/
polling.py
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/
polling.py
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# -*- coding: utf-8 -*-
"""
tornadio.polling
~~~~~~~~~~~~~~~~
This module implements socket.io polling transports.
:copyright: (c) 2011 by the Serge S. Koval, see AUTHORS for more details.
:license: Apache, see LICENSE for more details.
"""
import time
try:
import simplejson as json
except ImportError:
import json
from urllib import unquote
from tornado.web import RequestHandler, HTTPError, asynchronous
from tornadio import pollingsession
class TornadioPollingHandlerBase(RequestHandler):
"""All polling transport implementations derive from this class.
Polling transports have following things in common:
1. They use GET to read data from the server
2. They use POST to send data to the server
3. They use sessions - first message sent back from the server is session_id
4. Session is used to create one virtual connection for one or more HTTP
connections
5. If GET request is not running, data will be cached on server side. On
next GET request, all cached data will be sent to the client in one batch
6. If there were no GET requests for more than 15 seconds (default), virtual
connection will be closed - session entry will expire
"""
def __init__(self, router, session_id):
"""Default constructor.
Accepts router instance and session_id (if available) and handles
request.
"""
self.router = router
self.session_id = session_id
self.session = None
super(TornadioPollingHandlerBase, self).__init__(router.application,
router.request)
def _execute(self, transforms, *args, **kwargs):
# Initialize session either by creating new one or
# getting it from container
if not self.session_id:
session_expiry = self.router.settings['session_expiry']
self.session = self.router.sessions.create(
pollingsession.PollingSession,
session_expiry,
router=self.router,
args=args,
kwargs=kwargs)
else:
self.session = self.router.sessions.get(self.session_id)
if self.session is None or self.session.is_closed:
# TODO: Send back disconnect message?
raise HTTPError(401, 'Invalid session')
super(TornadioPollingHandlerBase, self)._execute(transforms,
*args, **kwargs)
@asynchronous
def get(self, *args, **kwargs):
"""Default GET handler."""
raise NotImplementedError()
@asynchronous
def post(self, *args, **kwargs):
"""Default POST handler."""
raise NotImplementedError()
def data_available(self, raw_data):
"""Called by the session when some data is available"""
raise NotImplementedError()
@asynchronous
def options(self, *args, **kwargs):
"""XHR cross-domain OPTIONS handler"""
self.preflight()
self.finish()
def preflight(self):
"""Handles request authentication"""
if self.request.headers.has_key('Origin'):
if self.verify_origin():
self.set_header('Access-Control-Allow-Origin',
self.request.headers['Origin'])
self.set_header('Access-Control-Allow-Credentials', 'true')
return True
else:
return False
else:
return True
def verify_origin(self):
"""Verify if request can be served"""
# TODO: Verify origin
return True
class TornadioXHRPollingSocketHandler(TornadioPollingHandlerBase):
"""XHR polling transport implementation.
Polling mechanism uses long-polling AJAX GET to read data from the server
and POST to send data to the server.
Properties of the XHR polling transport:
1. If there was no data for more than 20 seconds (by default) from the
server, GET connection will be closed to avoid HTTP timeouts. In this case
socket.io client-side will just make another GET request.
2. When new data is available on server-side, it will be sent through the
open GET connection or cached otherwise.
"""
def __init__(self, router, session_id):
self._timeout = None
self._timeout_interval = router.settings['xhr_polling_timeout']
super(TornadioXHRPollingSocketHandler, self).__init__(router,
session_id)
@asynchronous
def get(self, *args, **kwargs):
if not self.session.set_handler(self):
# Check to avoid double connections
# TODO: Error logging
raise HTTPError(401, 'Forbidden')
if not self.session.send_queue:
self._timeout = self.router.io_loop.add_timeout(
time.time() + self._timeout_interval,
self._polling_timeout)
else:
self.session.flush()
def _polling_timeout(self):
# TODO: Fix me
if self.session:
self.data_available('')
@asynchronous
def post(self, *args, **kwargs):
if not self.preflight():
raise HTTPError(401, 'unauthorized')
# Special case for IE XDomainRequest
ctype = self.request.headers.get("Content-Type", "").split(";")[0]
if ctype == '':
data = None
body = self.request.body
if body.startswith('data='):
data = unquote(body[5:])
else:
data = self.get_argument('data', None)
self.async_callback(self.session.raw_message)(data)
self.set_header('Content-Type', 'text/plain; charset=UTF-8')
self.write('ok')
self.finish()
def _detach(self):
if self.session:
self.session.remove_handler(self)
self.session = None
def on_connection_close(self):
self._detach()
def data_available(self, raw_data):
self.preflight()
self.set_header('Content-Type', 'text/plain; charset=UTF-8')
self.set_header('Content-Length', len(raw_data))
self.write(raw_data)
self.finish()
# Detach connection
self._detach()
class TornadioXHRMultipartSocketHandler(TornadioPollingHandlerBase):
"""XHR Multipart transport implementation.
