Remove the review bot app.

reviewbot/third_party/google-api-python-client/oauth2client/client.py

Index: reviewbot/third_party/google-api-python-client/oauth2client/client.py
===================================================================
--- reviewbot/third_party/google-api-python-client/oauth2client/client.py	(revision 221173)
+++ reviewbot/third_party/google-api-python-client/oauth2client/client.py	(working copy)
@@ -1,1364 +0,0 @@
-# Copyright (C) 2010 Google Inc.
-#
-# 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.
-
-"""An OAuth 2.0 client.
-
-Tools for interacting with OAuth 2.0 protected resources.
-"""
-
-__author__ = 'jcgregorio@google.com (Joe Gregorio)'
-
-import base64
-import clientsecrets
-import copy
-import datetime
-import httplib2
-import logging
-import os
-import sys
-import time
-import urllib
-import urlparse
-
-from oauth2client import GOOGLE_AUTH_URI
-from oauth2client import GOOGLE_REVOKE_URI
-from oauth2client import GOOGLE_TOKEN_URI
-from oauth2client import util
-from oauth2client.anyjson import simplejson
-
-HAS_OPENSSL = False
-HAS_CRYPTO = False
-try:
-  from oauth2client import crypt
-  HAS_CRYPTO = True
-  if crypt.OpenSSLVerifier is not None:
-    HAS_OPENSSL = True
-except ImportError:
-  pass
-
-try:
-  from urlparse import parse_qsl
-except ImportError:
-  from cgi import parse_qsl
-
-logger = logging.getLogger(__name__)
-
-# Expiry is stored in RFC3339 UTC format
-EXPIRY_FORMAT = '%Y-%m-%dT%H:%M:%SZ'
-
-# Which certs to use to validate id_tokens received.
-ID_TOKEN_VERIFICATON_CERTS = 'https://www.googleapis.com/oauth2/v1/certs'
-
-# Constant to use for the out of band OAuth 2.0 flow.
-OOB_CALLBACK_URN = 'urn:ietf:wg:oauth:2.0:oob'
-
-# Google Data client libraries may need to set this to [401, 403].
-REFRESH_STATUS_CODES = [401]
-
-
-class Error(Exception):
-  """Base error for this module."""
-
-
-class FlowExchangeError(Error):
-  """Error trying to exchange an authorization grant for an access token."""
-
-
-class AccessTokenRefreshError(Error):
-  """Error trying to refresh an expired access token."""
-
-
-class TokenRevokeError(Error):
-  """Error trying to revoke a token."""
-
-
-class UnknownClientSecretsFlowError(Error):
-  """The client secrets file called for an unknown type of OAuth 2.0 flow. """
-
-
-class AccessTokenCredentialsError(Error):
-  """Having only the access_token means no refresh is possible."""
-
-
-class VerifyJwtTokenError(Error):
-  """Could on retrieve certificates for validation."""
-
-
-class NonAsciiHeaderError(Error):
-  """Header names and values must be ASCII strings."""
-
-
-def _abstract():
-  raise NotImplementedError('You need to override this function')
-
-
-class MemoryCache(object):
-  """httplib2 Cache implementation which only caches locally."""
-
-  def __init__(self):
-    self.cache = {}
-
-  def get(self, key):
-    return self.cache.get(key)
-
-  def set(self, key, value):
-    self.cache[key] = value
-
-  def delete(self, key):
-    self.cache.pop(key, None)
-
-
-class Credentials(object):
-  """Base class for all Credentials objects.
-
-  Subclasses must define an authorize() method that applies the credentials to
-  an HTTP transport.
-
-  Subclasses must also specify a classmethod named 'from_json' that takes a JSON
-  string as input and returns an instaniated Credentials object.
-  """
-
-  NON_SERIALIZED_MEMBERS = ['store']
-
-  def authorize(self, http):
-    """Take an httplib2.Http instance (or equivalent) and authorizes it.
-
-    Authorizes it for the set of credentials, usually by replacing
-    http.request() with a method that adds in the appropriate headers and then
-    delegates to the original Http.request() method.
-
-    Args:
-      http: httplib2.Http, an http object to be used to make the refresh
-        request.
-    """
-    _abstract()
-
-  def refresh(self, http):
-    """Forces a refresh of the access_token.
-
-    Args:
-      http: httplib2.Http, an http object to be used to make the refresh
-        request.
-    """
-    _abstract()
-
-  def revoke(self, http):
-    """Revokes a refresh_token and makes the credentials void.
-
-    Args:
-      http: httplib2.Http, an http object to be used to make the revoke
-        request.
-    """
-    _abstract()
-
-  def apply(self, headers):
-    """Add the authorization to the headers.
-
-    Args:
-      headers: dict, the headers to add the Authorization header to.
-    """
-    _abstract()
-
-  def _to_json(self, strip):
-    """Utility function that creates JSON repr. of a Credentials object.
-
-    Args:
-      strip: array, An array of names of members to not include in the JSON.
-
-    Returns:
-       string, a JSON representation of this instance, suitable to pass to
-       from_json().
-    """
-    t = type(self)
-    d = copy.copy(self.__dict__)
-    for member in strip:
-      if member in d:
-        del d[member]
-    if 'token_expiry' in d and isinstance(d['token_expiry'], datetime.datetime):
-      d['token_expiry'] = d['token_expiry'].strftime(EXPIRY_FORMAT)
-    # Add in information we will need later to reconsistitue this instance.
