764 lines
27 KiB
Python
764 lines
27 KiB
Python
from __future__ import annotations
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import hmac
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import http
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import logging
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import os
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import re
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import selectors
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import socket
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import ssl as ssl_module
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import sys
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import threading
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import warnings
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from collections.abc import Iterable, Sequence
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from types import TracebackType
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from typing import Any, Callable, Mapping, cast
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from ..exceptions import InvalidHeader
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from ..extensions.base import ServerExtensionFactory
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from ..extensions.permessage_deflate import enable_server_permessage_deflate
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from ..frames import CloseCode
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from ..headers import (
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build_www_authenticate_basic,
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parse_authorization_basic,
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validate_subprotocols,
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)
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from ..http11 import SERVER, Request, Response
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from ..protocol import CONNECTING, OPEN, Event
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from ..server import ServerProtocol
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from ..typing import LoggerLike, Origin, StatusLike, Subprotocol
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from .connection import Connection
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from .utils import Deadline
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__all__ = ["serve", "unix_serve", "ServerConnection", "Server", "basic_auth"]
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class ServerConnection(Connection):
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"""
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:mod:`threading` implementation of a WebSocket server connection.
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:class:`ServerConnection` provides :meth:`recv` and :meth:`send` methods for
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receiving and sending messages.
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It supports iteration to receive messages::
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for message in websocket:
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process(message)
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The iterator exits normally when the connection is closed with close code
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1000 (OK) or 1001 (going away) or without a close code. It raises a
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:exc:`~websockets.exceptions.ConnectionClosedError` when the connection is
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closed with any other code.
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The ``ping_interval``, ``ping_timeout``, ``close_timeout``, and
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``max_queue`` arguments have the same meaning as in :func:`serve`.
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Args:
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socket: Socket connected to a WebSocket client.
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protocol: Sans-I/O connection.
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"""
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def __init__(
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self,
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socket: socket.socket,
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protocol: ServerProtocol,
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*,
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ping_interval: float | None = 20,
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ping_timeout: float | None = 20,
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close_timeout: float | None = 10,
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max_queue: int | None | tuple[int | None, int | None] = 16,
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) -> None:
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self.protocol: ServerProtocol
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self.request_rcvd = threading.Event()
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super().__init__(
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socket,
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protocol,
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ping_interval=ping_interval,
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ping_timeout=ping_timeout,
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close_timeout=close_timeout,
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max_queue=max_queue,
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)
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self.username: str # see basic_auth()
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self.handler: Callable[[ServerConnection], None] # see route()
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self.handler_kwargs: Mapping[str, Any] # see route()
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def respond(self, status: StatusLike, text: str) -> Response:
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"""
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Create a plain text HTTP response.
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``process_request`` and ``process_response`` may call this method to
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return an HTTP response instead of performing the WebSocket opening
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handshake.
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You can modify the response before returning it, for example by changing
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HTTP headers.
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Args:
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status: HTTP status code.
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text: HTTP response body; it will be encoded to UTF-8.
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Returns:
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HTTP response to send to the client.
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"""
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return self.protocol.reject(status, text)
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def handshake(
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self,
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process_request: (
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Callable[
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[ServerConnection, Request],
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Response | None,
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]
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| None
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) = None,
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process_response: (
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Callable[
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[ServerConnection, Request, Response],
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Response | None,
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]
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| None
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) = None,
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server_header: str | None = SERVER,
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timeout: float | None = None,
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) -> None:
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"""
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Perform the opening handshake.
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"""
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if not self.request_rcvd.wait(timeout):
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raise TimeoutError("timed out while waiting for handshake request")
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if self.request is not None:
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with self.send_context(expected_state=CONNECTING):
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response = None
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if process_request is not None:
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try:
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response = process_request(self, self.request)
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except Exception as exc:
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self.protocol.handshake_exc = exc
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response = self.protocol.reject(
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http.HTTPStatus.INTERNAL_SERVER_ERROR,
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(
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"Failed to open a WebSocket connection.\n"
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"See server log for more information.\n"
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),
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)
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if response is None:
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self.response = self.protocol.accept(self.request)
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else:
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self.response = response
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if server_header:
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self.response.headers["Server"] = server_header
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response = None
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if process_response is not None:
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try:
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response = process_response(self, self.request, self.response)
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except Exception as exc:
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self.protocol.handshake_exc = exc
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response = self.protocol.reject(
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http.HTTPStatus.INTERNAL_SERVER_ERROR,
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(
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"Failed to open a WebSocket connection.\n"
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"See server log for more information.\n"
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),
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)
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if response is not None:
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self.response = response
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self.protocol.send_response(self.response)
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# self.protocol.handshake_exc is set when the connection is lost before
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# receiving a request, when the request cannot be parsed, or when the
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# handshake fails, including when process_request or process_response
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# raises an exception.