Transport properties:
1. One persistent GET connection used to receive data from the server
2. Sends heartbeat messages to keep connection alive each 12 seconds
(by default)
"""
@asynchronous
def get(self, *args, **kwargs):
if not self.session.set_handler(self):
# TODO: Error logging
raise HTTPError(401, 'Forbidden')
self.set_header('Content-Type',
'multipart/x-mixed-replace;boundary="socketio; charset=UTF-8"')
self.set_header('Connection', 'keep-alive')
self.write('--socketio\n')
# Dump any queued messages
self.session.flush()
# We need heartbeats
self.session.reset_heartbeat()
@asynchronous
def post(self, *args, **kwargs):
if not self.preflight():
raise HTTPError(401, 'unauthorized')
data = self.get_argument('data')
self.async_callback(self.session.raw_message)(data)
self.set_header('Content-Type', 'text/plain; charset=UTF-8')
self.write('ok')
self.finish()
def on_connection_close(self):
if self.session:
self.session.stop_heartbeat()
self.session.remove_handler(self)
def data_available(self, raw_data):
self.preflight()
self.write("Content-Type: text/plain; charset=UTF-8\n\n")
self.write(raw_data + '\n')
self.write('--socketio\n')
self.flush()
self.session.delay_heartbeat()
class TornadioHtmlFileSocketHandler(TornadioPollingHandlerBase):
"""IE HtmlFile protocol implementation.
Uses hidden frame to stream data from the server in one connection.
Unfortunately, it is unknown if this transport works, as socket.io
client-side fails in IE7/8.
"""
@asynchronous
def get(self, *args, **kwargs):
if not self.session.set_handler(self):
raise HTTPError(401, 'Forbidden')
self.set_header('Content-Type', 'text/html; charset=UTF-8')
self.set_header('Connection', 'keep-alive')
self.set_header('Transfer-Encoding', 'chunked')
self.write('<html><body>%s' % (' ' * 244))
# Dump any queued messages
self.session.flush()
# We need heartbeats
self.session.reset_heartbeat()
@asynchronous
def post(self, *args, **kwargs):
if not self.preflight():
raise HTTPError(401, 'unauthorized')
data = self.get_argument('data')
self.async_callback(self.session.raw_message)(data)
self.set_header('Content-Type', 'text/plain; charset=UTF-8')
self.write('ok')
self.finish()
def on_connection_close(self):
if self.session:
self.session.stop_heartbeat()
self.session.remove_handler(self)
def data_available(self, raw_data):
self.write(
'<script>parent.s_(%s),document);</script>' % json.dumps(raw_data)
)
self.flush()
self.session.delay_heartbeat()
class TornadioJSONPSocketHandler(TornadioXHRPollingSocketHandler):
"""JSONP protocol implementation.
"""
def __init__(self, router, session_id):
self._index = None
super(TornadioJSONPSocketHandler, self).__init__(router, session_id)
@asynchronous
def get(self, *args, **kwargs):
self._index = kwargs.get('jsonp_index', None)
super(TornadioJSONPSocketHandler, self).get(*args, **kwargs)
@asynchronous
def post(self, *args, **kwargs):
self._index = kwargs.get('jsonp_index', None)
super(TornadioJSONPSocketHandler, self).post(*args, **kwargs)
def data_available(self, raw_data):
if not self._index:
raise HTTPError(401, 'unauthorized')
message = 'io.JSONP[%s]._(%s);' % (
self._index,
json.dumps(raw_data)
)
self.preflight()
self.set_header("Content-Type", "text/javascript; charset=UTF-8")
self.set_header("Content-Length", len(message))
self.write(message)
self.finish()
# Detach connection
self._detach()