def __set__(self, model_instance, value):
"""Compresses the value when the property is set."""
if not value:
self.length = 0
super(CompressedUtf8BlobProperty, self).__set__(model_instance, value)
else:
self.length = len(value)
value = compress.CompressedText(value, encoding='utf-8').Compressed()
super(CompressedUtf8BlobProperty, self).__set__(model_instance, value)
def get_value_for_datastore(self, model_instance):
"""Compresses the blob value on it's way to Datastore."""
value = super(CompressedUtf8BlobProperty,
self).get_value_for_datastore(model_instance)
if value is None:
self.length = 0
else:
self.length = len(value)
return db.Blob(
compress.CompressedText(value, encoding='utf-8').Compressed())
def __get__(self, model_instance, model_class):
"""Decompresses the blob value when the property is accessed."""
value = super(CompressedUtf8BlobProperty,
self).__get__(model_instance, model_class)
# __get__ super returns self when the model_instance is None, which happens
# when the property is accessed by a static member of a class, as opposed to
# by an instance. When this happens, return our class instance.
if value is self:
return self
return unicode(compress.CompressedText(
value, encoding='utf-8')).encode('utf-8')
def _GetInstance(self, arg=None, compression_threshold=0, **kwargs):
"""Return an instance of compress.CompressedText to test."""
return compress.CompressedText(
arg=arg, compression_threshold=compression_threshold, **kwargs)
