diff --git a/apiclient/channel.py b/apiclient/channel.py
new file mode 100644
index 0000000..61a7ec4
--- /dev/null
+++ b/apiclient/channel.py
@@ -0,0 +1,285 @@
+"""Channel notifications support.
+
+Classes and functions to support channel subscriptions and notifications
+on those channels.
+
+Notes:
+  - This code is based on experimental APIs and is subject to change.
+  - Notification does not do deduplication of notification ids, that's up to
+    the receiver.
+  - Storing the Channel between calls is up to the caller.
+
+
+Example setting up a channel:
+
+  # Create a new channel that gets notifications via webhook.
+  channel = new_webhook_channel("https://example.com/my_web_hook")
+
+  # Store the channel, keyed by 'channel.id'. Store it before calling the
+  # watch method because notifications may start arriving before the watch
+  # method returns.
+  ...
+
+  resp = service.objects().watchAll(
+    bucket="some_bucket_id", body=channel.body()).execute()
+  channel.update(resp)
+
+  # Store the channel, keyed by 'channel.id'. Store it after being updated
+  # since the resource_id value will now be correct, and that's needed to
+  # stop a subscription.
+  ...
+
+
+An example Webhook implementation using webapp2. Note that webapp2 puts
+headers in a case insensitive dictionary, as headers aren't guaranteed to
+always be upper case.
+
+  id = self.request.headers[X_GOOG_CHANNEL_ID]
+
+  # Retrieve the channel by id.
+  channel = ...
+
+  # Parse notification from the headers, including validating the id.
+  n = notification_from_headers(channel, self.request.headers)
+
+  # Do app specific stuff with the notification here.
+  if n.resource_state == 'sync':
+    # Code to handle sync state.
+  elif n.resource_state == 'exists':
+    # Code to handle the exists state.
+  elif n.resource_state == 'not_exists':
+    # Code to handle the not exists state.
+
+
+Example of unsubscribing.
+
+  service.channels().stop(channel.body())
+"""
+
+import datetime
+import uuid
+
+from apiclient import errors
+from oauth2client import util
+
+
+# The unix time epoch starts at midnight 1970.
+EPOCH = datetime.datetime.utcfromtimestamp(0)
+
+# Map the names of the parameters in the JSON channel description to
+# the parameter names we use in the Channel class.
+CHANNEL_PARAMS = {
+    'address': 'address',
+    'id': 'id',
+    'expiration': 'expiration',
+    'params': 'params',
+    'resourceId': 'resource_id',
+    'resourceUri': 'resource_uri',
+    'type': 'type',
+    'token': 'token',
+    }
+
+X_GOOG_CHANNEL_ID     = 'X-GOOG-CHANNEL-ID'
+X_GOOG_MESSAGE_NUMBER = 'X-GOOG-MESSAGE-NUMBER'
+X_GOOG_RESOURCE_STATE = 'X-GOOG-RESOURCE-STATE'
+X_GOOG_RESOURCE_URI   = 'X-GOOG-RESOURCE-URI'
+X_GOOG_RESOURCE_ID    = 'X-GOOG-RESOURCE-ID'
+
+
+def _upper_header_keys(headers):
+  new_headers = {}
+  for k, v in headers.iteritems():
+    new_headers[k.upper()] = v
+  return new_headers
+
+
+class Notification(object):
+  """A Notification from a Channel.
+
+  Notifications are not usually constructed directly, but are returned
+  from functions like notification_from_headers().
+
+  Attributes:
+    message_number: int, The unique id number of this notification.
+    state: str, The state of the resource being monitored.
+    uri: str, The address of the resource being monitored.
+    resource_id: str, The unique identifier of the version of the resource at
+      this event.
+  """
+  @util.positional(5)
+  def __init__(self, message_number, state, resource_uri, resource_id):
+    """Notification constructor.
+
+    Args:
+      message_number: int, The unique id number of this notification.
+      state: str, The state of the resource being monitored. Can be one
+        of "exists", "not_exists", or "sync".
+      resource_uri: str, The address of the resource being monitored.
+      resource_id: str, The identifier of the watched resource.
+    """
+    self.message_number = message_number
+    self.state = state
+    self.resource_uri = resource_uri
+    self.resource_id = resource_id
+
+
+class Channel(object):
+  """A Channel for notifications.
