't want to wait, let the
|
||
Python process exit, then the OS will take care of closing the TCP
|
||
connection.
|
||
|
||
Args:
|
||
code: WebSocket close code.
|
||
reason: WebSocket close reason.
|
||
|
||
"""
|
||
try:
|
||
await asyncio.wait_for(
|
||
self.write_close_frame(Close(code, reason)),
|
||
self.close_timeout,
|
||
**loop_if_py_lt_38(self.loop),
|
||
)
|
||
except asyncio.TimeoutError:
|
||
# If the close frame cannot be sent because the send buffers
|
||
# are full, the closing handshake won't complete anyway.
|
||
# Fail the connection to shut down faster.
|
||
self.fail_connection()
|
||
|
||
# If no close frame is received within the timeout, wait_for() cancels
|
||
# the data transfer task and raises TimeoutError.
|
||
|
||
# If close() is called multiple times concurrently and one of these
|
||
# calls hits the timeout, the data transfer task will be canceled.
|
||
# Other calls will receive a CancelledError here.
|
||
|
||
try:
|
||
# If close() is canceled during the wait, self.transfer_data_task
|
||
# is canceled before the timeout elapses.
|
||
await asyncio.wait_for(
|
||
self.transfer_data_task,
|
||
self.close_timeout,
|
||
**loop_if_py_lt_38(self.loop),
|
||
)
|
||
except (asyncio.TimeoutError, asyncio.CancelledError):
|
||
pass
|
||
|
||
# Wait for the close connection task to close the TCP connection.
|
||
await asyncio.shield(self.close_connection_task)
|
||
|
||
async def wait_closed(self) -> None:
|
||
"""
|
||
Wait until the connection is closed.
|
||
|
||
This coroutine is identical to the :attr:`closed` attribute, except it
|
||
can be awaited.
|
||
|
||
This can make it easier to detect connection termination, regardless
|
||
of its cause, in tasks that interact with the WebSocket connection.
|
||
|
||
"""
|
||
await asyncio.shield(self.connection_lost_waiter)
|
||
|
||
async def ping(self, data: Optional[Data] = None) -> Awaitable[None]:
|
||
"""
|
||
Send a Ping_.
|
||
|
||
.. _Ping: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.5.2
|
||
|
||
A ping may serve as a keepalive or as a check that the remote endpoint
|
||
received all messages up to this point
|
||
|
||
Canceling :meth:`ping` is discouraged. If :meth:`ping` doesn't return
|
||
immediately, it means the write buffer is full. If you don't want to
|
||
wait, you should close the connection.
|
||
|
||
Canceling the :class:`~asyncio.Future` returned by :meth:`ping` has no
|
||
effect.
|
||
|
||
Args:
|
||
data (Optional[Data]): payload of the ping; a string will be
|
||
encoded to UTF-8; or :obj:`None` to generate a payload
|
||
containing four random bytes.
|
||
|
||
Returns:
|
||
~asyncio.Future: A future that will be completed when the
|
||
corresponding pong is received. You can ignore it if you
|
||
don't intend to wait.
|
||
|
||
::
|
||
|
||
pong_waiter = await ws.ping()
|
||
await pong_waiter # only if you want to wait for the pong
|
||
|
||
Raises:
|
||
ConnectionClosed: when the connection is closed.
|
||
RuntimeError: if another ping was sent with the same data and
|
||
the corresponding pong wasn't received yet.
|
||
|
||
"""
|
||
await self.ensure_open()
|
||
|
||
if data is not None:
|
||
data = prepare_ctrl(data)
|
||
|
||
# Protect against duplicates if a payload is explicitly set.
|
||
if data in self.pings:
|
||
raise RuntimeError("already waiting for a pong with the same data")
|
||
|
||
# Generate a unique random payload otherwise.
|
||
while data is None or data in self.pings:
|
||
data = struct.pack("!I", random.getrandbits(32))
|
||
|
||
self.pings[data] = self.loop.create_future()
|
||
|
||
await self.write_frame(True, OP_PING, data)
|
||
|
||
return asyncio.shield(self.pings[data])
|
||
|
||
async def pong(self, data: Data = b"") -> None:
|
||
"""
|
||
Send a Pong_.
