97d1e4164b
We need to do this in the models.py files, otherwise the post_save signal might not be connected right away on launch of the application. Move them over there, add a dispatch_uid so it only gets hooked up once, and do some other function moving around so we don't have circular imports. Signed-off-by: Dan McGee <dan@archlinux.org>
69 lines
2.4 KiB
Python
69 lines
2.4 KiB
Python
try:
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import cPickle as pickle
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except ImportError:
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import pickle
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from django.core.cache import cache
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from django.utils.hashcompat import md5_constructor
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CACHE_TIMEOUT = 1800
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INVALIDATE_TIMEOUT = 15
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CACHE_PACKAGE_KEY = 'cache_package_latest'
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CACHE_NEWS_KEY = 'cache_news_latest'
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def cache_function_key(func, args, kwargs):
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raw = [func.__name__, func.__module__, args, kwargs]
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pickled = pickle.dumps(raw, protocol=pickle.HIGHEST_PROTOCOL)
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key = md5_constructor(pickled).hexdigest()
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return 'cache_function.' + func.__name__ + '.' + key
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def cache_function(length):
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"""
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A variant of the snippet posted by Jeff Wheeler at
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http://www.djangosnippets.org/snippets/109/
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Caches a function, using the function and its arguments as the key, and the
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return value as the value saved. It passes all arguments on to the
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function, as it should.
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The decorator itself takes a length argument, which is the number of
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seconds the cache will keep the result around.
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"""
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def decorator(func):
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def inner_func(*args, **kwargs):
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key = cache_function_key(func, args, kwargs)
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value = cache.get(key)
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if value is not None:
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return value
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else:
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result = func(*args, **kwargs)
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cache.set(key, result, length)
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return result
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return inner_func
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return decorator
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def clear_cache_function(func, args, kwargs):
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key = cache_function_key(func, args, kwargs)
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cache.delete(key)
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# utility to make a pair of django choices
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make_choice = lambda l: [(str(m), str(m)) for m in l]
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# These are in here because we would be jumping around in some import circles
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# and hoops otherwise. The only thing currently using these keys is the feed
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# caching stuff.
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def refresh_package_latest(**kwargs):
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# We could delete the value, but that could open a race condition
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# where the new data wouldn't have been committed yet by the calling
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# thread. Instead, explicitly set it to None for a short amount of time.
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# Hopefully by the time it expires we will have committed, and the cache
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# will be valid again. See "Scaling Django" by Mike Malone, slide 30.
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cache.set(CACHE_PACKAGE_KEY, None, INVALIDATE_TIMEOUT)
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def refresh_news_latest(**kwargs):
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# same thoughts apply as in refresh_package_latest
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cache.set(CACHE_NEWS_KEY, None, INVALIDATE_TIMEOUT)
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# vim: set ts=4 sw=4 et:
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