Source Code for Module oauth2client.file

  1  # Copyright (C) 2010 Google Inc. 
  2  # 
  3  # Licensed under the Apache License, Version 2.0 (the "License"); 
  4  # you may not use this file except in compliance with the License. 
  5  # You may obtain a copy of the License at 
  6  # 
  7  #      http://www.apache.org/licenses/LICENSE-2.0 
  8  # 
  9  # Unless required by applicable law or agreed to in writing, software 
 10  # distributed under the License is distributed on an "AS IS" BASIS, 
 11  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 12  # See the License for the specific language governing permissions and 
 13  # limitations under the License. 
 14   
 15  """Utilities for OAuth. 
 16   
 17  Utilities for making it easier to work with OAuth 2.0 
 18  credentials. 
 19  """ 
 20   
 21  __author__ = 'jcgregorio@google.com (Joe Gregorio)' 
 22   
 23  import os 
 24  import stat 
 25  import threading 
 26   
 27  from anyjson import simplejson 
 28  from client import Storage as BaseStorage 
 29  from client import Credentials 
 30   
 31   
 32 -class CredentialsFileSymbolicLinkError(Exception): 
 33    """Credentials files must not be symbolic links.""" 
 34   
 35   
 36 -class Storage(BaseStorage): 
 37    """Store and retrieve a single credential to and from a file.""" 
 38   
 39 -  def __init__(self, filename): 
 40      self._filename = filename 
 41      self._lock = threading.Lock() 
 42   
 43 -  def _validate_file(self): 
 44      if os.path.islink(self._filename): 
 45        raise CredentialsFileSymbolicLinkError( 
 46            'File: %s is a symbolic link.' % self._filename) 
 47   
 48 -  def acquire_lock(self): 
 49      """Acquires any lock necessary to access this Storage. 
 50   
 51      This lock is not reentrant.""" 
 52      self._lock.acquire() 
 53   
 54 -  def release_lock(self): 
 55      """Release the Storage lock. 
 56   
 57      Trying to release a lock that isn't held will result in a 
 58      RuntimeError. 
 59      """ 
 60      self._lock.release() 
 61   
 62 -  def locked_get(self): 
 63      """Retrieve Credential from file. 
 64   
 65      Returns: 
 66        oauth2client.client.Credentials 
 67   
 68      Raises: 
 69        CredentialsFileSymbolicLinkError if the file is a symbolic link. 
 70      """ 
 71      credentials = None 
 72      self._validate_file() 
 73      try: 
 74        f = open(self._filename, 'rb') 
 75        content = f.read() 
 76        f.close() 
 77      except IOError: 
 78        return credentials 
 79   
 80      try: 
 81        credentials = Credentials.new_from_json(content) 
 82        credentials.set_store(self) 
 83      except ValueError: 
 84        pass 
 85   
 86      return credentials 
 87   
 88 -  def _create_file_if_needed(self): 
 89      """Create an empty file if necessary. 
 90   
 91      This method will not initialize the file. Instead it implements a 
 92      simple version of "touch" to ensure the file has been created. 
 93      """ 
 94      if not os.path.exists(self._filename): 
 95        old_umask = os.umask(0177) 
 96        try: 
 97          open(self._filename, 'a+b').close() 
 98        finally: 
 99          os.umask(old_umask) 
100   
101 -  def locked_put(self, credentials): 
102      """Write Credentials to file. 
103   
104      Args: 
105        credentials: Credentials, the credentials to store. 
106   
107      Raises: 
108        CredentialsFileSymbolicLinkError if the file is a symbolic link. 
109      """ 
110   
111      self._create_file_if_needed() 
112      self._validate_file() 
113      f = open(self._filename, 'wb') 
114      f.write(credentials.to_json()) 
115      f.close() 
116   
117 -  def locked_delete(self): 
118      """Delete Credentials file. 
119   
120      Args: 
121        credentials: Credentials, the credentials to store. 
122      """ 
123   
124      os.unlink(self._filename) 
125