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Your IP : 216.73.216.191
import base64
import gzip
import importlib
import io
import logging
import secrets
import zlib
from . import packet
from . import payload
default_logger = logging.getLogger('engineio.server')
class BaseServer:
compression_methods = ['gzip', 'deflate']
event_names = ['connect', 'disconnect', 'message']
valid_transports = ['polling', 'websocket']
_default_monitor_clients = True
sequence_number = 0
def __init__(self, async_mode=None, ping_interval=25, ping_timeout=20,
max_http_buffer_size=1000000, allow_upgrades=True,
http_compression=True, compression_threshold=1024,
cookie=None, cors_allowed_origins=None,
cors_credentials=True, logger=False, json=None,
async_handlers=True, monitor_clients=None, transports=None,
**kwargs):
self.ping_timeout = ping_timeout
if isinstance(ping_interval, tuple):
self.ping_interval = ping_interval[0]
self.ping_interval_grace_period = ping_interval[1]
else:
self.ping_interval = ping_interval
self.ping_interval_grace_period = 0
self.max_http_buffer_size = max_http_buffer_size
self.allow_upgrades = allow_upgrades
self.http_compression = http_compression
self.compression_threshold = compression_threshold
self.cookie = cookie
self.cors_allowed_origins = cors_allowed_origins
self.cors_credentials = cors_credentials
self.async_handlers = async_handlers
self.sockets = {}
self.handlers = {}
self.log_message_keys = set()
self.start_service_task = monitor_clients \
if monitor_clients is not None else self._default_monitor_clients
self.service_task_handle = None
self.service_task_event = None
if json is not None:
packet.Packet.json = json
if not isinstance(logger, bool):
self.logger = logger
else:
self.logger = default_logger
if self.logger.level == logging.NOTSET:
if logger:
self.logger.setLevel(logging.INFO)
else:
self.logger.setLevel(logging.ERROR)
self.logger.addHandler(logging.StreamHandler())
modes = self.async_modes()
if async_mode is not None:
modes = [async_mode] if async_mode in modes else []
self._async = None
self.async_mode = None
for mode in modes:
try:
self._async = importlib.import_module(
'engineio.async_drivers.' + mode)._async
asyncio_based = self._async['asyncio'] \
if 'asyncio' in self._async else False
if asyncio_based != self.is_asyncio_based():
continue # pragma: no cover
self.async_mode = mode
break
except ImportError:
pass
if self.async_mode is None:
raise ValueError('Invalid async_mode specified')
if self.is_asyncio_based() and \
('asyncio' not in self._async or not
self._async['asyncio']): # pragma: no cover
raise ValueError('The selected async_mode is not asyncio '
'compatible')
if not self.is_asyncio_based() and 'asyncio' in self._async and \
self._async['asyncio']: # pragma: no cover
raise ValueError('The selected async_mode requires asyncio and '
'must use the AsyncServer class')
if transports is not None:
if isinstance(transports, str):
transports = [transports]
transports = [transport for transport in transports
if transport in self.valid_transports]
if not transports:
raise ValueError('No valid transports provided')
self.transports = transports or self.valid_transports
self.logger.info('Server initialized for %s.', self.async_mode)
def is_asyncio_based(self):
return False
def async_modes(self):
return ['eventlet', 'gevent_uwsgi', 'gevent', 'threading']
def on(self, event, handler=None):
"""Register an event handler.
:param event: The event name. Can be ``'connect'``, ``'message'`` or
``'disconnect'``.
:param handler: The function that should be invoked to handle the
event. When this parameter is not given, the method
acts as a decorator for the handler function.
Example usage::
# as a decorator:
@eio.on('connect')
def connect_handler(sid, environ):
print('Connection request')
if environ['REMOTE_ADDR'] in blacklisted:
return False # reject
# as a method:
def message_handler(sid, msg):
print('Received message: ', msg)
eio.send(sid, 'response')
eio.on('message', message_handler)
The handler function receives the ``sid`` (session ID) for the
client as first argument. The ``'connect'`` event handler receives the
WSGI environment as a second argument, and can return ``False`` to
reject the connection. The ``'message'`` handler receives the message
payload as a second argument. The ``'disconnect'`` handler does not
take a second argument.
"""
if event not in self.event_names:
raise ValueError('Invalid event')
def set_handler(handler):
self.handlers[event] = handler
return handler
if handler is None:
return set_handler
set_handler(handler)
def transport(self, sid):
"""Return the name of the transport used by the client.
The two possible values returned by this function are ``'polling'``
and ``'websocket'``.
:param sid: The session of the client.
"""
return 'websocket' if self._get_socket(sid).upgraded else 'polling'
def create_queue(self, *args, **kwargs):
"""Create a queue object using the appropriate async model.
This is a utility function that applications can use to create a queue
without having to worry about using the correct call for the selected
async mode.
"""
return self._async['queue'](*args, **kwargs)
def get_queue_empty_exception(self):
"""Return the queue empty exception for the appropriate async model.
This is a utility function that applications can use to work with a
queue without having to worry about using the correct call for the
selected async mode.
"""
return self._async['queue_empty']
def create_event(self, *args, **kwargs):
"""Create an event object using the appropriate async model.
This is a utility function that applications can use to create an
event without having to worry about using the correct call for the
selected async mode.
