mediagoblin/storage/cloudfiles.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 '''
  18 Make it so that ``import cloudfiles`` does not pick THIS file, but the
  19 python-cloudfiles one.
  20
  21 http://docs.python.org/whatsnew/2.5.html#pep-328-absolute-and-relative-imports
  22 '''
  23 from __future__ import absolute_import
  24
  25 from mediagoblin.storage import StorageInterface, clean_listy_filepath
  26
  27 import cloudfiles
  28 import mimetypes
  29
  30
  31 class CloudFilesStorage(StorageInterface):
  32     '''
  33     OpenStack/Rackspace Cloud's Swift/CloudFiles support
  34     '''
  35
  36     local_storage = False
  37
  38     def __init__(self, **kwargs):
  39         self.param_container = kwargs.get('cloudfiles_container')
  40         self.param_user = kwargs.get('cloudfiles_user')
  41         self.param_api_key = kwargs.get('cloudfiles_api_key')
  42         self.param_host = kwargs.get('cloudfiles_host')
  43         self.param_use_servicenet = kwargs.get('cloudfiles_use_servicenet')
  44
  45         if not self.param_host:
  46             print('No CloudFiles host URL specified, '
  47                   'defaulting to Rackspace US')
  48
  49         self.connection = cloudfiles.get_connection(
  50             username=self.param_user,
  51             api_key=self.param_api_key,
  52             servicenet=True if self.param_use_servicenet == 'true' or \
  53                 self.param_use_servicenet == True else False)
  54
  55         if not self.param_container == \
  56                 self.connection.get_container(self.param_container):
  57             self.container = self.connection.create_container(
  58                 self.param_container)
  59             self.container.make_public(
  60                 ttl=60 * 60 * 2)
  61         else:
  62             self.container = self.connection.get_container(
  63                 self.param_container)
  64
  65         self.container_uri = self.container.public_uri()
  66
  67     def _resolve_filepath(self, filepath):
  68         return '/'.join(
  69             clean_listy_filepath(filepath))
  70
  71     def file_exists(self, filepath):
  72         try:
  73             object = self.container.get_object(
  74                 self._resolve_filepath(filepath))
  75             return True
  76         except cloudfiles.errors.NoSuchObject:
  77             return False
  78
  79     def get_file(self, filepath, *args, **kwargs):
  80         """
  81         - Doesn't care about the "mode" argument
  82         """
  83         try:
  84             obj = self.container.get_object(
  85                 self._resolve_filepath(filepath))
  86         except cloudfiles.errors.NoSuchObject:
  87             obj = self.container.create_object(
  88                 self._resolve_filepath(filepath))
  89
  90             mimetype = mimetypes.guess_type(
  91                 filepath[-1])
  92
  93             if mimetype:
  94                 obj.content_type = mimetype[0]
  95
  96         return CloudFilesStorageObjectWrapper(obj, *args, **kwargs)
  97
  98     def delete_file(self, filepath):
  99         # TODO: Also delete unused directories if empty (safely, with
 100         # checks to avoid race conditions).
 101         self.container.delete_object(
 102             self._resolve_filepath(filepath))
 103
 104     def file_url(self, filepath):
 105         return '/'.join([
 106                 self.container_uri,
 107                 self._resolve_filepath(filepath)])
 108
 109
 110 class CloudFilesStorageObjectWrapper():
 111     """
 112     Wrapper for python-cloudfiles's cloudfiles.storage_object.Object
 113     used to circumvent the mystic `medium.jpg` corruption issue, where
 114     we had both python-cloudfiles and PIL doing buffering on both
 115     ends and that breaking things.
 116
 117     This wrapper currently meets mediagoblin's needs for a public_store
 118     file-like object.
 119     """
 120     def __init__(self, storage_object, *args, **kwargs):
 121         self.storage_object = storage_object
 122
 123     def read(self, *args, **kwargs):
 124         return self.storage_object.read(*args, **kwargs)
 125
 126     def write(self, data, *args, **kwargs):
 127         """
 128         write data to the cloudfiles storage object
 129
 130         The original motivation for this wrapper is to ensure
 131         that buffered writing to a cloudfiles storage object does not overwrite
 132         any preexisting data.
 133
 134         Currently this method does not support any write modes except "append".
 135         However if we should need it it would be easy implement.
 136         """
 137         if self.storage_object.size and type(data) == str:
 138             data = self.read() + data
 139
 140         self.storage_object.write(data, *args, **kwargs)
 141
 142     def close(self):
 143         pass
 144
 145     def __enter__(self):
 146         """
 147         Context Manager API implementation
 148         http://docs.python.org/library/stdtypes.html#context-manager-types
 149         """
 150         return self
 151
 152     def __exit__(self, *exc_info):
 153         """
 154         Context Manger API implementation
 155         see self.__enter__()
 156         """
 157         self.close()