+
+  Usually not constructed directly, instead it is returned from helper
+  functions like new_webhook_channel().
+
+  Attributes:
+    type: str, The type of delivery mechanism used by this channel. For
+      example, 'web_hook'.
+    id: str, A UUID for the channel.
+    token: str, An arbitrary string associated with the channel that
+      is delivered to the target address with each event delivered
+      over this channel.
+    address: str, The address of the receiving entity where events are
+      delivered. Specific to the channel type.
+    expiration: int, The time, in milliseconds from the epoch, when this
+      channel will expire.
+    params: dict, A dictionary of string to string, with additional parameters
+      controlling delivery channel behavior.
+    resource_id: str, An opaque id that identifies the resource that is
+      being watched. Stable across different API versions.
+    resource_uri: str, The canonicalized ID of the watched resource.
+  """
+
+  @util.positional(5)
+  def __init__(self, type, id, token, address, expiration=None,
+               params=None, resource_id="", resource_uri=""):
+    """Create a new Channel.
+
+    In user code, this Channel constructor will not typically be called
+    manually since there are functions for creating channels for each specific
+    type with a more customized set of arguments to pass.
+
+    Args:
+      type: str, The type of delivery mechanism used by this channel. For
+        example, 'web_hook'.
+      id: str, A UUID for the channel.
+      token: str, An arbitrary string associated with the channel that
+        is delivered to the target address with each event delivered
+        over this channel.
+      address: str,  The address of the receiving entity where events are
+        delivered. Specific to the channel type.
+      expiration: int, The time, in milliseconds from the epoch, when this
+        channel will expire.
+      params: dict, A dictionary of string to string, with additional parameters
+        controlling delivery channel behavior.
+      resource_id: str, An opaque id that identifies the resource that is
+        being watched. Stable across different API versions.
+      resource_uri: str, The canonicalized ID of the watched resource.
+    """
+    self.type = type
+    self.id = id
+    self.token = token
+    self.address = address
+    self.expiration = expiration
+    self.params = params
+    self.resource_id = resource_id
+    self.resource_uri = resource_uri
+
+  def body(self):
+    """Build a body from the Channel.
+
+    Constructs a dictionary that's appropriate for passing into watch()
+    methods as the value of body argument.
+
+    Returns:
+      A dictionary representation of the channel.
+    """
+    result = {
+        'id': self.id,
+        'token': self.token,
+        'type': self.type,
+        'address': self.address
+        }
+    if self.params:
+      result['params'] = self.params
+    if self.resource_id:
+      result['resourceId'] = self.resource_id
+    if self.resource_uri:
+      result['resourceUri'] = self.resource_uri
+    if self.expiration:
+      result['expiration'] = self.expiration
+
+    return result
+
+  def update(self, resp):
+    """Update a channel with information from the response of watch().
+
+    When a request is sent to watch() a resource, the response returned
+    from the watch() request is a dictionary with updated channel information,
+    such as the resource_id, which is needed when stopping a subscription.
+
+    Args:
+      resp: dict, The response from a watch() method.
+    """
+    for json_name, param_name in CHANNEL_PARAMS.iteritems():
+      value = resp.get(json_name)
+      if value is not None:
+        setattr(self, param_name, value)
+
+
+def notification_from_headers(channel, headers):
+  """Parse a notification from the webhook request headers, validate
+    the notification, and return a Notification object.
+
+  Args:
+    channel: Channel, The channel that the notification is associated with.
+    headers: dict, A dictionary like object that contains the request headers
+      from the webhook HTTP request.
+
+  Returns:
+    A Notification object.
+
+  Raises:
+    errors.InvalidNotificationError if the notification is invalid.
+    ValueError if the X-GOOG-MESSAGE-NUMBER can't be converted to an int.
+  """
+  headers = _upper_header_keys(headers)
+  channel_id = headers[X_GOOG_CHANNEL_ID]
+  if channel.id != channel_id:
+    raise errors.InvalidNotificationError(
+        'Channel id mismatch: %s != %s' % (channel.id, channel_id))
+  else:
+    message_number = int(headers[X_GOOG_MESSAGE_NUMBER])
+    state = headers[X_GOOG_RESOURCE_STATE]
+    resource_uri = headers[X_GOOG_RESOURCE_URI]
+    resource_id = headers[X_GOOG_RESOURCE_ID]
+    return Notification(message_number, state, resource_uri, resource_id)
+
+
+@util.positional(2)
+def new_webhook_channel(url, token=None, expiration=None, params=None):
+    """Create a new webhook Channel.
