Initial snapshot.

LICENSE

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api.py

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+# Copyright 2014, Ian Gulliver
+#
+# 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 webapp2
+
+from google.appengine.api import channel
+from google.appengine.ext import db
+
+from cosmopolite.lib import auth
+from cosmopolite.lib import models
+from cosmopolite.lib import security
+from cosmopolite.lib import session
+from cosmopolite.lib import utils
+
+import config
+
+
+class GetUser(webapp2.RequestHandler):
+  @utils.chaos_monkey
+  @utils.returns_json
+  @utils.local_namespace
+  @security.google_user_xsrf_protection
+  @security.weak_security_checks
+  @session.session_required
+  def post(self):
+    ret = {}
+    if self.verified_google_user:
+      ret['google_user'] = self.verified_google_user.email()
+    return ret
+
+
+class SetValue(webapp2.RequestHandler):
+  @utils.chaos_monkey
+  @utils.returns_json
+  @utils.local_namespace
+  @security.google_user_xsrf_protection
+  @security.weak_security_checks
+  @session.session_required
+  @db.transactional()
+  def post(self):
+    entry_key = self.request.get('key')
+    entry_value = self.request.get('value')
+
+    entries = (models.StateEntry.all()
+               .ancestor(self.client.parent_key())
+               .filter('entry_key =', entry_key)
+               .fetch(1))
+    if entries:
+      entry = entries[0]
+      entry.entry_value = entry_value
+    else:
+      entry = models.StateEntry(
+          parent=self.client.parent_key(),
+          entry_key=entry_key,
+          entry_value=entry_value)
+
+    entry.put()
+    clients = (models.Client.all(keys_only=True)
+               .ancestor(self.client.parent_key()))
+    for client in clients:
+      entry.SendToClient(client)
+
+    return {}
+
+
+class GetValue(webapp2.RequestHandler):
+  @utils.chaos_monkey
+  @utils.returns_json
+  @utils.local_namespace
+  @security.google_user_xsrf_protection
+  @security.weak_security_checks
+  @session.session_required
+  @db.transactional()
+  def post(self):
+    entry_key = self.request.get('key')
+
+    entries = (models.StateEntry.all()
+               .ancestor(self.client.parent_key())
+               .filter('entry_key =', entry_key)
+               .fetch(1))
+    if entries:
+      return {
+          'value': entries[0].entry_value
+      }
+
+    return {}
+
+
+class CreateChannel(webapp2.RequestHandler):
+  @utils.chaos_monkey
+  @utils.returns_json
+  @utils.local_namespace
+  @security.google_user_xsrf_protection
+  @security.weak_security_checks
+  @session.session_required
+  def post(self):
+    token = channel.create_channel(
+        client_id=str(self.client.key()),
+        duration_minutes=config.CHANNEL_DURATION_SECONDS / 60)
+    entries = (models.StateEntry.all()
+               .ancestor(self.client.parent_key()))
+    for entry in entries:
+      entry.SendToClient(self.client.key())
+    return {
+      'token': token,
+    }
+
+
+app = webapp2.WSGIApplication([
+  (config.URL_PREFIX + '/api/createChannel', CreateChannel),
+  (config.URL_PREFIX + '/api/getUser', GetUser),
+  (config.URL_PREFIX + '/api/getValue', GetValue),
+  (config.URL_PREFIX + '/api/setValue', SetValue),
+])

auth.py

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+# Copyright 2014, Ian Gulliver
+#
+# 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 webapp2
+
+from google.appengine.api import users
+
+from cosmopolite.lib import security
+
+import config
+
+
+class Login(webapp2.RequestHandler):
+  @security.weak_security_checks
+  def get(self):
+    self.redirect(users.create_login_url(
+        dest_url=config.URL_PREFIX + '/static/login_complete.html'))
+
+
+class Logout(webapp2.RequestHandler):
+  @security.weak_security_checks
+  def get(self):
+    self.redirect(users.create_logout_url(
+        dest_url=config.URL_PREFIX + '/static/logout_complete.html'))
+
+
+app = webapp2.WSGIApplication([
+  (config.URL_PREFIX + '/auth/login', Login),
+  (config.URL_PREFIX + '/auth/logout', Logout),
+])