|
||
|
||
.. _Pong: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.5.3
|
||
|
||
An unsolicited pong may serve as a unidirectional heartbeat.
|
||
|
||
Canceling :meth:`pong` is discouraged. If :meth:`pong` doesn't return
|
||
immediately, it means the write buffer is full. If you don't want to
|
||
wait, you should close the connection.
|
||
|
||
Args:
|
||
data (Data): payload of the pong; a string will be encoded to
|
||
UTF-8.
|
||
|
||
Raises:
|
||
ConnectionClosed: when the connection is closed.
|
||
|
||
"""
|
||
await self.ensure_open()
|
||
|
||
data = prepare_ctrl(data)
|
||
|
||
await self.write_frame(True, OP_PONG, data)
|
||
|
||
# Private methods - no guarantees.
|
||
|
||
def connection_closed_exc(self) -> ConnectionClosed:
|
||
exc: ConnectionClosed
|
||
if (
|
||
self.close_rcvd is not None
|
||
and self.close_rcvd.code in OK_CLOSE_CODES
|
||
and self.close_sent is not None
|
||
and self.close_sent.code in OK_CLOSE_CODES
|
||
):
|
||
exc = ConnectionClosedOK(
|
||
self.close_rcvd,
|
||
self.close_sent,
|
||
self.close_rcvd_then_sent,
|
||
)
|
||
else:
|
||
exc = ConnectionClosedError(
|
||
self.close_rcvd,
|
||
self.close_sent,
|
||
self.close_rcvd_then_sent,
|
||
)
|
||
# Chain to the exception that terminated data transfer, if any.
|
||
exc.__cause__ = self.transfer_data_exc
|
||
return exc
|
||
|
||
async def ensure_open(self) -> None:
|
||
"""
|
||
Check that the WebSocket connection is open.
|
||
|
||
Raise :exc:`~websockets.exceptions.ConnectionClosed` if it isn't.
|
||
|
||
"""
|
||
# Handle cases from most common to least common for performance.
|
||
if self.state is State.OPEN:
|
||
# If self.transfer_data_task exited without a closing handshake,
|
||
# self.close_connection_task may be closing the connection, going
|
||
# straight from OPEN to CLOSED.
|
||
if self.transfer_data_task.done():
|
||
await asyncio.shield(self.close_connection_task)
|
||
raise self.connection_closed_exc()
|
||
else:
|
||
return
|
||
|
||
if self.state is State.CLOSED:
|
||
raise self.connection_closed_exc()
|
||
|
||
if self.state is State.CLOSING:
|
||
# If we started the closing handshake, wait for its completion to
|
||
# get the proper close code and reason. self.close_connection_task
|
||
# will complete within 4 or 5 * close_timeout after close(). The
|
||
# CLOSING state also occurs when failing the connection. In that
|
||
# case self.close_connection_task will complete even faster.
|
||
await asyncio.shield(self.close_connection_task)
|
||
raise self.connection_closed_exc()
|
||
|
||
# Control may only reach this point in buggy third-party subclasses.
|
||
assert self.state is State.CONNECTING
|
||
raise InvalidState("WebSocket connection isn't established yet")
|
||
|
||
async def transfer_data(self) -> None:
|
||
"""
|
||
Read incoming messages and put them in a queue.
|
||
|
||
This coroutine runs in a task until the closing handshake is started.
|
||
|
||
"""
|
||
try:
|
||
while True:
|
||
message = await self.read_message()
|
||
|
||
# Exit the loop when receiving a close frame.
|
||
if message is None:
|
||
break
|
||
|
||
# Wait until there's room in the queue (if necessary).
|
||
if self.max_queue is not None:
|
||
while len(self.messages) >= self.max_queue:
|
||
self._put_message_waiter = self.loop.create_future()
|
||
try:
|
||
await asyncio.shield(self._put_message_waiter)
|
||
finally:
|
||
self._put_message_waiter = None
|
||
|
||
# Put the message in the queue.
|
||
self.messages.append(message)
