mygpo/web/logo.py

   1 #
   2 # This file is part of my.gpodder.org.
   3 #
   4 # my.gpodder.org is free software: you can redistribute it and/or modify it
   5 # 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 (at your
   7 # option) any later version.
   8 #
   9 # my.gpodder.org is distributed in the hope that it will be useful, but
  10 # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  11 # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
  12 # License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with my.gpodder.org. If not, see <http://www.gnu.org/licenses/>.
  16 #
  17
  18 import os.path
  19 import io
  20 from datetime import datetime
  21 from glob import glob
  22 import errno
  23 import hashlib
  24 import struct
  25
  26 from PIL import Image, ImageDraw
  27
  28 from django.core.urlresolvers import reverse
  29 from django.conf import settings
  30 from django.http import Http404, HttpResponse, HttpResponseNotFound
  31 from django.views.generic.base import View
  32 from django.utils.decorators import method_decorator
  33 from django.views.decorators.http import last_modified
  34 from django.contrib.staticfiles.storage import staticfiles_storage
  35
  36 import logging
  37 logger = logging.getLogger(__name__)
  38
  39 LOGO_DIR = os.path.join(settings.MEDIA_ROOT, 'logo')
  40
  41
  42 def _last_modified(request, size, prefix, filename):
  43
  44     target = os.path.join(LOGO_DIR, size, prefix, filename)
  45
  46     try:
  47         return datetime.fromtimestamp(os.path.getmtime(target))
  48
  49     except OSError:
  50         return None
  51
  52
  53 class CoverArt(View):
  54
  55     @method_decorator(last_modified(_last_modified))
  56     def get(self, request, size, prefix, filename):
  57
  58         size = int(size)
  59
  60         target = self.get_thumbnail(size, prefix, filename)
  61         original = self.get_original(prefix, filename)
  62
  63         if os.path.exists(target):
  64             return self.send_file(target)
  65
  66         if not os.path.exists(original):
  67             raise Http404('Cover Art not available' + original)
  68
  69         target_dir = self.get_dir(target)
  70
  71         try:
  72             im = Image.open(original)
  73             if im.mode not in ('RGB', 'RGBA'):
  74                 im = im.convert('RGB')
  75         except IOError:
  76             raise Http404('Cannot open cover file')
  77
  78         try:
  79             im.thumbnail((size, size), Image.ANTIALIAS)
  80             resized = im
  81         except (struct.error, IOError, IndexError) as ex:
  82             # raised when trying to read an interlaced PNG;
  83             logger.warn('Could not create thumbnail: %s', str(ex))
  84
  85             # we use the original instead
  86             return self.send_file(original)
  87
  88         # If it's a RGBA image, composite it onto a white background for JPEG
  89         if resized.mode == 'RGBA':
  90             background = Image.new('RGB', resized.size)
  91             draw = ImageDraw.Draw(background)
  92             draw.rectangle((-1, -1, resized.size[0]+1, resized.size[1]+1),
  93                            fill=(255, 255, 255))
  94             del draw
  95             resized = Image.composite(resized, background, resized)
  96
  97         sio = io.BytesIO()
  98
  99         try:
 100             resized.save(sio, 'JPEG', optimize=True, progression=True,
 101                          quality=80)
 102         except IOError as ex:
 103             return self.send_file(original)
 104
 105         s = sio.getvalue()
 106
 107         fp = open(target, 'wb')
 108         fp.write(s)
 109         fp.close()
 110
 111         return self.send_file(target)
 112
 113     # the length of the prefix is defined here and in web/urls.py
 114     @staticmethod
 115     def get_prefix(filename):
 116         return filename[:3]
 117
 118     @staticmethod
 119     def get_thumbnail(size, prefix, filename):
 120         return os.path.join(LOGO_DIR, str(size), prefix, filename)
 121
 122     @staticmethod
 123     def get_existing_thumbnails(prefix, filename):
 124         files = glob(os.path.join(LOGO_DIR, '*', prefix, filename))
 125         return [f for f in files if 'original' not in f]
 126
 127     @staticmethod
 128     def get_original(prefix, filename):
 129         return os.path.join(LOGO_DIR, 'original', prefix, filename)
 130
 131     @staticmethod
 132     def get_dir(filename):
 133         path = os.path.dirname(filename)
 134         try:
 135             os.makedirs(path)
 136
 137         except OSError as ose:
 138             if ose.errno != errno.EEXIST:
 139                 raise
 140
 141         return path
 142
 143     def send_file(self, filename):
 144         try:
 145             f = open(filename, 'rb')
 146         except IOError:
 147             return HttpResponseNotFound()
 148
 149         resp = HttpResponse(content_type='image/jpeg')
 150         resp.status_code = 200
 151         resp.write(f.read())
 152         return resp
 153
 154
 155 def get_logo_url(podcast, size):
 156     """ Return the logo URL for the podcast """
 157
 158     if podcast.logo_url:
 159         filename = hashlib.sha1(podcast.logo_url.encode('utf-8')).hexdigest()
 160         prefix = CoverArt.get_prefix(filename)
 161         return reverse('logo', args=[size, prefix, filename])
 162
 163     else:
 164         filename = 'podcast-%d.png' % (hash(podcast.title) % 5, )
 165         return staticfiles_storage.url('logo/{0}'.format(filename))