def fetch_thumbnails(images, sizes=None):
"""
Regenerate EXISTING thumbnails, so we don't need to call redis when using
thumbnails.get() or thumbnails.all(). Currently only support redis backend.
NotImeplementedError will be raised, if backend is not supported
"""
# NOTE: This is just working for redis based backend and same backend
# different backend among thumbnails may results in bugs
if not images:
return
backend = images[0].thumbnails.metadata_backend
try:
pipeline = backend.redis.pipeline()
except AttributeError:
raise NotImplementedError('Only Redis metadata backend is implemented')
for image in images:
thumbnails = image.thumbnails
key = thumbnails.metadata_backend.get_thumbnail_key(
thumbnails.source_image.name)
if sizes:
pipeline.hmget(key, sizes)
else:
pipeline.hgetall(key)
# if sizes is provided results will be list of lists, else it will be list of dicts
results = pipeline.execute()
for image, data in zip(images, results):
thumbnails = image.thumbnails
source_name = thumbnails.source_image.name
thumbnails._thumbnails = {}
if sizes:
# data shold be list, thus group it with its size beforehand
items = zip(sizes, data)
else:
# data should be dict
items = data.items()
for size, name in items:
if not name:
continue
image_meta = ImageMeta(source_name, name, size)
thumbnails._thumbnails[compat.as_text(size)] = Thumbnail(
image_meta, thumbnails.storage)
def __init__(self, source_name, name, size):
self.source_name = source_name
self.name = compat.as_text(name)
self.size = compat.as_text(size)
def get_source(self, name):
return compat.as_text(self.redis.hget(self.get_source_key(name), name))
def get_thumbnail(self, source_name, size):
name = compat.as_text(self.redis.hget(self.get_thumbnail_key(source_name), size))
if name:
return ImageMeta(source_name, name, size)
return None
def get_source(self, name):
return compat.as_text(self.redis.hget(self.get_source_key(name), name))
def get_thumbnail(self, source_name, size):
name = compat.as_text(
self.redis.hget(self.get_thumbnail_key(source_name), size))
if name:
return ImageMeta(source_name, name, size)
return None