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 PIL_FILTERS = {
  32     'NEAREST': Image.NEAREST,
  33     'BILINEAR': Image.BILINEAR,
  34     'BICUBIC': Image.BICUBIC,
  35     'ANTIALIAS': Image.ANTIALIAS}
  36
  37
  38 def resize_image(entry, filename, new_path, exif_tags, workdir, new_size,
  39                  size_limits=(0, 0)):
  40     """
  41     Store a resized version of an image and return its pathname.
  42
  43     Arguments:
  44     entry -- the entry for the image to resize
  45     filename -- the filename of the original image being resized
  46     new_path -- public file path for the new resized image
  47     exif_tags -- EXIF data for the original image
  48     workdir -- directory path for storing converted image files
  49     new_size -- 2-tuple size for the resized image
  50     """
  51     try:
  52         resized = Image.open(filename)
  53     except IOError:
  54         raise BadMediaFail()
  55     resized = exif_fix_image_orientation(resized, exif_tags)  # Fix orientation
  56
  57     filter_config = \
  58             mgg.global_config['media_type:mediagoblin.media_types.image']\
  59                 ['resize_filter']
  60
  61     try:
  62         resize_filter = PIL_FILTERS[filter_config.upper()]
  63     except KeyError:
  64         raise Exception('Filter "{0}" not found, choose one of {1}'.format(
  65             unicode(filter_config),
  66             u', '.join(PIL_FILTERS.keys())))
  67
  68     resized.thumbnail(new_size, resize_filter)
  69
  70     # Copy the new file to the conversion subdir, then remotely.
  71     tmp_resized_filename = os.path.join(workdir, new_path[-1])
  72     with file(tmp_resized_filename, 'w') as resized_file:
  73         resized.save(resized_file)
  74     mgg.public_store.copy_local_to_storage(tmp_resized_filename, new_path)
  75
  76
  77 SUPPORTED_FILETYPES = ['png', 'gif', 'jpg', 'jpeg']
  78
  79
  80 def sniff_handler(media_file, **kw):
  81     if kw.get('media') is not None:  # That's a double negative!
  82         name, ext = os.path.splitext(kw['media'].filename)
  83         clean_ext = ext[1:].lower()  # Strip the . from ext and make lowercase
  84
  85         if clean_ext in SUPPORTED_FILETYPES:
  86             _log.info('Found file extension in supported filetypes')
  87             return True
  88         else:
  89             _log.debug('Media present, extension not found in {0}'.format(
  90                     SUPPORTED_FILETYPES))
  91     else:
  92         _log.warning('Need additional information (keyword argument \'media\')'
  93                      ' to be able to handle sniffing')
  94
  95     return False
  96
  97
  98 @get_workbench
  99 def process_image(entry, workbench=None):
 100     """Code to process an image. Will be run by celery.
 101
 102     A Workbench() represents a local tempory dir. It is automatically
 103     cleaned up when this function exits.
 104     """
 105     # Conversions subdirectory to avoid collisions
 106     conversions_subdir = os.path.join(
 107         workbench.dir, 'conversions')
 108     os.mkdir(conversions_subdir)
 109     queued_filepath = entry.queued_media_file
 110     queued_filename = workbench.localized_file(
 111         mgg.queue_store, queued_filepath,
 112         'source')
 113     name_builder = FilenameBuilder(queued_filename)
 114
 115     # EXIF extraction
 116     exif_tags = extract_exif(queued_filename)
 117     gps_data = get_gps_data(exif_tags)
 118
 119     # Always create a small thumbnail
 120     thumb_filepath = create_pub_filepath(
 121         entry, name_builder.fill('{basename}.thumbnail{ext}'))
 122     resize_image(entry, queued_filename, thumb_filepath,
 123                 exif_tags, conversions_subdir,
 124                 (mgg.global_config['media:thumb']['max_width'],
 125                  mgg.global_config['media:thumb']['max_height']))
 126
 127     # If the size of the original file exceeds the specified size of a `medium`
 128     # file, a `.medium.jpg` files is created and later associated with the media
 129     # entry.
 130     medium = Image.open(queued_filename)
 131     if medium.size[0] > mgg.global_config['media:medium']['max_width'] \
 132         or medium.size[1] > mgg.global_config['media:medium']['max_height'] \
 133         or exif_image_needs_rotation(exif_tags):
 134         medium_filepath = create_pub_filepath(
 135             entry, name_builder.fill('{basename}.medium{ext}'))
 136         resize_image(
 137             entry, queued_filename, medium_filepath,
 138             exif_tags, conversions_subdir,
 139             (mgg.global_config['media:medium']['max_width'],
 140              mgg.global_config['media:medium']['max_height']))
 141     else:
 142         medium_filepath = None
 143
 144     # Copy our queued local workbench to its final destination
 145     original_filepath = create_pub_filepath(
 146             entry, name_builder.fill('{basename}{ext}'))
 147     mgg.public_store.copy_local_to_storage(queued_filename, original_filepath)
 148
 149     # Remove queued media file from storage and database
 150     mgg.queue_store.delete_file(queued_filepath)
 151     entry.queued_media_file = []
 152
 153     # Insert media file information into database
 154     media_files_dict = entry.setdefault('media_files', {})
 155     media_files_dict[u'thumb'] = thumb_filepath
 156     media_files_dict[u'original'] = original_filepath
 157     if medium_filepath:
 158         media_files_dict[u'medium'] = medium_filepath
 159
 160     # Insert exif data into database
 161     exif_all = clean_exif(exif_tags)
 162
 163     if len(exif_all):
 164         entry.media_data_init(exif_all=exif_all)
 165
 166     if len(gps_data):
 167         for key in list(gps_data.keys()):
 168             gps_data['gps_' + key] = gps_data.pop(key)
 169         entry.media_data_init(**gps_data)
 170
 171
 172 if __name__ == '__main__':
 173     import sys
 174     import pprint
 175
 176     pp = pprint.PrettyPrinter()
 177
 178     result = extract_exif(sys.argv[1])
 179     gps = get_gps_data(result)
 180     clean = clean_exif(result)
 181     useful = get_useful(clean)
 182
 183     print pp.pprint(
 184         clean)