try:

    from functools import wraps

except ImportError:

    from django.utils.functional import wraps  # Python 2.4 fallback.

from django.utils.cache import patch_vary_headers

from django.utils.decorators import available_attrs

def vary_on_headers(*headers):

    """

    A view decorator that adds the specified headers to the Vary header of the

    response. Usage:

       @vary_on_headers('Cookie', 'Accept-language')

       def index(request):

           ...

    Note that the header names are not case-sensitive.

    """

    def decorator(func):

        def inner_func(*args, **kwargs):

            response = func(*args, **kwargs)

            patch_vary_headers(response, headers)

            return response

        return wraps(func, assigned=available_attrs(func))(inner_func)

    return decorator

def vary_on_cookie(func):

    """

    A view decorator that adds "Cookie" to the Vary header of a response. This

    indicates that a page's contents depends on cookies. Usage:

        @vary_on_cookie

        def index(request):

            ...

    """

    def inner_func(*args, **kwargs):

        response = func(*args, **kwargs)

        patch_vary_headers(response, ('Cookie',))

        return response

    return wraps(func, assigned=available_attrs(func))(inner_func)