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