+
+    Args:
+      url: str, URL to post notifications to.
+      token: str, An arbitrary string associated with the channel that
+        is delivered to the target address with each notification delivered
+        over this channel.
+      expiration: datetime.datetime, A time in the future when the channel
+        should expire. Can also be None if the subscription should use the
+        default expiration. Note that different services may have different
+        limits on how long a subscription lasts. Check the response from the
+        watch() method to see the value the service has set for an expiration
+        time.
+      params: dict, Extra parameters to pass on channel creation. Currently
+        not used for webhook channels.
+    """
+    expiration_ms = 0
+    if expiration:
+      delta = expiration - EPOCH
+      expiration_ms = delta.microseconds/1000 + (
+          delta.seconds + delta.days*24*3600)*1000
+      if expiration_ms < 0:
+        expiration_ms = 0
+
+    return Channel('web_hook', str(uuid.uuid4()),
+                   token, url, expiration=expiration_ms,
+                   params=params)
+
diff --git a/apiclient/errors.py b/apiclient/errors.py
index 2bf9149..ef2b161 100644
--- a/apiclient/errors.py
+++ b/apiclient/errors.py
@@ -102,6 +102,9 @@
   """The given chunksize is not valid."""
   pass
 
+class InvalidNotificationError(Error):
+  """The channel Notification is invalid."""
+  pass
 
 class BatchError(HttpError):
   """Error occured during batch operations."""
diff --git a/apiclient/push.py b/apiclient/push.py
deleted file mode 100644
index c520faf..0000000
--- a/apiclient/push.py
+++ /dev/null
@@ -1,274 +0,0 @@
-# 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.
-
-"""Push notifications support.
-
-This code is based on experimental APIs and is subject to change.
-"""
-
-__author__ = 'afshar@google.com (Ali Afshar)'
-
-import binascii
-import collections
-import os
-import urllib
-
-SUBSCRIBE = 'X-GOOG-SUBSCRIBE'
-SUBSCRIPTION_ID = 'X-GOOG-SUBSCRIPTION-ID'
-TOPIC_ID = 'X-GOOG-TOPIC-ID'
-TOPIC_URI = 'X-GOOG-TOPIC-URI'
-CLIENT_TOKEN = 'X-GOOG-CLIENT-TOKEN'
-EVENT_TYPE = 'X-GOOG-EVENT-TYPE'
-UNSUBSCRIBE = 'X-GOOG-UNSUBSCRIBE'
-
-
-class InvalidSubscriptionRequestError(ValueError):
-  """The request cannot be subscribed."""
-
-
-def new_token():
-  """Gets a random token for use as a client_token in push notifications.
-
-  Returns:
-    str, a new random token.
-  """
-  return binascii.hexlify(os.urandom(32))
-
-
-class Channel(object):
-  """Base class for channel types."""
-
-  def __init__(self, channel_type, channel_args):
-    """Create a new Channel.
-
-    You probably won't need to create this channel manually, since there are
-    subclassed Channel for each specific type with a more customized set of
-    arguments to pass. However, you may wish to just create it manually here.
-
-    Args:
-      channel_type: str, the type of channel.
-      channel_args: dict, arguments to pass to the channel.
-    """
-    self.channel_type = channel_type
-    self.channel_args = channel_args
-
-  def as_header_value(self):
-    """Create the appropriate header for this channel.
-
-    Returns:
-      str encoded channel description suitable for use as a header.
-    """
-    return '%s?%s' % (self.channel_type, urllib.urlencode(self.channel_args))
-
-  def write_header(self, headers):
-    """Write the appropriate subscribe header to a headers dict.
-
-    Args:
-      headers: dict, headers to add subscribe header to.
-    """
-    headers[SUBSCRIBE] = self.as_header_value()
-
-
-class WebhookChannel(Channel):
-  """Channel for registering web hook notifications."""
