app/soc/views/helper/gdata_apis/oauth.py

#!/usr/bin/env python2.5
#
# Copyright 2011 the Melange authors.
#
# 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.

"""Generic views and tools for OAuth.
"""


from gdata import auth
from gdata.alt import appengine
from gdata.docs import service as docs_service

from google.appengine.api import memcache

from django.conf import settings

from soc.logic import system


def createDocsService(data):
  """Create and return a Docs Service.
  """

  request = data.request
  site = data.site
  service = docs_service.DocsService(source=settings.GDATA_SOURCE)
  if system.isSecondaryHostname(request):
    consumer_key = site.secondary_gdata_consumer_key
    consumer_secret = site.secondary_gdata_consumer_secret
  else:
    consumer_key = site.gdata_consumer_key
    consumer_secret = site.gdata_consumer_secret

  if not consumer_key or not consumer_secret:
    return

  service.SetOAuthInputParameters(
      auth.OAuthSignatureMethod.HMAC_SHA1, consumer_key.encode('utf-8'),
      consumer_secret.encode('utf-8'), settings.GDATA_SCOPES)
  appengine.run_on_appengine(service)
  return service


def getAccessToken(user):
  """Returns access token for an user.
  """

  access_token = memcache.get("%s;%s" %
                              (user.key().name(), system.getRawHostname()),
                              namespace='access_token')
  if isinstance(access_token, auth.OAuthToken):
    return access_token


def createDocsServiceWithAccessToken(data):
  """Returns Docs Service which uses user's access token.
  """

  user = data.user
  service = createDocsService(data)
  access_token = getAccessToken(user)
  service.access_token = access_token
  return service


def deleteAccessToken(user):
  """Deletes access token of user.
  """

  memcache.set("%s;%s" % (user.key().name(), system.getRawHostname()),
               None, namespace='access_token')


def generateOAuthRedirectURL(service, user, next):
  """Returns OAuth redirect URL for authenticating user.
  """

  req_token = service.FetchOAuthRequestToken(
      scopes=settings.GDATA_SCOPES,
      oauth_callback='http://%s%s' % (system.getRawHostname(), next))
  memcache.add(user.key().name(), req_token.secret, 300,
               namespace='request_token_secret')
  approval_page_url = service.GenerateOAuthAuthorizationURL(
      extra_params={'hd': 'default'})
  return approval_page_url


def checkOAuthVerifier(service, data):
  """Checks for OAuth verifier and exchanges token with access token.
  """

  request = data.request
  user = data.user
  oauth_token = auth.OAuthTokenFromUrl(
      request.get_full_path())
  if oauth_token:
    oauth_token.secret = memcache.get(user.key().name(),
                                      namespace='request_token_secret')
    oauth_token.oauth_input_params = service.GetOAuthInputParameters()
    service.SetOAuthToken(oauth_token)

    oauth_verifier = request.GET.get('oauth_verifier', '')
    access_token = service.UpgradeToOAuthAccessToken(
        oauth_verifier=oauth_verifier)

    if access_token:
      memcache.set('%s;%s' %
                   (user.key().name(), system.getRawHostname()),
                   access_token, namespace='access_token')