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1664 lines
60 KiB
1664 lines
60 KiB
"""Implementation of the WebSocket protocol.
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`WebSockets <http://dev.w3.org/html5/websockets/>`_ allow for bidirectional
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communication between the browser and server.
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WebSockets are supported in the current versions of all major browsers,
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although older versions that do not support WebSockets are still in use
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(refer to http://caniuse.com/websockets for details).
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This module implements the final version of the WebSocket protocol as
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defined in `RFC 6455 <http://tools.ietf.org/html/rfc6455>`_. Certain
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browser versions (notably Safari 5.x) implemented an earlier draft of
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the protocol (known as "draft 76") and are not compatible with this module.
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.. versionchanged:: 4.0
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Removed support for the draft 76 protocol version.
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"""
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import abc
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import asyncio
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import base64
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import hashlib
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import os
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import sys
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import struct
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import tornado.escape
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import tornado.web
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from urllib.parse import urlparse
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import zlib
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from tornado.concurrent import Future, future_set_result_unless_cancelled
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from tornado.escape import utf8, native_str, to_unicode
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from tornado import gen, httpclient, httputil
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from tornado.ioloop import IOLoop, PeriodicCallback
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from tornado.iostream import StreamClosedError, IOStream
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from tornado.log import gen_log, app_log
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from tornado import simple_httpclient
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from tornado.queues import Queue
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from tornado.tcpclient import TCPClient
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from tornado.util import _websocket_mask
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from typing import (
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TYPE_CHECKING,
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cast,
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Any,
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Optional,
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Dict,
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Union,
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List,
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Awaitable,
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Callable,
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Tuple,
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Type,
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)
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from types import TracebackType
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if TYPE_CHECKING:
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from typing_extensions import Protocol
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# The zlib compressor types aren't actually exposed anywhere
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# publicly, so declare protocols for the portions we use.
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class _Compressor(Protocol):
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def compress(self, data: bytes) -> bytes:
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pass
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def flush(self, mode: int) -> bytes:
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pass
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class _Decompressor(Protocol):
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unconsumed_tail = b"" # type: bytes
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def decompress(self, data: bytes, max_length: int) -> bytes:
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pass
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class _WebSocketDelegate(Protocol):
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# The common base interface implemented by WebSocketHandler on
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# the server side and WebSocketClientConnection on the client
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# side.
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def on_ws_connection_close(
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self, close_code: int = None, close_reason: str = None
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) -> None:
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pass
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def on_message(self, message: Union[str, bytes]) -> Optional["Awaitable[None]"]:
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pass
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def on_ping(self, data: bytes) -> None:
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pass
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def on_pong(self, data: bytes) -> None:
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pass
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def log_exception(
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self,
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typ: Optional[Type[BaseException]],
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value: Optional[BaseException],
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tb: Optional[TracebackType],
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) -> None:
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pass
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_default_max_message_size = 10 * 1024 * 1024
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class WebSocketError(Exception):
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pass
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class WebSocketClosedError(WebSocketError):
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"""Raised by operations on a closed connection.
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.. versionadded:: 3.2
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"""
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pass
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class _DecompressTooLargeError(Exception):
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pass
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class _WebSocketParams(object):
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def __init__(
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self,
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ping_interval: float = None,
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ping_timeout: float = None,
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max_message_size: int = _default_max_message_size,
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compression_options: Dict[str, Any] = None,
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) -> None:
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self.ping_interval = ping_interval
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self.ping_timeout = ping_timeout
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self.max_message_size = max_message_size
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self.compression_options = compression_options
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class WebSocketHandler(tornado.web.RequestHandler):
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"""Subclass this class to create a basic WebSocket handler.
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Override `on_message` to handle incoming messages, and use
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`write_message` to send messages to the client. You can also
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override `open` and `on_close` to handle opened and closed
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connections.
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Custom upgrade response headers can be sent by overriding
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`~tornado.web.RequestHandler.set_default_headers` or
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`~tornado.web.RequestHandler.prepare`.
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See http://dev.w3.org/html5/websockets/ for details on the
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JavaScript interface. The protocol is specified at
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http://tools.ietf.org/html/rfc6455.
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Here is an example WebSocket handler that echos back all received messages
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back to the client:
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.. testcode::
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class EchoWebSocket(tornado.websocket.WebSocketHandler):
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def open(self):
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print("WebSocket opened")
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def on_message(self, message):
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self.write_message(u"You said: " + message)
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def on_close(self):
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print("WebSocket closed")
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.. testoutput::
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:hide:
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WebSockets are not standard HTTP connections. The "handshake" is
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HTTP, but after the handshake, the protocol is
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message-based. Consequently, most of the Tornado HTTP facilities
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are not available in handlers of this type. The only communication
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methods available to you are `write_message()`, `ping()`, and
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`close()`. Likewise, your request handler class should implement
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`open()` method rather than ``get()`` or ``post()``.
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If you map the handler above to ``/websocket`` in your application, you can
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invoke it in JavaScript with::
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var ws = new WebSocket("ws://localhost:8888/websocket");
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ws.onopen = function() {
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ws.send("Hello, world");
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};
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ws.onmessage = function (evt) {
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alert(evt.data);
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};
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This script pops up an alert box that says "You said: Hello, world".
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Web browsers allow any site to open a websocket connection to any other,
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instead of using the same-origin policy that governs other network
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access from javascript. This can be surprising and is a potential
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security hole, so since Tornado 4.0 `WebSocketHandler` requires
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applications that wish to receive cross-origin websockets to opt in
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by overriding the `~WebSocketHandler.check_origin` method (see that
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method's docs for details). Failure to do so is the most likely
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cause of 403 errors when making a websocket connection.
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When using a secure websocket connection (``wss://``) with a self-signed
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certificate, the connection from a browser may fail because it wants
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to show the "accept this certificate" dialog but has nowhere to show it.
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You must first visit a regular HTML page using the same certificate
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to accept it before the websocket connection will succeed.
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If the application setting ``websocket_ping_interval`` has a non-zero
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value, a ping will be sent periodically, and the connection will be
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closed if a response is not received before the ``websocket_ping_timeout``.
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Messages larger than the ``websocket_max_message_size`` application setting
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(default 10MiB) will not be accepted.
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.. versionchanged:: 4.5
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Added ``websocket_ping_interval``, ``websocket_ping_timeout``, and
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``websocket_max_message_size``.
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"""
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def __init__(
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self,
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application: tornado.web.Application,
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request: httputil.HTTPServerRequest,
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**kwargs: Any
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) -> None:
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super(WebSocketHandler, self).__init__(application, request, **kwargs)
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self.ws_connection = None # type: Optional[WebSocketProtocol]
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self.close_code = None # type: Optional[int]
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self.close_reason = None # type: Optional[str]
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self.stream = None # type: Optional[IOStream]
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self._on_close_called = False
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async def get(self, *args: Any, **kwargs: Any) -> None:
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self.open_args = args
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self.open_kwargs = kwargs
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# Upgrade header should be present and should be equal to WebSocket
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if self.request.headers.get("Upgrade", "").lower() != "websocket":
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self.set_status(400)
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log_msg = 'Can "Upgrade" only to "WebSocket".'
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self.finish(log_msg)
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gen_log.debug(log_msg)
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return
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# Connection header should be upgrade.
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# Some proxy servers/load balancers
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# might mess with it.
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headers = self.request.headers
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connection = map(
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lambda s: s.strip().lower(), headers.get("Connection", "").split(",")
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)
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if "upgrade" not in connection:
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self.set_status(400)
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log_msg = '"Connection" must be "Upgrade".'
