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