Package oauth2client :: Module file |
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# 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