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     exif_image_needs_rotation
  26
  27 def resize_image(entry, filename, new_path, exif_tags, workdir, new_size,
  28                  size_limits=(0, 0)):
  29     """Store a resized version of an image and return its pathname.
  30
  31     Arguments:
  32     entry -- the entry for the image to resize
  33     filename -- the filename of the original image being resized
  34     new_path -- public file path for the new resized image
  35     exif_tags -- EXIF data for the original image
  36     workdir -- directory path for storing converted image files
  37     new_size -- 2-tuple size for the resized image
  38     size_limits (optional) -- image is only resized if it exceeds this size
  39
  40     """
  41     try:
  42         resized = Image.open(filename)
  43     except IOError:
  44         raise BadMediaFail()
  45     resized = exif_fix_image_orientation(resized, exif_tags)  # Fix orientation
  46
  47     if ((resized.size[0] > size_limits[0]) or
  48         (resized.size[1] > size_limits[1])):
  49         resized.thumbnail(new_size, Image.ANTIALIAS)
  50
  51     # Copy the new file to the conversion subdir, then remotely.
  52     tmp_resized_filename = os.path.join(workdir, new_path[-1])
  53     with file(tmp_resized_filename, 'w') as resized_file:
  54         resized.save(resized_file)
  55     mgg.public_store.copy_local_to_storage(tmp_resized_filename, new_path)
  56
  57 def process_image(entry):
  58     """
  59     Code to process an image
  60     """
  61     workbench = mgg.workbench_manager.create_workbench()
  62     # Conversions subdirectory to avoid collisions
  63     conversions_subdir = os.path.join(
  64         workbench.dir, 'conversions')
  65     os.mkdir(conversions_subdir)
  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 = Image.open(queued_filename)
  86     if medium.size[0] > MEDIUM_SIZE[0] or medium.size[1] > MEDIUM_SIZE[1] \
  87             or exif_image_needs_rotation(exif_tags):
  88         medium_filepath = create_pub_filepath(
  89             entry, name_builder.fill('{basename}.medium{ext}'))
  90         resize_image(
  91             entry, queued_filename, medium_filepath,
  92             exif_tags, conversions_subdir, MEDIUM_SIZE, MEDIUM_SIZE)
  93     else:
  94         medium_filepath = None
  95
  96     # we have to re-read because unlike PIL, not everything reads
  97     # things in string representation :)
  98     queued_file = file(queued_filename, 'rb')
  99
 100     with queued_file:
 101         original_filepath = create_pub_filepath(
 102             entry, name_builder.fill('{basename}{ext}') )
 103
 104         with mgg.public_store.get_file(original_filepath, 'wb') \
 105             as original_file:
 106             original_file.write(queued_file.read())
 107
 108     # Remove queued media file from storage and database
 109     mgg.queue_store.delete_file(queued_filepath)
 110     entry.queued_media_file = []
 111
 112     # Insert media file information into database
 113     media_files_dict = entry.setdefault('media_files', {})
 114     media_files_dict['thumb'] = thumb_filepath
 115     media_files_dict['original'] = original_filepath
 116     if medium_filepath:
 117         media_files_dict['medium'] = medium_filepath
 118
 119     # Insert exif data into database
 120     exif_all = clean_exif(exif_tags)
 121
 122     if len(exif_all):
 123         entry.media_data_init(exif_all=exif_all)
 124
 125     if len(gps_data):
 126         for key in list(gps_data.keys()):
 127             gps_data['gps_' + key] = gps_data.pop(key)
 128         entry.media_data_init(**gps_data)
 129
 130     # clean up workbench
 131     workbench.destroy_self()
 132
 133 if __name__ == '__main__':
 134     import sys
 135     import pprint
 136
 137     pp = pprint.PrettyPrinter()
 138
 139     result = extract_exif(sys.argv[1])
 140     gps = get_gps_data(result)
 141     clean = clean_exif(result)
 142     useful = get_useful(clean)
 143
 144     print pp.pprint(
 145         clean)