-    d['_class'] = t.__name__
-    d['_module'] = t.__module__
-    return simplejson.dumps(d)
-
-  def to_json(self):
-    """Creating a JSON representation of an instance of Credentials.
-
-    Returns:
-       string, a JSON representation of this instance, suitable to pass to
-       from_json().
-    """
-    return self._to_json(Credentials.NON_SERIALIZED_MEMBERS)
-
-  @classmethod
-  def new_from_json(cls, s):
-    """Utility class method to instantiate a Credentials subclass from a JSON
-    representation produced by to_json().
-
-    Args:
-      s: string, JSON from to_json().
-
-    Returns:
-      An instance of the subclass of Credentials that was serialized with
-      to_json().
-    """
-    data = simplejson.loads(s)
-    # Find and call the right classmethod from_json() to restore the object.
-    module = data['_module']
-    try:
-      m = __import__(module)
-    except ImportError:
-      # In case there's an object from the old package structure, update it
-      module = module.replace('.apiclient', '')
-      m = __import__(module)
-
-    m = __import__(module, fromlist=module.split('.')[:-1])
-    kls = getattr(m, data['_class'])
-    from_json = getattr(kls, 'from_json')
-    return from_json(s)
-
-  @classmethod
-  def from_json(cls, s):
-    """Instantiate a Credentials object from a JSON description of it.
-
-    The JSON should have been produced by calling .to_json() on the object.
-
-    Args:
-      data: dict, A deserialized JSON object.
-
-    Returns:
-      An instance of a Credentials subclass.
-    """
-    return Credentials()
-
-
-class Flow(object):
-  """Base class for all Flow objects."""
-  pass
-
-
-class Storage(object):
-  """Base class for all Storage objects.
-
-  Store and retrieve a single credential. This class supports locking
-  such that multiple processes and threads can operate on a single
-  store.
-  """
-
-  def acquire_lock(self):
-    """Acquires any lock necessary to access this Storage.
-
-    This lock is not reentrant.
-    """
-    pass
-
-  def release_lock(self):
-    """Release the Storage lock.
-
-    Trying to release a lock that isn't held will result in a
-    RuntimeError.
-    """
-    pass
-
-  def locked_get(self):
-    """Retrieve credential.
-
-    The Storage lock must be held when this is called.
-
-    Returns:
-      oauth2client.client.Credentials
-    """
-    _abstract()
-
-  def locked_put(self, credentials):
-    """Write a credential.
-
-    The Storage lock must be held when this is called.
-
-    Args:
-      credentials: Credentials, the credentials to store.
-    """
-    _abstract()
-
-  def locked_delete(self):
-    """Delete a credential.
-
-    The Storage lock must be held when this is called.
-    """
-    _abstract()
-
-  def get(self):
-    """Retrieve credential.
-
-    The Storage lock must *not* be held when this is called.
-
-    Returns:
-      oauth2client.client.Credentials
-    """
-    self.acquire_lock()
-    try:
-      return self.locked_get()
-    finally:
-      self.release_lock()
-
-  def put(self, credentials):
-    """Write a credential.
-
-    The Storage lock must be held when this is called.
-
-    Args:
-      credentials: Credentials, the credentials to store.
-    """
-    self.acquire_lock()
-    try:
-      self.locked_put(credentials)
-    finally:
-      self.release_lock()
-
-  def delete(self):
-    """Delete credential.
-
-    Frees any resources associated with storing the credential.
-    The Storage lock must *not* be held when this is called.
-
-    Returns:
-      None
-    """
-    self.acquire_lock()
-    try:
-      return self.locked_delete()
-    finally:
-      self.release_lock()
-
-
-def clean_headers(headers):
-  """Forces header keys and values to be strings, i.e not unicode.
-
-  The httplib module just concats the header keys and values in a way that may
-  make the message header a unicode string, which, if it then tries to
-  contatenate to a binary request body may result in a unicode decode error.
-
-  Args:
-    headers: dict, A dictionary of headers.
-
-  Returns:
-    The same dictionary but with all the keys converted to strings.
-  """
-  clean = {}
-  try:
-    for k, v in headers.iteritems():
-      clean[str(k)] = str(v)
-  except UnicodeEncodeError:
-    raise NonAsciiHeaderError(k + ': ' + v)
-  return clean
-
-
-def _update_query_params(uri, params):
-  """Updates a URI with new query parameters.
-
-  Args:
-    uri: string, A valid URI, with potential existing query parameters.
-    params: dict, A dictionary of query parameters.
-
-  Returns:
-    The same URI but with the new query parameters added.
-  """
-  parts = list(urlparse.urlparse(uri))
-  query_params = dict(parse_qsl(parts[4])) # 4 is the index of the query part
-  query_params.update(params)
-  parts[4] = urllib.urlencode(query_params)
-  return urlparse.urlunparse(parts)
-
-
-class OAuth2Credentials(Credentials):
-  """Credentials object for OAuth 2.0.
-
-  Credentials can be applied to an httplib2.Http object using the authorize()
-  method, which then adds the OAuth 2.0 access token to each request.
-
-  OAuth2Credentials objects may be safely pickled and unpickled.
-  """
-
-  @util.positional(8)
-  def __init__(self, access_token, client_id, client_secret, refresh_token,
-               token_expiry, token_uri, user_agent, revoke_uri=None,
-               id_token=None, token_response=None):
-    """Create an instance of OAuth2Credentials.
-
-    This constructor is not usually called by the user, instead
-    OAuth2Credentials objects are instantiated by the OAuth2WebServerFlow.
