Improved error messages when people use cache_page in undocumented and now unsupported ways.

from django.utils.cache import patch_cache_control, add_never_cache_headers

from django.middleware.cache import CacheMiddleware

def cache_page(*args, **kwargs):

def cache_page(*args):

    # We need backwards compatibility with code which spells it this way:

    #   def my_view(): pass

    #   my_view = cache_page(123, my_view)

    # and this way:

    #   my_view = cache_page(123)(my_view)

    # We also add some asserts to give better error messages in case people are

    # using other ways to call cache_page that no longer work.

    timeout = args[0]

    if len(args) > 1:

        assert len(args) == 2, "cache_page accepts at most 2 arguments"

        fn = args[1]

        assert callable(fn), "cache_page is expecting 2nd argument to be a callable"

        return decorator_from_middleware_with_args(CacheMiddleware)(timeout)(fn)

    else:

        return decorator_from_middleware_with_args(CacheMiddleware)(timeout)