|
||
|
||
# Notify recv().
|
||
if self._pop_message_waiter is not None:
|
||
self._pop_message_waiter.set_result(None)
|
||
self._pop_message_waiter = None
|
||
|
||
except asyncio.CancelledError as exc:
|
||
self.transfer_data_exc = exc
|
||
# If fail_connection() cancels this task, avoid logging the error
|
||
# twice and failing the connection again.
|
||
raise
|
||
|
||
except ProtocolError as exc:
|
||
self.transfer_data_exc = exc
|
||
self.fail_connection(1002)
|
||
|
||
except (ConnectionError, TimeoutError, EOFError) as exc:
|
||
# Reading data with self.reader.readexactly may raise:
|
||
# - most subclasses of ConnectionError if the TCP connection
|
||
# breaks, is reset, or is aborted;
|
||
# - TimeoutError if the TCP connection times out;
|
||
# - IncompleteReadError, a subclass of EOFError, if fewer
|
||
# bytes are available than requested.
|
||
self.transfer_data_exc = exc
|
||
self.fail_connection(1006)
|
||
|
||
except UnicodeDecodeError as exc:
|
||
self.transfer_data_exc = exc
|
||
self.fail_connection(1007)
|
||
|
||
except PayloadTooBig as exc:
|
||
self.transfer_data_exc = exc
|
||
self.fail_connection(1009)
|
||
|
||
except Exception as exc:
|
||
# This shouldn't happen often because exceptions expected under
|
||
# regular circumstances are handled above. If it does, consider
|
||
# catching and handling more exceptions.
|
||
self.logger.error("data transfer failed", exc_info=True)
|
||
|
||
self.transfer_data_exc = exc
|
||
self.fail_connection(1011)
|
||
|
||
async def read_message(self) -> Optional[Data]:
|
||
"""
|
||
Read a single message from the connection.
|
||
|
||
Re-assemble data frames if the message is fragmented.
|
||
|
||
Return :obj:`None` when the closing handshake is started.
|
||
|
||
"""
|
||
frame = await self.read_data_frame(max_size=self.max_size)
|
||
|
||
# A close frame was received.
|
||
if frame is None:
|
||
return None
|
||
|
||
if frame.opcode == OP_TEXT:
|
||
text = True
|
||
elif frame.opcode == OP_BINARY:
|
||
text = False
|
||
else: # frame.opcode == OP_CONT
|
||
raise ProtocolError("unexpected opcode")
|
||
|
||
# Shortcut for the common case - no fragmentation
|
||
if frame.fin:
|
||
return frame.data.decode("utf-8") if text else frame.data
|
||
|
||
# 5.4. Fragmentation
|
||
chunks: List[Data] = []
|
||
max_size = self.max_size
|
||
if text:
|
||
decoder_factory = codecs.getincrementaldecoder("utf-8")
|
||
decoder = decoder_factory(errors="strict")
|
||
if max_size is None:
|
||
|
||
def append(frame: Frame) -> None:
|
||
nonlocal chunks
|
||
chunks.append(decoder.decode(frame.data, frame.fin))
|
||
|
||
else:
|
||
|
||
def append(frame: Frame) -> None:
|
||
nonlocal chunks, max_size
|
||
chunks.append(decoder.decode(frame.data, frame.fin))
|
||
assert isinstance(max_size, int)
|
||
max_size -= len(frame.data)
|
||
|
||
else:
|
||
if max_size is None:
|
||
|
||
def append(frame: Frame) -> None:
|
||
nonlocal chunks
|
||
chunks.append(frame.data)
|
||
|
||
else:
|
||
|
||
def append(frame: Frame) -> None:
|
||
nonlocal chunks, max_size
|
||
chunks.append(frame.data)
|
||
assert isinstance(max_size, int)
|
||
max_size -= len(frame.data)
|
||
|
||
append(frame)
|
||
|
||
while not frame.fin:
|
||
frame = await self.read_data_frame(max_size=max_size)
|
||
if frame is None:
|
||
raise ProtocolError("incomplete fragmented message")
|
||
if frame.opcode != OP_CONT:
|
||
raise ProtocolError("unexpected opcode")
|
||
append(frame)
|
||
|
||
return ("" if text else b"").join(chunks)
|
||
|
||
async def read_data_frame(self, max_size: Optional[int]) -> Optional[Frame]:
|
||
"""
|
||
Read a single data frame from the connection.
