apps/sorl/thumbnail/fields.py

   1 from UserDict import DictMixin
   2 try:
   3     from cStringIO import StringIO
   4 except ImportError:
   5     from StringIO import StringIO
   6
   7 from django.db.models.fields.files import ImageField, ImageFieldFile
   8 from django.core.files.base import ContentFile
   9 from django.utils.safestring import mark_safe
  10 from django.utils.html import escape
  11
  12 from sorl.thumbnail.base import Thumbnail
  13 from sorl.thumbnail.main import DjangoThumbnail, build_thumbnail_name
  14 from sorl.thumbnail.utils import delete_thumbnails
  15
  16
  17 REQUIRED_ARGS = ('size',)
  18 ALL_ARGS = {
  19     'size': 'requested_size',
  20     'options': 'opts',
  21     'quality': 'quality',
  22     'basedir': 'basedir',
  23     'subdir': 'subdir',
  24     'prefix': 'prefix',
  25     'extension': 'extension',
  26 }
  27 BASE_ARGS = {
  28     'size': 'requested_size',
  29     'options': 'opts',
  30     'quality': 'quality',
  31 }
  32 TAG_HTML = '<img src="%(src)s" width="%(width)s" height="%(height)s" alt="" />'
  33
  34
  35 class ThumbsDict(object, DictMixin):
  36     def __init__(self, descriptor):
  37         super(ThumbsDict, self).__init__()
  38         self.descriptor = descriptor
  39
  40     def keys(self):
  41         return self.descriptor.field.extra_thumbnails.keys()
  42
  43
  44 class LazyThumbs(ThumbsDict):
  45     def __init__(self, *args, **kwargs):
  46         super(LazyThumbs, self).__init__(*args, **kwargs)
  47         self.cached = {}
  48
  49     def __getitem__(self, key):
  50         thumb = self.cached.get(key)
  51         if not thumb:
  52             args = self.descriptor.field.extra_thumbnails[key]
  53             thumb = self.descriptor._build_thumbnail(args)
  54             self.cached[key] = thumb
  55         return thumb
  56
  57     def keys(self):
  58         return self.descriptor.field.extra_thumbnails.keys()
  59
  60
  61 class ThumbTags(ThumbsDict):
  62     def __getitem__(self, key):
  63         thumb = self.descriptor.extra_thumbnails[key]
  64         return self.descriptor._build_thumbnail_tag(thumb)
  65
  66
  67 class BaseThumbnailFieldFile(ImageFieldFile):
  68     def _build_thumbnail(self, args):
  69         # Build the DjangoThumbnail kwargs.
  70         kwargs = {}
  71         for k, v in args.items():
  72             kwargs[ALL_ARGS[k]] = v
  73         # Build the destination filename and return the thumbnail.
  74         name_kwargs = {}
  75         for key in ['size', 'options', 'quality', 'basedir', 'subdir',
  76                     'prefix', 'extension']:
  77             name_kwargs[key] = args.get(key)
  78         source = getattr(self.instance, self.field.name)
  79         dest = build_thumbnail_name(source.name, **name_kwargs)
  80         return DjangoThumbnail(source, relative_dest=dest, **kwargs)
  81
  82     def _build_thumbnail_tag(self, thumb):
  83         opts = dict(src=escape(thumb), width=thumb.width(),
  84                     height=thumb.height())
  85         return mark_safe(self.field.thumbnail_tag % opts)
  86
  87     def _get_extra_thumbnails(self):
  88         if self.field.extra_thumbnails is None:
  89             return None
  90         if not hasattr(self, '_extra_thumbnails'):
  91             self._extra_thumbnails = LazyThumbs(self)
  92         return self._extra_thumbnails
  93     extra_thumbnails = property(_get_extra_thumbnails)
  94
  95     def _get_extra_thumbnails_tag(self):
  96         if self.field.extra_thumbnails is None:
  97             return None
  98         return ThumbTags(self)
  99     extra_thumbnails_tag = property(_get_extra_thumbnails_tag)
 100
 101     def save(self, *args, **kwargs):
 102         # Optionally generate the thumbnails after the image is saved.
 103         super(BaseThumbnailFieldFile, self).save(*args, **kwargs)
 104         if self.field.generate_on_save:
 105             self.generate_thumbnails()
 106
 107     def delete(self, *args, **kwargs):
 108         # Delete any thumbnails too (and not just ones defined here in case
 109         # the {% thumbnail %} tag was used or the thumbnail sizes changed).
 110         relative_source_path = getattr(self.instance, self.field.name).name
 111         delete_thumbnails(relative_source_path)
 112         super(BaseThumbnailFieldFile, self).delete(*args, **kwargs)
 113
 114     def generate_thumbnails(self):
 115         # Getting the thumbs generates them.
