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, FilenameBuilder
  26 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  27     extract_exif, clean_exif, get_gps_data, get_useful, \
  28     exif_image_needs_rotation
  29
  30 _log = logging.getLogger(__name__)
  31
  32 PIL_FILTERS = {
  33     'NEAREST': Image.NEAREST,
  34     'BILINEAR': Image.BILINEAR,
  35     'BICUBIC': Image.BICUBIC,
  36     'ANTIALIAS': Image.ANTIALIAS}
  37
  38
  39 def resize_image(proc_state, resized, keyname, target_name, new_size,
  40                  exif_tags, workdir):
  41     """
  42     Store a resized version of an image and return its pathname.
  43
  44     Arguments:
  45     proc_state -- the processing state for the image to resize
  46     resized -- an image from Image.open() of the original image being resized
  47     keyname -- Under what key to save in the db.
  48     target_name -- 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     config = mgg.global_config['media_type:mediagoblin.media_types.image']
  54
  55     resized = exif_fix_image_orientation(resized, exif_tags)  # Fix orientation
  56
  57     filter_config = config['resize_filter']
  58     try:
  59         resize_filter = PIL_FILTERS[filter_config.upper()]
  60     except KeyError:
  61         raise Exception('Filter "{0}" not found, choose one of {1}'.format(
  62             unicode(filter_config),
  63             u', '.join(PIL_FILTERS.keys())))
  64
  65     resized.thumbnail(new_size, resize_filter)
  66
  67     # Copy the new file to the conversion subdir, then remotely.
  68     tmp_resized_filename = os.path.join(workdir, target_name)
  69     with file(tmp_resized_filename, 'w') as resized_file:
  70         resized.save(resized_file, quality=config['quality'])
  71     proc_state.store_public(keyname, tmp_resized_filename, target_name)
  72
  73
  74 def resize_tool(proc_state, force, keyname, target_name,
  75                 conversions_subdir, exif_tags):
  76     # filename -- the filename of the original image being resized
  77     filename = proc_state.get_queued_filename()
  78     max_width = mgg.global_config['media:' + keyname]['max_width']
  79     max_height = mgg.global_config['media:' + keyname]['max_height']
  80     # If the size of the original file exceeds the specified size for the desized
  81     # file, a target_name file is created and later associated with the media
  82     # entry.
  83     # Also created if the file needs rotation, or if forced.
  84     try:
  85         im = Image.open(filename)
  86     except IOError:
  87         raise BadMediaFail()
  88     if force \
  89         or im.size[0] > max_width \
  90         or im.size[1] > max_height \
  91         or exif_image_needs_rotation(exif_tags):
  92         resize_image(
  93             proc_state, im, unicode(keyname), target_name,
  94             (max_width, max_height),
  95             exif_tags, conversions_subdir)
  96
  97
  98 SUPPORTED_FILETYPES = ['png', 'gif', 'jpg', 'jpeg']
  99
 100
 101 def sniff_handler(media_file, **kw):
 102     if kw.get('media') is not None:  # That's a double negative!
 103         name, ext = os.path.splitext(kw['media'].filename)
 104         clean_ext = ext[1:].lower()  # Strip the . from ext and make lowercase
 105
 106         if clean_ext in SUPPORTED_FILETYPES:
 107             _log.info('Found file extension in supported filetypes')
 108             return True
 109         else:
 110             _log.debug('Media present, extension not found in {0}'.format(
 111                     SUPPORTED_FILETYPES))
 112     else:
 113         _log.warning('Need additional information (keyword argument \'media\')'
 114                      ' to be able to handle sniffing')
 115
 116     return False
 117
 118
 119 def process_image(proc_state):
 120     """Code to process an image. Will be run by celery.
 121
 122     A Workbench() represents a local tempory dir. It is automatically
 123     cleaned up when this function exits.
 124     """
 125     entry = proc_state.entry
 126     workbench = proc_state.workbench
 127
 128     # Conversions subdirectory to avoid collisions
 129     conversions_subdir = os.path.join(
 130         workbench.dir, 'conversions')
 131     os.mkdir(conversions_subdir)
 132
 133     queued_filename = proc_state.get_queued_filename()
 134     name_builder = FilenameBuilder(queued_filename)
 135
 136     # EXIF extraction
 137     exif_tags = extract_exif(queued_filename)
 138     gps_data = get_gps_data(exif_tags)
 139
 140     # Always create a small thumbnail
 141     resize_tool(proc_state, True, 'thumb',
 142                 name_builder.fill('{basename}.thumbnail{ext}'),
 143                 conversions_subdir, exif_tags)
 144
 145     # Possibly create a medium
 146     resize_tool(proc_state, False, 'medium',
 147                 name_builder.fill('{basename}.medium{ext}'),
 148                 conversions_subdir, exif_tags)
 149
 150     # Copy our queued local workbench to its final destination
 151     proc_state.copy_original(name_builder.fill('{basename}{ext}'))
 152
 153     # Remove queued media file from storage and database
 154     proc_state.delete_queue_file()
 155
 156     # Insert exif data into database
 157     exif_all = clean_exif(exif_tags)
 158
 159     if len(exif_all):
 160         entry.media_data_init(exif_all=exif_all)
 161
 162     if len(gps_data):
 163         for key in list(gps_data.keys()):
 164             gps_data['gps_' + key] = gps_data.pop(key)
 165         entry.media_data_init(**gps_data)
 166
 167
 168 if __name__ == '__main__':
 169     import sys
 170     import pprint
 171
 172     pp = pprint.PrettyPrinter()
 173
 174     result = extract_exif(sys.argv[1])
 175     gps = get_gps_data(result)
 176     clean = clean_exif(result)
 177     useful = get_useful(clean)
 178
 179     print pp.pprint(
 180         clean)