|
||
|
||
Process control frames received before the next data frame.
|
||
|
||
Return :obj:`None` if a close frame is encountered before any data frame.
|
||
|
||
"""
|
||
# 6.2. Receiving Data
|
||
while True:
|
||
frame = await self.read_frame(max_size)
|
||
|
||
# 5.5. Control Frames
|
||
if frame.opcode == OP_CLOSE:
|
||
# 7.1.5. The WebSocket Connection Close Code
|
||
# 7.1.6. The WebSocket Connection Close Reason
|
||
self.close_rcvd = Close.parse(frame.data)
|
||
if self.close_sent is not None:
|
||
self.close_rcvd_then_sent = False
|
||
try:
|
||
# Echo the original data instead of re-serializing it with
|
||
# Close.serialize() because that fails when the close frame
|
||
# is empty and Close.parse() synthetizes a 1005 close code.
|
||
await self.write_close_frame(self.close_rcvd, frame.data)
|
||
except ConnectionClosed:
|
||
# Connection closed before we could echo the close frame.
|
||
pass
|
||
return None
|
||
|
||
elif frame.opcode == OP_PING:
|
||
# Answer pings, unless connection is CLOSING.
|
||
if self.state is State.OPEN:
|
||
try:
|
||
await self.pong(frame.data)
|
||
except ConnectionClosed:
|
||
# Connection closed while draining write buffer.
|
||
pass
|
||
|
||
elif frame.opcode == OP_PONG:
|
||
if frame.data in self.pings:
|
||
# Sending a pong for only the most recent ping is legal.
|
||
# Acknowledge all previous pings too in that case.
|
||
ping_id = None
|
||
ping_ids = []
|
||
for ping_id, ping in self.pings.items():
|
||
ping_ids.append(ping_id)
|
||
if not ping.done():
|
||
ping.set_result(None)
|
||
if ping_id == frame.data:
|
||
break
|
||
else: # pragma: no cover
|
||
assert False, "ping_id is in self.pings"
|
||
# Remove acknowledged pings from self.pings.
|
||
for ping_id in ping_ids:
|
||
del self.pings[ping_id]
|
||
|
||
# 5.6. Data Frames
|
||
else:
|
||
return frame
|
||
|
||
async def read_frame(self, max_size: Optional[int]) -> Frame:
|
||
"""
|
||
Read a single frame from the connection.
|
||
|
||
"""
|
||
frame = await Frame.read(
|
||
self.reader.readexactly,
|
||
mask=not self.is_client,
|
||
max_size=max_size,
|
||
extensions=self.extensions,
|
||
)
|
||
if self.debug:
|
||
self.logger.debug("< %s", frame)
|
||
return frame
|
||
|
||
def write_frame_sync(self, fin: bool, opcode: int, data: bytes) -> None:
|
||
frame = Frame(fin, Opcode(opcode), data)
|
||
if self.debug:
|
||
self.logger.debug("> %s", frame)
|
||
frame.write(
|
||
self.transport.write,
|
||
mask=self.is_client,
|
||
extensions=self.extensions,
|
||
)
|
||
|
||
async def drain(self) -> None:
|
||
try:
|
||
# drain() cannot be called concurrently by multiple coroutines:
|
||
# http://bugs.python.org/issue29930. Remove this lock when no
|
||
# version of Python where this bugs exists is supported anymore.
|
||
async with self._drain_lock:
|
||
# Handle flow control automatically.
|
||
await self._drain()
|
||
except ConnectionError:
|
||
# Terminate the connection if the socket died.
|
||
self.fail_connection()
|
||
# Wait until the connection is closed to raise ConnectionClosed
|
||
# with the correct code and reason.
|
||
await self.ensure_open()
|
||
|
||
async def write_frame(
|
||
self, fin: bool, opcode: int, data: bytes, *, _state: int = State.OPEN
|
||
) -> None:
|
||
# Defensive assertion for protocol compliance.
|
||
if self.state is not _state: # pragma: no cover
|
||
raise InvalidState(
|
||
f"Cannot write to a WebSocket in the {self.state.name} state"
|
||
)
|
||
self.write_frame_sync(fin, opcode, data)
|
||
await self.drain()
|
||
|
||
async def write_close_frame(
|
||
self, close: Close, data: Optional[bytes] = None
|
||
) -> None:
|
||
"""
|
||
Write a close frame if and only if the connection state is OPEN.