-
-    Args:
-      access_token: string, access token.
-      client_id: string, client identifier.
-      client_secret: string, client secret.
-      refresh_token: string, refresh token.
-      token_expiry: datetime, when the access_token expires.
-      token_uri: string, URI of token endpoint.
-      user_agent: string, The HTTP User-Agent to provide for this application.
-      revoke_uri: string, URI for revoke endpoint. Defaults to None; a token
-        can't be revoked if this is None.
-      id_token: object, The identity of the resource owner.
-      token_response: dict, the decoded response to the token request. None
-        if a token hasn't been requested yet. Stored because some providers
-        (e.g. wordpress.com) include extra fields that clients may want.
-
-    Notes:
-      store: callable, A callable that when passed a Credential
-        will store the credential back to where it came from.
-        This is needed to store the latest access_token if it
-        has expired and been refreshed.
-    """
-    self.access_token = access_token
-    self.client_id = client_id
-    self.client_secret = client_secret
-    self.refresh_token = refresh_token
-    self.store = None
-    self.token_expiry = token_expiry
-    self.token_uri = token_uri
-    self.user_agent = user_agent
-    self.revoke_uri = revoke_uri
-    self.id_token = id_token
-    self.token_response = token_response
-
-    # True if the credentials have been revoked or expired and can't be
-    # refreshed.
-    self.invalid = False
-
-  def authorize(self, http):
-    """Authorize an httplib2.Http instance with these credentials.
-
-    The modified http.request method will add authentication headers to each
-    request and will refresh access_tokens when a 401 is received on a
-    request. In addition the http.request method has a credentials property,
-    http.request.credentials, which is the Credentials object that authorized
-    it.
-
-    Args:
-       http: An instance of httplib2.Http
-         or something that acts like it.
-
-    Returns:
-       A modified instance of http that was passed in.
-
-    Example:
-
-      h = httplib2.Http()
-      h = credentials.authorize(h)
-
-    You can't create a new OAuth subclass of httplib2.Authenication
-    because it never gets passed the absolute URI, which is needed for
-    signing. So instead we have to overload 'request' with a closure
-    that adds in the Authorization header and then calls the original
-    version of 'request()'.
-    """
-    request_orig = http.request
-
-    # The closure that will replace 'httplib2.Http.request'.
-    @util.positional(1)
-    def new_request(uri, method='GET', body=None, headers=None,
-                    redirections=httplib2.DEFAULT_MAX_REDIRECTS,
-                    connection_type=None):
-      if not self.access_token:
-        logger.info('Attempting refresh to obtain initial access_token')
-        self._refresh(request_orig)
-
-      # Modify the request headers to add the appropriate
-      # Authorization header.
-      if headers is None:
-        headers = {}
-      self.apply(headers)
-
-      if self.user_agent is not None:
-        if 'user-agent' in headers:
-          headers['user-agent'] = self.user_agent + ' ' + headers['user-agent']
-        else:
-          headers['user-agent'] = self.user_agent
-
-      resp, content = request_orig(uri, method, body, clean_headers(headers),
-                                   redirections, connection_type)
-
-      if resp.status in REFRESH_STATUS_CODES:
-        logger.info('Refreshing due to a %s' % str(resp.status))
-        self._refresh(request_orig)
-        self.apply(headers)
-        return request_orig(uri, method, body, clean_headers(headers),
-                            redirections, connection_type)
-      else:
-        return (resp, content)
-
-    # Replace the request method with our own closure.
-    http.request = new_request
-
-    # Set credentials as a property of the request method.
-    setattr(http.request, 'credentials', self)
-
-    return http
-
-  def refresh(self, http):
-    """Forces a refresh of the access_token.
-
-    Args:
-      http: httplib2.Http, an http object to be used to make the refresh
-        request.
-    """
-    self._refresh(http.request)
-
-  def revoke(self, http):
-    """Revokes a refresh_token and makes the credentials void.
-
-    Args:
-      http: httplib2.Http, an http object to be used to make the revoke
-        request.
-    """
-    self._revoke(http.request)
-
-  def apply(self, headers):
-    """Add the authorization to the headers.
-
-    Args:
-      headers: dict, the headers to add the Authorization header to.
-    """
-    headers['Authorization'] = 'Bearer ' + self.access_token
-
-  def to_json(self):
-    return self._to_json(Credentials.NON_SERIALIZED_MEMBERS)
-
-  @classmethod
-  def from_json(cls, s):
-    """Instantiate a Credentials object from a JSON description of it. The JSON
-    should have been produced by calling .to_json() on the object.
-
-    Args:
-      data: dict, A deserialized JSON object.
-
-    Returns:
-      An instance of a Credentials subclass.
-    """
-    data = simplejson.loads(s)
-    if 'token_expiry' in data and not isinstance(data['token_expiry'],
-        datetime.datetime):
-      try:
-        data['token_expiry'] = datetime.datetime.strptime(
-            data['token_expiry'], EXPIRY_FORMAT)
-      except:
-        data['token_expiry'] = None
-    retval = cls(
-        data['access_token'],
-        data['client_id'],
-        data['client_secret'],
-        data['refresh_token'],
-        data['token_expiry'],
-        data['token_uri'],
-        data['user_agent'],
-        revoke_uri=data.get('revoke_uri', None),
-        id_token=data.get('id_token', None),
-        token_response=data.get('token_response', None))
-    retval.invalid = data['invalid']
-    return retval
-
-  @property
-  def access_token_expired(self):
-    """True if the credential is expired or invalid.