-
-  def __init__(self, url, app_engine=False):
-    """Create a new WebhookChannel
-
-    Args:
-      url: str, URL to post notifications to.
-      app_engine: bool, default=False, whether the destination for the
-      notifications is an App Engine application.
-    """
-    super(WebhookChannel, self).__init__(
-        channel_type='web_hook',
-        channel_args={
-            'url': url,
-            'app_engine': app_engine and 'true' or 'false',
-        }
-    )
-
-
-class Headers(collections.defaultdict):
-  """Headers for managing subscriptions."""
-
-
-  ALL_HEADERS = set([SUBSCRIBE, SUBSCRIPTION_ID, TOPIC_ID, TOPIC_URI,
-                     CLIENT_TOKEN, EVENT_TYPE, UNSUBSCRIBE])
-
-  def __init__(self):
-    """Create a new subscription configuration instance."""
-    collections.defaultdict.__init__(self, str)
-
-  def __setitem__(self, key, value):
-    """Set a header value, ensuring the key is an allowed value.
-
-    Args:
-      key: str, the header key.
-      value: str, the header value.
-    Raises:
-      ValueError if key is not one of the accepted headers.
-    """
-    normal_key = self._normalize_key(key)
-    if normal_key not in self.ALL_HEADERS:
-      raise ValueError('Header name must be one of %s.' % self.ALL_HEADERS)
-    else:
-      return collections.defaultdict.__setitem__(self, normal_key, value)
-
-  def __getitem__(self, key):
-    """Get a header value, normalizing the key case.
-
-    Args:
-      key: str, the header key.
-    Returns:
-      String header value.
-    Raises:
-      KeyError if the key is not one of the accepted headers.
-    """
-    normal_key = self._normalize_key(key)
-    if normal_key not in self.ALL_HEADERS:
-      raise ValueError('Header name must be one of %s.' % self.ALL_HEADERS)
-    else:
-      return collections.defaultdict.__getitem__(self, normal_key)
-
-  def _normalize_key(self, key):
-    """Normalize a header name for use as a key."""
-    return key.upper()
-
-  def items(self):
-    """Generator for each header."""
-    for header in self.ALL_HEADERS:
-      value = self[header]
-      if value:
-        yield header, value
-
-  def write(self, headers):
-    """Applies the subscription headers.
-
-    Args:
-      headers: dict of headers to insert values into.
-    """
-    for header, value in self.items():
-      headers[header.lower()] = value
-
-  def read(self, headers):
-    """Read from headers.
-
-    Args:
-      headers: dict of headers to read from.
-    """
-    for header in self.ALL_HEADERS:
-      if header.lower() in headers:
-        self[header] = headers[header.lower()]
-
-
-class Subscription(object):
-  """Information about a subscription."""
-
-  def __init__(self):
-    """Create a new Subscription."""
-    self.headers = Headers()
-
-  @classmethod
-  def for_request(cls, request, channel, client_token=None):
-    """Creates a subscription and attaches it to a request.
-
-    Args:
-      request: An http.HttpRequest to modify for making a subscription.
-      channel: A apiclient.push.Channel describing the subscription to
-               create.
-      client_token: (optional) client token to verify the notification.
-
-    Returns:
-      New subscription object.
-    """
-    subscription = cls.for_channel(channel=channel, client_token=client_token)
-    subscription.headers.write(request.headers)
-    if request.method != 'GET':
-      raise InvalidSubscriptionRequestError(
-          'Can only subscribe to requests which are GET.')
-    request.method = 'POST'
-
-    def _on_response(response, subscription=subscription):
-      """Called with the response headers. Reads the subscription headers."""
-      subscription.headers.read(response)
-
-    request.add_response_callback(_on_response)
-    return subscription
-
-  @classmethod
-  def for_channel(cls, channel, client_token=None):
-    """Alternate constructor to create a subscription from a channel.
-
-    Args:
-      channel: A apiclient.push.Channel describing the subscription to
-               create.
-      client_token: (optional) client token to verify the notification.
-
-    Returns:
-      New subscription object.
-    """
-    subscription = cls()
-    channel.write_header(subscription.headers)
-    if client_token is None:
-      client_token = new_token()
-    subscription.headers[SUBSCRIPTION_ID] = new_token()
-    subscription.headers[CLIENT_TOKEN] = client_token
-    return subscription
-
-  def verify(self, headers):
-    """Verifies that a webhook notification has the correct client_token.