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self.finish(log_msg)
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gen_log.debug(log_msg)
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return
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# Handle WebSocket Origin naming convention differences
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# The difference between version 8 and 13 is that in 8 the
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# client sends a "Sec-Websocket-Origin" header and in 13 it's
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# simply "Origin".
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if "Origin" in self.request.headers:
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origin = self.request.headers.get("Origin")
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else:
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origin = self.request.headers.get("Sec-Websocket-Origin", None)
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# If there was an origin header, check to make sure it matches
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# according to check_origin. When the origin is None, we assume it
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# did not come from a browser and that it can be passed on.
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if origin is not None and not self.check_origin(origin):
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self.set_status(403)
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log_msg = "Cross origin websockets not allowed"
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self.finish(log_msg)
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gen_log.debug(log_msg)
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return
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self.ws_connection = self.get_websocket_protocol()
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if self.ws_connection:
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await self.ws_connection.accept_connection(self)
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else:
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self.set_status(426, "Upgrade Required")
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self.set_header("Sec-WebSocket-Version", "7, 8, 13")
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stream = None
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@property
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def ping_interval(self) -> Optional[float]:
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"""The interval for websocket keep-alive pings.
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Set websocket_ping_interval = 0 to disable pings.
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"""
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return self.settings.get("websocket_ping_interval", None)
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@property
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def ping_timeout(self) -> Optional[float]:
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"""If no ping is received in this many seconds,
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close the websocket connection (VPNs, etc. can fail to cleanly close ws connections).
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Default is max of 3 pings or 30 seconds.
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"""
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return self.settings.get("websocket_ping_timeout", None)
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@property
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def max_message_size(self) -> int:
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"""Maximum allowed message size.
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If the remote peer sends a message larger than this, the connection
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will be closed.
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Default is 10MiB.
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"""
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return self.settings.get(
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"websocket_max_message_size", _default_max_message_size
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)
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def write_message(
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self, message: Union[bytes, str, Dict[str, Any]], binary: bool = False
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) -> "Future[None]":
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"""Sends the given message to the client of this Web Socket.
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The message may be either a string or a dict (which will be
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encoded as json). If the ``binary`` argument is false, the
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message will be sent as utf8; in binary mode any byte string
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is allowed.
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If the connection is already closed, raises `WebSocketClosedError`.
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Returns a `.Future` which can be used for flow control.
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|
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.. versionchanged:: 3.2
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`WebSocketClosedError` was added (previously a closed connection
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would raise an `AttributeError`)
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.. versionchanged:: 4.3
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Returns a `.Future` which can be used for flow control.
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.. versionchanged:: 5.0
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Consistently raises `WebSocketClosedError`. Previously could
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sometimes raise `.StreamClosedError`.
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"""
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if self.ws_connection is None or self.ws_connection.is_closing():
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raise WebSocketClosedError()
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if isinstance(message, dict):
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message = tornado.escape.json_encode(message)
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return self.ws_connection.write_message(message, binary=binary)
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|
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def select_subprotocol(self, subprotocols: List[str]) -> Optional[str]:
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"""Override to implement subprotocol negotiation.
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``subprotocols`` is a list of strings identifying the
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subprotocols proposed by the client. This method may be
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overridden to return one of those strings to select it, or
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``None`` to not select a subprotocol.
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Failure to select a subprotocol does not automatically abort
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the connection, although clients may close the connection if
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none of their proposed subprotocols was selected.
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The list may be empty, in which case this method must return
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None. This method is always called exactly once even if no
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subprotocols were proposed so that the handler can be advised
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of this fact.
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.. versionchanged:: 5.1
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Previously, this method was called with a list containing
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an empty string instead of an empty list if no subprotocols
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were proposed by the client.
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"""
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return None
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@property
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def selected_subprotocol(self) -> Optional[str]:
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"""The subprotocol returned by `select_subprotocol`.
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.. versionadded:: 5.1
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"""
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assert self.ws_connection is not None
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return self.ws_connection.selected_subprotocol
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|
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def get_compression_options(self) -> Optional[Dict[str, Any]]:
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"""Override to return compression options for the connection.
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|
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If this method returns None (the default), compression will
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be disabled. If it returns a dict (even an empty one), it
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will be enabled. The contents of the dict may be used to
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control the following compression options:
|
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|
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``compression_level`` specifies the compression level.
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|
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``mem_level`` specifies the amount of memory used for the internal compression state.
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|
|
These parameters are documented in details here:
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https://docs.python.org/3.6/library/zlib.html#zlib.compressobj
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|
|
.. versionadded:: 4.1
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|
|
.. versionchanged:: 4.5
|
|
|
|
Added ``compression_level`` and ``mem_level``.
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"""
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# TODO: Add wbits option.
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return None
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|
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def open(self, *args: str, **kwargs: str) -> Optional[Awaitable[None]]:
|
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"""Invoked when a new WebSocket is opened.
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|
|
The arguments to `open` are extracted from the `tornado.web.URLSpec`
|
|
regular expression, just like the arguments to
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`tornado.web.RequestHandler.get`.
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`open` may be a coroutine. `on_message` will not be called until
|
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`open` has returned.
|
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|
|
.. versionchanged:: 5.1
|
|
|
|
``open`` may be a coroutine.
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"""
|
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pass
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|
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def on_message(self, message: Union[str, bytes]) -> Optional[Awaitable[None]]:
|
|
"""Handle incoming messages on the WebSocket
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|
|
This method must be overridden.
|
|
|
|
.. versionchanged:: 4.5
|
|
|
|
``on_message`` can be a coroutine.
|
|
"""
|
|
raise NotImplementedError
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|
|
def ping(self, data: Union[str, bytes] = b"") -> None:
|
|
"""Send ping frame to the remote end.
|
|
|
|
The data argument allows a small amount of data (up to 125
|
|
bytes) to be sent as a part of the ping message. Note that not
|
|
all websocket implementations expose this data to
|
|
applications.
|
|
|
|
Consider using the ``websocket_ping_interval`` application
|
|
setting instead of sending pings manually.
|
|
|
|
.. versionchanged:: 5.1
|
|
|
|
The data argument is now optional.
|
|
|
|
"""
|
|
data = utf8(data)
|
|
if self.ws_connection is None or self.ws_connection.is_closing():
|
|
raise WebSocketClosedError()
|
|
self.ws_connection.write_ping(data)
|
|
|
|
def on_pong(self, data: bytes) -> None:
|
|
"""Invoked when the response to a ping frame is received."""
|
|
pass
|
|
|
|
def on_ping(self, data: bytes) -> None:
|
|
"""Invoked when the a ping frame is received."""
|
|
pass
|
|
|
|
def on_close(self) -> None:
|
|
"""Invoked when the WebSocket is closed.
|
|
|
|
If the connection was closed cleanly and a status code or reason
|
|
phrase was supplied, these values will be available as the attributes
|
|
``self.close_code`` and ``self.close_reason``.
|
|
|
|
.. versionchanged:: 4.0
|
|
|
|
Added ``close_code`` and ``close_reason`` attributes.
|
|
"""
|
|
pass
|
|
|
|
def close(self, code: int = None, reason: str = None) -> None:
|
|
"""Closes this Web Socket.
|
|
|
|
Once the close handshake is successful the socket will be closed.
|
|
|
|
``code`` may be a numeric status code, taken from the values
|
|
defined in `RFC 6455 section 7.4.1
|
|
<https://tools.ietf.org/html/rfc6455#section-7.4.1>`_.
|
|
``reason`` may be a textual message about why the connection is
|
|
closing. These values are made available to the client, but are
|
|
not otherwise interpreted by the websocket protocol.
|
|
|
|
.. versionchanged:: 4.0
|
|
|
|
Added the ``code`` and ``reason`` arguments.