channel.py

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+# Copyright 2014, Ian Gulliver
+#
+# 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 webapp2
+
+from google.appengine.ext import db
+
+from cosmopolite.lib import auth
+from cosmopolite.lib import models
+from cosmopolite.lib import utils
+
+
+class OnChannelConnect(webapp2.RequestHandler):
+  @utils.local_namespace
+  @db.transactional()
+  def post(self):
+    client = models.Client.get(self.request.get('from'))
+    client.channel_active = True
+    client.put()
+
+class OnChannelDisconnect(webapp2.RequestHandler):
+  @utils.local_namespace
+  @db.transactional()
+  def post(self):
+    client = models.Client.get(self.request.get('from'))
+    client.channel_active = False
+    client.put()
+
+
+app = webapp2.WSGIApplication([
+  ('/_ah/channel/connected/', OnChannelConnect),
+  ('/_ah/channel/disconnected/', OnChannelDisconnect),
+])

config.py

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+# Co-existence
+URL_PREFIX = '/cosmopolite'
+NAMESPACE = 'cosmopolite'
+
+# Timings
+CHANNEL_DURATION_SECONDS = 60 * 60 * 2  # 2 hours
+
+# Probabilities
+CHAOS_PROBABILITY = 0.50

include.yaml

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+handlers:
+- url: /cosmopolite/api/.*
+  script: cosmopolite.api.app
+  secure: always
+
+- url: /cosmopolite/auth/.*
+  script: cosmopolite.auth.app
+  secure: always
+
+- url: /_ah/channel/.*
+  script: cosmopolite.channel.app
+
+- url: /cosmopolite/static
+  static_dir: cosmopolite/static
+  secure: always
+  http_headers:
+    X-Frame-Options: DENY
+    X-Content-Type-Options: nosniff
+    Strict-Transport-Security: max-age=31536000; includeSubDomains

lib/auth.py

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+# Copyright 2014, Ian Gulliver
+#
+# 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 hashlib
+import hmac
+import random
+import string
+
+from google.appengine.api import memcache
+from google.appengine.ext import db
+
+
+class BadSignature(Exception):
+  pass
+
+
+class AuthKey(db.Model):
+  auth_key = db.ByteStringProperty(required=True)
+  live = db.BooleanProperty(required=True, default=True)
+
+
+_KEY_CHARS = string.ascii_letters + string.digits
+_KEY_LENGTH = 64
+
+def GetAuthKey():
+  auth_key = memcache.get('auth_key')
+  if auth_key:
+    return auth_key
+
+  for key in AuthKey.all().filter('live =', True):
+    auth_key = key.auth_key
+
+  if not auth_key:
+    auth_key = ''.join(random.choice(_KEY_CHARS) for _ in xrange(_KEY_LENGTH))
+    AuthKey(auth_key=auth_key).put()
+
+  memcache.set('auth_key', auth_key)
+  return auth_key
+
+
+def Sign(value):
+  sig = hmac.new(GetAuthKey(), str(value), hashlib.sha512) 
+  return '%s:%s' % (value, sig.hexdigest())
+
+
+def Parse(token):
+  if not token:
+    return None
+  value, sig_digest = token.split(':', 1)
+  if token != Sign(value):
+    raise BadSignature
+  return value
+
+
+def ParseKey(token):
+  if not token:
+    return None
+  return db.Key(encoded=Parse(token))

