from collections import namedtuple import copy import logging import json import multiprocessing import parser from parser import Message, Packet, MessageType, PacketType import requests import time try: from urllib import parse as parse_url except ImportError: from urlparse import urlparse as parse_url from .exceptions import ConnectionError, TimeoutError, PacketError from .transports import _get_response _SocketIOSession = namedtuple('_SocketIOSession', [ 'id', 'heartbeat_interval', 'connection_timeout', 'server_supported_transports', ]) _log = logging.getLogger(__name__) PROTOCOL_VERSION = 1 RETRY_INTERVAL_IN_SECONDS = 1 class BaseNamespace(object): 'Define client behavior' def __init__(self, _transport, path): self._transport = _transport self.path = path self._callback_by_event = {} self.initialize() def initialize(self): 'Initialize custom variables here; you can override this method' pass def message(self, data='', callback=None): self._transport.message(self.path, data, callback) def emit(self, event, *args, **kw): callback, args = find_callback(args, kw) if callback is not None: _log.warn("Callback was specified but is not supported."); self._transport.emit(self.path, event, args, None) def disconnect(self): self._transport.disconnect(self.path) def on(self, event, callback): 'Define a callback to handle a custom event emitted by the server' self._callback_by_event[event] = callback def on_connect(self): 'Called after server connects; you can override this method' _log.debug('%s [connect]', self.path) def on_disconnect(self): 'Called after server disconnects; you can override this method' _log.debug('%s [disconnect]', self.path) def on_heartbeat(self): 'Called after server sends a heartbeat; you can override this method' _log.debug('%s [heartbeat]', self.path) def on_message(self, data): 'Called after server sends a message; you can override this method' _log.info('%s [message] %s', self.path, data) def on_event(self, event, *args): """ Called after server sends an event; you can override this method. Called only if a custom event handler does not exist, such as one defined by namespace.on('my_event', my_function). """ callback, args = find_callback(args) arguments = [repr(_) for _ in args] if callback: arguments.append('callback(*args)') callback(*args) _log.info('%s [event] %s(%s)', self.path, event, ', '.join(arguments)) def on_error(self, reason, advice): 'Called after server sends an error; you can override this method' _log.info('%s [error] %s', self.path, advice) def on_noop(self): 'Called after server sends a noop; you can override this method' _log.info('%s [noop]', self.path) def on_open(self, *args): _log.info('%s [open] %s', self.path, args) def on_close(self, *args): _log.info('%s [close] %s', self.path, args) def on_retry(self, *args): _log.info('%s [retry] %s', self.path, args) def on_reconnect(self, *args): _log.info('%s [reconnect] %s', self.path, args) def _find_event_callback(self, event): # Check callbacks defined by on() try: return self._callback_by_event[event] except KeyError: pass # Check callbacks defined explicitly or use on_event() return getattr( self, 'on_' + event.replace(' ', '_'), lambda *args: self.on_event(event, *args)) class SocketIO(object): """Create a socket.io client that connects to a socket.io server at the specified host and port. - Define the behavior of the client by specifying a custom Namespace. - Prefix host with https:// to use SSL. - Set wait_for_connection=True to block until we have a connection. - Specify the transports you want to use. - Pass query params, headers, cookies, proxies as keyword arguments. SocketIO('localhost', 8000, params={'q': 'qqq'}, headers={'Authorization': 'Basic ' + b64encode('username:password')}, cookies={'a': 'aaa'}, proxies={'https': 'https://proxy.example.com:8080'}) """ def __init__( self, host, port=None, Namespace=BaseNamespace, wait_for_connection=True, **kw): self.is_secure, self.base_url = _parse_host(host, port) self.wait_for_connection = wait_for_connection self._namespace_by_path = {} self.kw = kw # These two fields work to control the heartbeat thread. self.heartbeat_terminator = None; self.heartbeat_thread = None; # Saved session information. self.session = None; # This is stores the set of paths (namespaces) that need to be # reconnected to. self.reconnect_paths = {}; # This sets of a chain of events that attempts to connect to # the server at the base namespace. self.define(Namespace) def __enter__(self): return self def __exit__(self, *exception_pack): self.disconnect() self._terminate_heartbeat(); def __del__(self): self.disconnect() self._terminate_heartbeat(); def _terminate_heartbeat(self): if self.heartbeat_terminator is not None: self.heartbeat_terminator.set(); #time.sleep(self.session.heartbeat_interval); self.heartbeat_thread.join(); def define(self, Namespace, path=''): if path: self._transport.connect(path) namespace = Namespace(self._transport, path) self._namespace_by_path[path] = namespace return namespace def on(self, event, callback, path=''): return self.get_namespace(path).on(event, callback) def message(self, data='', callback=None, path=''): self._transport.message(path, data, callback) def emit(self, event, *args, **kw): path = kw.get('path', '') callback, args = find_callback(args, kw) self._transport.emit(path, event, args, callback) def reconnect(self): """Reconnects to a set of namespaces. """ for path in self.reconnect_paths: # We avoid reconnecting to the default namespace because # socketIO_client connects to that already. if (len(self.reconnect_paths) > 1 and path is ''): continue; _log.debug("Reconnecting to path: %s" % repr(path)) self._transport.connect(path); self.reconnect_paths = {}; def wait(self, seconds=None, for_callbacks=False): """Wait in a loop and process events as defined in the namespaces. - Omit seconds, i.e. call wait() without arguments, to wait forever. """ warning_screen = _yield_warning_screen(seconds) for elapsed_time in warning_screen: try: try: self._process_events() except TimeoutError: pass if self._stop_waiting(for_callbacks): break # We will end up here in the case that we # disconnected, then reconnected AND we were # successful. if len(self.reconnect_paths) > 0: self.reconnect(); except ConnectionError as e: try: # This is where we end up if the connection was # severed. The client will disconnect here. if len(self.reconnect_paths) is 0: self.reconnect_paths = copy.deepcopy(self._namespace_by_path); self._terminate_heartbeat(); warning = Exception('[connection error] %s' % e) self._transport._connected = False; warning_screen.throw(warning) except StopIteration: _log.warn(warning) self.disconnect() _log.debug("[wait canceled]"); def _process_events(self): for packet in self._transport.recv_packet(): try: self._process_packet(packet) except PacketError as e: _log.warn('[packet error] %s', e) def _process_packet(self, packet): code, packet_id, path, data, p = packet namespace = self.get_namespace(path) delegate = None; try: delegate = self._get_delegate(code) except: pass; if delegate is not None: delegate(packet, namespace._find_event_callback) def _stop_waiting(self, for_callbacks): # Use __transport to make sure that we do not reconnect inadvertently if for_callbacks and not self.__transport.has_ack_callback: return True if self.__transport._wants_to_disconnect: return True return False def wait_for_callbacks(self, seconds=None): self.wait(seconds, for_callbacks=True) def disconnect(self, path=''): if self.connected: self._transport.disconnect(path) namespace = self._namespace_by_path[path] namespace.on_disconnect() if path: del self._namespace_by_path[path] @property def connected(self): return self.__transport.connected @property def _transport(self): try: if self.connected: return self.__transport except AttributeError: pass warning_screen = _yield_warning_screen(seconds=None) for elapsed_time in warning_screen: try: self.__transport = self._get_transport() break except ConnectionError as e: if not self.wait_for_connection: raise try: warning = Exception('[waiting for connection] %s' % e) warning_screen.throw(warning) except StopIteration: _log.warn(warning) return self.__transport def _upgrade(self): websocket = transports.WebsocketTransport(self.session, self.is_secure, self.base_url, **self.kw); websocket.send_packet(PacketType.PING, "", "probe"); for packet in websocket.recv_packet(): _log.debug("[websocket] Packet: %s" % str(packet)); (code, packet_id, path, data, p) = packet; if code == PacketType.PONG: packet = p; _log.debug("[PONG] %s" % repr(packet)); self.heartbeat_terminator.set(); # Technically we would need to pause the current # transport (which should be polling in this # implementation), but since we haven't actually # started a polling yet, we can upgrade without that. _log.debug("[upgrading] Sending upgrade request"); websocket.send_packet(PacketType.UPGRADE); self._start_heartbeat(websocket); return websocket; def _start_heartbeat(self, transport): _log.debug("[start heartbeat pacemaker]"); self.heartbeat_terminator = multiprocessing.Event(); self.heartbeat_thread = multiprocessing.Process( target = _make_heartbeat_pacemaker, args = (self.heartbeat_terminator, transport, self.session.heartbeat_interval / 2)); self.heartbeat_thread.start(); def _get_transport(self): self.session = _get_socketIO_session(self.is_secure, self.base_url, **self.kw); # Negotiate initial transport transport = transports.XHR_PollingTransport(self.session, self.is_secure, self.base_url, **self.kw); # Update namespaces for path, namespace in self._namespace_by_path.items(): namespace._transport = transport transport.connect(path) transport.set_timeout(self.session.connection_timeout); # Start the heartbeat pacemaker (PING). self._start_heartbeat(transport); # If websocket is available, upgrade to