|
|
"""
|
|
if self.ws_connection:
|
|
self.ws_connection.close(code, reason)
|
|
self.ws_connection = None
|
|
|
|
def check_origin(self, origin: str) -> bool:
|
|
"""Override to enable support for allowing alternate origins.
|
|
|
|
The ``origin`` argument is the value of the ``Origin`` HTTP
|
|
header, the url responsible for initiating this request. This
|
|
method is not called for clients that do not send this header;
|
|
such requests are always allowed (because all browsers that
|
|
implement WebSockets support this header, and non-browser
|
|
clients do not have the same cross-site security concerns).
|
|
|
|
Should return ``True`` to accept the request or ``False`` to
|
|
reject it. By default, rejects all requests with an origin on
|
|
a host other than this one.
|
|
|
|
This is a security protection against cross site scripting attacks on
|
|
browsers, since WebSockets are allowed to bypass the usual same-origin
|
|
policies and don't use CORS headers.
|
|
|
|
.. warning::
|
|
|
|
This is an important security measure; don't disable it
|
|
without understanding the security implications. In
|
|
particular, if your authentication is cookie-based, you
|
|
must either restrict the origins allowed by
|
|
``check_origin()`` or implement your own XSRF-like
|
|
protection for websocket connections. See `these
|
|
<https://www.christian-schneider.net/CrossSiteWebSocketHijacking.html>`_
|
|
`articles
|
|
<https://devcenter.heroku.com/articles/websocket-security>`_
|
|
for more.
|
|
|
|
To accept all cross-origin traffic (which was the default prior to
|
|
Tornado 4.0), simply override this method to always return ``True``::
|
|
|
|
def check_origin(self, origin):
|
|
return True
|
|
|
|
To allow connections from any subdomain of your site, you might
|
|
do something like::
|
|
|
|
def check_origin(self, origin):
|
|
parsed_origin = urllib.parse.urlparse(origin)
|
|
return parsed_origin.netloc.endswith(".mydomain.com")
|
|
|
|
.. versionadded:: 4.0
|
|
|
|
"""
|
|
parsed_origin = urlparse(origin)
|
|
origin = parsed_origin.netloc
|
|
origin = origin.lower()
|
|
|
|
host = self.request.headers.get("Host")
|
|
|
|
# Check to see that origin matches host directly, including ports
|
|
return origin == host
|
|
|
|
def set_nodelay(self, value: bool) -> None:
|
|
"""Set the no-delay flag for this stream.
|
|
|
|
By default, small messages may be delayed and/or combined to minimize
|
|
the number of packets sent. This can sometimes cause 200-500ms delays
|
|
due to the interaction between Nagle's algorithm and TCP delayed
|
|
ACKs. To reduce this delay (at the expense of possibly increasing
|
|
bandwidth usage), call ``self.set_nodelay(True)`` once the websocket
|
|
connection is established.
|
|
|
|
See `.BaseIOStream.set_nodelay` for additional details.
|
|
|
|
.. versionadded:: 3.1
|
|
"""
|
|
assert self.ws_connection is not None
|
|
self.ws_connection.set_nodelay(value)
|
|
|
|
def on_connection_close(self) -> None:
|
|
if self.ws_connection:
|
|
self.ws_connection.on_connection_close()
|
|
self.ws_connection = None
|
|
if not self._on_close_called:
|
|
self._on_close_called = True
|
|
self.on_close()
|
|
self._break_cycles()
|
|
|
|
def on_ws_connection_close(
|
|
self, close_code: int = None, close_reason: str = None
|
|
) -> None:
|
|
self.close_code = close_code
|
|
self.close_reason = close_reason
|
|
self.on_connection_close()
|
|
|
|
def _break_cycles(self) -> None:
|
|
# WebSocketHandlers call finish() early, but we don't want to
|
|
# break up reference cycles (which makes it impossible to call
|
|
# self.render_string) until after we've really closed the
|
|
# connection (if it was established in the first place,
|
|
# indicated by status code 101).
|
|
if self.get_status() != 101 or self._on_close_called:
|
|
super(WebSocketHandler, self)._break_cycles()
|
|
|
|
def send_error(self, *args: Any, **kwargs: Any) -> None:
|
|
if self.stream is None:
|
|
super(WebSocketHandler, self).send_error(*args, **kwargs)
|
|
else:
|
|
# If we get an uncaught exception during the handshake,
|
|
# we have no choice but to abruptly close the connection.
|
|
# TODO: for uncaught exceptions after the handshake,
|
|
# we can close the connection more gracefully.
|
|
self.stream.close()
|
|
|
|
def get_websocket_protocol(self) -> Optional["WebSocketProtocol"]:
|
|
websocket_version = self.request.headers.get("Sec-WebSocket-Version")
|
|
if websocket_version in ("7", "8", "13"):
|
|
params = _WebSocketParams(
|
|
ping_interval=self.ping_interval,
|
|
ping_timeout=self.ping_timeout,
|
|
max_message_size=self.max_message_size,
|
|
compression_options=self.get_compression_options(),
|
|
)
|
|
return WebSocketProtocol13(self, False, params)
|
|
return None
|
|
|
|
def _detach_stream(self) -> IOStream:
|
|
# disable non-WS methods
|
|
for method in [
|
|
"write",
|
|
"redirect",
|
|
"set_header",
|
|
"set_cookie",
|
|
"set_status",
|
|
"flush",
|
|
"finish",
|
|
]:
|
|
setattr(self, method, _raise_not_supported_for_websockets)
|
|
return self.detach()
|
|
|
|
|
|
def _raise_not_supported_for_websockets(*args: Any, **kwargs: Any) -> None:
|
|
raise RuntimeError("Method not supported for Web Sockets")
|
|
|
|
|
|
class WebSocketProtocol(abc.ABC):
|
|
"""Base class for WebSocket protocol versions.
|
|
"""
|
|
|
|
def __init__(self, handler: "_WebSocketDelegate") -> None:
|
|
self.handler = handler
|
|
self.stream = None # type: Optional[IOStream]
|
|
self.client_terminated = False
|
|
self.server_terminated = False
|
|
|
|
def _run_callback(
|
|
self, callback: Callable, *args: Any, **kwargs: Any
|
|
) -> "Optional[Future[Any]]":
|
|
"""Runs the given callback with exception handling.
|
|
|
|
If the callback is a coroutine, returns its Future. On error, aborts the
|
|
websocket connection and returns None.
|
|
"""
|
|
try:
|
|
result = callback(*args, **kwargs)
|
|
except Exception:
|
|
self.handler.log_exception(*sys.exc_info())
|
|
self._abort()
|
|
return None
|
|
else:
|
|
if result is not None:
|
|
result = gen.convert_yielded(result)
|
|
assert self.stream is not None
|
|
self.stream.io_loop.add_future(result, lambda f: f.result())
|
|
return result
|
|
|
|
def on_connection_close(self) -> None:
|
|
self._abort()
|
|
|
|
def _abort(self) -> None:
|
|
"""Instantly aborts the WebSocket connection by closing the socket"""
|
|
self.client_terminated = True
|
|
self.server_terminated = True
|
|
if self.stream is not None:
|
|
self.stream.close() # forcibly tear down the connection
|
|
self.close() # let the subclass cleanup
|
|
|
|
@abc.abstractmethod
|
|
def close(self, code: int = None, reason: str = None) -> None:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
def is_closing(self) -> bool:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
async def accept_connection(self, handler: WebSocketHandler) -> None:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
def write_message(
|
|
self, message: Union[str, bytes], binary: bool = False
|
|
) -> "Future[None]":
|
|
raise NotImplementedError()
|
|
|
|
@property
|
|
@abc.abstractmethod
|
|
def selected_subprotocol(self) -> Optional[str]:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
def write_ping(self, data: bytes) -> None:
|
|
raise NotImplementedError()
