Source code for websocket._app

import inspect
import selectors
import sys
import threading
import time
import traceback
from ._abnf import ABNF
from ._core import WebSocket, getdefaulttimeout
from ._exceptions import *
from . import _logging

"""
_app.py
websocket - WebSocket client library for Python

Copyright 2022 engn33r

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""

__all__ = ["WebSocketApp"]

RECONNECT = 0


def setReconnect(reconnectInterval):
    global RECONNECT
    RECONNECT = reconnectInterval


class DispatcherBase:
    """
    DispatcherBase
    """
    def __init__(self, app, ping_timeout):
        self.app = app
        self.ping_timeout = ping_timeout

    def timeout(self, seconds, callback):
        time.sleep(seconds)
        callback()

    def reconnect(self, seconds, reconnector):
        try:
            while True:
                _logging.info("reconnect() - retrying in %s seconds [%s frames in stack]" % (seconds, len(inspect.stack())))
                time.sleep(seconds)
                reconnector(reconnecting=True)
        except KeyboardInterrupt as e:
            _logging.info("User exited %s" % (e,))


class Dispatcher(DispatcherBase):
    """
    Dispatcher
    """
    def read(self, sock, read_callback, check_callback):
        while self.app.keep_running:
            sel = selectors.DefaultSelector()
            sel.register(self.app.sock.sock, selectors.EVENT_READ)

            r = sel.select(self.ping_timeout)
            if r:
                if not read_callback():
                    break
            check_callback()
            sel.close()


class SSLDispatcher(DispatcherBase):
    """
    SSLDispatcher
    """
    def read(self, sock, read_callback, check_callback):
        while self.app.keep_running:
            r = self.select()
            if r:
                if not read_callback():
                    break
            check_callback()

    def select(self):
        sock = self.app.sock.sock
        if sock.pending():
            return [sock,]

        sel = selectors.DefaultSelector()
        sel.register(sock, selectors.EVENT_READ)

        r = sel.select(self.ping_timeout)
        sel.close()

        if len(r) > 0:
            return r[0][0]


class WrappedDispatcher:
    """
    WrappedDispatcher
    """
    def __init__(self, app, ping_timeout, dispatcher):
        self.app = app
        self.ping_timeout = ping_timeout
        self.dispatcher = dispatcher
        dispatcher.signal(2, dispatcher.abort)  # keyboard interrupt

    def read(self, sock, read_callback, check_callback):
        self.dispatcher.read(sock, read_callback)
        self.ping_timeout and self.timeout(self.ping_timeout, check_callback)

    def timeout(self, seconds, callback):
        self.dispatcher.timeout(seconds, callback)

    def reconnect(self, seconds, reconnector):
        self.timeout(seconds, reconnector)