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# It isn't set when process_request or process_response sends an HTTP
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# response that rejects the handshake.
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if self.protocol.handshake_exc is not None:
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raise self.protocol.handshake_exc
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def process_event(self, event: Event) -> None:
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"""
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Process one incoming event.
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"""
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# First event - handshake request.
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if self.request is None:
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assert isinstance(event, Request)
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self.request = event
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self.request_rcvd.set()
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# Later events - frames.
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else:
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super().process_event(event)
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def recv_events(self) -> None:
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"""
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Read incoming data from the socket and process events.
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"""
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try:
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super().recv_events()
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finally:
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# If the connection is closed during the handshake, unblock it.
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self.request_rcvd.set()
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class Server:
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"""
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WebSocket server returned by :func:`serve`.
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This class mirrors the API of :class:`~socketserver.BaseServer`, notably the
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:meth:`~socketserver.BaseServer.serve_forever` and
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:meth:`~socketserver.BaseServer.shutdown` methods, as well as the context
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manager protocol.
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Args:
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socket: Server socket listening for new connections.
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handler: Handler for one connection. Receives the socket and address
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returned by :meth:`~socket.socket.accept`.
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logger: Logger for this server.
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It defaults to ``logging.getLogger("websockets.server")``.
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See the :doc:`logging guide <../../topics/logging>` for details.
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"""
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def __init__(
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self,
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socket: socket.socket,
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handler: Callable[[socket.socket, Any], None],
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logger: LoggerLike | None = None,
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) -> None:
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self.socket = socket
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self.handler = handler
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if logger is None:
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logger = logging.getLogger("websockets.server")
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self.logger = logger
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if sys.platform != "win32":
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self.shutdown_watcher, self.shutdown_notifier = os.pipe()
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def serve_forever(self) -> None:
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"""
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See :meth:`socketserver.BaseServer.serve_forever`.
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This method doesn't return. Calling :meth:`shutdown` from another thread
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stops the server.
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Typical use::
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with serve(...) as server:
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server.serve_forever()
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"""
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poller = selectors.DefaultSelector()
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try:
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poller.register(self.socket, selectors.EVENT_READ)
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except ValueError: # pragma: no cover
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# If shutdown() is called before poller.register(),
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# the socket is closed and poller.register() raises
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# ValueError: Invalid file descriptor: -1
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return
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if sys.platform != "win32":
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poller.register(self.shutdown_watcher, selectors.EVENT_READ)
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while True:
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poller.select()
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try:
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# If the socket is closed, this will raise an exception and exit
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# the loop. So we don't need to check the return value of select().
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sock, addr = self.socket.accept()
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except OSError:
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break
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# Since there isn't a mechanism for tracking connections and waiting
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# for them to terminate, we cannot use daemon threads, or else all
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# connections would be terminate brutally when closing the server.
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thread = threading.Thread(target=self.handler, args=(sock, addr))
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thread.start()
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def shutdown(self) -> None:
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"""
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See :meth:`socketserver.BaseServer.shutdown`.
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"""
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self.socket.close()
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if sys.platform != "win32":
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os.write(self.shutdown_notifier, b"x")
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def fileno(self) -> int:
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"""
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See :meth:`socketserver.BaseServer.fileno`.