|
|
|
|
# The entry points below are used by WebSocketClientConnection,
|
|
# which was introduced after we only supported a single version of
|
|
# WebSocketProtocol. The WebSocketProtocol/WebSocketProtocol13
|
|
# boundary is currently pretty ad-hoc.
|
|
@abc.abstractmethod
|
|
def _process_server_headers(
|
|
self, key: Union[str, bytes], headers: httputil.HTTPHeaders
|
|
) -> None:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
def start_pinging(self) -> None:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
async def _receive_frame_loop(self) -> None:
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractmethod
|
|
def set_nodelay(self, x: bool) -> None:
|
|
raise NotImplementedError()
|
|
|
|
|
|
class _PerMessageDeflateCompressor(object):
|
|
def __init__(
|
|
self,
|
|
persistent: bool,
|
|
max_wbits: Optional[int],
|
|
compression_options: Dict[str, Any] = None,
|
|
) -> None:
|
|
if max_wbits is None:
|
|
max_wbits = zlib.MAX_WBITS
|
|
# There is no symbolic constant for the minimum wbits value.
|
|
if not (8 <= max_wbits <= zlib.MAX_WBITS):
|
|
raise ValueError(
|
|
"Invalid max_wbits value %r; allowed range 8-%d",
|
|
max_wbits,
|
|
zlib.MAX_WBITS,
|
|
)
|
|
self._max_wbits = max_wbits
|
|
|
|
if (
|
|
compression_options is None
|
|
or "compression_level" not in compression_options
|
|
):
|
|
self._compression_level = tornado.web.GZipContentEncoding.GZIP_LEVEL
|
|
else:
|
|
self._compression_level = compression_options["compression_level"]
|
|
|
|
if compression_options is None or "mem_level" not in compression_options:
|
|
self._mem_level = 8
|
|
else:
|
|
self._mem_level = compression_options["mem_level"]
|
|
|
|
if persistent:
|
|
self._compressor = self._create_compressor() # type: Optional[_Compressor]
|
|
else:
|
|
self._compressor = None
|
|
|
|
def _create_compressor(self) -> "_Compressor":
|
|
return zlib.compressobj(
|
|
self._compression_level, zlib.DEFLATED, -self._max_wbits, self._mem_level
|
|
)
|
|
|
|
def compress(self, data: bytes) -> bytes:
|
|
compressor = self._compressor or self._create_compressor()
|
|
data = compressor.compress(data) + compressor.flush(zlib.Z_SYNC_FLUSH)
|
|
assert data.endswith(b"\x00\x00\xff\xff")
|
|
return data[:-4]
|
|
|
|
|
|
class _PerMessageDeflateDecompressor(object):
|
|
def __init__(
|
|
self,
|
|
persistent: bool,
|
|
max_wbits: Optional[int],
|
|
max_message_size: int,
|
|
compression_options: Dict[str, Any] = None,
|
|
) -> None:
|
|
self._max_message_size = max_message_size
|
|
if max_wbits is None:
|
|
max_wbits = zlib.MAX_WBITS
|
|
if not (8 <= max_wbits <= zlib.MAX_WBITS):
|
|
raise ValueError(
|
|
"Invalid max_wbits value %r; allowed range 8-%d",
|
|
max_wbits,
|
|
zlib.MAX_WBITS,
|
|
)
|
|
self._max_wbits = max_wbits
|
|
if persistent:
|
|
self._decompressor = (
|
|
self._create_decompressor()
|
|
) # type: Optional[_Decompressor]
|
|
else:
|
|
self._decompressor = None
|
|
|
|
def _create_decompressor(self) -> "_Decompressor":
|
|
return zlib.decompressobj(-self._max_wbits)
|
|
|
|
def decompress(self, data: bytes) -> bytes:
|
|
decompressor = self._decompressor or self._create_decompressor()
|
|
result = decompressor.decompress(
|
|
data + b"\x00\x00\xff\xff", self._max_message_size
|
|
)
|
|
if decompressor.unconsumed_tail:
|
|
raise _DecompressTooLargeError()
|
|
return result
|
|
|
|
|
|
class WebSocketProtocol13(WebSocketProtocol):
|
|
"""Implementation of the WebSocket protocol from RFC 6455.
|
|
|
|
This class supports versions 7 and 8 of the protocol in addition to the
|
|
final version 13.
|
|
"""
|
|
|
|
# Bit masks for the first byte of a frame.
|
|
FIN = 0x80
|
|
RSV1 = 0x40
|
|
RSV2 = 0x20
|
|
RSV3 = 0x10
|
|
RSV_MASK = RSV1 | RSV2 | RSV3
|
|
OPCODE_MASK = 0x0F
|
|
|
|
stream = None # type: IOStream
|
|
|
|
def __init__(
|
|
self,
|
|
handler: "_WebSocketDelegate",
|
|
mask_outgoing: bool,
|
|
params: _WebSocketParams,
|
|
) -> None:
|
|
WebSocketProtocol.__init__(self, handler)
|
|
self.mask_outgoing = mask_outgoing
|
|
self.params = params
|
|
self._final_frame = False
|
|
self._frame_opcode = None
|
|
self._masked_frame = None
|
|
self._frame_mask = None # type: Optional[bytes]
|
|
self._frame_length = None
|
|
self._fragmented_message_buffer = None # type: Optional[bytes]
|
|
self._fragmented_message_opcode = None
|
|
self._waiting = None # type: object
|
|
self._compression_options = params.compression_options
|
|
self._decompressor = None # type: Optional[_PerMessageDeflateDecompressor]
|
|
self._compressor = None # type: Optional[_PerMessageDeflateCompressor]
|
|
self._frame_compressed = None # type: Optional[bool]
|
|
# The total uncompressed size of all messages received or sent.
|
|
# Unicode messages are encoded to utf8.
|
|
# Only for testing; subject to change.
|
|
self._message_bytes_in = 0
|
|
self._message_bytes_out = 0
|
|
# The total size of all packets received or sent. Includes
|
|
# the effect of compression, frame overhead, and control frames.
|
|
self._wire_bytes_in = 0
|
|
self._wire_bytes_out = 0
|
|
self.ping_callback = None # type: Optional[PeriodicCallback]
|
|
self.last_ping = 0.0
|
|
self.last_pong = 0.0
|
|
self.close_code = None # type: Optional[int]
|
|
self.close_reason = None # type: Optional[str]
|
|
|
|
# Use a property for this to satisfy the abc.
|
|
@property
|
|
def selected_subprotocol(self) -> Optional[str]:
|
|
return self._selected_subprotocol
|
|
|
|
@selected_subprotocol.setter
|
|
def selected_subprotocol(self, value: Optional[str]) -> None:
|
|
self._selected_subprotocol = value
|
|
|
|
async def accept_connection(self, handler: WebSocketHandler) -> None:
|
|
try:
|
|
self._handle_websocket_headers(handler)
|
|
except ValueError:
|
|
handler.set_status(400)
|
|
log_msg = "Missing/Invalid WebSocket headers"
|
|
handler.finish(log_msg)
|
|
gen_log.debug(log_msg)
|
|
return
|
|
|
|
try:
|
|
await self._accept_connection(handler)
|
|
except asyncio.CancelledError:
|
|
self._abort()
|
|
return
|
|
except ValueError:
|
|
gen_log.debug("Malformed WebSocket request received", exc_info=True)
|
|
self._abort()
|
|
return
|
|
|
|
def _handle_websocket_headers(self, handler: WebSocketHandler) -> None:
|
|
"""Verifies all invariant- and required headers
|
|
|
|
If a header is missing or have an incorrect value ValueError will be
|
|
raised
|
|
"""
|
|
fields = ("Host", "Sec-Websocket-Key", "Sec-Websocket-Version")
|
|
if not all(map(lambda f: handler.request.headers.get(f), fields)):
|
|
raise ValueError("Missing/Invalid WebSocket headers")
|
|
|
|
@staticmethod
|
|
def compute_accept_value(key: Union[str, bytes]) -> str:
|
|
"""Computes the value for the Sec-WebSocket-Accept header,
|
|
given the value for Sec-WebSocket-Key.
