import logging import json import requests import time from collections import namedtuple from urlparse import urlparse from .exceptions import ConnectionError, TimeoutError, PacketError from .transports import _get_response, _negotiate_transport, TRANSPORTS _SocketIOSession = namedtuple('_SocketIOSession', [ 'id', 'heartbeat_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) self._transport.emit(self.path, event, args, callback) 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, transports=TRANSPORTS, **kw): self.is_secure, self.base_url = _parse_host(host, port) self.wait_for_connection = wait_for_connection self._namespace_by_path = {} self.client_supported_transports = transports self.kw = kw self.define(Namespace) def __enter__(self): return self def __exit__(self, *exception_pack): self.disconnect() def __del__(self): self.disconnect() 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 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. """ try: 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 self.heartbeat_pacemaker.send(elapsed_time) except ConnectionError as e: try: warning = Exception('[connection error] %s' % e) warning_screen.throw(warning) except StopIteration: _log.warn(warning) self.disconnect() except KeyboardInterrupt: pass 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 = packet namespace = self.get_namespace(path) delegate = self._get_delegate(code) 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 _get_transport(self): socketIO_session = _get_socketIO_session( self.is_secure, self.base_url, **self.kw) _log.debug('[transports available] %s', ' '.join( socketIO_session.server_supported_transports)) # Initialize heartbeat_pacemaker self.heartbeat_pacemaker = self._make_heartbeat_pacemaker( heartbeat_interval=socketIO_session.heartbeat_timeout / 2) self.heartbeat_pacemaker.next() # Negotiate transport transport = _negotiate_transport( self.client_supported_transports, socketIO_session, self.is_secure, self.base_url, **self.kw) # Update namespaces for namespace in self._namespace_by_path.values(): namespace._transport = transport return transport def _make_heartbeat_pacemaker(self, heartbeat_interval): heartbeat_time = 0 while True: elapsed_time = (yield) if elapsed_time - heartbeat_time > heartbeat_interval: heartbeat_time = elapsed_time self._transport.send_heartbeat() 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 = packet value_by_name = json.loads(data) event = value_by_name['name'] args = value_by_name.get('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 = urlparse(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/%s' % ( url_pack.hostname, port, url_pack.path, PROTOCOL_VERSION) 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/' % ('https' if is_secure else 'http', base_url) try: response = _get_response(requests.get, server_url, **kw) except TimeoutError as e: raise ConnectionError(e) response_parts = response.text.split(':') return _SocketIOSession( id=response_parts[0], heartbeat_timeout=int(response_parts[1]), server_supported_transports=response_parts[3].split(','))