-
-    If the token_expiry isn't set, we assume the token doesn't expire.
-    """
-    if self.invalid:
-      return True
-
-    if not self.token_expiry:
-      return False
-
-    now = datetime.datetime.utcnow()
-    if now >= self.token_expiry:
-      logger.info('access_token is expired. Now: %s, token_expiry: %s',
-                  now, self.token_expiry)
-      return True
-    return False
-
-  def set_store(self, store):
-    """Set the Storage for the credential.
-
-    Args:
-      store: Storage, an implementation of Stroage object.
-        This is needed to store the latest access_token if it
-        has expired and been refreshed. This implementation uses
-        locking to check for updates before updating the
-        access_token.
-    """
-    self.store = store
-
-  def _updateFromCredential(self, other):
-    """Update this Credential from another instance."""
-    self.__dict__.update(other.__getstate__())
-
-  def __getstate__(self):
-    """Trim the state down to something that can be pickled."""
-    d = copy.copy(self.__dict__)
-    del d['store']
-    return d
-
-  def __setstate__(self, state):
-    """Reconstitute the state of the object from being pickled."""
-    self.__dict__.update(state)
-    self.store = None
-
-  def _generate_refresh_request_body(self):
-    """Generate the body that will be used in the refresh request."""
-    body = urllib.urlencode({
-        'grant_type': 'refresh_token',
-        'client_id': self.client_id,
-        'client_secret': self.client_secret,
-        'refresh_token': self.refresh_token,
-        })
-    return body
-
-  def _generate_refresh_request_headers(self):
-    """Generate the headers that will be used in the refresh request."""
-    headers = {
-        'content-type': 'application/x-www-form-urlencoded',
-    }
-
-    if self.user_agent is not None:
-      headers['user-agent'] = self.user_agent
-
-    return headers
-
-  def _refresh(self, http_request):
-    """Refreshes the access_token.
-
-    This method first checks by reading the Storage object if available.
-    If a refresh is still needed, it holds the Storage lock until the
-    refresh is completed.
-
-    Args:
-      http_request: callable, a callable that matches the method signature of
-        httplib2.Http.request, used to make the refresh request.
-
-    Raises:
-      AccessTokenRefreshError: When the refresh fails.
-    """
-    if not self.store:
-      self._do_refresh_request(http_request)
-    else:
-      self.store.acquire_lock()
-      try:
-        new_cred = self.store.locked_get()
-        if (new_cred and not new_cred.invalid and
-            new_cred.access_token != self.access_token):
-          logger.info('Updated access_token read from Storage')
-          self._updateFromCredential(new_cred)
-        else:
-          self._do_refresh_request(http_request)
-      finally:
-        self.store.release_lock()
-
-  def _do_refresh_request(self, http_request):
-    """Refresh the access_token using the refresh_token.
-
-    Args:
-      http_request: callable, a callable that matches the method signature of
-        httplib2.Http.request, used to make the refresh request.
-
-    Raises:
-      AccessTokenRefreshError: When the refresh fails.
-    """
-    body = self._generate_refresh_request_body()
-    headers = self._generate_refresh_request_headers()
-
-    logger.info('Refreshing access_token')
-    resp, content = http_request(
-        self.token_uri, method='POST', body=body, headers=headers)
-    if resp.status == 200:
-      # TODO(jcgregorio) Raise an error if loads fails?
-      d = simplejson.loads(content)
-      self.token_response = d
-      self.access_token = d['access_token']
-      self.refresh_token = d.get('refresh_token', self.refresh_token)
-      if 'expires_in' in d:
-        self.token_expiry = datetime.timedelta(
-            seconds=int(d['expires_in'])) + datetime.datetime.utcnow()
-      else:
-        self.token_expiry = None
-      if self.store:
-        self.store.locked_put(self)
-    else:
-      # An {'error':...} response body means the token is expired or revoked,
-      # so we flag the credentials as such.
-      logger.info('Failed to retrieve access token: %s' % content)
-      error_msg = 'Invalid response %s.' % resp['status']
-      try:
-        d = simplejson.loads(content)
-        if 'error' in d:
-          error_msg = d['error']
-          self.invalid = True
-          if self.store:
-            self.store.locked_put(self)
-      except StandardError:
-        pass
-      raise AccessTokenRefreshError(error_msg)
-
-  def _revoke(self, http_request):
-    """Revokes the refresh_token and deletes the store if available.
-
-    Args:
-      http_request: callable, a callable that matches the method signature of
-        httplib2.Http.request, used to make the revoke request.
-    """
-    self._do_revoke(http_request, self.refresh_token)
-
-  def _do_revoke(self, http_request, token):
-    """Revokes the credentials and deletes the store if available.
-
-    Args:
-      http_request: callable, a callable that matches the method signature of
-        httplib2.Http.request, used to make the refresh request.
-      token: A string used as the token to be revoked. Can be either an
-        access_token or refresh_token.
-
-    Raises:
-      TokenRevokeError: If the revoke request does not return with a 200 OK.
-    """
-    logger.info('Revoking token')
-    query_params = {'token': token}
-    token_revoke_uri = _update_query_params(self.revoke_uri, query_params)
-    resp, content = http_request(token_revoke_uri)
-    if resp.status == 200:
-      self.invalid = True
-    else:
-      error_msg = 'Invalid response %s.' % resp.status
-      try:
-        d = simplejson.loads(content)
-        if 'error' in d:
-          error_msg = d['error']
-      except StandardError:
-        pass
-      raise TokenRevokeError(error_msg)
-
-    if self.store:
-      self.store.delete()
-
-
-class AccessTokenCredentials(OAuth2Credentials):
-  """Credentials object for OAuth 2.0.