|
|
"""
|
|
sha1 = hashlib.sha1()
|
|
sha1.update(utf8(key))
|
|
sha1.update(b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11") # Magic value
|
|
return native_str(base64.b64encode(sha1.digest()))
|
|
|
|
def _challenge_response(self, handler: WebSocketHandler) -> str:
|
|
return WebSocketProtocol13.compute_accept_value(
|
|
cast(str, handler.request.headers.get("Sec-Websocket-Key"))
|
|
)
|
|
|
|
async def _accept_connection(self, handler: WebSocketHandler) -> None:
|
|
subprotocol_header = handler.request.headers.get("Sec-WebSocket-Protocol")
|
|
if subprotocol_header:
|
|
subprotocols = [s.strip() for s in subprotocol_header.split(",")]
|
|
else:
|
|
subprotocols = []
|
|
self.selected_subprotocol = handler.select_subprotocol(subprotocols)
|
|
if self.selected_subprotocol:
|
|
assert self.selected_subprotocol in subprotocols
|
|
handler.set_header("Sec-WebSocket-Protocol", self.selected_subprotocol)
|
|
|
|
extensions = self._parse_extensions_header(handler.request.headers)
|
|
for ext in extensions:
|
|
if ext[0] == "permessage-deflate" and self._compression_options is not None:
|
|
# TODO: negotiate parameters if compression_options
|
|
# specifies limits.
|
|
self._create_compressors("server", ext[1], self._compression_options)
|
|
if (
|
|
"client_max_window_bits" in ext[1]
|
|
and ext[1]["client_max_window_bits"] is None
|
|
):
|
|
# Don't echo an offered client_max_window_bits
|
|
# parameter with no value.
|
|
del ext[1]["client_max_window_bits"]
|
|
handler.set_header(
|
|
"Sec-WebSocket-Extensions",
|
|
httputil._encode_header("permessage-deflate", ext[1]),
|
|
)
|
|
break
|
|
|
|
handler.clear_header("Content-Type")
|
|
handler.set_status(101)
|
|
handler.set_header("Upgrade", "websocket")
|
|
handler.set_header("Connection", "Upgrade")
|
|
handler.set_header("Sec-WebSocket-Accept", self._challenge_response(handler))
|
|
handler.finish()
|
|
|
|
self.stream = handler._detach_stream()
|
|
|
|
self.start_pinging()
|
|
try:
|
|
open_result = handler.open(*handler.open_args, **handler.open_kwargs)
|
|
if open_result is not None:
|
|
await open_result
|
|
except Exception:
|
|
handler.log_exception(*sys.exc_info())
|
|
self._abort()
|
|
return
|
|
|
|
await self._receive_frame_loop()
|
|
|
|
def _parse_extensions_header(
|
|
self, headers: httputil.HTTPHeaders
|
|
) -> List[Tuple[str, Dict[str, str]]]:
|
|
extensions = headers.get("Sec-WebSocket-Extensions", "")
|
|
if extensions:
|
|
return [httputil._parse_header(e.strip()) for e in extensions.split(",")]
|
|
return []
|
|
|
|
def _process_server_headers(
|
|
self, key: Union[str, bytes], headers: httputil.HTTPHeaders
|
|
) -> None:
|
|
"""Process the headers sent by the server to this client connection.
|
|
|
|
'key' is the websocket handshake challenge/response key.
|
|
"""
|
|
assert headers["Upgrade"].lower() == "websocket"
|
|
assert headers["Connection"].lower() == "upgrade"
|
|
accept = self.compute_accept_value(key)
|
|
assert headers["Sec-Websocket-Accept"] == accept
|
|
|
|
extensions = self._parse_extensions_header(headers)
|
|
for ext in extensions:
|
|
if ext[0] == "permessage-deflate" and self._compression_options is not None:
|
|
self._create_compressors("client", ext[1])
|
|
else:
|
|
raise ValueError("unsupported extension %r", ext)
|
|
|
|
self.selected_subprotocol = headers.get("Sec-WebSocket-Protocol", None)
|
|
|
|
def _get_compressor_options(
|
|
self,
|
|
side: str,
|
|
agreed_parameters: Dict[str, Any],
|
|
compression_options: Dict[str, Any] = None,
|
|
) -> Dict[str, Any]:
|
|
"""Converts a websocket agreed_parameters set to keyword arguments
|
|
for our compressor objects.
|
|
"""
|
|
options = dict(
|
|
persistent=(side + "_no_context_takeover") not in agreed_parameters
|
|
) # type: Dict[str, Any]
|
|
wbits_header = agreed_parameters.get(side + "_max_window_bits", None)
|
|
if wbits_header is None:
|
|
options["max_wbits"] = zlib.MAX_WBITS
|
|
else:
|
|
options["max_wbits"] = int(wbits_header)
|
|
options["compression_options"] = compression_options
|
|
return options
|
|
|
|
def _create_compressors(
|
|
self,
|
|
side: str,
|
|
agreed_parameters: Dict[str, Any],
|
|
compression_options: Dict[str, Any] = None,
|
|
) -> None:
|
|
# TODO: handle invalid parameters gracefully
|
|
allowed_keys = set(
|
|
[
|
|
"server_no_context_takeover",
|
|
"client_no_context_takeover",
|
|
"server_max_window_bits",
|
|
"client_max_window_bits",
|
|
]
|
|
)
|
|
for key in agreed_parameters:
|
|
if key not in allowed_keys:
|
|
raise ValueError("unsupported compression parameter %r" % key)
|
|
other_side = "client" if (side == "server") else "server"
|
|
self._compressor = _PerMessageDeflateCompressor(
|
|
**self._get_compressor_options(side, agreed_parameters, compression_options)
|
|
)
|
|
self._decompressor = _PerMessageDeflateDecompressor(
|
|
max_message_size=self.params.max_message_size,
|
|
**self._get_compressor_options(
|
|
other_side, agreed_parameters, compression_options
|
|
)
|
|
)
|
|
|
|
def _write_frame(
|
|
self, fin: bool, opcode: int, data: bytes, flags: int = 0
|
|
) -> "Future[None]":
|
|
data_len = len(data)
|
|
if opcode & 0x8:
|
|
# All control frames MUST have a payload length of 125
|
|
# bytes or less and MUST NOT be fragmented.
|
|
if not fin:
|
|
raise ValueError("control frames may not be fragmented")
|
|
if data_len > 125:
|
|
raise ValueError("control frame payloads may not exceed 125 bytes")
|
|
if fin:
|
|
finbit = self.FIN
|
|
else:
|
|
finbit = 0
|
|
frame = struct.pack("B", finbit | opcode | flags)
|
|
if self.mask_outgoing:
|
|
mask_bit = 0x80
|
|
else:
|
|
mask_bit = 0
|
|
if data_len < 126:
|
|
frame += struct.pack("B", data_len | mask_bit)
|
|
elif data_len <= 0xFFFF:
|
|
frame += struct.pack("!BH", 126 | mask_bit, data_len)
|
|
else:
|
|
frame += struct.pack("!BQ", 127 | mask_bit, data_len)
|
|
if self.mask_outgoing:
|
|
mask = os.urandom(4)
|
|
data = mask + _websocket_mask(mask, data)
|
|
frame += data
|
|
self._wire_bytes_out += len(frame)
|
|
return self.stream.write(frame)
|
|
|
|
def write_message(
|
|
self, message: Union[str, bytes], binary: bool = False
|
|
) -> "Future[None]":
|
|
"""Sends the given message to the client of this Web Socket."""