[docs]class WebSocketApp: """ Higher level of APIs are provided. The interface is like JavaScript WebSocket object. """
[docs] def __init__(self, url, header=None, on_open=None, on_message=None, on_error=None, on_close=None, on_ping=None, on_pong=None, on_cont_message=None, keep_running=True, get_mask_key=None, cookie=None, subprotocols=None, on_data=None, socket=None): """ WebSocketApp initialization Parameters ---------- url: str Websocket url. header: list or dict Custom header for websocket handshake. on_open: function Callback object which is called at opening websocket. on_open has one argument. The 1st argument is this class object. on_message: function Callback object which is called when received data. on_message has 2 arguments. The 1st argument is this class object. The 2nd argument is utf-8 data received from the server. on_error: function Callback object which is called when we get error. on_error has 2 arguments. The 1st argument is this class object. The 2nd argument is exception object. on_close: function Callback object which is called when connection is closed. on_close has 3 arguments. The 1st argument is this class object. The 2nd argument is close_status_code. The 3rd argument is close_msg. on_cont_message: function Callback object which is called when a continuation frame is received. on_cont_message has 3 arguments. The 1st argument is this class object. The 2nd argument is utf-8 string which we get from the server. The 3rd argument is continue flag. if 0, the data continue to next frame data on_data: function Callback object which is called when a message received. This is called before on_message or on_cont_message, and then on_message or on_cont_message is called. on_data has 4 argument. The 1st argument is this class object. The 2nd argument is utf-8 string which we get from the server. The 3rd argument is data type. ABNF.OPCODE_TEXT or ABNF.OPCODE_BINARY will be came. The 4th argument is continue flag. If 0, the data continue keep_running: bool This parameter is obsolete and ignored. get_mask_key: function A callable function to get new mask keys, see the WebSocket.set_mask_key's docstring for more information. cookie: str Cookie value. subprotocols: list List of available sub protocols. Default is None. socket: socket Pre-initialized stream socket. """ self.url = url self.header = header if header is not None else [] self.cookie = cookie self.on_open = on_open self.on_message = on_message self.on_data = on_data self.on_error = on_error self.on_close = on_close self.on_ping = on_ping self.on_pong = on_pong self.on_cont_message = on_cont_message self.keep_running = False self.get_mask_key = get_mask_key self.sock = None self.last_ping_tm = 0 self.last_pong_tm = 0 self.subprotocols = subprotocols self.prepared_socket = socket self.has_errored = False
[docs] def send(self, data, opcode=ABNF.OPCODE_TEXT): """ send message Parameters ---------- data: str Message to send. If you set opcode to OPCODE_TEXT, data must be utf-8 string or unicode. opcode: int Operation code of data. Default is OPCODE_TEXT. """ if not self.sock or self.sock.send(data, opcode) == 0: raise WebSocketConnectionClosedException( "Connection is already closed.")
[docs] def close(self, **kwargs): """ Close websocket connection. """ self.keep_running = False if self.sock: self.sock.close(**kwargs) self.sock = None
def _send_ping(self, interval, event, payload): while not event.wait(interval): self.last_ping_tm = time.time() if self.sock: try: self.sock.ping(payload) except Exception as ex: _logging.warning("send_ping routine terminated: {}".format(ex)) break
[docs] def run_forever(self, sockopt=None, sslopt=None, ping_interval=0, ping_timeout=None, ping_payload="", http_proxy_host=None, http_proxy_port=None, http_no_proxy=None, http_proxy_auth=None, http_proxy_timeout=None, skip_utf8_validation=False, host=None, origin=None, dispatcher=None, suppress_origin=False, proxy_type=None, reconnect=None): """ Run event loop for WebSocket framework. This loop is an infinite loop and is alive while websocket is available. Parameters ---------- sockopt: tuple Values for socket.setsockopt. sockopt must be tuple and each element is argument of sock.setsockopt. sslopt: dict Optional dict object for ssl socket option. ping_interval: int or float Automatically send "ping" command every specified period (in seconds). If set to 0, no ping is sent periodically. ping_timeout: int or float Timeout (in seconds) if the pong message is not received. ping_payload: str Payload message to send with each ping. http_proxy_host: str HTTP proxy host name. http_proxy_port: int or str HTTP proxy port. If not set, set to 80. http_proxy_timeout: int or float HTTP proxy timeout, default is 60 sec as per python-socks. http_proxy_auth: tuple HTTP proxy auth information. tuple of username and password. Default is None. http_no_proxy: list Whitelisted host names that don't use the proxy. skip_utf8_validation: bool skip utf8 validation. host: str update host header. origin: str update origin header. dispatcher: Dispatcher object customize reading data from socket. suppress_origin: bool suppress outputting origin header. Returns ------- teardown: bool False if the `WebSocketApp` is closed or caught KeyboardInterrupt, True if any other exception was raised during a loop. """ if reconnect is None: