mediagoblin/media_types/__init__.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 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 import os
  18 import sys
  19 import logging
  20 import tempfile
  21
  22 from mediagoblin import mg_globals
  23 from mediagoblin.tools.translate import lazy_pass_to_ugettext as _
  24
  25 _log = logging.getLogger(__name__)
  26
  27 class FileTypeNotSupported(Exception):
  28     pass
  29
  30 class InvalidFileType(Exception):
  31     pass
  32
  33
  34 def sniff_media(media):
  35     '''
  36     Iterate through the enabled media types and find those suited
  37     for a certain file.
  38     '''
  39     media_file = tempfile.NamedTemporaryFile()
  40     media_file.write(media.file.read())
  41     media.file.seek(0)
  42     for media_type, manager in get_media_managers():
  43         _log.info('Sniffing {0}'.format(media_type))
  44         if manager['sniff_handler'](media_file, media=media):
  45             return media_type, manager
  46
  47     raise FileTypeNotSupported(
  48         # TODO: Provide information on which file types are supported
  49         _(u'Sorry, I don\'t support that file type :('))
  50
  51
  52 def get_media_types():
  53     """
  54     Generator, yields the available media types
  55     """
  56     for media_type in mg_globals.app_config['media_types']:
  57         yield media_type
  58
  59
  60 def get_media_managers():
  61     '''
  62     Generator, yields all enabled media managers
  63     '''
  64     for media_type in get_media_types():
  65         __import__(media_type)
  66
  67         yield media_type, sys.modules[media_type].MEDIA_MANAGER
  68
  69
  70 def get_media_manager(_media_type):
  71     '''
  72     Get the MEDIA_MANAGER based on a media type string
  73
  74     Example::
  75         get_media_type('mediagoblin.media_types.image')
  76     '''
  77     if not _media_type:
  78         return False
  79
  80     for media_type, manager in get_media_managers():
  81         if media_type in _media_type:
  82             return manager
  83
  84     # Nope?  Then raise an error
  85     raise FileTypeNotSupported(
  86         "MediaManager not in enabled types.  Check media_types in config?")
  87
  88
  89 def get_media_type_and_manager(filename):
  90     '''
  91     Get the media type and manager based on a filename
  92     '''
  93     if filename.find('.') > 0:
  94         # Get the file extension
  95         ext = os.path.splitext(filename)[1].lower()
  96     else:
  97         raise InvalidFileType(
  98             _(u'Could not extract any file extension from "{filename}"').format(
  99                 filename=filename))
 100
 101     for media_type, manager in get_media_managers():
 102         # Omit the dot from the extension and match it against
 103         # the media manager
 104         if ext[1:] in manager['accepted_extensions']:
 105             return media_type, manager
 106     else:
 107         raise FileTypeNotSupported(
 108             # TODO: Provide information on which file types are supported
 109             _(u'Sorry, I don\'t support that file type :('))