lib/models.py

@@ -0,0 +1,111 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014, Ian Gulliver
+#
+# 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 json
+import logging
+
+from google.appengine.api import channel
+from google.appengine.ext import db
+
+
+# Profile
+# ↳ Client
+# ↳ StateEntry
+#
+# Subject
+# ↳ Subscription (⤴︎ Client)
+
+
+class Profile(db.Model):
+  google_user = db.UserProperty()
+
+  @classmethod
+  def FromGoogleUser(cls, google_user):
+    if not google_user:
+      profile = Profile()
+      profile.put()
+      return profile
+
+    profiles = Profile.all().filter('google_user =', google_user).fetch(1)
+    if profiles:
+      return profiles[0]
+    else:
+      # TODO(flamingcow): Fetch-then-store uniqueness is a race.
+      profile = Profile(google_user=google_user)
+      profile.put()
+      return profile
+
+  @db.transactional(xg=True)
+  def MergeFrom(self, source_profile):
+    # Merge from another profile into this one, using last_set time as the
+    # arbiter.
+    my_states = {}
+    for state_entry in (StateEntry.all()
+                        .ancestor(self)
+                        .run()):
+      my_states[state_entry.entry_key] = state_entry
+
+    for state_entry in (StateEntry.all()
+                        .ancestor(source_profile)
+                        .run()):
+      my_state_entry = my_states.get(state_entry.entry_key, None)
+      if my_state_entry:
+        if state_entry.last_set > my_state_entry.last_set:
+          # newer, merge in
+          my_state_entry.entry_value = state_entry.entry_value
+          my_state_entry.put()
+      else:
+        # entirely new, add
+        StateEntry(parent=self,
+            entry_key=state_entry.entry_key,
+            entry_value=state_entry.entry_value
+            ).put()
+
+
+class Client(db.Model):
+  first_seen = db.DateTimeProperty(required=True, auto_now_add=True)
+  channel_active = db.BooleanProperty(required=True, default=False)
+
+  @classmethod
+  def FromProfile(cls, profile):
+    client = cls(parent=profile)
+    client.put()
+    return client
+
+  @classmethod
+  def FromGoogleUser(cls, google_user):
+    profile = Profile.FromGoogleUser(google_user)
+    return cls.FromProfile(profile)
+
+
+class StateEntry(db.Model):
+  last_set = db.DateTimeProperty(required=True, auto_now=True)
+  entry_key = db.StringProperty(required=True)
+  entry_value = db.StringProperty(required=True)
+
+  def SendToClient(self, client_id):
+    channel.send_message(str(client_id), json.dumps({
+        'message_type': 'state',
+        'key': self.entry_key,
+        'value': self.entry_value,
+    }))
+
+
+class Subject(db.Model):
+  name = db.StringProperty(required=True)
+
+
+class Subscription(db.Model):
+  client = db.ReferenceProperty(reference_class=Client)

lib/security.py

@@ -0,0 +1,70 @@
+# Copyright 2014, Ian Gulliver
+#
+# 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 functools
+
+from google.appengine.api import users
+
+from cosmopolite.lib import auth
+
+
+def google_user_xsrf_protection(handler):
+  """Validate google user cookie.
+
+  We can't trust that the action being requested is being made by this user due
+  to XSRF concerns (since google user is stored in a cookie). We have to make
+  sure that this user can actually receive responses, so we ask them to pass a
+  second token about their user that we can validate.
+  """
+
+  @functools.wraps(handler)
+  def ValidateGoogleUser(self):
+    self.verified_google_user = None
+
+    google_user = users.get_current_user()
+    if not google_user:
+      return handler(self)
+
+    google_user_id = auth.Parse(self.request.get('google_user_id', None))
+    if (not google_user_id or 
+        google_user_id != google_user.user_id()):
+      return {
+        'status': 'retry',
+        'google_user_id': auth.Sign(google_user.user_id()),
+      }
+
+    self.verified_google_user = google_user
+    return handler(self)
+
+  return ValidateGoogleUser
+
+
+def weak_security_checks(handler):
+
+  @functools.wraps(handler)
+  def CheckOriginHeader(self):
+    origin = self.request.headers.get('Origin')
+    if origin:
+      host = self.request.headers.get('Host')
+      possible_origins = {
+        'http://%s' % host,
+        'https://%s' % host,
+      }
+      if origin not in possible_origins:
+        self.error(403)
+        self.response.out.write('Origin/Host header mismatch')
+        return
+    return handler(self)
+
+  return CheckOriginHeader

