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