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
  35 import logging
  36 logger = logging.getLogger(__name__)
  37
  38 LOGO_DIR = os.path.join(settings.BASE_DIR, '..', 'htdocs', 'media', 'logo')
  39
  40
  41 def _last_modified(request, size, prefix, filename):
  42
  43     target = os.path.join(LOGO_DIR, size, prefix, filename)
  44
  45     try:
  46         return datetime.fromtimestamp(os.path.getmtime(target))
  47
  48     except OSError:
  49         return None
  50
  51
  52 class CoverArt(View):
  53
  54     @method_decorator(last_modified(_last_modified))
  55     def get(self, request, size, prefix, filename):
  56
  57         size = int(size)
  58
  59         target = self.get_thumbnail(size, prefix, filename)
  60         original = self.get_original(prefix, filename)
  61
  62         if os.path.exists(target):
  63             return self.send_file(target)
  64
  65         if not os.path.exists(original):
  66             raise Http404('Cover Art not available' + original)
  67
  68         target_dir = self.get_dir(target)
  69
  70         try:
  71             im = Image.open(original)
  72             if im.mode not in ('RGB', 'RGBA'):
  73                 im = im.convert('RGB')
  74         except IOError:
  75             raise Http404('Cannot open cover file')
  76
  77         try:
  78             im.thumbnail((size, size), Image.ANTIALIAS)
  79             resized = im
  80         except (struct.error, IOError, IndexError) as ex:
  81             # raised when trying to read an interlaced PNG;
  82             logger.warn('Could not create thumbnail: %s', str(ex))
  83
  84             # we use the original instead
  85             return self.send_file(original)
  86
  87         # If it's a RGBA image, composite it onto a white background for JPEG
  88         if resized.mode == 'RGBA':
  89             background = Image.new('RGB', resized.size)
  90             draw = ImageDraw.Draw(background)
  91             draw.rectangle((-1, -1, resized.size[0]+1, resized.size[1]+1),
  92                            fill=(255, 255, 255))
  93             del draw
  94             resized = Image.composite(resized, background, resized)
  95
  96         sio = io.BytesIO()
  97
  98         try:
  99             resized.save(sio, 'JPEG', optimize=True, progression=True,
 100                          quality=80)
 101         except IOError as ex:
 102             return self.send_file(original)
 103
 104         s = sio.getvalue()
 105
 106         fp = open(target, 'wb')
 107         fp.write(s)
 108         fp.close()
 109
 110         return self.send_file(target)
 111
 112     # the length of the prefix is defined here and in web/urls.py
 113     @staticmethod
 114     def get_prefix(filename):
 115         return filename[:3]
 116
 117     @staticmethod
 118     def get_thumbnail(size, prefix, filename):
 119         return os.path.join(LOGO_DIR, str(size), prefix, filename)
 120
 121     @staticmethod
 122     def get_existing_thumbnails(prefix, filename):
 123         files = glob(os.path.join(LOGO_DIR, '*', prefix, filename))
 124         return [f for f in files if 'original' not in f]
 125
 126     @staticmethod
 127     def get_original(prefix, filename):
 128         return os.path.join(LOGO_DIR, 'original', prefix, filename)
 129
 130     @staticmethod
 131     def get_dir(filename):
 132         path = os.path.dirname(filename)
 133         try:
 134             os.makedirs(path)
 135
 136         except OSError as ose:
 137             if ose.errno != errno.EEXIST:
 138                 raise
 139
 140         return path
 141
 142     def send_file(self, filename):
 143         try:
 144             f = open(filename, 'rb')
 145         except IOError:
 146             return HttpResponseNotFound()
 147
 148         resp = HttpResponse(content_type='image/jpeg')
 149         resp.status_code = 200
 150         resp.write(f.read())
 151         return resp
 152
 153
 154 def get_logo_url(podcast, size):
 155     """ Return the logo URL for the podcast """
 156
 157     if podcast.logo_url:
 158         filename = hashlib.sha1(podcast.logo_url.encode('utf-8')).hexdigest()
 159     else:
 160         filename = 'podcast-%d.png' % (hash(podcast.title) % 5, )
 161
 162     prefix = CoverArt.get_prefix(filename)
 163
 164     return reverse('logo', args=[size, prefix, filename])