lib/session.py

@@ -0,0 +1,88 @@
+# Copyright 2014, Ian Gulliver
+#
+# 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 functools
+
+from google.appengine.api import users
+
+from cosmopolite.lib import auth
+from cosmopolite.lib import models
+
+
+def _CheckClientAndGoogleUser(client, google_user):
+  if not google_user:
+    # Nothing to check. If there's a user on the profile, it can stay there.
+    return client
+
+  client_profile_google_user = client.parent().google_user
+  if client_profile_google_user:
+    if client_profile_google_user == google_user:
+      return client
+    else:
+      # Shared computer? Google account wins.
+      return models.Client.FromGoogleUser(google_user)
+
+  # User just signed in. Their anonymous profile gets permanently
+  # associated with this Google account.
+  profiles = (models.Profile.all()
+              .filter('google_user =', google_user)
+              .fetch(1))
+  if profiles:
+    # We can't convert the anonymous profile because there's already
+    # a profile for this Google user. Create a new client_id pointing to that
+    # profile.
+    # TODO(flamingcow): Fetch-then-store uniqueness is a race.
+    google_profile = profiles[0]
+    google_profile.MergeFrom(client.parent_key())
+    return models.Client.FromProfile(google_profile)
+
+  # First time signin.
+  client_profile = client.parent()
+  client_profile.google_user = google_user
+  client_profile.put()
+  return client
+
+
+def session_required(handler):
+  """Find or create a session for this user.
+
+  Find or create a Client and Profile for this user. Muck with the return value
+  to wrap it in an object that contains session info for the client.
+
+  Make sure to wrap this in google_user_xsrf_protection.
+  """
+
+  @functools.wraps(handler)
+  def FindOrCreateSession(self):
+    client_key = auth.ParseKey(self.request.get('client_id', None))
+
+    # The hunt for a Profile begins.
+    if client_key:
+      self.client = _CheckClientAndGoogleUser(
+          models.Client.get(client_key),
+          self.verified_google_user)
+    else:
+      self.client = models.Client.FromGoogleUser(self.verified_google_user)
+
+    ret = {
+        'status': 'ok',
+        'response': handler(self),
+    }
+    if client_key != self.client.key():
+      # Tell the client that this changed
+      ret['client_id'] = auth.Sign(self.client.key())
+
+    return ret
+
+  return FindOrCreateSession

lib/utils.py

@@ -0,0 +1,56 @@
+# Copyright 2014, Ian Gulliver
+#
+# 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 functools
+import json
+import random
+
+from google.appengine.api import namespace_manager
+
+from cosmopolite import config
+
+from cosmopolite.lib import auth
+
+
+def returns_json(handler):
+
+  @functools.wraps(handler)
+  def SerializeResult(self):
+    json.dump(handler(self), self.response.out)
+
+  return SerializeResult
+
+
+def chaos_monkey(handler):
+
+  @functools.wraps(handler)
+  def IntroduceFailures(self):
+    if random.random() < config.CHAOS_PROBABILITY:
+      self.response.headers['Retry-After'] = '0'
+      self.error(503)
+      return
+    return handler(self)
+
+  return IntroduceFailures
+
+
+def local_namespace(handler):
+
+  @functools.wraps(handler)
+  def SetNamespace(self):
+    import logging
+    namespace_manager.set_namespace(config.NAMESPACE)
+    return handler(self)
+
+  return SetNamespace