-
-  Credentials can be applied to an httplib2.Http object using the
-  authorize() method, which then signs each request from that object
-  with the OAuth 2.0 access token. This set of credentials is for the
-  use case where you have acquired an OAuth 2.0 access_token from
-  another place such as a JavaScript client or another web
-  application, and wish to use it from Python. Because only the
-  access_token is present it can not be refreshed and will in time
-  expire.
-
-  AccessTokenCredentials objects may be safely pickled and unpickled.
-
-  Usage:
-    credentials = AccessTokenCredentials('<an access token>',
-      'my-user-agent/1.0')
-    http = httplib2.Http()
-    http = credentials.authorize(http)
-
-  Exceptions:
-    AccessTokenCredentialsExpired: raised when the access_token expires or is
-      revoked.
-  """
-
-  def __init__(self, access_token, user_agent, revoke_uri=None):
-    """Create an instance of OAuth2Credentials
-
-    This is one of the few types if Credentials that you should contrust,
-    Credentials objects are usually instantiated by a Flow.
-
-    Args:
-      access_token: string, access token.
-      user_agent: string, The HTTP User-Agent to provide for this application.
-      revoke_uri: string, URI for revoke endpoint. Defaults to None; a token
-        can't be revoked if this is None.
-    """
-    super(AccessTokenCredentials, self).__init__(
-        access_token,
-        None,
-        None,
-        None,
-        None,
-        None,
-        user_agent,
-        revoke_uri=revoke_uri)
-
-
-  @classmethod
-  def from_json(cls, s):
-    data = simplejson.loads(s)
-    retval = AccessTokenCredentials(
-        data['access_token'],
-        data['user_agent'])
-    return retval
-
-  def _refresh(self, http_request):
-    raise AccessTokenCredentialsError(
-        'The access_token is expired or invalid and can\'t be refreshed.')
-
-  def _revoke(self, http_request):
-    """Revokes the access_token and deletes the store if available.
-
-    Args:
-      http_request: callable, a callable that matches the method signature of
-        httplib2.Http.request, used to make the revoke request.
-    """
-    self._do_revoke(http_request, self.access_token)
-
-
-class AssertionCredentials(OAuth2Credentials):
-  """Abstract Credentials object used for OAuth 2.0 assertion grants.
-
-  This credential does not require a flow to instantiate because it
-  represents a two legged flow, and therefore has all of the required
-  information to generate and refresh its own access tokens. It must
-  be subclassed to generate the appropriate assertion string.
-
-  AssertionCredentials objects may be safely pickled and unpickled.
-  """
-
-  @util.positional(2)
-  def __init__(self, assertion_type, user_agent=None,
-               token_uri=GOOGLE_TOKEN_URI,
-               revoke_uri=GOOGLE_REVOKE_URI,
-               **unused_kwargs):
-    """Constructor for AssertionFlowCredentials.
-
-    Args:
-      assertion_type: string, assertion type that will be declared to the auth
-        server
-      user_agent: string, The HTTP User-Agent to provide for this application.
-      token_uri: string, URI for token endpoint. For convenience
-        defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-      revoke_uri: string, URI for revoke endpoint.
-    """
-    super(AssertionCredentials, self).__init__(
-        None,
-        None,
-        None,
-        None,
-        None,
-        token_uri,
-        user_agent,
-        revoke_uri=revoke_uri)
-    self.assertion_type = assertion_type
-
-  def _generate_refresh_request_body(self):
-    assertion = self._generate_assertion()
-
-    body = urllib.urlencode({
-        'assertion': assertion,
-        'grant_type': 'urn:ietf:params:oauth:grant-type:jwt-bearer',
-        })
-
-    return body
-
-  def _generate_assertion(self):
-    """Generate the assertion string that will be used in the access token
-    request.
-    """
-    _abstract()
-
-  def _revoke(self, http_request):
-    """Revokes the access_token and deletes the store if available.
-
-    Args:
-      http_request: callable, a callable that matches the method signature of
-        httplib2.Http.request, used to make the revoke request.
-    """
-    self._do_revoke(http_request, self.access_token)
-
-
-if HAS_CRYPTO:
-  # PyOpenSSL and PyCrypto are not prerequisites for oauth2client, so if it is
-  # missing then don't create the SignedJwtAssertionCredentials or the
-  # verify_id_token() method.
-
-  class SignedJwtAssertionCredentials(AssertionCredentials):
-    """Credentials object used for OAuth 2.0 Signed JWT assertion grants.
-
-    This credential does not require a flow to instantiate because it represents
-    a two legged flow, and therefore has all of the required information to
-    generate and refresh its own access tokens.
-
-    SignedJwtAssertionCredentials requires either PyOpenSSL, or PyCrypto 2.6 or
-    later. For App Engine you may also consider using AppAssertionCredentials.
-    """
-
-    MAX_TOKEN_LIFETIME_SECS = 3600 # 1 hour in seconds
-
-    @util.positional(4)
-    def __init__(self,
-        service_account_name,
-        private_key,
-        scope,
-        private_key_password='notasecret',
-        user_agent=None,
-        token_uri=GOOGLE_TOKEN_URI,
-        revoke_uri=GOOGLE_REVOKE_URI,
-        **kwargs):
-      """Constructor for SignedJwtAssertionCredentials.
