mirror of
https://github.com/Hopiu/django-imagekit.git
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82 lines
2.3 KiB
Python
82 lines
2.3 KiB
Python
from ..utils import get_singleton
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from django.core.cache import get_cache
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from django.core.exceptions import ImproperlyConfigured
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def get_default_image_cache_backend():
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"""
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Get the default image cache backend.
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"""
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from django.conf import settings
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return get_singleton(settings.IMAGEKIT_DEFAULT_IMAGE_CACHE_BACKEND,
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'image cache backend')
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class InvalidImageCacheBackendError(ImproperlyConfigured):
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pass
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class CachedValidationBackend(object):
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@property
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def cache(self):
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if not getattr(self, '_cache', None):
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from django.conf import settings
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self._cache = get_cache(settings.IMAGEKIT_CACHE_BACKEND)
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return self._cache
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def get_key(self, file):
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from django.conf import settings
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return '%s%s-valid' % (settings.IMAGEKIT_CACHE_PREFIX, file.get_hash())
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def is_invalid(self, file):
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key = self.get_key(file)
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cached_value = self.cache.get(key)
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if cached_value is None:
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cached_value = self._is_invalid(file)
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self.cache.set(key, cached_value)
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return cached_value
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def validate(self, file):
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if self.is_invalid(file):
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self._validate(file)
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self.cache.set(self.get_key(file), True)
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def invalidate(self, file):
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if not self.is_invalid(file):
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self._invalidate(file)
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self.cache.set(self.get_key(file), False)
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class Simple(CachedValidationBackend):
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"""
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The most basic image cache backend. Files are considered valid if they
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exist. To invalidate a file, it's deleted; to validate one, it's generated
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immediately.
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"""
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def _is_invalid(self, file):
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if not getattr(file, '_file', None):
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# No file on object. Have to check storage.
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return not file.storage.exists(file.name)
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return False
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def _validate(self, file):
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"""
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Generates a new image by running the processors on the source file.
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"""
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file.generate()
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def invalidate(self, file):
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"""
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Invalidate the file by deleting it. We override ``invalidate()``
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instead of ``_invalidate()`` because we don't really care to check
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whether the file is invalid or not.
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"""
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file.delete(save=False)
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def clear(self, file):
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file.delete(save=False)
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