static/cosmopolite.js

@@ -0,0 +1,211 @@
+/*
+Copyright 2014, Ian Gulliver
+
+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.
+*/
+
+var cosmopolite = {};
+
+cosmopolite.Client = function(opt_callbacks, opt_urlPrefix, opt_namespace) {
+  this.callbacks_ = opt_callbacks || {};
+  this.urlPrefix_ = opt_urlPrefix || '/cosmopolite';
+  this.namespace_ = opt_namespace || 'cosmopolite';
+
+  this.stateCache_ = {};
+
+  var scripts = [
+    'https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js',
+    '/_ah/channel/jsapi',
+  ];
+  this.numScriptsToLoad_ = scripts.length;
+  for (var i = 0; i < scripts.length; i++) {
+    var script = document.createElement('script');
+    script.src = scripts[i];
+    script.onload = this.onLoad_.bind(this);
+    document.body.appendChild(script);
+  }
+};
+
+cosmopolite.Client.prototype.onLoad_ = function() {
+  if (--this.numScriptsToLoad_ > 0) {
+    return;
+  }
+  this.$ = jQuery.noConflict(true);
+  this.registerMessageHandlers_();
+  this.getUser_();
+  this.createChannel_();
+};
+
+// Message from another browser window
+cosmopolite.Client.prototype.onReceiveMessage_ = function(data) {
+  switch (data) {
+    case 'login_complete':
+      this.getUser_();
+      break;
+    case 'logout_complete':
+      localStorage.removeItem(this.namespace_ + ':client_id');
+      localStorage.removeItem(this.namespace_ + ':google_user_id');
+      this.$('#google_user').empty();
+      this.getUser_();
+      break;
+    default:
+      console.log('Unknown message type');
+      break;
+  }
+};
+
+cosmopolite.Client.prototype.registerMessageHandlers_ = function() {
+  this.$(window).on('message', this.$.proxy(function(e) {
+    if (e.originalEvent.origin != window.location.origin) {
+      console.log(
+        'Received message from bad origin: ' + e.originalEvent.origin);
+      return;
+    }
+    console.log('Received message: ' + e.originalEvent.data);
+    this.onReceiveMessage_(e.originalEvent.data);
+  }, this));
+};
+
+cosmopolite.Client.prototype.sendRPC_ = function(command, data, onSuccess, delay) {
+  if (this.namespace_ + ':client_id' in localStorage) {
+    data['client_id'] = localStorage[this.namespace_ + ':client_id'];
+  }
+  if (this.namespace_ + ':google_user_id' in localStorage) {
+    data['google_user_id'] = localStorage[this.namespace_ + ':google_user_id'];
+  }
+  this.$.ajax({
+    url: this.urlPrefix_ + '/api/' + command,
+    type: 'post',
+    data: data,
+    dataType: 'json',
+    context: this,
+  })
+    .done(function(data, stat, xhr) {
+      if ('google_user_id' in data) {
+        localStorage[this.namespace_ + ':google_user_id'] =
+          data['google_user_id'];
+      }
+      if ('client_id' in data) {
+        localStorage[this.namespace_ + ':client_id'] = data['client_id'];
+      }
+      if (data['status'] == 'retry') {
+        // Discard delay
+        this.sendRPC_(command, data, onSuccess);
+        return;
+      }
+      if (data['status'] != 'ok') {
+        console.log(
+            'Server returned unknown status (' + data['status'] + ') for RPC '
+            + command);
+        // TODO(flamingcow): Refresh the page? Show an alert?
+        return;
+      }
+      if (onSuccess) {
+      	this.$.proxy(onSuccess, this)(data.response);
+      }
+    })
+    .fail(function(xhr) {
+      var intDelay =
+        xhr.getResponseHeader('Retry-After') ||
+        Math.min(32, Math.max(2, delay || 2));
+      console.log(
+        'RPC ' + command + ' failed. Will retry in ' + intDelay + ' seconds');
+      function retry() {
+        this.sendRPC_(command, data, onSuccess, Math.pow(intDelay, 2));
+      }
+      window.setTimeout(this.$.proxy(retry, this), intDelay * 1000);
+    });
+};
+
+cosmopolite.Client.prototype.getUser_ = function() {
+  this.sendRPC_('getUser', {}, function(data) {
+    if ('google_user' in data) {
+      if ('onLogin' in this.callbacks_) {
+        this.callbacks_['onLogin'](
+          data['google_user'],
+	  this.urlPrefix_ + '/auth/logout');
+      }
+    } else {
+      if ('onLogout' in this.callbacks_) {
+        this.callbacks_['onLogout'](
+          this.urlPrefix_ + '/auth/login');
+      }
+    }
+  });
+};
+
+cosmopolite.Client.prototype.setValue = function(key, value) {
+  this.sendRPC_('setValue', {
+    'key': key,
+    'value': value,
+  })
+};
+
+cosmopolite.Client.prototype.getValue = function(key) {
+  return this.stateCache_[key];
+};
+
+cosmopolite.Client.prototype.createChannel_ = function() {
+  this.sendRPC_('createChannel', {}, this.onCreateChannel_);
+};
+
+cosmopolite.Client.prototype.onCreateChannel_ = function(data) {
+  var channel = new goog.appengine.Channel(data['token']);
+  console.log('Opening channel...');
+  this.socket = channel.open({
+    onopen: this.$.proxy(this.onSocketOpen_, this),
+    onclose: this.$.proxy(this.onSocketClose_, this),
+    onmessage: this.$.proxy(this.onSocketMessage_, this),
+    onerror: this.$.proxy(this.onSocketError_, this),
+  });
+};
+
+cosmopolite.Client.prototype.onSocketOpen_ = function() {
+  console.log('Channel opened');
+};
+
+cosmopolite.Client.prototype.onSocketClose_ = function() {
+  if (!this.socket) {
+    return;
+  }
+  console.log('Channel closed');
+  this.socket = null;
+  this.createChannel_();
+};
+
+cosmopolite.Client.prototype.onSocketMessage_ = function(msg) {
+  console.log('message: ' + msg.data);
+  var parsed = JSON.parse(msg.data);
+  switch (parsed.message_type) {
+    case 'state':
+      var key = parsed['key'];
+      var value = parsed['value'];
+      if (this.stateCache_[key] == value) {
+        // Duplicate message.
+        break;
+      }
+      this.stateCache_[key] = value;
+      if ('onStateChange' in this.callbacks_) {
+        this.callbacks_['onStateChange'](key, value);
+      }
+      break;
+    default:
+      console.log('Unknown message type: ' + parsed.message_type);
+      break;
+  }
+}
+
+cosmopolite.Client.prototype.onSocketError_ = function(msg) {
+  console.log('Socket error: ' + msg);
+  this.socket.close();
+};

