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
  23 import Image
  24 import 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
  33 LOGO_DIR = os.path.join(settings.BASE_DIR, '..', 'htdocs', 'media', 'logo')
  34
  35
  36 def _last_modified(request, size, prefix, filename):
  37
  38     target = os.path.join(LOGO_DIR, size, prefix, filename)
  39
  40     try:
  41         return datetime.fromtimestamp(os.path.getmtime(target))
  42
  43     except OSError:
  44         return None
  45
  46
  47
  48 class CoverArt(View):
  49
  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:
  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             print ex
  79             # raised when trying to read an interlaced PNG;
  80             # we use the original instead
  81             return self.send_file(original)
  82
  83         # If it's a RGBA image, composite it onto a white background for JPEG
  84         if resized.mode == 'RGBA':
  85             background = Image.new('RGB', resized.size)
  86             draw = ImageDraw.Draw(background)
  87             draw.rectangle((-1, -1, resized.size[0]+1, resized.size[1]+1), \
  88                     fill=(255, 255, 255))
  89             del draw
  90             resized = Image.composite(resized, background, resized)
  91
  92         io = StringIO.StringIO()
  93
  94         try:
  95             resized.save(io, 'JPEG', optimize=True, progression=True, quality=80)
  96         except Exception as ex:
  97             print ex
  98             return self.send_file(original)
  99
 100         s = io.getvalue()
 101
 102         fp = open(target, 'wb')
 103         fp.write(s)
 104         fp.close()
 105
 106         return self.send_file(target)
 107
 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
 128     @staticmethod
 129     def get_dir(filename):
 130         path = os.path.dirname(filename)
 131         if not os.path.isdir(path):
 132             os.makedirs(path)
 133         return path
 134
 135
 136     def send_file(self, filename):
 137         resp = HttpResponse(content_type='image/jpeg')
 138         resp.status_code = 200
 139         f = open(filename)
 140         resp.write(f.read())
 141         return resp