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
  23 from mediagoblin.tools.exif import exif_fix_image_orientation, \
  24     extract_exif, clean_exif, get_gps_data, get_useful
  25
  26 MAX_FILENAME_LENGTH = 255  # the limit in VFAT -- seems like a good baseline
  27
  28 def resize_image(entry, filename, basename, file_tail, exif_tags, workdir,
  29                  new_size, size_limits=(0, 0)):
  30     """Store a resized version of an image and return its pathname.
  31
  32     Arguments:
  33     entry -- the entry for the image to resize
  34     filename -- the filename of the original image being resized
  35     basename -- simple basename of the given filename
  36     file_tail -- ending string and extension for the resized filename
  37     exif_tags -- EXIF data for the original image
  38     workdir -- directory path for storing converted image files
  39     new_size -- 2-tuple size for the resized image
  40     size_limits (optional) -- image is only resized if it exceeds this size
  41
  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
  49     if ((resized.size[0] > size_limits[0]) or
  50         (resized.size[1] > size_limits[1])):
  51         resized.thumbnail(new_size, Image.ANTIALIAS)
  52
  53     # Truncate basename as needed so len(basename + file_tail) <= 255
  54     resized_filename = (basename[:MAX_FILENAME_LENGTH - len(file_tail)] +
  55                         file_tail)
  56     resized_filepath = create_pub_filepath(entry, resized_filename)
  57
  58     # Copy the new file to the conversion subdir, then remotely.
  59     tmp_resized_filename = os.path.join(workdir, resized_filename)
  60     with file(tmp_resized_filename, 'w') as resized_file:
  61         resized.save(resized_file)
  62     mgg.public_store.copy_local_to_storage(
  63         tmp_resized_filename, resized_filepath)
  64     return resized_filepath
  65
  66 def process_image(entry):
  67     """
  68     Code to process an image
  69     """
  70     workbench = mgg.workbench_manager.create_workbench()
  71     # Conversions subdirectory to avoid collisions
  72     conversions_subdir = os.path.join(
  73         workbench.dir, 'conversions')
  74     os.mkdir(conversions_subdir)
  75
  76     queued_filepath = entry.queued_media_file
  77     queued_filename = workbench.localized_file(
  78         mgg.queue_store, queued_filepath,
  79         'source')
  80
  81     filename_bits = os.path.splitext(queued_filename)
  82     basename = os.path.split(filename_bits[0])[1]
  83     extension = filename_bits[1].lower()
  84
  85     # EXIF extraction
  86     exif_tags = extract_exif(queued_filename)
  87     gps_data = get_gps_data(exif_tags)
  88
  89     # Always create a small thumbnail
  90     thumb_filepath = resize_image(entry, queued_filename, basename,
  91                                   '.thumbnail' + extension, exif_tags,
  92                                   conversions_subdir, THUMB_SIZE)
  93
  94     # If the size of the original file exceeds the specified size of a `medium`
  95     # file, a `.medium.jpg` files is created and later associated with the media
  96     # entry.
  97     medium_filepath = resize_image(entry, queued_filename, basename,
  98                                    '.medium' + extension, exif_tags,
  99                                    conversions_subdir, MEDIUM_SIZE, MEDIUM_SIZE)
 100
 101     # we have to re-read because unlike PIL, not everything reads
 102     # things in string representation :)
 103     queued_file = file(queued_filename, 'rb')
 104
 105     with queued_file:
 106         #create_pub_filepath(entry, queued_filepath[-1])
 107         original_filepath = create_pub_filepath(entry, basename + extension)
 108
 109         with mgg.public_store.get_file(original_filepath, 'wb') \
 110             as original_file:
 111             original_file.write(queued_file.read())
 112
 113     # Remove queued media file from storage and database
 114     mgg.queue_store.delete_file(queued_filepath)
 115     entry.queued_media_file = []
 116
 117     # Insert media file information into database
 118     media_files_dict = entry.setdefault('media_files', {})
 119     media_files_dict['thumb'] = thumb_filepath
 120     media_files_dict['original'] = original_filepath
 121     media_files_dict['medium'] = medium_filepath
 122
 123     # Insert exif data into database
 124     media_data = entry.setdefault('media_data', {})
 125
 126     # TODO: Fix for sql media_data, when exif is in sql
 127     if media_data is not None:
 128         media_data['exif'] = {
 129             'clean': clean_exif(exif_tags)}
 130         media_data['exif']['useful'] = get_useful(
 131             media_data['exif']['clean'])
 132
 133     if len(gps_data):
 134         for key in list(gps_data.keys()):
 135             gps_data['gps_' + key] = gps_data.pop(key)
 136         entry.media_data_init(**gps_data)
 137
 138     # clean up workbench
 139     workbench.destroy_self()
 140
 141 if __name__ == '__main__':
 142     import sys
 143     import pprint
 144
 145     pp = pprint.PrettyPrinter()
 146
 147     result = extract_exif(sys.argv[1])
 148     gps = get_gps_data(result)
 149     clean = clean_exif(result)
 150     useful = get_useful(clean)
 151
 152     print pp.pprint(
 153         clean)