static/debug.html

@@ -0,0 +1,79 @@
+<html>
+  <head>
+    <script type="text/javascript" src="/cosmopolite/static/cosmopolite.js" charset="UTF-8"></script>
+    <style>
+a {
+  text-decoration: none;
+}
+    </style>
+  </head>
+  <body>
+    <div>Google user: <span id="google_user"></span></div>
+
+    <div>
+      Key:
+      <select id="keys">
+        <option></option>
+        <option>(add new)</option>
+      </select>
+      <input type="button" id="set" value="Set">
+      <br />
+      <textarea id="value" rows="10" cols="40"></textarea>
+    </div>
+    <script>
+window.addEventListener('load', function() {
+  var googleUser = document.getElementById('google_user');
+  var keys = document.getElementById('keys');
+
+  var callbacks = {
+    onLogin: function(username, logout_url) {
+      googleUser.innerHTML =
+        username +
+        ' <a href="' + logout_url + '" target="_blank">(log out)</a>';
+    },
+    onLogout: function(login_url) {
+      googleUser.innerHTML =
+        '<a href="' + login_url + '" target="_blank">(log in)</a>';
+    },
+    onStateChange: function(key, value) {
+      for (var i = 0; i < keys.options.length; ++i) {
+        if (keys.options[i].value == key) {
+          break;
+        };
+        if (keys.options[i].value > key) {
+          var option = document.createElement('option');
+          option.text = key;
+          keys.options.add(option, i);
+          break;
+        };
+      };
+      if (i == keys.options.length) {
+        var option = document.createElement('option');
+        option.text = key;
+        keys.options.add(option);
+      }
+    },
+  };
+
+  var debug = new cosmopolite.Client(callbacks);
+
+  document.getElementById('set').addEventListener('click', function() {
+    debug.setValue(
+      document.getElementById('keys').value,
+      document.getElementById('value').value);
+  });
+
+  document.getElementById('keys').addEventListener('change', function() {
+    if (this.value == '(add new)') {
+      var new_key = prompt('New key name:');
+      callbacks['onStateChange'](new_key, '');
+      this.value = new_key;
+      return;
+    }
+    var value = document.getElementById('value');
+    value.value = debug.getValue(this.value);
+  });
+});
+    </script>
+  </body>
+</html>

static/login_complete.html

@@ -0,0 +1,8 @@
+<html>
+  <head>
+    <script type="text/javascript">
+      window.opener.postMessage('login_complete', window.location.origin);
+      window.close();
+    </script>
+  </head>
+</html>

static/logout_complete.html

@@ -0,0 +1,8 @@
+<html>
+  <head>
+    <script type="text/javascript">
+      window.opener.postMessage('logout_complete', window.location.origin);
+      window.close();
+    </script>
+  </head>
+</html>