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