text: try:
      from functools import wraps
  except ImportError:
      from django.utils.functional import wraps  # Python 2.4 fallback.
  
  from django.utils.decorators import decorator_from_middleware_with_args, available_attrs
  from django.utils.cache import patch_cache_control, add_never_cache_headers
  from django.middleware.cache import CacheMiddleware
  
  
  def cache_page(*args, **kwargs):
      """
      Decorator for views that tries getting the page from the cache and
      populates the cache if the page isn't in the cache yet.
  
      The cache is keyed by the URL and some data from the headers.
      Additionally there is the key prefix that is used to distinguish different
      cache areas in a multi-site setup. You could use the
      sites.get_current().domain, for example, as that is unique across a Django
      project.
  
      Additionally, all headers from the response's Vary header will be taken
      into account on caching -- just like the middleware does.
      """
      # We need backwards compatibility with code which spells it this way:
      #   def my_view(): pass
      #   my_view = cache_page(my_view, 123)
      # and this way:
      #   my_view = cache_page(123)(my_view)
      # and this:
      #   my_view = cache_page(my_view, 123, key_prefix="foo")
      # and this:
      #   my_view = cache_page(123, key_prefix="foo")(my_view)
      # and possibly this way (?):
      #   my_view = cache_page(123, my_view)
      # and also this way:
      #   my_view = cache_page(my_view)
      # and also this way:
      #   my_view = cache_page()(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.
      key_prefix = kwargs.pop('key_prefix', None)
      assert not kwargs, "The only keyword argument accepted is key_prefix"
      if len(args) > 1:
          assert len(args) == 2, "cache_page accepts at most 2 arguments"
          if callable(args[0]):
              return decorator_from_middleware_with_args(CacheMiddleware)(cache_timeout=args[1], key_prefix=key_prefix)(args[0])
          elif callable(args[1]):
              return decorator_from_middleware_with_args(CacheMiddleware)(cache_timeout=args[0], key_prefix=key_prefix)(args[1])
          else:
              assert False, "cache_page must be passed a view function if called with two arguments"
      elif len(args) == 1:
          if callable(args[0]):
              return decorator_from_middleware_with_args(CacheMiddleware)(key_prefix=key_prefix)(args[0])
          else:
              return decorator_from_middleware_with_args(CacheMiddleware)(cache_timeout=args[0], key_prefix=key_prefix)
      else:
          return decorator_from_middleware_with_args(CacheMiddleware)(key_prefix=key_prefix)
  
  
  def cache_control(**kwargs):
      def _cache_controller(viewfunc):
          def _cache_controlled(request, *args, **kw):
              response = viewfunc(request, *args, **kw)
              patch_cache_control(response, **kwargs)
              return response
          return wraps(viewfunc, assigned=available_attrs(viewfunc))(_cache_controlled)
      return _cache_controller
  
  
  def never_cache(view_func):
      """
      Decorator that adds headers to a response so that it will
      never be cached.
      """
      def _wrapped_view_func(request, *args, **kwargs):
          response = view_func(request, *args, **kwargs)
          add_never_cache_headers(response)
          return response
      return wraps(view_func, assigned=available_attrs(view_func))(_wrapped_view_func)
  