mediagoblin/media_types/image/processing.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011 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 celery.task import Task
  21 from celery import registry
  22
  23 from mediagoblin.db.util import ObjectId
  24 from mediagoblin import mg_globals as mgg
  25
  26 from mediagoblin.processing import BaseProcessingFail, \
  27     mark_entry_failed, BadMediaFail, create_pub_filepath, THUMB_SIZE, \
  28     MEDIUM_SIZE
  29
  30 ################################
  31 # Media processing initial steps
  32 ################################
  33
  34
  35 def process_image(entry):
  36     """
  37     Code to process an image
  38     """
  39     workbench = mgg.workbench_manager.create_workbench()
  40     # Conversions subdirectory to avoid collisions
  41     conversions_subdir = os.path.join(
  42         workbench.dir, 'conversions')
  43     os.mkdir(conversions_subdir)
  44
  45     queued_filepath = entry['queued_media_file']
  46     queued_filename = workbench.localized_file(
  47         mgg.queue_store, queued_filepath,
  48         'source')
  49
  50     extension = os.path.splitext(queued_filename)[1]
  51
  52     try:
  53         thumb = Image.open(queued_filename)
  54     except IOError:
  55         raise BadMediaFail()
  56
  57     thumb.thumbnail(THUMB_SIZE, Image.ANTIALIAS)
  58
  59     # Copy the thumb to the conversion subdir, then remotely.
  60     thumb_filename = 'thumbnail' + extension
  61     thumb_filepath = create_pub_filepath(entry, thumb_filename)
  62     tmp_thumb_filename = os.path.join(
  63         conversions_subdir, thumb_filename)
  64     with file(tmp_thumb_filename, 'w') as thumb_file:
  65         thumb.save(thumb_file)
  66     mgg.public_store.copy_local_to_storage(
  67         tmp_thumb_filename, thumb_filepath)
  68
  69     # If the size of the original file exceeds the specified size of a `medium`
  70     # file, a `medium.jpg` files is created and later associated with the media
  71     # entry.
  72     medium = Image.open(queued_filename)
  73     medium_processed = False
  74
  75     if medium.size[0] > MEDIUM_SIZE[0] or medium.size[1] > MEDIUM_SIZE[1]:
  76         medium.thumbnail(MEDIUM_SIZE, Image.ANTIALIAS)
  77
  78         medium_filename = 'medium' + extension
  79         medium_filepath = create_pub_filepath(entry, medium_filename)
  80         tmp_medium_filename = os.path.join(
  81             conversions_subdir, medium_filename)
  82
  83         with file(tmp_medium_filename, 'w') as medium_file:
  84             medium.save(medium_file)
  85
  86         mgg.public_store.copy_local_to_storage(
  87             tmp_medium_filename, medium_filepath)
  88
  89         medium_processed = True
  90
  91     # we have to re-read because unlike PIL, not everything reads
  92     # things in string representation :)
  93     queued_file = file(queued_filename, 'rb')
  94
  95     with queued_file:
  96         original_filepath = create_pub_filepath(entry, queued_filepath[-1])
  97
  98         with mgg.public_store.get_file(original_filepath, 'wb') \
  99             as original_file:
 100             original_file.write(queued_file.read())
 101
 102     mgg.queue_store.delete_file(queued_filepath)
 103     entry['queued_media_file'] = []
 104     media_files_dict = entry.setdefault('media_files', {})
 105     media_files_dict['thumb'] = thumb_filepath
 106     media_files_dict['original'] = original_filepath
 107     if medium_processed:
 108         media_files_dict['medium'] = medium_filepath
 109
 110     # clean up workbench
 111     workbench.destroy_self()