-
-      Args:
-        service_account_name: string, id for account, usually an email address.
-        private_key: string, private key in PKCS12 or PEM format.
-        scope: string or iterable of strings, scope(s) of the credentials being
-          requested.
-        private_key_password: string, password for private_key, unused if
-          private_key is in PEM format.
-        user_agent: string, HTTP User-Agent to provide for this application.
-        token_uri: string, URI for token endpoint. For convenience
-          defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-        revoke_uri: string, URI for revoke endpoint.
-        kwargs: kwargs, Additional parameters to add to the JWT token, for
-          example prn=joe@xample.org."""
-
-      super(SignedJwtAssertionCredentials, self).__init__(
-          None,
-          user_agent=user_agent,
-          token_uri=token_uri,
-          revoke_uri=revoke_uri,
-          )
-
-      self.scope = util.scopes_to_string(scope)
-
-      # Keep base64 encoded so it can be stored in JSON.
-      self.private_key = base64.b64encode(private_key)
-
-      self.private_key_password = private_key_password
-      self.service_account_name = service_account_name
-      self.kwargs = kwargs
-
-    @classmethod
-    def from_json(cls, s):
-      data = simplejson.loads(s)
-      retval = SignedJwtAssertionCredentials(
-          data['service_account_name'],
-          base64.b64decode(data['private_key']),
-          data['scope'],
-          private_key_password=data['private_key_password'],
-          user_agent=data['user_agent'],
-          token_uri=data['token_uri'],
-          **data['kwargs']
-          )
-      retval.invalid = data['invalid']
-      retval.access_token = data['access_token']
-      return retval
-
-    def _generate_assertion(self):
-      """Generate the assertion that will be used in the request."""
-      now = long(time.time())
-      payload = {
-          'aud': self.token_uri,
-          'scope': self.scope,
-          'iat': now,
-          'exp': now + SignedJwtAssertionCredentials.MAX_TOKEN_LIFETIME_SECS,
-          'iss': self.service_account_name
-      }
-      payload.update(self.kwargs)
-      logger.debug(str(payload))
-
-      private_key = base64.b64decode(self.private_key)
-      return crypt.make_signed_jwt(crypt.Signer.from_string(
-          private_key, self.private_key_password), payload)
-
-  # Only used in verify_id_token(), which is always calling to the same URI
-  # for the certs.
-  _cached_http = httplib2.Http(MemoryCache())
-
-  @util.positional(2)
-  def verify_id_token(id_token, audience, http=None,
-      cert_uri=ID_TOKEN_VERIFICATON_CERTS):
-    """Verifies a signed JWT id_token.
-
-    This function requires PyOpenSSL and because of that it does not work on
-    App Engine.
-
-    Args:
-      id_token: string, A Signed JWT.
-      audience: string, The audience 'aud' that the token should be for.
-      http: httplib2.Http, instance to use to make the HTTP request. Callers
-        should supply an instance that has caching enabled.
-      cert_uri: string, URI of the certificates in JSON format to
-        verify the JWT against.
-
-    Returns:
-      The deserialized JSON in the JWT.
-
-    Raises:
-      oauth2client.crypt.AppIdentityError if the JWT fails to verify.
-    """
-    if http is None:
-      http = _cached_http
-
-    resp, content = http.request(cert_uri)
-
-    if resp.status == 200:
-      certs = simplejson.loads(content)
-      return crypt.verify_signed_jwt_with_certs(id_token, certs, audience)
-    else:
-      raise VerifyJwtTokenError('Status code: %d' % resp.status)
-
-
-def _urlsafe_b64decode(b64string):
-  # Guard against unicode strings, which base64 can't handle.
-  b64string = b64string.encode('ascii')
-  padded = b64string + '=' * (4 - len(b64string) % 4)
-  return base64.urlsafe_b64decode(padded)
-
-
-def _extract_id_token(id_token):
-  """Extract the JSON payload from a JWT.
-
-  Does the extraction w/o checking the signature.
-
-  Args:
-    id_token: string, OAuth 2.0 id_token.
-
-  Returns:
-    object, The deserialized JSON payload.
-  """
-  segments = id_token.split('.')
-
-  if (len(segments) != 3):
-    raise VerifyJwtTokenError(
-      'Wrong number of segments in token: %s' % id_token)
-
-  return simplejson.loads(_urlsafe_b64decode(segments[1]))
-
-
-def _parse_exchange_token_response(content):
-  """Parses response of an exchange token request.
-
-  Most providers return JSON but some (e.g. Facebook) return a
-  url-encoded string.
-
-  Args:
-    content: The body of a response
-
-  Returns:
-    Content as a dictionary object. Note that the dict could be empty,
-    i.e. {}. That basically indicates a failure.
-  """
-  resp = {}
-  try:
-    resp = simplejson.loads(content)
-  except StandardError:
-    # different JSON libs raise different exceptions,
-    # so we just do a catch-all here
-    resp = dict(parse_qsl(content))
-
-  # some providers respond with 'expires', others with 'expires_in'
-  if resp and 'expires' in resp:
-    resp['expires_in'] = resp.pop('expires')
-
-  return resp
-
-
-@util.positional(4)
-def credentials_from_code(client_id, client_secret, scope, code,
-                          redirect_uri='postmessage', http=None,
-                          user_agent=None, token_uri=GOOGLE_TOKEN_URI,
-                          auth_uri=GOOGLE_AUTH_URI,
-                          revoke_uri=GOOGLE_REVOKE_URI):
-  """Exchanges an authorization code for an OAuth2Credentials object.
