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 try:
  18     from PIL import Image
  19 except ImportError:
  20     import Image
  21 import os
  22 import logging
  23
  24 from mediagoblin import mg_globals as mgg
  25 from mediagoblin.processing import BadMediaFail, \
  26     create_pub_filepath, FilenameBuilder
  27 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  28     extract_exif, clean_exif, get_gps_data, get_useful, \
  29     exif_image_needs_rotation
  30
  31 _log = logging.getLogger(__name__)
  32
  33 PIL_FILTERS = {
  34     'NEAREST': Image.NEAREST,
  35     'BILINEAR': Image.BILINEAR,
  36     'BICUBIC': Image.BICUBIC,
  37     'ANTIALIAS': Image.ANTIALIAS}
  38
  39
  40 def resize_image(entry, filename, new_path, exif_tags, workdir, new_size,
  41                  size_limits=(0, 0)):
  42     """
  43     Store a resized version of an image and return its pathname.
  44
  45     Arguments:
  46     entry -- the entry for the image to resize
  47     filename -- the filename of the original image being resized
  48     new_path -- public file path for the new resized image
  49     exif_tags -- EXIF data for the original image
  50     workdir -- directory path for storing converted image files
  51     new_size -- 2-tuple size for the resized image
  52     """
  53     try:
  54         resized = Image.open(filename)
  55     except IOError:
  56         raise BadMediaFail()
  57     resized = exif_fix_image_orientation(resized, exif_tags)  # Fix orientation
  58
  59     filter_config = \
  60             mgg.global_config['media_type:mediagoblin.media_types.image']\
  61                 ['resize_filter']
  62
  63     try:
  64         resize_filter = PIL_FILTERS[filter_config.upper()]
  65     except KeyError:
  66         raise Exception('Filter "{0}" not found, choose one of {1}'.format(
  67             unicode(filter_config),
  68             u', '.join(PIL_FILTERS.keys())))
  69
  70     resized.thumbnail(new_size, resize_filter)
  71
  72     # Copy the new file to the conversion subdir, then remotely.
  73     tmp_resized_filename = os.path.join(workdir, new_path[-1])
  74     with file(tmp_resized_filename, 'w') as resized_file:
  75         resized.save(resized_file)
  76     mgg.public_store.copy_local_to_storage(tmp_resized_filename, new_path)
  77
  78
  79 SUPPORTED_FILETYPES = ['png', 'gif', 'jpg', 'jpeg']
  80
  81
  82 def sniff_handler(media_file, **kw):
  83     if kw.get('media') is not None:  # That's a double negative!
  84         name, ext = os.path.splitext(kw['media'].filename)
  85         clean_ext = ext[1:].lower()  # Strip the . from ext and make lowercase
  86
  87         if clean_ext in SUPPORTED_FILETYPES:
  88             _log.info('Found file extension in supported filetypes')
  89             return True
  90         else:
  91             _log.debug('Media present, extension not found in {0}'.format(
  92                     SUPPORTED_FILETYPES))
  93     else:
  94         _log.warning('Need additional information (keyword argument \'media\')'
  95                      ' to be able to handle sniffing')
  96
  97     return False
  98
  99
 100 def process_image(proc_state):
 101     """Code to process an image. Will be run by celery.
 102
 103     A Workbench() represents a local tempory dir. It is automatically
 104     cleaned up when this function exits.
 105     """
 106     entry = proc_state.entry
 107     workbench = proc_state.workbench
 108
 109     # Conversions subdirectory to avoid collisions
 110     conversions_subdir = os.path.join(
 111         workbench.dir, 'conversions')
 112     os.mkdir(conversions_subdir)
 113
 114     queued_filename = proc_state.get_queued_filename()
 115     name_builder = FilenameBuilder(queued_filename)
 116
 117     # EXIF extraction
 118     exif_tags = extract_exif(queued_filename)
 119     gps_data = get_gps_data(exif_tags)
 120
 121     # Always create a small thumbnail
 122     thumb_filepath = create_pub_filepath(
 123         entry, name_builder.fill('{basename}.thumbnail{ext}'))
 124     resize_image(entry, queued_filename, thumb_filepath,
 125                 exif_tags, conversions_subdir,
 126                 (mgg.global_config['media:thumb']['max_width'],
 127                  mgg.global_config['media:thumb']['max_height']))
 128     entry.media_files[u'thumb'] = thumb_filepath
 129
 130     # If the size of the original file exceeds the specified size of a `medium`
 131     # file, a `.medium.jpg` files is created and later associated with the media
 132     # entry.
 133     medium = Image.open(queued_filename)
 134     if medium.size[0] > mgg.global_config['media:medium']['max_width'] \
 135         or medium.size[1] > mgg.global_config['media:medium']['max_height'] \
 136         or exif_image_needs_rotation(exif_tags):
 137         medium_filepath = create_pub_filepath(
 138             entry, name_builder.fill('{basename}.medium{ext}'))
 139         resize_image(
 140             entry, queued_filename, medium_filepath,
 141             exif_tags, conversions_subdir,
 142             (mgg.global_config['media:medium']['max_width'],
 143              mgg.global_config['media:medium']['max_height']))
 144         entry.media_files[u'medium'] = medium_filepath
 145
 146     # Copy our queued local workbench to its final destination
 147     proc_state.copy_original(name_builder.fill('{basename}{ext}'))
 148
 149     # Remove queued media file from storage and database
 150     proc_state.delete_queue_file()
 151
 152     # Insert exif data into database
 153     exif_all = clean_exif(exif_tags)
 154
 155     if len(exif_all):
 156         entry.media_data_init(exif_all=exif_all)
 157
 158     if len(gps_data):
 159         for key in list(gps_data.keys()):
 160             gps_data['gps_' + key] = gps_data.pop(key)
 161         entry.media_data_init(**gps_data)
 162
 163
 164 if __name__ == '__main__':
 165     import sys
 166     import pprint
 167
 168     pp = pprint.PrettyPrinter()
 169
 170     result = extract_exif(sys.argv[1])
 171     gps = get_gps_data(result)
 172     clean = clean_exif(result)
 173     useful = get_useful(clean)
 174
 175     print pp.pprint(
 176         clean)