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"""
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return self.socket.fileno()
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def __enter__(self) -> Server:
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return self
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def __exit__(
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self,
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exc_type: type[BaseException] | None,
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exc_value: BaseException | None,
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traceback: TracebackType | None,
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) -> None:
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self.shutdown()
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def __getattr__(name: str) -> Any:
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if name == "WebSocketServer":
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warnings.warn( # deprecated in 13.0 - 2024-08-20
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"WebSocketServer was renamed to Server",
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DeprecationWarning,
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)
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return Server
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raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
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def serve(
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handler: Callable[[ServerConnection], None],
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host: str | None = None,
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port: int | None = None,
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*,
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# TCP/TLS
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sock: socket.socket | None = None,
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ssl: ssl_module.SSLContext | None = None,
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# WebSocket
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origins: Sequence[Origin | re.Pattern[str] | None] | None = None,
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extensions: Sequence[ServerExtensionFactory] | None = None,
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subprotocols: Sequence[Subprotocol] | None = None,
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select_subprotocol: (
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Callable[
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[ServerConnection, Sequence[Subprotocol]],
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Subprotocol | None,
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]
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| None
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) = None,
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compression: str | None = "deflate",
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# HTTP
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process_request: (
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Callable[
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[ServerConnection, Request],
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Response | None,
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]
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| None
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) = None,
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process_response: (
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Callable[
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[ServerConnection, Request, Response],
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Response | None,
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]
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| None
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) = None,
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server_header: str | None = SERVER,
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# Timeouts
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open_timeout: float | None = 10,
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ping_interval: float | None = 20,
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ping_timeout: float | None = 20,
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close_timeout: float | None = 10,
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# Limits
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max_size: int | None = 2**20,
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max_queue: int | None | tuple[int | None, int | None] = 16,
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# Logging
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logger: LoggerLike | None = None,
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# Escape hatch for advanced customization
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create_connection: type[ServerConnection] | None = None,
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**kwargs: Any,
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) -> Server:
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"""
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Create a WebSocket server listening on ``host`` and ``port``.
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Whenever a client connects, the server creates a :class:`ServerConnection`,
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performs the opening handshake, and delegates to the ``handler``.
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The handler receives the :class:`ServerConnection` instance, which you can
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use to send and receive messages.
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Once the handler completes, either normally or with an exception, the server
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performs the closing handshake and closes the connection.
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This function returns a :class:`Server` whose API mirrors
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:class:`~socketserver.BaseServer`. Treat it as a context manager to ensure
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that it will be closed and call :meth:`~Server.serve_forever` to serve
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requests::
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from websockets.sync.server import serve
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def handler(websocket):
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...
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with serve(handler, ...) as server:
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server.serve_forever()
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Args:
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handler: Connection handler. It receives the WebSocket connection,
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which is a :class:`ServerConnection`, in argument.
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host: Network interfaces the server binds to.
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See :func:`~socket.create_server` for details.
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port: TCP port the server listens on.
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See :func:`~socket.create_server` for details.
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sock: Preexisting TCP socket. ``sock`` replaces ``host`` and ``port``.
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You may call :func:`socket.create_server` to create a suitable TCP
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socket.
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ssl: Configuration for enabling TLS on the connection.
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origins: Acceptable values of the ``Origin`` header, for defending
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against Cross-Site WebSocket Hijacking attacks. Values can be
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:class:`str` to test for an exact match or regular expressions
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compiled by :func:`re.compile` to test against a pattern. Include
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:obj:`None` in the list if the lack of an origin is acceptable.
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extensions: List of supported extensions, in order in which they
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should be negotiated and run.
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subprotocols: List of supported subprotocols, in order of decreasing
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preference.
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select_subprotocol: Callback for selecting a subprotocol among
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those supported by the client and the server. It receives a
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:class:`ServerConnection` (not a
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:class:`~websockets.server.ServerProtocol`!) instance and a list of
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subprotocols offered by the client. Other than the first argument,
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it has the same behavior as the
|
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:meth:`ServerProtocol.select_subprotocol
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<websockets.server.ServerProtocol.select_subprotocol>` method.
|
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compression: The "permessage-deflate" extension is enabled by default.
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Set ``compression`` to :obj:`None` to disable it. See the
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:doc:`compression guide <../../topics/compression>` for details.
|
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process_request: Intercept the request during the opening handshake.
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Return an HTTP response to force the response. Return :obj:`None` to
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continue normally. When you force an HTTP 101 Continue response, the
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handshake is successful. Else, the connection is aborted.