-
-  Args:
-    client_id: string, client identifier.
-    client_secret: string, client secret.
-    scope: string or iterable of strings, scope(s) to request.
-    code: string, An authroization code, most likely passed down from
-      the client
-    redirect_uri: string, this is generally set to 'postmessage' to match the
-      redirect_uri that the client specified
-    http: httplib2.Http, optional http instance to use to do the fetch
-    token_uri: string, URI for token endpoint. For convenience
-      defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-    auth_uri: string, URI for authorization endpoint. For convenience
-      defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-    revoke_uri: string, URI for revoke endpoint. For convenience
-      defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-
-  Returns:
-    An OAuth2Credentials object.
-
-  Raises:
-    FlowExchangeError if the authorization code cannot be exchanged for an
-     access token
-  """
-  flow = OAuth2WebServerFlow(client_id, client_secret, scope,
-                             redirect_uri=redirect_uri, user_agent=user_agent,
-                             auth_uri=auth_uri, token_uri=token_uri,
-                             revoke_uri=revoke_uri)
-
-  credentials = flow.step2_exchange(code, http=http)
-  return credentials
-
-
-@util.positional(3)
-def credentials_from_clientsecrets_and_code(filename, scope, code,
-                                            message = None,
-                                            redirect_uri='postmessage',
-                                            http=None,
-                                            cache=None):
-  """Returns OAuth2Credentials from a clientsecrets file and an auth code.
-
-  Will create the right kind of Flow based on the contents of the clientsecrets
-  file or will raise InvalidClientSecretsError for unknown types of Flows.
-
-  Args:
-    filename: string, File name of clientsecrets.
-    scope: string or iterable of strings, scope(s) to request.
-    code: string, An authorization code, most likely passed down from
-      the client
-    message: string, A friendly string to display to the user if the
-      clientsecrets file is missing or invalid. If message is provided then
-      sys.exit will be called in the case of an error. If message in not
-      provided then clientsecrets.InvalidClientSecretsError will be raised.
-    redirect_uri: string, this is generally set to 'postmessage' to match the
-      redirect_uri that the client specified
-    http: httplib2.Http, optional http instance to use to do the fetch
-    cache: An optional cache service client that implements get() and set()
-      methods. See clientsecrets.loadfile() for details.
-
-  Returns:
-    An OAuth2Credentials object.
-
-  Raises:
-    FlowExchangeError if the authorization code cannot be exchanged for an
-     access token
-    UnknownClientSecretsFlowError if the file describes an unknown kind of Flow.
-    clientsecrets.InvalidClientSecretsError if the clientsecrets file is
-      invalid.
-  """
-  flow = flow_from_clientsecrets(filename, scope, message=message, cache=cache,
-                                 redirect_uri=redirect_uri)
-  credentials = flow.step2_exchange(code, http=http)
-  return credentials
-
-
-class OAuth2WebServerFlow(Flow):
-  """Does the Web Server Flow for OAuth 2.0.
-
-  OAuth2WebServerFlow objects may be safely pickled and unpickled.
-  """
-
-  @util.positional(4)
-  def __init__(self, client_id, client_secret, scope,
-               redirect_uri=None,
-               user_agent=None,
-               auth_uri=GOOGLE_AUTH_URI,
-               token_uri=GOOGLE_TOKEN_URI,
-               revoke_uri=GOOGLE_REVOKE_URI,
-               **kwargs):
-    """Constructor for OAuth2WebServerFlow.
-
-    The kwargs argument is used to set extra query parameters on the
-    auth_uri. For example, the access_type and approval_prompt
-    query parameters can be set via kwargs.
-
-    Args:
-      client_id: string, client identifier.
-      client_secret: string client secret.
-      scope: string or iterable of strings, scope(s) of the credentials being
-        requested.
-      redirect_uri: string, Either the string 'urn:ietf:wg:oauth:2.0:oob' for
-        a non-web-based application, or a URI that handles the callback from
-        the authorization server.
-      user_agent: string, HTTP User-Agent to provide for this application.
-      auth_uri: string, URI for authorization endpoint. For convenience
-        defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-      token_uri: string, URI for token endpoint. For convenience
-        defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-      revoke_uri: string, URI for revoke endpoint. For convenience
-        defaults to Google's endpoints but any OAuth 2.0 provider can be used.
-      **kwargs: dict, The keyword arguments are all optional and required
-                        parameters for the OAuth calls.
-    """
-    self.client_id = client_id
-    self.client_secret = client_secret
-    self.scope = util.scopes_to_string(scope)
-    self.redirect_uri = redirect_uri
-    self.user_agent = user_agent
-    self.auth_uri = auth_uri
-    self.token_uri = token_uri
-    self.revoke_uri = revoke_uri
-    self.params = {
-        'access_type': 'offline',
-        'response_type': 'code',
-    }
-    self.params.update(kwargs)
-
-  @util.positional(1)
-  def step1_get_authorize_url(self, redirect_uri=None):
-    """Returns a URI to redirect to the provider.
-
-    Args:
-      redirect_uri: string, Either the string 'urn:ietf:wg:oauth:2.0:oob' for
-        a non-web-based application, or a URI that handles the callback from
-        the authorization server. This parameter is deprecated, please move to
-        passing the redirect_uri in via the constructor.