|
|
if binary:
|
|
opcode = 0x2
|
|
else:
|
|
opcode = 0x1
|
|
message = tornado.escape.utf8(message)
|
|
assert isinstance(message, bytes)
|
|
self._message_bytes_out += len(message)
|
|
flags = 0
|
|
if self._compressor:
|
|
message = self._compressor.compress(message)
|
|
flags |= self.RSV1
|
|
# For historical reasons, write methods in Tornado operate in a semi-synchronous
|
|
# mode in which awaiting the Future they return is optional (But errors can
|
|
# still be raised). This requires us to go through an awkward dance here
|
|
# to transform the errors that may be returned while presenting the same
|
|
# semi-synchronous interface.
|
|
try:
|
|
fut = self._write_frame(True, opcode, message, flags=flags)
|
|
except StreamClosedError:
|
|
raise WebSocketClosedError()
|
|
|
|
async def wrapper() -> None:
|
|
try:
|
|
await fut
|
|
except StreamClosedError:
|
|
raise WebSocketClosedError()
|
|
|
|
return asyncio.ensure_future(wrapper())
|
|
|
|
def write_ping(self, data: bytes) -> None:
|
|
"""Send ping frame."""
|
|
assert isinstance(data, bytes)
|
|
self._write_frame(True, 0x9, data)
|
|
|
|
async def _receive_frame_loop(self) -> None:
|
|
try:
|
|
while not self.client_terminated:
|
|
await self._receive_frame()
|
|
except StreamClosedError:
|
|
self._abort()
|
|
self.handler.on_ws_connection_close(self.close_code, self.close_reason)
|
|
|
|
async def _read_bytes(self, n: int) -> bytes:
|
|
data = await self.stream.read_bytes(n)
|
|
self._wire_bytes_in += n
|
|
return data
|
|
|
|
async def _receive_frame(self) -> None:
|
|
# Read the frame header.
|
|
data = await self._read_bytes(2)
|
|
header, mask_payloadlen = struct.unpack("BB", data)
|
|
is_final_frame = header & self.FIN
|
|
reserved_bits = header & self.RSV_MASK
|
|
opcode = header & self.OPCODE_MASK
|
|
opcode_is_control = opcode & 0x8
|
|
if self._decompressor is not None and opcode != 0:
|
|
# Compression flag is present in the first frame's header,
|
|
# but we can't decompress until we have all the frames of
|
|
# the message.
|
|
self._frame_compressed = bool(reserved_bits & self.RSV1)
|
|
reserved_bits &= ~self.RSV1
|
|
if reserved_bits:
|
|
# client is using as-yet-undefined extensions; abort
|
|
self._abort()
|
|
return
|
|
is_masked = bool(mask_payloadlen & 0x80)
|
|
payloadlen = mask_payloadlen & 0x7F
|
|
|
|
# Parse and validate the length.
|
|
if opcode_is_control and payloadlen >= 126:
|
|
# control frames must have payload < 126
|
|
self._abort()
|
|
return
|
|
if payloadlen < 126:
|
|
self._frame_length = payloadlen
|
|
elif payloadlen == 126:
|
|
data = await self._read_bytes(2)
|
|
payloadlen = struct.unpack("!H", data)[0]
|
|
elif payloadlen == 127:
|
|
data = await self._read_bytes(8)
|
|
payloadlen = struct.unpack("!Q", data)[0]
|
|
new_len = payloadlen
|
|
if self._fragmented_message_buffer is not None:
|
|
new_len += len(self._fragmented_message_buffer)
|
|
if new_len > self.params.max_message_size:
|
|
self.close(1009, "message too big")
|
|
self._abort()
|
|
return
|
|
|
|
# Read the payload, unmasking if necessary.
|
|
if is_masked:
|
|
self._frame_mask = await self._read_bytes(4)
|
|
data = await self._read_bytes(payloadlen)
|
|
if is_masked:
|
|
assert self._frame_mask is not None
|
|
data = _websocket_mask(self._frame_mask, data)
|
|
|
|
# Decide what to do with this frame.
|
|
if opcode_is_control:
|
|
# control frames may be interleaved with a series of fragmented
|
|
# data frames, so control frames must not interact with
|
|
# self._fragmented_*
|
|
if not is_final_frame:
|
|
# control frames must not be fragmented
|
|
self._abort()
|
|
return
|
|
elif opcode == 0: # continuation frame
|
|
if self._fragmented_message_buffer is None:
|
|
# nothing to continue
|
|
self._abort()
|
|
return
|
|
self._fragmented_message_buffer += data
|
|
if is_final_frame:
|
|
opcode = self._fragmented_message_opcode
|
|
data = self._fragmented_message_buffer
|
|
self._fragmented_message_buffer = None
|
|
else: # start of new data message
|
|
if self._fragmented_message_buffer is not None:
|
|
# can't start new message until the old one is finished
|
|
self._abort()
|
|
return
|
|
if not is_final_frame:
|
|
self._fragmented_message_opcode = opcode
|
|
self._fragmented_message_buffer = data
|
|
|
|
if is_final_frame:
|
|
handled_future = self._handle_message(opcode, data)
|
|
if handled_future is not None:
|
|
await handled_future
|
|
|
|
def _handle_message(self, opcode: int, data: bytes) -> "Optional[Future[None]]":
|
|
"""Execute on_message, returning its Future if it is a coroutine."""
|
|
if self.client_terminated:
|
|
return None
|
|
|
|
if self._frame_compressed:
|
|
assert self._decompressor is not None
|
|
try:
|
|
data = self._decompressor.decompress(data)
|
|
except _DecompressTooLargeError:
|
|
self.close(1009, "message too big after decompression")
|
|
self._abort()
|
|
return None
|
|
|
|
if opcode == 0x1:
|
|
# UTF-8 data
|
|
self._message_bytes_in += len(data)
|
|
try:
|
|
decoded = data.decode("utf-8")
|
|
except UnicodeDecodeError:
|
|
self._abort()
|
|
return None
|
|
return self._run_callback(self.handler.on_message, decoded)
|
|
elif opcode == 0x2:
|
|
# Binary data
|
|
self._message_bytes_in += len(data)
|
|
return self._run_callback(self.handler.on_message, data)
|
|
elif opcode == 0x8:
|
|
# Close
|
|
self.client_terminated = True
|
|
if len(data) >= 2:
|
|
self.close_code = struct.unpack(">H", data[:2])[0]
|
|
if len(data) > 2:
|
|
self.close_reason = to_unicode(data[2:])
|
|
# Echo the received close code, if any (RFC 6455 section 5.5.1).
|
|
self.close(self.close_code)
|
|
elif opcode == 0x9:
|
|
# Ping
|
|
try:
|
|
self._write_frame(True, 0xA, data)
|
|
except StreamClosedError:
|
|
self._abort()
|
|
self._run_callback(self.handler.on_ping, data)
|
|
elif opcode == 0xA:
|
|
# Pong
|
|
self.last_pong = IOLoop.current().time()
|
|
return self._run_callback(self.handler.on_pong, data)
|
|
else:
|
|
self._abort()
|
|
return None
|
|
|
|
def close(self, code: int = None, reason: str = None) -> None:
|
|
"""Closes the WebSocket connection."""