-
-    Args:
-      headers: dict of request headers for a push notification.
-
-    Returns:
-      Boolean value indicating whether the notification is verified.
-    """
-    new_subscription = Subscription()
-    new_subscription.headers.read(headers)
-    return new_subscription.client_token == self.client_token
-
-  @property
-  def subscribe(self):
-    """Subscribe header value."""
-    return self.headers[SUBSCRIBE]
-
-  @property
-  def subscription_id(self):
-    """Subscription ID header value."""
-    return self.headers[SUBSCRIPTION_ID]
-
-  @property
-  def topic_id(self):
-    """Topic ID header value."""
-    return self.headers[TOPIC_ID]
-
-  @property
-  def topic_uri(self):
-    """Topic URI header value."""
-    return self.headers[TOPIC_URI]
-
-  @property
-  def client_token(self):
-    """Client Token header value."""
-    return self.headers[CLIENT_TOKEN]
-
-  @property
-  def event_type(self):
-    """Event Type header value."""
-    return self.headers[EVENT_TYPE]
-
-  @property
-  def unsubscribe(self):
-    """Unsuscribe header value."""
-    return self.headers[UNSUBSCRIBE]
diff --git a/tests/test_channel.py b/tests/test_channel.py
new file mode 100644
index 0000000..f6a6d55
--- /dev/null
+++ b/tests/test_channel.py
@@ -0,0 +1,124 @@
+"""Notification channels tests."""
+
+__author__ = 'jcgregorio@google.com (Joe Gregorio)'
+
+import unittest
+import datetime
+
+from apiclient import channel
+from apiclient import errors
+
+
+class TestChannel(unittest.TestCase):
+  def test_basic(self):
+    ch = channel.Channel('web_hook', 'myid', 'mytoken',
+                         'http://example.org/callback',
+                         expiration=0,
+                         params={'extra': 'info'},
+                         resource_id='the_resource_id',
+                         resource_uri='http://example.com/resource_1')
+
+    # Converting to a body.
+    body = ch.body()
+    self.assertEqual('http://example.org/callback', body['address'])
+    self.assertEqual('myid', body['id'])
+    self.assertEqual('missing', body.get('expiration', 'missing'))
+    self.assertEqual('info', body['params']['extra'])
+    self.assertEqual('the_resource_id', body['resourceId'])
+    self.assertEqual('http://example.com/resource_1', body['resourceUri'])
+    self.assertEqual('web_hook', body['type'])
+
+    # Converting to a body with expiration set.
+    ch.expiration = 1
+    body = ch.body()
+    self.assertEqual(1, body.get('expiration', 'missing'))
+
+    # Converting to a body after updating with a response body.
+    ch.update({
+        'resourceId': 'updated_res_id',
+        'resourceUri': 'updated_res_uri',
+        'some_random_parameter': 2,
+        })
+
+    body = ch.body()
+    self.assertEqual('http://example.org/callback', body['address'])
+    self.assertEqual('myid', body['id'])
+    self.assertEqual(1, body.get('expiration', 'missing'))
+    self.assertEqual('info', body['params']['extra'])
+    self.assertEqual('updated_res_id', body['resourceId'])
+    self.assertEqual('updated_res_uri', body['resourceUri'])
+    self.assertEqual('web_hook', body['type'])
+
+  def test_new_webhook_channel(self):
+    ch = channel.new_webhook_channel('http://example.com/callback')
+    self.assertEqual(0, ch.expiration)
+    self.assertEqual('http://example.com/callback', ch.address)
+    self.assertEqual(None, ch.params)
+
+    # New channel with an obviously wrong expiration time.
+    ch = channel.new_webhook_channel(
+        'http://example.com/callback',
+        expiration=datetime.datetime(1965, 1, 1))
+    self.assertEqual(0, ch.expiration)
+
+    # New channel with an expiration time.
+    ch = channel.new_webhook_channel(
+        'http://example.com/callback',
+        expiration=datetime.datetime(1970, 1, 1, second=5))
+    self.assertEqual(5000, ch.expiration)
+    self.assertEqual('http://example.com/callback', ch.address)
+    self.assertEqual(None, ch.params)
+
+    # New channel with an expiration time and params.