"""
return self._async['event'](*args, **kwargs)
def generate_id(self):
"""Generate a unique session id."""
id = base64.b64encode(
secrets.token_bytes(12) + self.sequence_number.to_bytes(3, 'big'))
self.sequence_number = (self.sequence_number + 1) & 0xffffff
return id.decode('utf-8').replace('/', '_').replace('+', '-')
def _generate_sid_cookie(self, sid, attributes):
"""Generate the sid cookie."""
cookie = attributes.get('name', 'io') + '=' + sid
for attribute, value in attributes.items():
if attribute == 'name':
continue
if callable(value):
value = value()
if value is True:
cookie += '; ' + attribute
else:
cookie += '; ' + attribute + '=' + value
return cookie
def _upgrades(self, sid, transport):
"""Return the list of possible upgrades for a client connection."""
if not self.allow_upgrades or self._get_socket(sid).upgraded or \
transport == 'websocket':
return []
if self._async['websocket'] is None: # pragma: no cover
self._log_error_once(
'The WebSocket transport is not available, you must install a '
'WebSocket server that is compatible with your async mode to '
'enable it. See the documentation for details.',
'no-websocket')
return []
return ['websocket']
def _get_socket(self, sid):
"""Return the socket object for a given session."""
try:
s = self.sockets[sid]
except KeyError:
raise KeyError('Session not found')
if s.closed:
del self.sockets[sid]
raise KeyError('Session is disconnected')
return s
def _ok(self, packets=None, headers=None, jsonp_index=None):
"""Generate a successful HTTP response."""
if packets is not None:
if headers is None:
headers = []
headers += [('Content-Type', 'text/plain; charset=UTF-8')]
return {'status': '200 OK',
'headers': headers,
'response': payload.Payload(packets=packets).encode(
jsonp_index=jsonp_index).encode('utf-8')}
else:
return {'status': '200 OK',
'headers': [('Content-Type', 'text/plain')],
'response': b'OK'}
def _bad_request(self, message=None):
"""Generate a bad request HTTP error response."""
if message is None:
message = 'Bad Request'
message = packet.Packet.json.dumps(message)
return {'status': '400 BAD REQUEST',
'headers': [('Content-Type', 'text/plain')],
'response': message.encode('utf-8')}
def _method_not_found(self):
"""Generate a method not found HTTP error response."""
return {'status': '405 METHOD NOT FOUND',
'headers': [('Content-Type', 'text/plain')],
'response': b'Method Not Found'}
def _unauthorized(self, message=None):
"""Generate a unauthorized HTTP error response."""
if message is None:
message = 'Unauthorized'
message = packet.Packet.json.dumps(message)
return {'status': '401 UNAUTHORIZED',
'headers': [('Content-Type', 'application/json')],
'response': message.encode('utf-8')}
def _cors_allowed_origins(self, environ):
default_origins = []
if 'wsgi.url_scheme' in environ and 'HTTP_HOST' in environ:
default_origins.append('{scheme}://{host}'.format(
scheme=environ['wsgi.url_scheme'], host=environ['HTTP_HOST']))
if 'HTTP_X_FORWARDED_PROTO' in environ or \
'HTTP_X_FORWARDED_HOST' in environ:
scheme = environ.get(
'HTTP_X_FORWARDED_PROTO',
environ['wsgi.url_scheme']).split(',')[0].strip()
default_origins.append('{scheme}://{host}'.format(
scheme=scheme, host=environ.get(
'HTTP_X_FORWARDED_HOST', environ['HTTP_HOST']).split(
',')[0].strip()))
if self.cors_allowed_origins is None:
allowed_origins = default_origins
elif self.cors_allowed_origins == '*':
allowed_origins = None
elif isinstance(self.cors_allowed_origins, str):
allowed_origins = [self.cors_allowed_origins]
elif callable(self.cors_allowed_origins):
origin = environ.get('HTTP_ORIGIN')
allowed_origins = [origin] \
if self.cors_allowed_origins(origin) else []
else:
allowed_origins = self.cors_allowed_origins
return allowed_origins
def _cors_headers(self, environ):
"""Return the cross-origin-resource-sharing headers."""
if self.cors_allowed_origins == []:
# special case, CORS handling is completely disabled
return []
headers = []
allowed_origins = self._cors_allowed_origins(environ)
if 'HTTP_ORIGIN' in environ and \
(allowed_origins is None or environ['HTTP_ORIGIN'] in
allowed_origins):
headers = [('Access-Control-Allow-Origin', environ['HTTP_ORIGIN'])]
if environ['REQUEST_METHOD'] == 'OPTIONS':
headers += [('Access-Control-Allow-Methods', 'OPTIONS, GET, POST')]
if 'HTTP_ACCESS_CONTROL_REQUEST_HEADERS' in environ:
headers += [('Access-Control-Allow-Headers',
environ['HTTP_ACCESS_CONTROL_REQUEST_HEADERS'])]
if self.cors_credentials:
headers += [('Access-Control-Allow-Credentials', 'true')]
return headers
def _gzip(self, response):
"""Apply gzip compression to a response."""
bytesio = io.BytesIO()
with gzip.GzipFile(fileobj=bytesio, mode='w') as gz:
gz.write(response)
return bytesio.getvalue()
def _deflate(self, response):
"""Apply deflate compression to a response."""
return zlib.compress(response)
def _log_error_once(self, message, message_key):
"""Log message with logging.ERROR level the first time, then log
with given level."""
if message_key not in self.log_message_keys:
self.logger.error(message + ' (further occurrences of this error '
'will be logged with level INFO)')
self.log_message_keys.add(message_key)
else:
self.logger.info(message)