mediagoblin/media_types/image/processing.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 Image
  18 import os
  19 import logging
  20
  21 from mediagoblin import mg_globals as mgg
  22 from mediagoblin.processing import BadMediaFail, \
  23     create_pub_filepath, FilenameBuilder
  24 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  25     extract_exif, clean_exif, get_gps_data, get_useful, \
  26     exif_image_needs_rotation
  27
  28 _log = logging.getLogger(__name__)
  29
  30 PIL_FILTERS = {
  31     'NEAREST': Image.NEAREST,
  32     'BILINEAR': Image.BILINEAR,
  33     'BICUBIC': Image.BICUBIC,
  34     'ANTIALIAS': Image.ANTIALIAS}
  35
  36
  37 def resize_image(entry, filename, new_path, exif_tags, workdir, new_size,
  38                  size_limits=(0, 0)):
  39     """
  40     Store a resized version of an image and return its pathname.
  41
  42     Arguments:
  43     entry -- the entry for the image to resize
  44     filename -- the filename of the original image being resized
  45     new_path -- public file path for the new resized image
  46     exif_tags -- EXIF data for the original image
  47     workdir -- directory path for storing converted image files
  48     new_size -- 2-tuple size for the resized image
  49     """
  50     try:
  51         resized = Image.open(filename)
  52     except IOError:
  53         raise BadMediaFail()
  54     resized = exif_fix_image_orientation(resized, exif_tags)  # Fix orientation
  55
  56     filter_config = \
  57             mgg.global_config['media_type:mediagoblin.media_types.image']\
  58                 ['resize_filter']
  59
  60     try:
  61         resize_filter = PIL_FILTERS[filter_config.upper()]
  62     except KeyError:
  63         raise Exception('Filter "{0}" not found, choose one of {1}'.format(
  64             unicode(filter_config),
  65             u', '.join(PIL_FILTERS.keys())))
  66
  67     resized.thumbnail(new_size, resize_filter)
  68
  69     # Copy the new file to the conversion subdir, then remotely.
  70     tmp_resized_filename = os.path.join(workdir, new_path[-1])
  71     with file(tmp_resized_filename, 'w') as resized_file:
  72         resized.save(resized_file)
  73     mgg.public_store.copy_local_to_storage(tmp_resized_filename, new_path)
  74
  75
  76 SUPPORTED_FILETYPES = ['png', 'gif', 'jpg', 'jpeg']
  77
  78
  79 def sniff_handler(media_file, **kw):
  80     if kw.get('media') is not None:  # That's a double negative!
  81         name, ext = os.path.splitext(kw['media'].filename)
  82         clean_ext = ext[1:].lower()  # Strip the . from ext and make lowercase
  83
  84         if clean_ext in SUPPORTED_FILETYPES:
  85             _log.info('Found file extension in supported filetypes')
  86             return True
  87         else:
  88             _log.debug('Media present, extension not found in {0}'.format(
  89                     SUPPORTED_FILETYPES))
  90     else:
  91         _log.warning('Need additional information (keyword argument \'media\')'
  92                      ' to be able to handle sniffing')
  93
  94     return False
  95
  96
  97 def process_image(proc_state):
  98     """Code to process an image. Will be run by celery.
  99
 100     A Workbench() represents a local tempory dir. It is automatically
 101     cleaned up when this function exits.
 102     """
 103     entry = proc_state.entry
 104     workbench = proc_state.workbench
 105
 106     # Conversions subdirectory to avoid collisions
 107     conversions_subdir = os.path.join(
 108         workbench.dir, 'conversions')
 109     os.mkdir(conversions_subdir)
 110
 111     queued_filename = proc_state.get_queued_filename()
 112     name_builder = FilenameBuilder(queued_filename)
 113
 114     # EXIF extraction
 115     exif_tags = extract_exif(queued_filename)
 116     gps_data = get_gps_data(exif_tags)
 117
 118     # Always create a small thumbnail
 119     thumb_filepath = create_pub_filepath(
 120         entry, name_builder.fill('{basename}.thumbnail{ext}'))
 121     resize_image(entry, queued_filename, thumb_filepath,
 122                 exif_tags, conversions_subdir,
 123                 (mgg.global_config['media:thumb']['max_width'],
 124                  mgg.global_config['media:thumb']['max_height']))
 125     entry.media_files[u'thumb'] = thumb_filepath
 126
 127     # If the size of the original file exceeds the specified size of a `medium`
 128     # file, a `.medium.jpg` files is created and later associated with the media
 129     # entry.
 130     medium = Image.open(queued_filename)
 131     if medium.size[0] > mgg.global_config['media:medium']['max_width'] \
 132         or medium.size[1] > mgg.global_config['media:medium']['max_height'] \
 133         or exif_image_needs_rotation(exif_tags):
 134         medium_filepath = create_pub_filepath(
 135             entry, name_builder.fill('{basename}.medium{ext}'))
 136         resize_image(
 137             entry, queued_filename, medium_filepath,
 138             exif_tags, conversions_subdir,
 139             (mgg.global_config['media:medium']['max_width'],
 140              mgg.global_config['media:medium']['max_height']))
 141         entry.media_files[u'medium'] = medium_filepath
 142
 143     # Copy our queued local workbench to its final destination
 144     proc_state.copy_original(name_builder.fill('{basename}{ext}'))
 145
 146     # Remove queued media file from storage and database
 147     proc_state.delete_queue_file()
 148
 149     # Insert exif data into database
 150     exif_all = clean_exif(exif_tags)
 151
 152     if len(exif_all):
 153         entry.media_data_init(exif_all=exif_all)
 154
 155     if len(gps_data):
 156         for key in list(gps_data.keys()):
 157             gps_data['gps_' + key] = gps_data.pop(key)
 158         entry.media_data_init(**gps_data)
 159
 160
 161 if __name__ == '__main__':
 162     import sys
 163     import pprint
 164
 165     pp = pprint.PrettyPrinter()
 166
 167     result = extract_exif(sys.argv[1])
 168     gps = get_gps_data(result)
 169     clean = clean_exif(result)
 170     useful = get_useful(clean)
 171
 172     print pp.pprint(
 173         clean)