mediagoblin/media_types/ascii/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 import chardet
  17 import os
  18 import Image
  19 import logging
  20
  21 from mediagoblin import mg_globals as mgg
  22 from mediagoblin.decorators import get_workbench
  23 from mediagoblin.processing import create_pub_filepath
  24 from mediagoblin.media_types.ascii import asciitoimage
  25
  26 _log = logging.getLogger(__name__)
  27
  28 SUPPORTED_EXTENSIONS = ['txt', 'asc', 'nfo']
  29
  30
  31 def sniff_handler(media_file, **kw):
  32     if kw.get('media') is not None:
  33         name, ext = os.path.splitext(kw['media'].filename)
  34         clean_ext = ext[1:].lower()
  35
  36         if clean_ext in SUPPORTED_EXTENSIONS:
  37             return True
  38
  39     return False
  40
  41
  42 @get_workbench
  43 def process_ascii(entry, workbench=None):
  44     """Code to process a txt file. Will be run by celery.
  45
  46     A Workbench() represents a local tempory dir. It is automatically
  47     cleaned up when this function exits.
  48     """
  49     ascii_config = mgg.global_config['media_type:mediagoblin.media_types.ascii']
  50     # Conversions subdirectory to avoid collisions
  51     conversions_subdir = os.path.join(
  52         workbench.dir, 'conversions')
  53     os.mkdir(conversions_subdir)
  54
  55     queued_filepath = entry.queued_media_file
  56     queued_filename = workbench.localized_file(
  57         mgg.queue_store, queued_filepath,
  58         'source')
  59
  60     queued_file = file(queued_filename, 'rb')
  61
  62     with queued_file:
  63         queued_file_charset = chardet.detect(queued_file.read())
  64
  65         # Only select a non-utf-8 charset if chardet is *really* sure
  66         # Tested with "Feli\x0109an superjaron", which was detecte
  67         if queued_file_charset['confidence'] < 0.9:
  68             interpreted_charset = 'utf-8'
  69         else:
  70             interpreted_charset = queued_file_charset['encoding']
  71
  72         _log.info('Charset detected: {0}\nWill interpret as: {1}'.format(
  73                 queued_file_charset,
  74                 interpreted_charset))
  75
  76         queued_file.seek(0)  # Rewind the queued file
  77
  78         thumb_filepath = create_pub_filepath(
  79             entry, 'thumbnail.png')
  80
  81         tmp_thumb_filename = os.path.join(
  82             conversions_subdir, thumb_filepath[-1])
  83
  84         ascii_converter_args = {}
  85
  86         if ascii_config['thumbnail_font']:
  87             ascii_converter_args.update(
  88                     {'font': ascii_config['thumbnail_font']})
  89
  90         converter = asciitoimage.AsciiToImage(
  91                **ascii_converter_args)
  92
  93         thumb = converter._create_image(
  94             queued_file.read())
  95
  96         with file(tmp_thumb_filename, 'w') as thumb_file:
  97             thumb.thumbnail(
  98                 (mgg.global_config['media:thumb']['max_width'],
  99                  mgg.global_config['media:thumb']['max_height']),
 100                 Image.ANTIALIAS)
 101             thumb.save(thumb_file)
 102
 103         _log.debug('Copying local file to public storage')
 104         mgg.public_store.copy_local_to_storage(
 105             tmp_thumb_filename, thumb_filepath)
 106
 107         queued_file.seek(0)
 108
 109         original_filepath = create_pub_filepath(entry, queued_filepath[-1])
 110
 111         with mgg.public_store.get_file(original_filepath, 'wb') \
 112             as original_file:
 113             original_file.write(queued_file.read())
 114
 115         queued_file.seek(0)  # Rewind *again*
 116
 117         unicode_filepath = create_pub_filepath(entry, 'ascii-portable.txt')
 118
 119         with mgg.public_store.get_file(unicode_filepath, 'wb') \
 120                 as unicode_file:
 121             # Decode the original file from its detected charset (or UTF8)
 122             # Encode the unicode instance to ASCII and replace any non-ASCII
 123             # with an HTML entity (&#
 124             unicode_file.write(
 125                 unicode(queued_file.read().decode(
 126                         interpreted_charset)).encode(
 127                     'ascii',
 128                     'xmlcharrefreplace'))
 129
 130     # Remove queued media file from storage and database.
 131     # queued_filepath is in the task_id directory which should
 132     # be removed too, but fail if the directory is not empty to be on
 133     # the super-safe side.
 134     mgg.queue_store.delete_file(queued_filepath)      # rm file
 135     mgg.queue_store.delete_dir(queued_filepath[:-1])  # rm dir
 136     entry.queued_media_file = []
 137
 138     media_files_dict = entry.setdefault('media_files', {})
 139     media_files_dict['thumb'] = thumb_filepath
 140     media_files_dict['unicode'] = unicode_filepath
 141     media_files_dict['original'] = original_filepath
 142
 143     entry.save()