|
||
|
||
This dedicated coroutine must be used for writing close frames to
|
||
ensure that at most one close frame is sent on a given connection.
|
||
|
||
"""
|
||
# Test and set the connection state before sending the close frame to
|
||
# avoid sending two frames in case of concurrent calls.
|
||
if self.state is State.OPEN:
|
||
# 7.1.3. The WebSocket Closing Handshake is Started
|
||
self.state = State.CLOSING
|
||
if self.debug:
|
||
self.logger.debug("= connection is CLOSING")
|
||
|
||
self.close_sent = close
|
||
if self.close_rcvd is not None:
|
||
self.close_rcvd_then_sent = True
|
||
if data is None:
|
||
data = close.serialize()
|
||
|
||
# 7.1.2. Start the WebSocket Closing Handshake
|
||
await self.write_frame(True, OP_CLOSE, data, _state=State.CLOSING)
|
||
|
||
async def keepalive_ping(self) -> None:
|
||
"""
|
||
Send a Ping frame and wait for a Pong frame at regular intervals.
|
||
|
||
This coroutine exits when the connection terminates and one of the
|
||
following happens:
|
||
|
||
- :meth:`ping` raises :exc:`ConnectionClosed`, or
|
||
- :meth:`close_connection` cancels :attr:`keepalive_ping_task`.
|
||
|
||
"""
|
||
if self.ping_interval is None:
|
||
return
|
||
|
||
try:
|
||
while True:
|
||
await asyncio.sleep(
|
||
self.ping_interval,
|
||
**loop_if_py_lt_38(self.loop),
|
||
)
|
||
|
||
# ping() raises CancelledError if the connection is closed,
|
||
# when close_connection() cancels self.keepalive_ping_task.
|
||
|
||
# ping() raises ConnectionClosed if the connection is lost,
|
||
# when connection_lost() calls abort_pings().
|
||
|
||
self.logger.debug("% sending keepalive ping")
|
||
pong_waiter = await self.ping()
|
||
|
||
if self.ping_timeout is not None:
|
||
try:
|
||
await asyncio.wait_for(
|
||
pong_waiter,
|
||
self.ping_timeout,
|
||
**loop_if_py_lt_38(self.loop),
|
||
)
|
||
self.logger.debug("% received keepalive pong")
|
||
except asyncio.TimeoutError:
|
||
if self.debug:
|
||
self.logger.debug("! timed out waiting for keepalive pong")
|
||
self.fail_connection(1011, "keepalive ping timeout")
|
||
break
|
||
|
||
# Remove this branch when dropping support for Python < 3.8
|
||
# because CancelledError no longer inherits Exception.
|
||
except asyncio.CancelledError:
|
||
raise
|
||
|
||
except ConnectionClosed:
|
||
pass
|
||
|
||
except Exception:
|
||
self.logger.error("keepalive ping failed", exc_info=True)
|
||
|
||
async def close_connection(self) -> None:
|
||
"""
|
||
7.1.1. Close the WebSocket Connection
|
||
|
||
When the opening handshake succeeds, :meth:`connection_open` starts
|
||
this coroutine in a task. It waits for the data transfer phase to
|
||
complete then it closes the TCP connection cleanly.
|
||
|
||
When the opening handshake fails, :meth:`fail_connection` does the
|
||
same. There's no data transfer phase in that case.