it immediately. # TODO(sean): We could run this on a separate thread for # maximum efficiency although that would require some # synchronization to ensure buffers are flushed, etc. if "websocket" in self.session.server_supported_transports: try: return self._upgrade(); except: pass; return transport def get_namespace(self, path=''): try: return self._namespace_by_path[path] except KeyError: raise PacketError('unexpected namespace path (%s)' % path) def _get_delegate(self, code): try: return { '0': self._on_disconnect, '1': self._on_connect, '2': self._on_heartbeat, '3': self._on_message, '4': self._on_json, '5': self._on_event, '6': self._on_ack, '7': self._on_error, '8': self._on_noop, }[code] except KeyError: raise PacketError('unexpected code (%s)' % code) def _on_disconnect(self, packet, find_event_callback): find_event_callback('disconnect')() def _on_connect(self, packet, find_event_callback): find_event_callback('connect')() def _on_heartbeat(self, packet, find_event_callback): find_event_callback('heartbeat')() def _on_message(self, packet, find_event_callback): code, packet_id, path, data = packet args = [data] if packet_id: args.append(self._prepare_to_send_ack(path, packet_id)) find_event_callback('message')(*args) def _on_json(self, packet, find_event_callback): code, packet_id, path, data = packet args = [json.loads(data)] if packet_id: args.append(self._prepare_to_send_ack(path, packet_id)) find_event_callback('message')(*args) def _on_event(self, packet, find_event_callback): code, packet_id, path, data, p = packet packet = p; # Accoding to the documentation # (https://github.com/automattic/socket.io-protocol#event), # the event name is the first entry in the message array, and # the arguments are the rest of the entries. event = packet.payload.message[0]; args = packet.payload.message[1:] if len(packet.payload.message) > 1 else []; _log.debug("[event] %s (%s)" % (repr(event), repr(args))); if packet_id: args.append(self._prepare_to_send_ack(path, packet_id)) find_event_callback(event)(*args) def _on_ack(self, packet, find_event_callback): code, packet_id, path, data = packet data_parts = data.split('+', 1) packet_id = data_parts[0] try: ack_callback = self._transport.get_ack_callback(packet_id) except KeyError: return args = json.loads(data_parts[1]) if len(data_parts) > 1 else [] ack_callback(*args) def _on_error(self, packet, find_event_callback): code, packet_id, path, data = packet reason, advice = data.split('+', 1) find_event_callback('error')(reason, advice) def _on_noop(self, packet, find_event_callback): find_event_callback('noop')() def _prepare_to_send_ack(self, path, packet_id): 'Return function that acknowledges the server' return lambda *args: self._transport.ack(path, packet_id, *args) def find_callback(args, kw=None): 'Return callback whether passed as a last argument or as a keyword' if args and callable(args[-1]): return args[-1], args[:-1] try: return kw['callback'], args except (KeyError, TypeError): return None, args def _parse_host(host, port): if not host.startswith('http'): host = 'http://' + host url_pack = parse_url(host) is_secure = url_pack.scheme == 'https' port = port or url_pack.port or (443 if is_secure else 80) base_url = '%s:%d%s/socket.io' % (url_pack.hostname, port, url_pack.path) return is_secure, base_url def _yield_warning_screen(seconds=None): last_warning = None for elapsed_time in _yield_elapsed_time(seconds): try: yield elapsed_time except Exception as warning: warning = str(warning) if last_warning != warning: last_warning = warning _log.warn(warning) time.sleep(RETRY_INTERVAL_IN_SECONDS) def _yield_elapsed_time(seconds=None): start_time = time.time() if seconds is None: while True: yield time.time() - start_time while time.time() - start_time < seconds: yield time.time() - start_time def _get_socketIO_session(is_secure, base_url, **kw): server_url = '%s://%s/?EIO=%d&transport=polling' \ % ('https' if is_secure else 'http', base_url, parser.ENGINE_PROTOCOL) _log.debug('[session] %s', server_url) try: response = _get_response(requests.get, server_url, **kw) except TimeoutError as e: raise ConnectionError(e) _log.debug("[response] %s", response.text); for packet in parser.decode_response(response): _log.debug("[decoded] %s", str(packet)); if packet.type is not parser.PacketType.OPEN: _log.warn("Got unexpected packet during connection handshake: %d" % packet.type); return None; handshake = json.loads(packet.payload); return _SocketIOSession( id = handshake["sid"], heartbeat_interval = int(handshake["pingInterval"]) / 1000, connection_timeout = int(handshake["pingTimeout"]) / 1000, server_supported_transports = handshake["upgrades"]); def _make_heartbeat_pacemaker(terminator, transport, heartbeat_interval): while True: if terminator.wait(heartbeat_interval): break; _log.debug("[hearbeat]"); try: transport.send_heartbeat(); except: pass; _log.debug("[heartbeat terminated]");