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