|
||
|
||
"""
|
||
try:
|
||
# Wait for the data transfer phase to complete.
|
||
if hasattr(self, "transfer_data_task"):
|
||
try:
|
||
await self.transfer_data_task
|
||
except asyncio.CancelledError:
|
||
pass
|
||
|
||
# Cancel the keepalive ping task.
|
||
if hasattr(self, "keepalive_ping_task"):
|
||
self.keepalive_ping_task.cancel()
|
||
|
||
# A client should wait for a TCP close from the server.
|
||
if self.is_client and hasattr(self, "transfer_data_task"):
|
||
if await self.wait_for_connection_lost():
|
||
# Coverage marks this line as a partially executed branch.
|
||
# I supect a bug in coverage. Ignore it for now.
|
||
return # pragma: no cover
|
||
if self.debug:
|
||
self.logger.debug("! timed out waiting for TCP close")
|
||
|
||
# Half-close the TCP connection if possible (when there's no TLS).
|
||
if self.transport.can_write_eof():
|
||
if self.debug:
|
||
self.logger.debug("x half-closing TCP connection")
|
||
# write_eof() doesn't document which exceptions it raises.
|
||
# "[Errno 107] Transport endpoint is not connected" happens
|
||
# but it isn't completely clear under which circumstances.
|
||
try:
|
||
self.transport.write_eof()
|
||
except OSError: # pragma: no cover
|
||
pass
|
||
|
||
if await self.wait_for_connection_lost():
|
||
# Coverage marks this line as a partially executed branch.
|
||
# I supect a bug in coverage. Ignore it for now.
|
||
return # pragma: no cover
|
||
if self.debug:
|
||
self.logger.debug("! timed out waiting for TCP close")
|
||
|
||
finally:
|
||
# The try/finally ensures that the transport never remains open,
|
||
# even if this coroutine is canceled (for example).
|
||
await self.close_transport()
|
||
|
||
async def close_transport(self) -> None:
|
||
"""
|
||
Close the TCP connection.
|
||
|
||
"""
|
||
# If connection_lost() was called, the TCP connection is closed.
|
||
# However, if TLS is enabled, the transport still needs closing.
|
||
# Else asyncio complains: ResourceWarning: unclosed transport.
|
||
if self.connection_lost_waiter.done() and self.transport.is_closing():
|
||
return
|
||
|
||
# Close the TCP connection. Buffers are flushed asynchronously.
|
||
if self.debug:
|
||
self.logger.debug("x closing TCP connection")
|
||
self.transport.close()
|
||
|
||
if await self.wait_for_connection_lost():
|
||
return
|
||
if self.debug:
|
||
self.logger.debug("! timed out waiting for TCP close")
|
||
|
||
# Abort the TCP connection. Buffers are discarded.
|
||
if self.debug:
|
||
self.logger.debug("x aborting TCP connection")
|
||
self.transport.abort()
|
||
|
||
# connection_lost() is called quickly after aborting.
|
||
# Coverage marks this line as a partially executed branch.
|
||
# I supect a bug in coverage. Ignore it for now.
|
||
await self.wait_for_connection_lost() # pragma: no cover
|
||
|
||
async def wait_for_connection_lost(self) -> bool:
|
||
"""
|
||
Wait until the TCP connection is closed or ``self.close_timeout`` elapses.
|
||
|
||
Return :obj:`True` if the connection is closed and :obj:`False`
|
||
otherwise.
|
||
|
||
"""
|
||
if not self.connection_lost_waiter.done():
|
||
try:
|
||
await asyncio.wait_for(
|
||
asyncio.shield(self.connection_lost_waiter),
|
||
self.close_timeout,
|
||
**loop_if_py_lt_38(self.loop),
|
||
)
|
||
except asyncio.TimeoutError:
|
||
pass
|
||
# Re-check self.connection_lost_waiter.done() synchronously because
|
||
# connection_lost() could run between the moment the timeout occurs
|
||
# and the moment this coroutine resumes running.
|
||
return self.connection_lost_waiter.done()
|
||
|
||
def fail_connection(self, code: int = 1006, reason: str = "") -> None:
|
||
"""
|
||
7.1.7. Fail the WebSocket Connection
|
||
|
||
This requires:
|
||
|
||
1. Stopping all processing of incoming data, which means cancelling
|
||
:attr:`transfer_data_task`. The close code will be 1006 unless a
|
||
close frame was received earlier.
|
||
|
||
2. Sending a close frame with an appropriate code if the opening
|
||
handshake succeeded and the other side is likely to process it.
|
||
|
||
3. Closing the connection. :meth:`close_connection` takes care of
|
||
this once :attr:`transfer_data_task` exits after being canceled.