|
|
if not self.server_terminated:
|
|
if not self.stream.closed():
|
|
if code is None and reason is not None:
|
|
code = 1000 # "normal closure" status code
|
|
if code is None:
|
|
close_data = b""
|
|
else:
|
|
close_data = struct.pack(">H", code)
|
|
if reason is not None:
|
|
close_data += utf8(reason)
|
|
try:
|
|
self._write_frame(True, 0x8, close_data)
|
|
except StreamClosedError:
|
|
self._abort()
|
|
self.server_terminated = True
|
|
if self.client_terminated:
|
|
if self._waiting is not None:
|
|
self.stream.io_loop.remove_timeout(self._waiting)
|
|
self._waiting = None
|
|
self.stream.close()
|
|
elif self._waiting is None:
|
|
# Give the client a few seconds to complete a clean shutdown,
|
|
# otherwise just close the connection.
|
|
self._waiting = self.stream.io_loop.add_timeout(
|
|
self.stream.io_loop.time() + 5, self._abort
|
|
)
|
|
|
|
def is_closing(self) -> bool:
|
|
"""Return ``True`` if this connection is closing.
|
|
|
|
The connection is considered closing if either side has
|
|
initiated its closing handshake or if the stream has been
|
|
shut down uncleanly.
|
|
"""
|
|
return self.stream.closed() or self.client_terminated or self.server_terminated
|
|
|
|
@property
|
|
def ping_interval(self) -> Optional[float]:
|
|
interval = self.params.ping_interval
|
|
if interval is not None:
|
|
return interval
|
|
return 0
|
|
|
|
@property
|
|
def ping_timeout(self) -> Optional[float]:
|
|
timeout = self.params.ping_timeout
|
|
if timeout is not None:
|
|
return timeout
|
|
assert self.ping_interval is not None
|
|
return max(3 * self.ping_interval, 30)
|
|
|
|
def start_pinging(self) -> None:
|
|
"""Start sending periodic pings to keep the connection alive"""
|
|
assert self.ping_interval is not None
|
|
if self.ping_interval > 0:
|
|
self.last_ping = self.last_pong = IOLoop.current().time()
|
|
self.ping_callback = PeriodicCallback(
|
|
self.periodic_ping, self.ping_interval * 1000
|
|
)
|
|
self.ping_callback.start()
|
|
|
|
def periodic_ping(self) -> None:
|
|
"""Send a ping to keep the websocket alive
|
|
|
|
Called periodically if the websocket_ping_interval is set and non-zero.
|
|
"""
|
|
if self.is_closing() and self.ping_callback is not None:
|
|
self.ping_callback.stop()
|
|
return
|
|
|
|
# Check for timeout on pong. Make sure that we really have
|
|
# sent a recent ping in case the machine with both server and
|
|
# client has been suspended since the last ping.
|
|
now = IOLoop.current().time()
|
|
since_last_pong = now - self.last_pong
|
|
since_last_ping = now - self.last_ping
|
|
assert self.ping_interval is not None
|
|
assert self.ping_timeout is not None
|
|
if (
|
|
since_last_ping < 2 * self.ping_interval
|
|
and since_last_pong > self.ping_timeout
|
|
):
|
|
self.close()
|
|
return
|
|
|
|
self.write_ping(b"")
|
|
self.last_ping = now
|
|
|
|
def set_nodelay(self, x: bool) -> None:
|
|
self.stream.set_nodelay(x)
|
|
|
|
|
|
class WebSocketClientConnection(simple_httpclient._HTTPConnection):
|
|
"""WebSocket client connection.
|
|
|
|
This class should not be instantiated directly; use the
|
|
`websocket_connect` function instead.
|
|
"""
|
|
|
|
protocol = None # type: WebSocketProtocol
|
|
|
|
def __init__(
|
|
self,
|
|
request: httpclient.HTTPRequest,
|
|
on_message_callback: Callable[[Union[None, str, bytes]], None] = None,
|
|
compression_options: Dict[str, Any] = None,
|
|
ping_interval: float = None,
|
|
ping_timeout: float = None,
|
|
max_message_size: int = _default_max_message_size,
|
|
subprotocols: Optional[List[str]] = [],
|
|
) -> None:
|
|
self.connect_future = Future() # type: Future[WebSocketClientConnection]
|
|
self.read_queue = Queue(1) # type: Queue[Union[None, str, bytes]]
|
|
self.key = base64.b64encode(os.urandom(16))
|
|
self._on_message_callback = on_message_callback
|
|
self.close_code = None # type: Optional[int]
|
|
self.close_reason = None # type: Optional[str]
|
|
self.params = _WebSocketParams(
|
|
ping_interval=ping_interval,
|
|
ping_timeout=ping_timeout,
|
|
max_message_size=max_message_size,
|
|
compression_options=compression_options,
|
|
)
|
|
|
|
scheme, sep, rest = request.url.partition(":")
|
|
scheme = {"ws": "http", "wss": "https"}[scheme]
|
|
request.url = scheme + sep + rest
|
|
request.headers.update(
|
|
{
|
|
"Upgrade": "websocket",
|
|
"Connection": "Upgrade",
|
|
"Sec-WebSocket-Key": self.key,
|
|
"Sec-WebSocket-Version": "13",
|
|
}
|
|
)
|
|
if subprotocols is not None:
|
|
request.headers["Sec-WebSocket-Protocol"] = ",".join(subprotocols)
|
|
if compression_options is not None:
|
|
# Always offer to let the server set our max_wbits (and even though
|
|
# we don't offer it, we will accept a client_no_context_takeover
|
|
# from the server).
|
|
# TODO: set server parameters for deflate extension
|
|
# if requested in self.compression_options.
|
|
request.headers[
|
|
"Sec-WebSocket-Extensions"
|
|
] = "permessage-deflate; client_max_window_bits"
|
|
|
|
self.tcp_client = TCPClient()
|
|
super(WebSocketClientConnection, self).__init__(
|
|
None,
|
|
request,
|
|
lambda: None,
|
|
self._on_http_response,
|
|
104857600,
|
|
self.tcp_client,
|
|
65536,
|
|
104857600,
|
|
)
|
|
|
|
def close(self, code: int = None, reason: str = None) -> None:
|
|
"""Closes the websocket connection.
|
|
|
|
``code`` and ``reason`` are documented under
|
|
`WebSocketHandler.close`.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
.. versionchanged:: 4.0
|
|
|
|
Added the ``code`` and ``reason`` arguments.
|
|
"""
|
|
if self.protocol is not None:
|
|
self.protocol.close(code, reason)
|
|
self.protocol = None # type: ignore
|
|
|
|
def on_connection_close(self) -> None:
|
|
if not self.connect_future.done():
|
|
self.connect_future.set_exception(StreamClosedError())
|
|
self._on_message(None)
|
|
self.tcp_client.close()
|
|
super(WebSocketClientConnection, self).on_connection_close()
|
|
|
|
def on_ws_connection_close(
|
|
self, close_code: int = None, close_reason: str = None
|
|
) -> None:
|
|
self.close_code = close_code
|
|
self.close_reason = close_reason
|
|
self.on_connection_close()
|
|
|
|
def _on_http_response(self, response: httpclient.HTTPResponse) -> None:
|
|
if not self.connect_future.done():
|
|
if response.error:
|
|
self.connect_future.set_exception(response.error)
|
|
else:
|
|
self.connect_future.set_exception(
|
|
WebSocketError("Non-websocket response")
|
|
)
|
|
|
|
async def headers_received(
|
|
self,
|
|
start_line: Union[httputil.RequestStartLine, httputil.ResponseStartLine],
|
|
headers: httputil.HTTPHeaders,
|
|
) -> None:
|
|
assert isinstance(start_line, httputil.ResponseStartLine)
|
|
if start_line.code != 101:
|
|
await super(WebSocketClientConnection, self).headers_received(
|
|
start_line, headers
|
|
)
|
|
return
|
|
|
|
if self._timeout is not None:
|
|
self.io_loop.remove_timeout(self._timeout)
|
|
self._timeout = None
|
|
|
|
self.headers = headers
|
|
self.protocol = self.get_websocket_protocol()
|
|
self.protocol._process_server_headers(self.key, self.headers)
|
|
self.protocol.stream = self.connection.detach()
|
|
|
|
IOLoop.current().add_callback(self.protocol._receive_frame_loop)
|
|
self.protocol.start_pinging()
|
|
|
|
# Once we've taken over the connection, clear the final callback
|
|
# we set on the http request. This deactivates the error handling
|
|
# in simple_httpclient that would otherwise interfere with our
|
|
# ability to see exceptions.
|
|
self.final_callback = None # type: ignore
|
|
|
|
future_set_result_unless_cancelled(self.connect_future, self)
|
|
|
|
def write_message(
|
|
self, message: Union[str, bytes], binary: bool = False
|
|
) -> "Future[None]":
|
|
"""Sends a message to the WebSocket server.