+    ch = channel.new_webhook_channel(
+        'http://example.com/callback',
+        expiration=datetime.datetime(1970, 1, 1, second=5, microsecond=1000),
+        params={'some':'stuff'})
+    self.assertEqual(5001, ch.expiration)
+    self.assertEqual('http://example.com/callback', ch.address)
+    self.assertEqual({'some': 'stuff'}, ch.params)
+
+
+class TestNotification(unittest.TestCase):
+  def test_basic(self):
+    n = channel.Notification(12, 'sync', 'http://example.org',
+                     'http://example.org/v1')
+
+    self.assertEqual(12, n.message_number)
+    self.assertEqual('sync', n.state)
+    self.assertEqual('http://example.org', n.resource_uri)
+    self.assertEqual('http://example.org/v1', n.resource_id)
+
+  def test_notification_from_headers(self):
+    headers = {
+        'X-GoOG-CHANNEL-ID': 'myid',
+        'X-Goog-MESSAGE-NUMBER': '1',
+        'X-Goog-rESOURCE-STATE': 'sync',
+        'X-Goog-reSOURCE-URI': 'http://example.com/',
+        'X-Goog-resOURCE-ID': 'http://example.com/resource_1',
+        }
+
+    ch = channel.Channel('web_hook', 'myid', 'mytoken',
+                         'http://example.org/callback',
+                         expiration=0,
+                         params={'extra': 'info'},
+                         resource_id='the_resource_id',
+                         resource_uri='http://example.com/resource_1')
+
+    # Good test case.
+    n = channel.notification_from_headers(ch, headers)
+    self.assertEqual('http://example.com/resource_1', n.resource_id)
+    self.assertEqual('http://example.com/', n.resource_uri)
+    self.assertEqual('sync', n.state)
+    self.assertEqual(1, n.message_number)
+
+    # Detect id mismatch.
+    ch.id = 'different_id'
+    try:
+      n = channel.notification_from_headers(ch, headers)
+      self.fail('Should have raised exception')
+    except errors.InvalidNotificationError:
+      pass
+
+    # Set the id back to a correct value.
+    ch.id = 'myid'
diff --git a/tests/test_push.py b/tests/test_push.py
deleted file mode 100644
index 7c5ce0d..0000000
--- a/tests/test_push.py
+++ /dev/null
@@ -1,277 +0,0 @@
-# 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.
-
-"""Push notifications tests."""
-
-__author__ = 'afshar@google.com (Ali Afshar)'
-
-import unittest
-
-from apiclient import push
-from apiclient import model
-from apiclient import http
-from test_discovery import assertUrisEqual
-
-
-class ClientTokenGeneratorTest(unittest.TestCase):
-
-  def test_next(self):
-    t = push.new_token()
-    self.assertTrue(t)
-
-
-class ChannelTest(unittest.TestCase):
-
-  def test_creation_noargs(self):
-    c = push.Channel(channel_type='my_channel_type', channel_args={})
-    self.assertEqual('my_channel_type', c.channel_type)
-    self.assertEqual({}, c.channel_args)
-
-  def test_creation_args(self):
-    c = push.Channel(channel_type='my_channel_type',
-                         channel_args={'a': 'b'})
-    self.assertEqual('my_channel_type', c.channel_type)
-    self.assertEqual({'a':'b'}, c.channel_args)
-
-  def test_as_header_value_noargs(self):
-    c = push.Channel(channel_type='my_channel_type', channel_args={})
-    self.assertEqual('my_channel_type?', c.as_header_value())
-
-  def test_as_header_value_args(self):
-    c = push.Channel(channel_type='my_channel_type',
-                         channel_args={'a': 'b'})
-    self.assertEqual('my_channel_type?a=b', c.as_header_value())
-
-  def test_as_header_value_args_space(self):
-    c = push.Channel(channel_type='my_channel_type',
-                         channel_args={'a': 'b c'})
-    self.assertEqual('my_channel_type?a=b+c', c.as_header_value())
-
-  def test_as_header_value_args_escape(self):
-    c = push.Channel(channel_type='my_channel_type',
