redirect user after update in class based view in django

I'm using Django 1.11.

I'm using Class based view for update profile page, to updated auth user profile info.

myapp/accounts/views.py

class UpdateProfile(UpdateView):
    model = User
    fields = ['first_name', 'last_name']

    template_name = 'accounts/update.html'

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.request = None

    def get_object(self, queryset=None):
        return self.request.user

This works fine for updating profile. But after update, it gives error

No URL to redirect to.  Either provide a url or define a get_absolute_url method on the Model.

I followed some YouTube tutorials here which is using method based view and form.py to generate form, There I can check for request method and call form.save() and then redirect user to profile page (probably index).

1. How can I do I check if data updated and then redirect user to index class in my class?

2. Is this method suitable for editing data using pk?

I also want to generate flash message after updation for which I can use

messages.success(request, "Profile updated")

3. Since class is not have request object, how to use messages in class based view?