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
  20 from mediagoblin import mg_globals as mgg
  21 from mediagoblin.processing import BadMediaFail, \
  22     create_pub_filepath, THUMB_SIZE, MEDIUM_SIZE, FilenameBuilder
  23 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  24     extract_exif, clean_exif, get_gps_data, get_useful
  25
  26 def resize_image(entry, filename, new_path, exif_tags, workdir, new_size,
  27                  size_limits=(0, 0)):
  28     """Store a resized version of an image and return its pathname.
  29
  30     Arguments:
  31     entry -- the entry for the image to resize
  32     filename -- the filename of the original image being resized
  33     new_path -- public file path for the new resized image
  34     exif_tags -- EXIF data for the original image
  35     workdir -- directory path for storing converted image files
  36     new_size -- 2-tuple size for the resized image
  37     size_limits (optional) -- image is only resized if it exceeds this size
  38
  39     """
  40     try:
  41         resized = Image.open(filename)
  42     except IOError:
  43         raise BadMediaFail()
  44     resized = exif_fix_image_orientation(resized, exif_tags)  # Fix orientation
  45
  46     if ((resized.size[0] > size_limits[0]) or
  47         (resized.size[1] > size_limits[1])):
  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 def process_image(entry):
  57     """
  58     Code to process an image
  59     """
  60     workbench = mgg.workbench_manager.create_workbench()
  61     # Conversions subdirectory to avoid collisions
  62     conversions_subdir = os.path.join(
  63         workbench.dir, 'conversions')
  64     os.mkdir(conversions_subdir)
  65
  66     queued_filepath = entry.queued_media_file
  67     queued_filename = workbench.localized_file(
  68         mgg.queue_store, queued_filepath,
  69         'source')
  70     name_builder = FilenameBuilder(queued_filename)
  71
  72     # EXIF extraction
  73     exif_tags = extract_exif(queued_filename)
  74     gps_data = get_gps_data(exif_tags)
  75
  76     # Always create a small thumbnail
  77     thumb_filepath = create_pub_filepath(
  78         entry, name_builder.fill('{basename}.thumbnail{ext}'))
  79     resize_image(entry, queued_filename, thumb_filepath,
  80                  exif_tags, conversions_subdir, THUMB_SIZE)
  81
  82     # If the size of the original file exceeds the specified size of a `medium`
  83     # file, a `.medium.jpg` files is created and later associated with the media
  84     # entry.
  85     medium_filepath = create_pub_filepath(
  86         entry, name_builder.fill('{basename}.medium{ext}'))
  87     resize_image(entry, queued_filename, medium_filepath,
  88                  exif_tags, conversions_subdir, MEDIUM_SIZE, MEDIUM_SIZE)
  89
  90     # we have to re-read because unlike PIL, not everything reads
  91     # things in string representation :)
  92     queued_file = file(queued_filename, 'rb')
  93
  94     with queued_file:
  95         original_filepath = create_pub_filepath(
  96             entry, name_builder.fill('{basename}{ext}') )
  97
  98         with mgg.public_store.get_file(original_filepath, 'wb') \
  99             as original_file:
 100             original_file.write(queued_file.read())
 101
 102     # Remove queued media file from storage and database
 103     mgg.queue_store.delete_file(queued_filepath)
 104     entry.queued_media_file = []
 105
 106     # Insert media file information into database
 107     media_files_dict = entry.setdefault('media_files', {})
 108     media_files_dict['thumb'] = thumb_filepath
 109     media_files_dict['original'] = original_filepath
 110     media_files_dict['medium'] = medium_filepath
 111
 112     # Insert exif data into database
 113     exif_all = clean_exif(exif_tags)
 114
 115     if len(exif_all):
 116         entry.media_data_init(exif_all=exif_all)
 117
 118     if len(gps_data):
 119         for key in list(gps_data.keys()):
 120             gps_data['gps_' + key] = gps_data.pop(key)
 121         entry.media_data_init(**gps_data)
 122
 123     # clean up workbench
 124     workbench.destroy_self()
 125
 126 if __name__ == '__main__':
 127     import sys
 128     import pprint
 129
 130     pp = pprint.PrettyPrinter()
 131
 132     result = extract_exif(sys.argv[1])
 133     gps = get_gps_data(result)
 134     clean = clean_exif(result)
 135     useful = get_useful(clean)
 136
 137     print pp.pprint(
 138         clean)