-
-    Returns:
-      A URI as a string to redirect the user to begin the authorization flow.
-    """
-    if redirect_uri is not None:
-      logger.warning(('The redirect_uri parameter for'
-          'OAuth2WebServerFlow.step1_get_authorize_url is deprecated. Please'
-          'move to passing the redirect_uri in via the constructor.'))
-      self.redirect_uri = redirect_uri
-
-    if self.redirect_uri is None:
-      raise ValueError('The value of redirect_uri must not be None.')
-
-    query_params = {
-        'client_id': self.client_id,
-        'redirect_uri': self.redirect_uri,
-        'scope': self.scope,
-    }
-    query_params.update(self.params)
-    return _update_query_params(self.auth_uri, query_params)
-
-  @util.positional(2)
-  def step2_exchange(self, code, http=None):
-    """Exhanges a code for OAuth2Credentials.
-
-    Args:
-      code: string or dict, either the code as a string, or a dictionary
-        of the query parameters to the redirect_uri, which contains
-        the code.
-      http: httplib2.Http, optional http instance to use to do the fetch
-
-    Returns:
-      An OAuth2Credentials object that can be used to authorize requests.
-
-    Raises:
-      FlowExchangeError if a problem occured exchanging the code for a
-      refresh_token.
-    """
-
-    if not (isinstance(code, str) or isinstance(code, unicode)):
-      if 'code' not in code:
-        if 'error' in code:
-          error_msg = code['error']
-        else:
-          error_msg = 'No code was supplied in the query parameters.'
-        raise FlowExchangeError(error_msg)
-      else:
-        code = code['code']
-
-    body = urllib.urlencode({
-        'grant_type': 'authorization_code',
-        'client_id': self.client_id,
-        'client_secret': self.client_secret,
-        'code': code,
-        'redirect_uri': self.redirect_uri,
-        'scope': self.scope,
-        })
-    headers = {
-        'content-type': 'application/x-www-form-urlencoded',
-    }
-
-    if self.user_agent is not None:
-      headers['user-agent'] = self.user_agent
-
-    if http is None:
-      http = httplib2.Http()
-
-    resp, content = http.request(self.token_uri, method='POST', body=body,
-                                 headers=headers)
-    d = _parse_exchange_token_response(content)
-    if resp.status == 200 and 'access_token' in d:
-      access_token = d['access_token']
-      refresh_token = d.get('refresh_token', None)
-      token_expiry = None
-      if 'expires_in' in d:
-        token_expiry = datetime.datetime.utcnow() + datetime.timedelta(
-            seconds=int(d['expires_in']))
-
-      if 'id_token' in d:
-        d['id_token'] = _extract_id_token(d['id_token'])
-
-      logger.info('Successfully retrieved access token')
-      return OAuth2Credentials(access_token, self.client_id,
-                               self.client_secret, refresh_token, token_expiry,
-                               self.token_uri, self.user_agent,
-                               revoke_uri=self.revoke_uri,
-                               id_token=d.get('id_token', None),
-                               token_response=d)
-    else:
-      logger.info('Failed to retrieve access token: %s' % content)
-      if 'error' in d:
-        # you never know what those providers got to say
-        error_msg = unicode(d['error'])
-      else:
-        error_msg = 'Invalid response: %s.' % str(resp.status)
-      raise FlowExchangeError(error_msg)
-
-
-@util.positional(2)
-def flow_from_clientsecrets(filename, scope, redirect_uri=None,
-                            message=None, cache=None):
-  """Create a Flow from a clientsecrets file.
-
-  Will create the right kind of Flow based on the contents of the clientsecrets
-  file or will raise InvalidClientSecretsError for unknown types of Flows.
-
-  Args:
-    filename: string, File name of client secrets.
-    scope: string or iterable of strings, scope(s) to request.
-    redirect_uri: string, Either the string 'urn:ietf:wg:oauth:2.0:oob' for
-      a non-web-based application, or a URI that handles the callback from
-      the authorization server.
-    message: string, A friendly string to display to the user if the
-      clientsecrets file is missing or invalid. If message is provided then
-      sys.exit will be called in the case of an error. If message in not
-      provided then clientsecrets.InvalidClientSecretsError will be raised.
-    cache: An optional cache service client that implements get() and set()
-      methods. See clientsecrets.loadfile() for details.
-
-  Returns:
-    A Flow object.
-
-  Raises:
-    UnknownClientSecretsFlowError if the file describes an unknown kind of Flow.
-    clientsecrets.InvalidClientSecretsError if the clientsecrets file is
-      invalid.
-  """
-  try:
-    client_type, client_info = clientsecrets.loadfile(filename, cache=cache)
-    if client_type in (clientsecrets.TYPE_WEB, clientsecrets.TYPE_INSTALLED):
-      constructor_kwargs = {
-          'redirect_uri': redirect_uri,
-          'auth_uri': client_info['auth_uri'],
-          'token_uri': client_info['token_uri'],
-      }
-      revoke_uri = client_info.get('revoke_uri')
-      if revoke_uri is not None:
-        constructor_kwargs['revoke_uri'] = revoke_uri
-      return OAuth2WebServerFlow(
-          client_info['client_id'], client_info['client_secret'],
-          scope, **constructor_kwargs)
-
-  except clientsecrets.InvalidClientSecretsError:
-    if message:
-      sys.exit(message)
-    else:
-      raise
-  else:
-    raise UnknownClientSecretsFlowError(
-        'This OAuth 2.0 flow is unsupported: %r' % client_type)