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process_response: Intercept the response during the opening handshake.
|
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Modify the response or return a new HTTP response to force the
|
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response. Return :obj:`None` to continue normally. When you force an
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HTTP 101 Continue response, the handshake is successful. Else, the
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connection is aborted.
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server_header: Value of the ``Server`` response header.
|
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It defaults to ``"Python/x.y.z websockets/X.Y"``. Setting it to
|
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:obj:`None` removes the header.
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open_timeout: Timeout for opening connections in seconds.
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:obj:`None` disables the timeout.
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ping_interval: Interval between keepalive pings in seconds.
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:obj:`None` disables keepalive.
|
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ping_timeout: Timeout for keepalive pings in seconds.
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:obj:`None` disables timeouts.
|
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close_timeout: Timeout for closing connections in seconds.
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:obj:`None` disables the timeout.
|
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max_size: Maximum size of incoming messages in bytes.
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:obj:`None` disables the limit.
|
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max_queue: High-water mark of the buffer where frames are received.
|
|
It defaults to 16 frames. The low-water mark defaults to ``max_queue
|
|
// 4``. You may pass a ``(high, low)`` tuple to set the high-water
|
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and low-water marks. If you want to disable flow control entirely,
|
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you may set it to ``None``, although that's a bad idea.
|
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logger: Logger for this server.
|
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It defaults to ``logging.getLogger("websockets.server")``. See the
|
|
:doc:`logging guide <../../topics/logging>` for details.
|
|
create_connection: Factory for the :class:`ServerConnection` managing
|
|
the connection. Set it to a wrapper or a subclass to customize
|
|
connection handling.
|
|
|
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Any other keyword arguments are passed to :func:`~socket.create_server`.
|
|
|
|
"""
|
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|
|
# Process parameters
|
|
|
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# Backwards compatibility: ssl used to be called ssl_context.
|
|
if ssl is None and "ssl_context" in kwargs:
|
|
ssl = kwargs.pop("ssl_context")
|
|
warnings.warn( # deprecated in 13.0 - 2024-08-20
|
|
"ssl_context was renamed to ssl",
|
|
DeprecationWarning,
|
|
)
|
|
|
|
if subprotocols is not None:
|
|
validate_subprotocols(subprotocols)
|
|
|
|
if compression == "deflate":
|
|
extensions = enable_server_permessage_deflate(extensions)
|
|
elif compression is not None:
|
|
raise ValueError(f"unsupported compression: {compression}")
|
|
|
|
if create_connection is None:
|
|
create_connection = ServerConnection
|
|
|
|
# Bind socket and listen
|
|
|
|
# Private APIs for unix_connect()
|
|
unix: bool = kwargs.pop("unix", False)
|
|
path: str | None = kwargs.pop("path", None)
|
|
|
|
if sock is None:
|
|
if unix:
|
|
if path is None:
|
|
raise ValueError("missing path argument")
|
|
kwargs.setdefault("family", socket.AF_UNIX)
|
|
sock = socket.create_server(path, **kwargs)
|
|
else:
|
|
sock = socket.create_server((host, port), **kwargs)
|
|
else:
|
|
if path is not None:
|
|
raise ValueError("path and sock arguments are incompatible")
|
|
|
|
# Initialize TLS wrapper
|
|
|
|
if ssl is not None:
|
|
sock = ssl.wrap_socket(
|
|
sock,
|
|
server_side=True,
|
|
# Delay TLS handshake until after we set a timeout on the socket.
|
|
do_handshake_on_connect=False,
|
|
)
|
|
|
|
# Define request handler
|
|
|
|
def conn_handler(sock: socket.socket, addr: Any) -> None:
|
|
# Calculate timeouts on the TLS and WebSocket handshakes.
|
|
# The TLS timeout must be set on the socket, then removed
|
|
# to avoid conflicting with the WebSocket timeout in handshake().
|
|
deadline = Deadline(open_timeout)
|
|
|
|
try:
|
|
# Disable Nagle algorithm
|
|
|
|
if not unix:
|
|
sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True)
|
|
|
|
# Perform TLS handshake
|
|
|
|
if ssl is not None:
|
|
sock.settimeout(deadline.timeout())
|
|
# mypy cannot figure this out
|
|
assert isinstance(sock, ssl_module.SSLSocket)
|
|
sock.do_handshake()
|
|
sock.settimeout(None)
|
|
|
|
# Create a closure to give select_subprotocol access to connection.
|
|
protocol_select_subprotocol: (
|
|
Callable[
|
|
[ServerProtocol, Sequence[Subprotocol]],
|
|
Subprotocol | None,
|
|
]
|
|
| None
|
|
) = None
|
|
if select_subprotocol is not None:
|
|
|
|
def protocol_select_subprotocol(
|
|
protocol: ServerProtocol,
|
|
subprotocols: Sequence[Subprotocol],
|
|
) -> Subprotocol | None:
|
|
# mypy doesn't know that select_subprotocol is immutable.
|
|
assert select_subprotocol is not None
|
|
# Ensure this function is only used in the intended context.
|
|
assert protocol is connection.protocol
|
|
return select_subprotocol(connection, subprotocols)
|
|
|
|
# Initialize WebSocket protocol
|
|
|
|
protocol = ServerProtocol(
|
|
origins=origins,
|
|
extensions=extensions,
|
|
subprotocols=subprotocols,
|
|
select_subprotocol=protocol_select_subprotocol,
|
|
max_size=max_size,
|
|
logger=logger,
|
|
)
|
|
|
|
# Initialize WebSocket connection
|
|
|
|
assert create_connection is not None # help mypy
|
|
connection = create_connection(
|
|
sock,
|
|
protocol,
|
|
ping_interval=ping_interval,
|
|
ping_timeout=ping_timeout,
|
|
close_timeout=close_timeout,
|
|
max_queue=max_queue,
|
|
)
|
|
except Exception:
|
|
sock.close()
|
|
return
|
|
|
|
try:
|
|
try:
|
|
connection.handshake(
|
|
process_request,
|
|
process_response,
|
|
server_header,
|
|
deadline.timeout(),
|
|
)
|
|
except TimeoutError:
|
|
connection.close_socket()
|
|
connection.recv_events_thread.join()
|
|
return
|
|
except Exception:
|
|
connection.logger.error("opening handshake failed", exc_info=True)
|
|
connection.close_socket()
|
|
connection.recv_events_thread.join()
|
|
return
|
|
|
|
assert connection.protocol.state is OPEN
|
|
try:
|
|
connection.start_keepalive()
|
|
handler(connection)
|
|
except Exception:
|
|
connection.logger.error("connection handler failed", exc_info=True)
|
|
connection.close(CloseCode.INTERNAL_ERROR)
|
|
else:
|
|
connection.close()
|
|
|
|
except Exception: # pragma: no cover
|
|
# Don't leak sockets on unexpected errors.
|
|
sock.close()
|
|
|
|
# Initialize server
|
|
|
|
return Server(sock, conn_handler, logger)
|
|
|
|
|
|
def unix_serve(
|
|
handler: Callable[[ServerConnection], None],
|
|
path: str | None = None,
|
|
**kwargs: Any,
|
|
) -> Server:
|
|
"""
|
|
Create a WebSocket server listening on a Unix socket.
|
|
|
|
This function accepts the same keyword arguments as :func:`serve`.
|
|
|
|
It's only available on Unix.
|
|
|
|
It's useful for deploying a server behind a reverse proxy such as nginx.
|
|
|
|
Args:
|
|
handler: Connection handler. It receives the WebSocket connection,
|
|
which is a :class:`ServerConnection`, in argument.
|
|
path: File system path to the Unix socket.
|
|
|
|
"""
|
|
return serve(handler, unix=True, path=path, **kwargs)
|
|
|
|
|
|
def is_credentials(credentials: Any) -> bool:
|
|
try:
|
|
username, password = credentials
|
|
except (TypeError, ValueError):
|
|
return False
|
|
else:
|
|
return isinstance(username, str) and isinstance(password, str)
|
|
|
|
|
|
def basic_auth(
|
|
realm: str = "",
|
|
credentials: tuple[str, str] | Iterable[tuple[str, str]] | None = None,
|
|
check_credentials: Callable[[str, str], bool] | None = None,
|
|
) -> Callable[[ServerConnection, Request], Response | None]:
|
|
"""
|
|
Factory for ``process_request`` to enforce HTTP Basic Authentication.