-                         channel_args={'a': 'b%c'})
-    self.assertEqual('my_channel_type?a=b%25c', c.as_header_value())
-
-  def test_write_header_noargs(self):
-    c = push.Channel(channel_type='my_channel_type', channel_args={})
-    headers = {}
-    c.write_header(headers)
-    self.assertEqual('my_channel_type?', headers['X-GOOG-SUBSCRIBE'])
-
-  def test_write_header_args(self):
-    c = push.Channel(channel_type='my_channel_type',
-                         channel_args={'a': 'b'})
-    headers = {}
-    c.write_header(headers)
-    self.assertEqual('my_channel_type?a=b', headers['X-GOOG-SUBSCRIBE'])
-
-  def test_write_header_args_space(self):
-    c = push.Channel(channel_type='my_channel_type',
-                         channel_args={'a': 'b c'})
-    headers = {}
-    c.write_header(headers)
-    self.assertEqual('my_channel_type?a=b+c', headers['X-GOOG-SUBSCRIBE'])
-
-  def test_write_header_args_escape(self):
-    c = push.Channel(channel_type='my_channel_type',
-                         channel_args={'a': 'b%c'})
-    headers = {}
-    c.write_header(headers)
-    self.assertEqual('my_channel_type?a=b%25c', headers['X-GOOG-SUBSCRIBE'])
-
-
-class WebhookChannelTest(unittest.TestCase):
-
-  def test_creation_no_appengine(self):
-    c = push.WebhookChannel('http://example.org')
-    assertUrisEqual(self,
-                    'web_hook?url=http%3A%2F%2Fexample.org&app_engine=false',
-                    c.as_header_value())
-
-  def test_creation_appengine(self):
-    c = push.WebhookChannel('http://example.org', app_engine=True)
-    assertUrisEqual(self,
-                    'web_hook?url=http%3A%2F%2Fexample.org&app_engine=true',
-                    c.as_header_value())
-
-
-class HeadersTest(unittest.TestCase):
-
-  def test_creation(self):
-    h = push.Headers()
-    self.assertEqual('', h[push.SUBSCRIBE])
-
-  def test_items(self):
-    h = push.Headers()
-    h[push.SUBSCRIBE] = 'my_channel_type'
-    self.assertEqual([(push.SUBSCRIBE, 'my_channel_type')], list(h.items()))
-
-  def test_items_non_whitelisted(self):
-    h = push.Headers()
-    def set_bad_header(h=h):
-      h['X-Banana'] = 'my_channel_type'
-    self.assertRaises(ValueError, set_bad_header)
-
-  def test_read(self):
-    h = push.Headers()
-    h.read({'x-goog-subscribe': 'my_channel_type'})
-    self.assertEqual([(push.SUBSCRIBE, 'my_channel_type')], list(h.items()))
-
-  def test_read_non_whitelisted(self):
-    h = push.Headers()
-    h.read({'X-Banana': 'my_channel_type'})
-    self.assertEqual([], list(h.items()))
-
-  def test_write(self):
-    h = push.Headers()
-    h[push.SUBSCRIBE] = 'my_channel_type'
-    headers = {}
-    h.write(headers)
-    self.assertEqual({'x-goog-subscribe': 'my_channel_type'}, headers)
-
-
-class SubscriptionTest(unittest.TestCase):
-
-  def test_create(self):
-    s = push.Subscription()
-    self.assertEqual('', s.client_token)
-
-  def test_create_for_channnel(self):
-    c = push.WebhookChannel('http://example.org')
-    s = push.Subscription.for_channel(c)
-    self.assertTrue(s.client_token)
-    assertUrisEqual(self,
-                    'web_hook?url=http%3A%2F%2Fexample.org&app_engine=false',
-                    s.subscribe)
-
-  def test_create_for_channel_client_token(self):
-    c = push.WebhookChannel('http://example.org')
-    s = push.Subscription.for_channel(c, client_token='my_token')
-    self.assertEqual('my_token', s.client_token)
-    assertUrisEqual(self,
-                    'web_hook?url=http%3A%2F%2Fexample.org&app_engine=false',
-                    s.subscribe)
-
-  def test_subscribe(self):
-    s = push.Subscription()
-    s.headers[push.SUBSCRIBE] = 'my_header'
-    self.assertEqual('my_header', s.subscribe)
-
-  def test_subscription_id(self):
