Question

I’m trying to break-down the following code in Django to figure out what it’s doing and edit it if necessary, but I can’t quite figure out what a few of these functions are doing or where they’re coming from.

Are test_func and view_func Django specific or are these built-in python functions?

Conclusion:
I’m not sure how/why I overlooked the fact that these were simply being defined as arguments to the functions. I need to start paying better attention to details.

Here’s the Django function I’m trying to break down / figure out:

def user_passes_test(test_func, login_url=None, redirect_field_name=REDIRECT_FIELD_NAME):
    """
    Decorator for views that checks that the user passes the given test,
    redirecting to the log-in page if necessary. The test should be a callable
    that takes the user object and returns True if the user passes.
    """

    def decorator(view_func):
        @wraps(view_func, assigned=available_attrs(view_func))
        def _wrapped_view(request, *args, **kwargs):
            print test_func
            if test_func(request.user):
                return view_func(request, *args, **kwargs)
            path = request.build_absolute_uri()
            # If the login url is the same scheme and net location then just
            # use the path as the "next" url.
            login_scheme, login_netloc = urlparse.urlparse(login_url or
                                                        settings.LOGIN_URL)[:2]
            current_scheme, current_netloc = urlparse.urlparse(path)[:2]
            if ((not login_scheme or login_scheme == current_scheme) and
                (not login_netloc or login_netloc == current_netloc)):
                path = request.get_full_path()
            from django.contrib.auth.views import redirect_to_login
            return redirect_to_login(path, login_url, redirect_field_name)
        return _wrapped_view
    return decorator

Answer 1

view_func is a Django view. test_func is a function “that checks that the user passes the given test”.

So, you write a function that asks for something from the user, and returns True if they pass. Then you pass that function to user_passes_test and it creates a decorator you can use to first test a user before they get to see your view, like so:

@user_passes_test
def test_intelligence(user):
    if is_intelligent:
        return True
    else:
        return False

@test_intelligence
def my_view(request):
    #this is the view you only want intelligent people to see
    pass

Decorators are mentioned under Function Definitions in the docs. wraps is a decorator that preserves the signature of the function being wrapped (name, args, etc) through the decoration process. It’s located in functools.