|
|
|
|
:func:`basic_auth` is designed to integrate with :func:`serve` as follows::
|
|
|
|
from websockets.sync.server import basic_auth, serve
|
|
|
|
with serve(
|
|
...,
|
|
process_request=basic_auth(
|
|
realm="my dev server",
|
|
credentials=("hello", "iloveyou"),
|
|
),
|
|
):
|
|
|
|
If authentication succeeds, the connection's ``username`` attribute is set.
|
|
If it fails, the server responds with an HTTP 401 Unauthorized status.
|
|
|
|
One of ``credentials`` or ``check_credentials`` must be provided; not both.
|
|
|
|
Args:
|
|
realm: Scope of protection. It should contain only ASCII characters
|
|
because the encoding of non-ASCII characters is undefined. Refer to
|
|
section 2.2 of :rfc:`7235` for details.
|
|
credentials: Hard coded authorized credentials. It can be a
|
|
``(username, password)`` pair or a list of such pairs.
|
|
check_credentials: Function that verifies credentials.
|
|
It receives ``username`` and ``password`` arguments and returns
|
|
whether they're valid.
|
|
Raises:
|
|
TypeError: If ``credentials`` or ``check_credentials`` is wrong.
|
|
ValueError: If ``credentials`` and ``check_credentials`` are both
|
|
provided or both not provided.
|
|
|
|
"""
|
|
if (credentials is None) == (check_credentials is None):
|
|
raise ValueError("provide either credentials or check_credentials")
|
|
|
|
if credentials is not None:
|
|
if is_credentials(credentials):
|
|
credentials_list = [cast(tuple[str, str], credentials)]
|
|
elif isinstance(credentials, Iterable):
|
|
credentials_list = list(cast(Iterable[tuple[str, str]], credentials))
|
|
if not all(is_credentials(item) for item in credentials_list):
|
|
raise TypeError(f"invalid credentials argument: {credentials}")
|
|
else:
|
|
raise TypeError(f"invalid credentials argument: {credentials}")
|
|
|
|
credentials_dict = dict(credentials_list)
|
|
|
|
def check_credentials(username: str, password: str) -> bool:
|
|
try:
|
|
expected_password = credentials_dict[username]
|
|
except KeyError:
|
|
return False
|
|
return hmac.compare_digest(expected_password, password)
|
|
|
|
assert check_credentials is not None # help mypy
|
|
|
|
def process_request(
|
|
connection: ServerConnection,
|
|
request: Request,
|
|
) -> Response | None:
|
|
"""
|
|
Perform HTTP Basic Authentication.
|
|
|
|
If it succeeds, set the connection's ``username`` attribute and return
|
|
:obj:`None`. If it fails, return an HTTP 401 Unauthorized responss.
|
|
|
|
"""
|
|
try:
|
|
authorization = request.headers["Authorization"]
|
|
except KeyError:
|
|
response = connection.respond(
|
|
http.HTTPStatus.UNAUTHORIZED,
|
|
"Missing credentials\n",
|
|
)
|
|
response.headers["WWW-Authenticate"] = build_www_authenticate_basic(realm)
|
|
return response
|
|
|
|
try:
|
|
username, password = parse_authorization_basic(authorization)
|
|
except InvalidHeader:
|
|
response = connection.respond(
|
|
http.HTTPStatus.UNAUTHORIZED,
|
|
"Unsupported credentials\n",
|
|
)
|
|
response.headers["WWW-Authenticate"] = build_www_authenticate_basic(realm)
|
|
return response
|
|
|
|
if not check_credentials(username, password):
|
|
response = connection.respond(
|
|
http.HTTPStatus.UNAUTHORIZED,
|
|
"Invalid credentials\n",
|
|
)
|
|
response.headers["WWW-Authenticate"] = build_www_authenticate_basic(realm)
|
|
return response
|
|
|
|
connection.username = username
|
|
return None
|
|
|
|
return process_request
|