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#!/usr/bin/env python
#
# Copyright 2009 Facebook
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import tornado.auth
import tornado.escape
import tornado.ioloop
import tornado.web
import os.path
import uuid
from tornado import gen
from tornado.options import define, options, parse_command_line
define("port", default=8888, help="run on the given port", type=int)
class MessageBuffer(object):
def __init__(self):
self.waiters = set()
self.cache = []
self.cache_size = 200
def wait_for_messages(self, callback, cursor=None):
if cursor:
new_count = 0
for msg in reversed(self.cache):
if msg["id"] == cursor:
break
new_count += 1
if new_count:
callback(self.cache[-new_count:])
return
self.waiters.add(callback)
def cancel_wait(self, callback):
self.waiters.remove(callback)
def new_messages(self, messages):
logging.info("Sending new message to %r listeners", len(self.waiters))
for callback in self.waiters:
try:
callback(messages)
except:
logging.error("Error in waiter callback", exc_info=True)
self.waiters = set()
self.cache.extend(messages)
if len(self.cache) > self.cache_size:
self.cache = self.cache[-self.cache_size:]
# Making this a non-singleton is left as an exercise for the reader.
global_message_buffer = MessageBuffer()
class BaseHandler(tornado.web.RequestHandler):
def get_current_user(self):
user_json = self.get_secure_cookie("chatdemo_user")
if not user_json: return None
return tornado.escape.json_decode(user_json)
class MainHandler(BaseHandler):
@tornado.web.authenticated
def get(self):
self.render("index.html", messages=global_message_buffer.cache)
class MessageNewHandler(BaseHandler):
@tornado.web.authenticated
def post(self):
message = {
"id": str(uuid.uuid4()),
"from": self.current_user["first_name"],
"body": self.get_argument("body"),
}
# to_basestring is necessary for Python 3's json encoder,
# which doesn't accept byte strings.
message["html"] = tornado.escape.to_basestring(
self.render_string("message.html", message=message))
if self.get_argument("next", None):
self.redirect(self.get_argument("next"))
else:
self.write(message)
global_message_buffer.new_messages([message])
class MessageUpdatesHandler(BaseHandler):
@tornado.web.authenticated
@tornado.web.asynchronous
def post(self):
cursor = self.get_argument("cursor", None)
global_message_buffer.wait_for_messages(self.on_new_messages,
cursor=cursor)
def on_new_messages(self, messages):
# Closed client connection
if self.request.connection.stream.closed():
return
self.finish(dict(messages=messages))
def on_connection_close(self):
global_message_buffer.cancel_wait(self.on_new_messages)
class AuthLoginHandler(BaseHandler, tornado.auth.GoogleMixin):
@gen.coroutine
def get(self):
if self.get_argument("openid.mode", None):
user = yield self.get_authenticated_user()
self.set_secure_cookie("chatdemo_user",
tornado.escape.json_encode(user))
self.redirect("/")
return
self.authenticate_redirect(ax_attrs=["name"])
class AuthLogoutHandler(BaseHandler):
def get(self):
self.clear_cookie("chatdemo_user")
self.write("You are now logged out")
def main():
parse_command_line()
app = tornado.web.Application(
[
(r"/", MainHandler),
(r"/auth/login", AuthLoginHandler),
(r"/auth/logout", AuthLogoutHandler),
(r"/a/message/new", MessageNewHandler),
(r"/a/message/updates", MessageUpdatesHandler),
],
cookie_secret="__TODO:_GENERATE_YOUR_OWN_RANDOM_VALUE_HERE__",
login_url="/auth/login",
template_path=os.path.join(os.path.dirname(__file__), "templates"),
static_path=os.path.join(os.path.dirname(__file__), "static"),
xsrf_cookies=True,
)
app.listen(options.port)
tornado.ioloop.IOLoop.instance().start()
if __name__ == "__main__":
main()
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