A Storage for Credentials that uses Redis

redis_storage.py

# 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.

"""A Redis based Storage.

A Storage for Credentials that uses Redis.
"""

__author__ = 'eduardo.marcolino@gmail.com (Eduardo Marcolino)'

import threading

from oauth2client.client import Storage as BaseStorage
from oauth2client.client import Credentials


class Storage(BaseStorage):
  """
  Usage:
    import redis
    from redis_storage import Storage

    r = redis.StrictRedis(host='localhost', port=6379)
    s = Storage(r, 'user1')
    credentials = s.get()
  """

  def __init__(self, redis_instance, user_key):
    """Constructor.

    Args:
      redis_instance: string, The name of the service under which the credentials
        are stored.
      user_key: string, The key of the user to store credentials for.
    """
    self._redis_instance = redis_instance
    self._user_key = user_key
    self._lock = threading.Lock()

  def acquire_lock(self):
    """Acquires any lock necessary to access this Storage.

    This lock is not reentrant."""
    self._lock.acquire()

  def release_lock(self):
    """Release the Storage lock.

    Trying to release a lock that isn't held will result in a
    RuntimeError.
    """
    self._lock.release()

  def locked_get(self):
    """Retrieve Credential from redis.

    Returns:
      oauth2client.client.Credentials
    """
    credentials = None
    content = self._redis_instance.get(self._user_key)

    if content is not None:
      try:
        credentials = Credentials.new_from_json(content)
        credentials.set_store(self)
      except ValueError:
        pass

    return credentials

  def locked_put(self, credentials):
    """Set Credentials to redis.

    Args:
      credentials: Credentials, the credentials to store.
    """
    self._redis_instance.set(self._user_key, credentials.to_json())

  def locked_delete(self):
    """Delete Credentials empty.

    Args:
      credentials: Credentials, the credentials to store.
    """
    self._redis_instance.set(self._user_key, '')