-    s = push.Subscription()
-    s.headers[push.SUBSCRIPTION_ID] = 'my_header'
-    self.assertEqual('my_header', s.subscription_id)
-
-  def test_subscription_id_set(self):
-    c = push.WebhookChannel('http://example.org')
-    s = push.Subscription.for_channel(c)
-    self.assertTrue(s.subscription_id)
-
-  def test_topic_id(self):
-    s = push.Subscription()
-    s.headers[push.TOPIC_ID] = 'my_header'
-    self.assertEqual('my_header', s.topic_id)
-
-  def test_topic_uri(self):
-    s = push.Subscription()
-    s.headers[push.TOPIC_URI] = 'my_header'
-    self.assertEqual('my_header', s.topic_uri)
-
-  def test_client_token(self):
-    s = push.Subscription()
-    s.headers[push.CLIENT_TOKEN] = 'my_header'
-    self.assertEqual('my_header', s.client_token)
-
-  def test_event_type(self):
-    s = push.Subscription()
-    s.headers[push.EVENT_TYPE] = 'my_header'
-    self.assertEqual('my_header', s.event_type)
-
-  def test_unsubscribe(self):
-    s = push.Subscription()
-    s.headers[push.UNSUBSCRIBE] = 'my_header'
-    self.assertEqual('my_header', s.unsubscribe)
-
-  def test_do_subscribe(self):
-    m = model.JsonModel()
-    request = http.HttpRequest(
-        None,
-        m.response,
-        'https://www.googleapis.com/someapi/v1/collection/?foo=bar',
-        method='GET',
-        body='{}',
-        headers={'content-type': 'application/json'})
-    h = http.HttpMockSequence([
-        ({'status': 200,
-          'X-Goog-Subscription-ID': 'my_subscription'},
-          '{}')])
-    c = push.Channel('my_channel', {})
-    s = push.Subscription.for_request(request, c)
-    request.execute(http=h)
-    self.assertEqual('my_subscription', s.subscription_id)
-
-  def test_subscribe_with_token(self):
-    m = model.JsonModel()
-    request = http.HttpRequest(
-        None,
-        m.response,
-        'https://www.googleapis.com/someapi/v1/collection/?foo=bar',
-        method='GET',
-        body='{}',
-        headers={'content-type': 'application/json'})
-    h = http.HttpMockSequence([
-        ({'status': 200,
-          'X-Goog-Subscription-ID': 'my_subscription'},
-          '{}')])
-    c = push.Channel('my_channel', {})
-    s = push.Subscription.for_request(request, c, client_token='my_token')
-    request.execute(http=h)
-    self.assertEqual('my_subscription', s.subscription_id)
-    self.assertEqual('my_token', s.client_token)
-
-  def test_verify_good_token(self):
-    s = push.Subscription()
-    s.headers['X-Goog-Client-Token'] = '123'
-    notification_headers = {'x-goog-client-token': '123'}
-    self.assertTrue(s.verify(notification_headers))
-
-  def test_verify_bad_token(self):
-    s = push.Subscription()
-    s.headers['X-Goog-Client-Token'] = '321'
-    notification_headers = {'x-goog-client-token': '123'}
-    self.assertFalse(s.verify(notification_headers))
-
-  def test_request_is_post(self):
-    m = model.JsonModel()
-    request = http.HttpRequest(
-        None,
-        m.response,
-        'https://www.googleapis.com/someapi/v1/collection/?foo=bar',
-        method='GET',
-        body='{}',
-        headers={'content-type': 'application/json'})
-    c = push.Channel('my_channel', {})
-    push.Subscription.for_request(request, c)
-    self.assertEqual('POST', request.method)
-
-  def test_non_get_error(self):
-    m = model.JsonModel()
-    request = http.HttpRequest(
-        None,
-        m.response,
-        'https://www.googleapis.com/someapi/v1/collection/?foo=bar',
-        method='POST',
-        body='{}',
-        headers={'content-type': 'application/json'})
-    c = push.Channel('my_channel', {})
-    self.assertRaises(push.InvalidSubscriptionRequestError,
-                      push.Subscription.for_request, request, c)