 116         if self.extra_thumbnails:
 117             self.extra_thumbnails.values()
 118
 119
 120 class ImageWithThumbnailsFieldFile(BaseThumbnailFieldFile):
 121     def _get_thumbnail(self):
 122         return self._build_thumbnail(self.field.thumbnail)
 123     thumbnail = property(_get_thumbnail)
 124
 125     def _get_thumbnail_tag(self):
 126         return self._build_thumbnail_tag(self.thumbnail)
 127     thumbnail_tag = property(_get_thumbnail_tag)
 128
 129     def generate_thumbnails(self, *args, **kwargs):
 130         self.thumbnail.generate()
 131         Super = super(ImageWithThumbnailsFieldFile, self)
 132         return Super.generate_thumbnails(*args, **kwargs)
 133
 134
 135 class ThumbnailFieldFile(BaseThumbnailFieldFile):
 136     def save(self, name, content, *args, **kwargs):
 137         new_content = StringIO()
 138         # Build the Thumbnail kwargs.
 139         thumbnail_kwargs = {}
 140         for k, argk in BASE_ARGS.items():
 141             if not k in self.field.thumbnail:
 142                 continue
 143             thumbnail_kwargs[argk] = self.field.thumbnail[k]
 144         Thumbnail(source=content, dest=new_content, **thumbnail_kwargs)
 145         new_content = ContentFile(new_content.read())
 146         super(ThumbnailFieldFile, self).save(name, new_content, *args,
 147                                              **kwargs)
 148
 149     def _get_thumbnail_tag(self):
 150         opts = dict(src=escape(self.url), width=self.width,
 151                     height=self.height)
 152         return mark_safe(self.field.thumbnail_tag % opts)
 153     thumbnail_tag = property(_get_thumbnail_tag)
 154
 155
 156 class BaseThumbnailField(ImageField):
 157     def __init__(self, *args, **kwargs):
 158         # The new arguments for this field aren't explicitly defined so that
 159         # users can still use normal ImageField positional arguments.
 160         self.extra_thumbnails = kwargs.pop('extra_thumbnails', None)
 161         self.thumbnail_tag = kwargs.pop('thumbnail_tag', TAG_HTML)
 162         self.generate_on_save = kwargs.pop('generate_on_save', False)
 163
 164         super(BaseThumbnailField, self).__init__(*args, **kwargs)
 165         _verify_thumbnail_attrs(self.thumbnail)
 166         if self.extra_thumbnails:
 167             for extra, attrs in self.extra_thumbnails.items():
 168                 name = "%r of 'extra_thumbnails'"
 169                 _verify_thumbnail_attrs(attrs, name)
 170
 171     def south_field_triple(self):
 172         """
 173         Return a suitable description of this field for South.
 174         """
 175         # We'll just introspect ourselves, since we inherit.
 176         from south.modelsinspector import introspector
 177         field_class = "django.db.models.fields.files.ImageField"
 178         args, kwargs = introspector(self)
 179         # That's our definition!
 180         return (field_class, args, kwargs)
 181
 182
 183 class ImageWithThumbnailsField(BaseThumbnailField):
 184     """
 185     photo = ImageWithThumbnailsField(
 186         upload_to='uploads',
 187         thumbnail={'size': (80, 80), 'options': ('crop', 'upscale'),
 188                    'extension': 'png'},
 189         extra_thumbnails={
 190             'admin': {'size': (70, 50), 'options': ('sharpen',)},
 191         }
 192     )
 193     """
 194     attr_class = ImageWithThumbnailsFieldFile
 195
 196     def __init__(self, *args, **kwargs):
 197         self.thumbnail = kwargs.pop('thumbnail', None)
 198         super(ImageWithThumbnailsField, self).__init__(*args, **kwargs)
 199
 200
 201 class ThumbnailField(BaseThumbnailField):
 202     """
 203     avatar = ThumbnailField(
 204         upload_to='uploads',
 205         size=(200, 200),
 206         options=('crop',),
 207         extra_thumbnails={
 208             'admin': {'size': (70, 50), 'options': (crop, 'sharpen')},
 209         }
 210     )
 211     """
 212     attr_class = ThumbnailFieldFile
 213
 214     def __init__(self, *args, **kwargs):
 215         self.thumbnail = {}
 216         for attr in ALL_ARGS:
 217             if attr in kwargs:
 218                 self.thumbnail[attr] = kwargs.pop(attr)
 219         super(ThumbnailField, self).__init__(*args, **kwargs)
 220
 221
 222 def _verify_thumbnail_attrs(attrs, name="'thumbnail'"):
 223     for arg in REQUIRED_ARGS:
 224         if arg not in attrs:
 225             raise TypeError('Required attr %r missing in %s arg' % (arg, name))
 226     for attr in attrs:
 227         if attr not in ALL_ARGS:
 228             raise TypeError('Invalid attr %r found in %s arg' % (arg, name))