|
||
|
||
(The specification describes these steps in the opposite order.)
|
||
|
||
"""
|
||
if self.debug:
|
||
self.logger.debug("! failing connection with code %d", code)
|
||
|
||
# Cancel transfer_data_task if the opening handshake succeeded.
|
||
# cancel() is idempotent and ignored if the task is done already.
|
||
if hasattr(self, "transfer_data_task"):
|
||
self.transfer_data_task.cancel()
|
||
|
||
# Send a close frame when the state is OPEN (a close frame was already
|
||
# sent if it's CLOSING), except when failing the connection because of
|
||
# an error reading from or writing to the network.
|
||
# Don't send a close frame if the connection is broken.
|
||
if code != 1006 and self.state is State.OPEN:
|
||
close = Close(code, reason)
|
||
|
||
# Write the close frame without draining the write buffer.
|
||
|
||
# Keeping fail_connection() synchronous guarantees it can't
|
||
# get stuck and simplifies the implementation of the callers.
|
||
# Not drainig the write buffer is acceptable in this context.
|
||
|
||
# This duplicates a few lines of code from write_close_frame().
|
||
|
||
self.state = State.CLOSING
|
||
if self.debug:
|
||
self.logger.debug("= connection is CLOSING")
|
||
|
||
# If self.close_rcvd was set, the connection state would be
|
||
# CLOSING. Therefore self.close_rcvd isn't set and we don't
|
||
# have to set self.close_rcvd_then_sent.
|
||
assert self.close_rcvd is None
|
||
self.close_sent = close
|
||
|
||
self.write_frame_sync(True, OP_CLOSE, close.serialize())
|
||
|
||
# Start close_connection_task if the opening handshake didn't succeed.
|
||
if not hasattr(self, "close_connection_task"):
|
||
self.close_connection_task = self.loop.create_task(self.close_connection())
|
||
|
||
def abort_pings(self) -> None:
|
||
"""
|
||
Raise ConnectionClosed in pending keepalive pings.
|
||
|
||
They'll never receive a pong once the connection is closed.
|
||
|
||
"""
|
||
assert self.state is State.CLOSED
|
||
exc = self.connection_closed_exc()
|
||
|
||
for ping in self.pings.values():
|
||
ping.set_exception(exc)
|
||
# If the exception is never retrieved, it will be logged when ping
|
||
# is garbage-collected. This is confusing for users.
|
||
# Given that ping is done (with an exception), canceling it does
|
||
# nothing, but it prevents logging the exception.
|
||
ping.cancel()
|
||
|
||
# asyncio.Protocol methods
|
||
|
||
def connection_made(self, transport: asyncio.BaseTransport) -> None:
|
||
"""
|
||
Configure write buffer limits.
|
||
|
||
The high-water limit is defined by ``self.write_limit``.
|
||
|
||
The low-water limit currently defaults to ``self.write_limit // 4`` in
|
||
:meth:`~asyncio.WriteTransport.set_write_buffer_limits`, which should
|
||
be all right for reasonable use cases of this library.
|
||
|
||
This is the earliest point where we can get hold of the transport,
|
||
which means it's the best point for configuring it.
|
||
|
||
"""
|
||
transport = cast(asyncio.Transport, transport)
|
||
transport.set_write_buffer_limits(self.write_limit)
|
||
self.transport = transport
|
||
|
||
# Copied from asyncio.StreamReaderProtocol
|
||
self.reader.set_transport(transport)
|
||
|
||
def connection_lost(self, exc: Optional[Exception]) -> None:
|
||
"""
|
||
7.1.4. The WebSocket Connection is Closed.
|
||
|
||
"""
|
||
self.state = State.CLOSED
|
||
self.logger.debug("= connection is CLOSED")
|
||
|
||
self.abort_pings()
