用装饰器覆盖Django视图

Question

I have a situation that requires redirecting users who are already logged in away from the login page to another page. I have seen mention that this can be accomplished with decorators which makes sense, but I am fairly new to using them. However, I am using the django login and a third party view (from django-registration). I do not want to change any of the code in django.contrib.auth or django-registration. How can I apply a decorator to a view that is not to be modified in order to get the desired behavior.

Thanks in advance!

UPDATE: I discovered that I mistakenly associated the login function with the registration module. django-registration has nothing to do with this issue. However, I still need to be able to override default login() behavior. Any thoughts?

Answer 1

Three more ways to do it, though you'll need to use your own urlconf for these:

1. Add the decorator to the view directly in the urlconf:

    ... (regexp, decorator(view)), ... 

   You need to import the view and the decorator into the urlconf though, which is why I don't like this one. I prefer to have as few imports in my urls.py's as possible.

2. Import the view into an <app>/views.py and add the decorator there:

    import view view = decorator(view) 

   Pretty much like Vinay's method though more explicit since you need an urlconf for it.

3. Wrap the view in a new view:

    import view @decorator def wrapperview(request, *args, **kwargs): ... other stuff ... return view(request, *args, **kwargs) 

   The last one is very handy when you need to change generic views. This is what I often end up doing anyway.

Whenever you use an urlconf, order of patterns matter, so you might need to shuffle around on which pattern gets called first.

Answer 2

If you have the decorator function and you know which view in django-registration you want to decorate, you could just do

registration.view_func = decorator_func(registration.view_func)

where registration is the module in django-registration which contains the view function you want to decorate, view_func is the view function you want to decorate, and decorator_func is the decorator.