reconnect = RECONNECT if ping_timeout is not None and ping_timeout <= 0: raise WebSocketException("Ensure ping_timeout > 0") if ping_interval is not None and ping_interval < 0: raise WebSocketException("Ensure ping_interval >= 0") if ping_timeout and ping_interval and ping_interval <= ping_timeout: raise WebSocketException("Ensure ping_interval > ping_timeout") if not sockopt: sockopt = [] if not sslopt: sslopt = {} if self.sock: raise WebSocketException("socket is already opened") thread = None self.keep_running = True self.last_ping_tm = 0 self.last_pong_tm = 0 def teardown(close_frame=None): """ Tears down the connection. Parameters ---------- close_frame: ABNF frame If close_frame is set, the on_close handler is invoked with the statusCode and reason from the provided frame. """ if thread and thread.is_alive(): event.set() thread.join() self.keep_running = False if self.sock: self.sock.close() close_status_code, close_reason = self._get_close_args( close_frame if close_frame else None) self.sock = None # Finally call the callback AFTER all teardown is complete self._callback(self.on_close, close_status_code, close_reason) def setSock(reconnecting=False): self.sock = WebSocket( self.get_mask_key, sockopt=sockopt, sslopt=sslopt, fire_cont_frame=self.on_cont_message is not None, skip_utf8_validation=skip_utf8_validation, enable_multithread=True) self.sock.settimeout(getdefaulttimeout()) try: self.sock.connect( self.url, header=self.header, cookie=self.cookie, http_proxy_host=http_proxy_host, http_proxy_port=http_proxy_port, http_no_proxy=http_no_proxy, http_proxy_auth=http_proxy_auth, http_proxy_timeout=http_proxy_timeout, subprotocols=self.subprotocols, host=host, origin=origin, suppress_origin=suppress_origin, proxy_type=proxy_type, socket=self.prepared_socket) self._callback(self.on_open) _logging.warning("websocket connected") dispatcher.read(self.sock.sock, read, check) except (WebSocketConnectionClosedException, ConnectionRefusedError, KeyboardInterrupt, SystemExit, Exception) as e: _logging.error("%s - %s" % (e, reconnect and "reconnecting" or "goodbye")) reconnecting or handleDisconnect(e) def read(): if not self.keep_running: return teardown() try: op_code, frame = self.sock.recv_data_frame(True) except (WebSocketConnectionClosedException, KeyboardInterrupt) as e: if custom_dispatcher: return handleDisconnect(e) else: raise e if op_code == ABNF.OPCODE_CLOSE: return teardown(frame) elif op_code == ABNF.OPCODE_PING: self._callback(self.on_ping, frame.data) elif op_code == ABNF.OPCODE_PONG: self.last_pong_tm = time.time() self._callback(self.on_pong, frame.data) elif op_code == ABNF.OPCODE_CONT and self.on_cont_message: self._callback(self.on_data, frame.data, frame.opcode, frame.fin) self._callback(self.on_cont_message, frame.data, frame.fin) else: data = frame.data if op_code == ABNF.OPCODE_TEXT: data = data.decode("utf-8") self._callback(self.on_data, data, frame.opcode, True) self._callback(self.on_message, data) return True def check(): if (ping_timeout): has_timeout_expired = time.time() - self.last_ping_tm > ping_timeout has_pong_not_arrived_after_last_ping = self.last_pong_tm - self.last_ping_tm < 0 has_pong_arrived_too_late = self.last_pong_tm - self.last_ping_tm > ping_timeout if (self.last_ping_tm and has_timeout_expired and (has_pong_not_arrived_after_last_ping or has_pong_arrived_too_late)): raise WebSocketTimeoutException("ping/pong timed out") return True def handleDisconnect(e): self.has_errored = True self._callback(self.on_error, e) if isinstance(e, SystemExit): # propagate SystemExit further raise if reconnect and not isinstance(e, KeyboardInterrupt): _logging.info("websocket disconnected (retrying in %s seconds) [%s frames in stack]" % (reconnect, len(inspect.stack()))) dispatcher.reconnect(reconnect, setSock) else: teardown() custom_dispatcher = bool(dispatcher) dispatcher = self.create_dispatcher(ping_timeout, dispatcher, not not sslopt) if ping_interval: event = threading.Event() thread = threading.Thread( target=self._send_ping, args=(ping_interval, event, ping_payload)) thread.daemon = True thread.start() setSock() return self.has_errored
def create_dispatcher(self, ping_timeout, dispatcher=None, is_ssl=False): if dispatcher: # If custom dispatcher is set, use WrappedDispatcher return WrappedDispatcher(self, ping_timeout, dispatcher) timeout = ping_timeout or 10 if is_ssl: return SSLDispatcher(self, timeout) return Dispatcher(self, timeout) def _get_close_args(self, close_frame): """ _get_close_args extracts the close code and reason from the close body if it exists (RFC6455 says WebSocket Connection Close Code is optional) """ # Need to catch the case where close_frame is None # Otherwise the following if statement causes an error if not self.on_close or not close_frame: return [None, None] # Extract close frame status code if close_frame.data and len(close_frame.data) >= 2: close_status_code = 256 * close_frame.data[0] + close_frame.data[1] reason = close_frame.data[2:].decode('utf-8') return [close_status_code, reason] else: # Most likely reached this because len(close_frame_data.data) < 2 return [None, None] def _callback(self, callback, *args): if callback: try: callback(self, *args) except Exception as e: _logging.error("error from callback {}: {}".format(callback, e)) if self.on_error: self.on_error(self, e)