|
||
|
||
# If self.connection_lost_waiter isn't pending, that's a bug, because:
|
||
# - it's set only here in connection_lost() which is called only once;
|
||
# - it must never be canceled.
|
||
self.connection_lost_waiter.set_result(None)
|
||
|
||
if True: # pragma: no cover
|
||
|
||
# Copied from asyncio.StreamReaderProtocol
|
||
if self.reader is not None:
|
||
if exc is None:
|
||
self.reader.feed_eof()
|
||
else:
|
||
self.reader.set_exception(exc)
|
||
|
||
# Copied from asyncio.FlowControlMixin
|
||
# Wake up the writer if currently paused.
|
||
if not self._paused:
|
||
return
|
||
waiter = self._drain_waiter
|
||
if waiter is None:
|
||
return
|
||
self._drain_waiter = None
|
||
if waiter.done():
|
||
return
|
||
if exc is None:
|
||
waiter.set_result(None)
|
||
else:
|
||
waiter.set_exception(exc)
|
||
|
||
def pause_writing(self) -> None: # pragma: no cover
|
||
assert not self._paused
|
||
self._paused = True
|
||
|
||
def resume_writing(self) -> None: # pragma: no cover
|
||
assert self._paused
|
||
self._paused = False
|
||
|
||
waiter = self._drain_waiter
|
||
if waiter is not None:
|
||
self._drain_waiter = None
|
||
if not waiter.done():
|
||
waiter.set_result(None)
|
||
|
||
def data_received(self, data: bytes) -> None:
|
||
self.reader.feed_data(data)
|
||
|
||
def eof_received(self) -> None:
|
||
"""
|
||
Close the transport after receiving EOF.
|
||
|
||
The WebSocket protocol has its own closing handshake: endpoints close
|
||
the TCP or TLS connection after sending and receiving a close frame.
|
||
|
||
As a consequence, they never need to write after receiving EOF, so
|
||
there's no reason to keep the transport open by returning :obj:`True`.
|
||
|
||
Besides, that doesn't work on TLS connections.
|
||
|
||
"""
|
||
self.reader.feed_eof()
|
||
|
||
|
||
def broadcast(websockets: Iterable[WebSocketCommonProtocol], message: Data) -> None:
|
||
"""
|
||
Broadcast a message to several WebSocket connections.
|
||
|
||
A string (:class:`str`) is sent as a Text_ frame. A bytestring or
|
||
bytes-like object (:class:`bytes`, :class:`bytearray`, or
|
||
:class:`memoryview`) is sent as a Binary_ frame.
|
||
|
||
.. _Text: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.6
|
||
.. _Binary: https://www.rfc-editor.org/rfc/rfc6455.html#section-5.6
|
||
|
||
:func:`broadcast` pushes the message synchronously to all connections even
|
||
if their write buffers are overflowing. There's no backpressure.
|
||
|
||
:func:`broadcast` skips silently connections that aren't open in order to
|
||
avoid errors on connections where the closing handshake is in progress.
|
||
|
||
If you broadcast messages faster than a connection can handle them,
|
||
messages will pile up in its write buffer until the connection times out.
|
||
Keep low values for ``ping_interval`` and ``ping_timeout`` to prevent
|
||
excessive memory usage by slow connections when you use :func:`broadcast`.
|
||
|
||
Unlike :meth:`~websockets.server.WebSocketServerProtocol.send`,
|
||
:func:`broadcast` doesn't support sending fragmented messages. Indeed,
|
||
fragmentation is useful for sending large messages without buffering
|
||
them in memory, while :func:`broadcast` buffers one copy per connection
|
||
as fast as possible.
|
||
|
||
Args:
|
||
websockets (Iterable[WebSocketCommonProtocol]): WebSocket connections
|
||
to which the message will be sent.
|
||
message (Data): message to send.
|
||
|
||
Raises:
|
||
RuntimeError: if a connection is busy sending a fragmented message.
|
||
TypeError: if ``message`` doesn't have a supported type.
|
||
|
||
"""
|
||
if not isinstance(message, (str, bytes, bytearray, memoryview)):
|
||
raise TypeError("data must be str or bytes-like")
|
||
|
||
opcode, data = prepare_data(message)
|
||
|
||
for websocket in websockets:
|
||
if websocket.state is not State.OPEN:
|
||
continue
|
||
|
||
if websocket._fragmented_message_waiter is not None:
|
||
raise RuntimeError("busy sending a fragmented message")
|
||
|
||
websocket.write_frame_sync(True, opcode, data)
|