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 StringIO
  20 from datetime import datetime
  21 from glob import glob
  22 import errno
  23
  24 import Image
  25 import ImageDraw
  26
  27 from django.conf import settings
  28 from django.http import Http404, HttpResponse
  29 from django.views.generic.base import View
  30 from django.utils.decorators import method_decorator
  31 from django.views.decorators.http import last_modified
  32
  33
  34 LOGO_DIR = os.path.join(settings.BASE_DIR, '..', 'htdocs', 'media', 'logo')
  35
  36
  37 def _last_modified(request, size, prefix, filename):
  38
  39     target = os.path.join(LOGO_DIR, size, prefix, filename)
  40
  41     try:
  42         return datetime.fromtimestamp(os.path.getmtime(target))
  43
  44     except OSError:
  45         return None
  46
  47
  48 class CoverArt(View):
  49
  50     @method_decorator(last_modified(_last_modified))
  51     def get(self, request, size, prefix, filename):
  52
  53         size = int(size)
  54
  55         target = self.get_thumbnail(size, prefix, filename)
  56         original = self.get_original(prefix, filename)
  57
  58         if os.path.exists(target):
  59             return self.send_file(target)
  60
  61         if not os.path.exists(original):
  62             raise Http404('Cover Art not available' + original)
  63
  64         target_dir = self.get_dir(target)
  65
  66         try:
  67             im = Image.open(original)
  68             if im.mode not in ('RGB', 'RGBA'):
  69                 im = im.convert('RGB')
  70         except IOError:
  71             raise Http404('Cannot open cover file')
  72
  73         try:
  74             im.thumbnail((size, size), Image.ANTIALIAS)
  75             resized = im
  76         except IOError as ex:
  77             print ex
  78             # raised when trying to read an interlaced PNG;
  79             # we use the original instead
  80             return self.send_file(original)
  81
  82         # If it's a RGBA image, composite it onto a white background for JPEG
  83         if resized.mode == 'RGBA':
  84             background = Image.new('RGB', resized.size)
  85             draw = ImageDraw.Draw(background)
  86             draw.rectangle((-1, -1, resized.size[0]+1, resized.size[1]+1),
  87                            fill=(255, 255, 255))
  88             del draw
  89             resized = Image.composite(resized, background, resized)
  90
  91         io = StringIO.StringIO()
  92
  93         try:
  94             resized.save(io, 'JPEG', optimize=True, progression=True,
  95                          quality=80)
  96         except IOError as ex:
  97             return self.send_file(original)
  98
  99         s = io.getvalue()
 100
 101         fp = open(target, 'wb')
 102         fp.write(s)
 103         fp.close()
 104
 105         return self.send_file(target)
 106
 107     # the length of the prefix is defined here and in web/urls.py
 108     @staticmethod
 109     def get_prefix(filename):
 110         return filename[:3]
 111
 112     @staticmethod
 113     def get_thumbnail(size, prefix, filename):
 114         return os.path.join(LOGO_DIR, str(size), prefix, filename)
 115
 116     @staticmethod
 117     def get_existing_thumbnails(prefix, filename):
 118         files = glob(os.path.join(LOGO_DIR, '*', prefix, filename))
 119         return filter(lambda f: 'original' not in f, files)
 120
 121     @staticmethod
 122     def get_original(prefix, filename):
 123         return os.path.join(LOGO_DIR, 'original', prefix, filename)
 124
 125     @staticmethod
 126     def get_dir(filename):
 127         path = os.path.dirname(filename)
 128         try:
 129             os.makedirs(path)
 130
 131         except OSError as ose:
 132             if ose.errno != errno.EEXIST:
 133                 raise
 134
 135         return path
 136
 137     def send_file(self, filename):
 138         resp = HttpResponse(content_type='image/jpeg')
 139         resp.status_code = 200
 140         f = open(filename)
 141         resp.write(f.read())
 142         return resp