|
|
|
|
If the stream is closed, raises `WebSocketClosedError`.
|
|
Returns a `.Future` which can be used for flow control.
|
|
|
|
.. versionchanged:: 5.0
|
|
Exception raised on a closed stream changed from `.StreamClosedError`
|
|
to `WebSocketClosedError`.
|
|
"""
|
|
return self.protocol.write_message(message, binary=binary)
|
|
|
|
def read_message(
|
|
self, callback: Callable[["Future[Union[None, str, bytes]]"], None] = None
|
|
) -> Awaitable[Union[None, str, bytes]]:
|
|
"""Reads a message from the WebSocket server.
|
|
|
|
If on_message_callback was specified at WebSocket
|
|
initialization, this function will never return messages
|
|
|
|
Returns a future whose result is the message, or None
|
|
if the connection is closed. If a callback argument
|
|
is given it will be called with the future when it is
|
|
ready.
|
|
"""
|
|
|
|
awaitable = self.read_queue.get()
|
|
if callback is not None:
|
|
self.io_loop.add_future(asyncio.ensure_future(awaitable), callback)
|
|
return awaitable
|
|
|
|
def on_message(self, message: Union[str, bytes]) -> Optional[Awaitable[None]]:
|
|
return self._on_message(message)
|
|
|
|
def _on_message(
|
|
self, message: Union[None, str, bytes]
|
|
) -> Optional[Awaitable[None]]:
|
|
if self._on_message_callback:
|
|
self._on_message_callback(message)
|
|
return None
|
|
else:
|
|
return self.read_queue.put(message)
|
|
|
|
def ping(self, data: bytes = b"") -> None:
|
|
"""Send ping frame to the remote end.
|
|
|
|
The data argument allows a small amount of data (up to 125
|
|
bytes) to be sent as a part of the ping message. Note that not
|
|
all websocket implementations expose this data to
|
|
applications.
|
|
|
|
Consider using the ``ping_interval`` argument to
|
|
`websocket_connect` instead of sending pings manually.
|
|
|
|
.. versionadded:: 5.1
|
|
|
|
"""
|
|
data = utf8(data)
|
|
if self.protocol is None:
|
|
raise WebSocketClosedError()
|
|
self.protocol.write_ping(data)
|
|
|
|
def on_pong(self, data: bytes) -> None:
|
|
pass
|
|
|
|
def on_ping(self, data: bytes) -> None:
|
|
pass
|
|
|
|
def get_websocket_protocol(self) -> WebSocketProtocol:
|
|
return WebSocketProtocol13(self, mask_outgoing=True, params=self.params)
|
|
|
|
@property
|
|
def selected_subprotocol(self) -> Optional[str]:
|
|
"""The subprotocol selected by the server.
|
|
|
|
.. versionadded:: 5.1
|
|
"""
|
|
return self.protocol.selected_subprotocol
|
|
|
|
def log_exception(
|
|
self,
|
|
typ: "Optional[Type[BaseException]]",
|
|
value: Optional[BaseException],
|
|
tb: Optional[TracebackType],
|
|
) -> None:
|
|
assert typ is not None
|
|
assert value is not None
|
|
app_log.error("Uncaught exception %s", value, exc_info=(typ, value, tb))
|
|
|
|
|
|
def websocket_connect(
|
|
url: Union[str, httpclient.HTTPRequest],
|
|
callback: Callable[["Future[WebSocketClientConnection]"], None] = None,
|
|
connect_timeout: float = None,
|
|
on_message_callback: Callable[[Union[None, str, bytes]], None] = None,
|
|
compression_options: Dict[str, Any] = None,
|
|
ping_interval: float = None,
|
|
ping_timeout: float = None,
|
|
max_message_size: int = _default_max_message_size,
|
|
subprotocols: List[str] = None,
|
|
) -> "Awaitable[WebSocketClientConnection]":
|
|
"""Client-side websocket support.
|
|
|
|
Takes a url and returns a Future whose result is a
|
|
`WebSocketClientConnection`.
|
|
|
|
``compression_options`` is interpreted in the same way as the
|
|
return value of `.WebSocketHandler.get_compression_options`.
|
|
|
|
The connection supports two styles of operation. In the coroutine
|
|
style, the application typically calls
|
|
`~.WebSocketClientConnection.read_message` in a loop::
|
|
|
|
conn = yield websocket_connect(url)
|
|
while True:
|
|
msg = yield conn.read_message()
|
|
if msg is None: break
|
|
# Do something with msg
|
|
|
|
In the callback style, pass an ``on_message_callback`` to
|
|
``websocket_connect``. In both styles, a message of ``None``
|
|
indicates that the connection has been closed.
|
|
|
|
``subprotocols`` may be a list of strings specifying proposed
|
|
subprotocols. The selected protocol may be found on the
|
|
``selected_subprotocol`` attribute of the connection object
|
|
when the connection is complete.
|
|
|
|
.. versionchanged:: 3.2
|
|
Also accepts ``HTTPRequest`` objects in place of urls.
|
|
|
|
.. versionchanged:: 4.1
|
|
Added ``compression_options`` and ``on_message_callback``.
|
|
|
|
.. versionchanged:: 4.5
|
|
Added the ``ping_interval``, ``ping_timeout``, and ``max_message_size``
|
|
arguments, which have the same meaning as in `WebSocketHandler`.
|
|
|
|
.. versionchanged:: 5.0
|
|
The ``io_loop`` argument (deprecated since version 4.1) has been removed.
|
|
|
|
.. versionchanged:: 5.1
|
|
Added the ``subprotocols`` argument.
|
|
"""
|
|
if isinstance(url, httpclient.HTTPRequest):
|
|
assert connect_timeout is None
|
|
request = url
|
|
# Copy and convert the headers dict/object (see comments in
|
|
# AsyncHTTPClient.fetch)
|
|
request.headers = httputil.HTTPHeaders(request.headers)
|
|
else:
|
|
request = httpclient.HTTPRequest(url, connect_timeout=connect_timeout)
|
|
request = cast(
|
|
httpclient.HTTPRequest,
|
|
httpclient._RequestProxy(request, httpclient.HTTPRequest._DEFAULTS),
|
|
)
|
|
conn = WebSocketClientConnection(
|
|
request,
|
|
on_message_callback=on_message_callback,
|
|
compression_options=compression_options,
|
|
ping_interval=ping_interval,
|
|
ping_timeout=ping_timeout,
|
|
max_message_size=max_message_size,
|
|
subprotocols=subprotocols,
|
|
)
|
|
if callback is not None:
|
|
IOLoop.current().add_future(conn.connect_future, callback)
|
|
return conn.connect_future
|