81 lines
3.5 KiB
Python
81 lines
3.5 KiB
Python
from functools import wraps
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from django.utils.decorators import decorator_from_middleware_with_args, available_attrs
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from django.utils.cache import patch_cache_control, add_never_cache_headers
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from django.middleware.cache import CacheMiddleware
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def cache_page(*args, **kwargs):
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"""
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Decorator for views that tries getting the page from the cache and
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populates the cache if the page isn't in the cache yet.
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The cache is keyed by the URL and some data from the headers.
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Additionally there is the key prefix that is used to distinguish different
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cache areas in a multi-site setup. You could use the
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sites.get_current().domain, for example, as that is unique across a Django
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project.
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Additionally, all headers from the response's Vary header will be taken
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into account on caching -- just like the middleware does.
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"""
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# We need backwards compatibility with code which spells it this way:
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# def my_view(): pass
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# my_view = cache_page(my_view, 123)
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# and this way:
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# my_view = cache_page(123)(my_view)
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# and this:
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# my_view = cache_page(my_view, 123, key_prefix="foo")
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# and this:
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# my_view = cache_page(123, key_prefix="foo")(my_view)
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# and possibly this way (?):
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# my_view = cache_page(123, my_view)
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# and also this way:
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# my_view = cache_page(my_view)
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# and also this way:
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# my_view = cache_page()(my_view)
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# We also add some asserts to give better error messages in case people are
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# using other ways to call cache_page that no longer work.
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cache_alias = kwargs.pop('cache', None)
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key_prefix = kwargs.pop('key_prefix', None)
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assert not kwargs, "The only keyword arguments are cache and key_prefix"
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if len(args) > 1:
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assert len(args) == 2, "cache_page accepts at most 2 arguments"
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if callable(args[0]):
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return decorator_from_middleware_with_args(CacheMiddleware)(cache_timeout=args[1], cache_alias=cache_alias, key_prefix=key_prefix)(args[0])
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elif callable(args[1]):
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return decorator_from_middleware_with_args(CacheMiddleware)(cache_timeout=args[0], cache_alias=cache_alias, key_prefix=key_prefix)(args[1])
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else:
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assert False, "cache_page must be passed a view function if called with two arguments"
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elif len(args) == 1:
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if callable(args[0]):
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return decorator_from_middleware_with_args(CacheMiddleware)(cache_alias=cache_alias, key_prefix=key_prefix)(args[0])
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else:
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return decorator_from_middleware_with_args(CacheMiddleware)(cache_timeout=args[0], cache_alias=cache_alias, key_prefix=key_prefix)
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else:
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return decorator_from_middleware_with_args(CacheMiddleware)(cache_alias=cache_alias, key_prefix=key_prefix)
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def cache_control(**kwargs):
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def _cache_controller(viewfunc):
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@wraps(viewfunc, assigned=available_attrs(viewfunc))
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def _cache_controlled(request, *args, **kw):
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response = viewfunc(request, *args, **kw)
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patch_cache_control(response, **kwargs)
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return response
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return _cache_controlled
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return _cache_controller
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def never_cache(view_func):
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"""
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Decorator that adds headers to a response so that it will
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never be cached.
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"""
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@wraps(view_func, assigned=available_attrs(view_func))
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def _wrapped_view_func(request, *args, **kwargs):
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response = view_func(request, *args, **kwargs)
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add_never_cache_headers(response)
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return response
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return _wrapped_view_func
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