forked from expo/troggle
b509390575
Copied from http://cucc@cucc.survex.com/svn/trunk/expoweb/troggle/, rev. 8338 by cucc @ 5/11/2009 3:08 AM
137 lines
4.6 KiB
Python
137 lines
4.6 KiB
Python
import os
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from datetime import datetime
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from django.conf import settings
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from django.core.files.base import ContentFile
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from django.db import models
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from django.db.models.base import ModelBase
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from django.utils.translation import ugettext_lazy as _
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from imagekit import specs
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from imagekit.lib import *
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from imagekit.options import Options
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from imagekit.utils import img_to_fobj
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# Modify image file buffer size.
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ImageFile.MAXBLOCK = getattr(settings, 'PIL_IMAGEFILE_MAXBLOCK', 256 * 2 ** 10)
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# Choice tuples for specifying the crop origin.
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# These are provided for convenience.
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CROP_HORZ_CHOICES = (
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(0, _('left')),
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(1, _('center')),
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(2, _('right')),
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)
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CROP_VERT_CHOICES = (
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(0, _('top')),
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(1, _('center')),
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(2, _('bottom')),
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)
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class ImageModelBase(ModelBase):
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""" ImageModel metaclass
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This metaclass parses IKOptions and loads the specified specification
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module.
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"""
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def __init__(cls, name, bases, attrs):
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parents = [b for b in bases if isinstance(b, ImageModelBase)]
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if not parents:
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return
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user_opts = getattr(cls, 'IKOptions', None)
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opts = Options(user_opts)
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try:
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module = __import__(opts.spec_module, {}, {}, [''])
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except ImportError:
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raise ImportError('Unable to load imagekit config module: %s' % \
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opts.spec_module)
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for spec in [spec for spec in module.__dict__.values() \
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if isinstance(spec, type) \
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and issubclass(spec, specs.ImageSpec) \
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and spec != specs.ImageSpec]:
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setattr(cls, spec.name(), specs.Descriptor(spec))
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opts.specs.append(spec)
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setattr(cls, '_ik', opts)
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class ImageModel(models.Model):
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""" Abstract base class implementing all core ImageKit functionality
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Subclasses of ImageModel are augmented with accessors for each defined
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image specification and can override the inner IKOptions class to customize
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storage locations and other options.
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"""
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__metaclass__ = ImageModelBase
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class Meta:
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abstract = True
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class IKOptions:
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pass
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def admin_thumbnail_view(self):
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if not self._imgfield:
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return None
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prop = getattr(self, self._ik.admin_thumbnail_spec, None)
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if prop is None:
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return 'An "%s" image spec has not been defined.' % \
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self._ik.admin_thumbnail_spec
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else:
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if hasattr(self, 'get_absolute_url'):
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return u'<a href="%s"><img src="%s"></a>' % \
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(self.get_absolute_url(), prop.url)
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else:
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return u'<a href="%s"><img src="%s"></a>' % \
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(self._imgfield.url, prop.url)
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admin_thumbnail_view.short_description = _('Thumbnail')
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admin_thumbnail_view.allow_tags = True
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@property
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def _imgfield(self):
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return getattr(self, self._ik.image_field)
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def _clear_cache(self):
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for spec in self._ik.specs:
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prop = getattr(self, spec.name())
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prop._delete()
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def _pre_cache(self):
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for spec in self._ik.specs:
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if spec.pre_cache:
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prop = getattr(self, spec.name())
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prop._create()
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def save(self, clear_cache=True, *args, **kwargs):
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is_new_object = self._get_pk_val is None
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super(ImageModel, self).save(*args, **kwargs)
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if is_new_object:
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clear_cache = False
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spec = self._ik.preprocessor_spec
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if spec is not None:
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newfile = self._imgfield.storage.open(str(self._imgfield))
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img = Image.open(newfile)
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img = spec.process(img, None)
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format = img.format or 'JPEG'
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if format != 'JPEG':
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imgfile = img_to_fobj(img, format)
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else:
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imgfile = img_to_fobj(img, format,
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quality=int(spec.quality),
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optimize=True)
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content = ContentFile(imgfile.read())
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newfile.close()
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name = str(self._imgfield)
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self._imgfield.storage.delete(name)
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self._imgfield.storage.save(name, content)
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if clear_cache and self._imgfield != '':
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self._clear_cache()
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self._pre_cache()
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def delete(self):
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assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname)
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self._clear_cache()
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models.Model.delete(self)
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