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Python Django Authentication Authentication LoginView

what's the point of the 'if form_class is None' in the 'form_valid' method ?

in the class LoginView, I can't understand why do we check if the form_class in none

    def get_form(self, form_class=None):
        if form_class is None:
            form_class=self.get_form_class()
        return form_class(self.request,**self.get_form_kwargs())

the whole class is:

class LoginView(generic.FormView):
    form_class = AuthenticationForm
    success_url = '/'
    template_name = "blog/post_form.html"

    def get_form(self, form_class=None):
        if form_class is None:
            form_class=self.get_form_class()
        return form_class(self.request,**self.get_form_kwargs())

    def form_valid(self, form):
        login(self.request,form.get_user())
        return super().form_valid(form)

why not just use something like:

    def get_form(self):
        return self.form_class(self.request,**self.get_form_kwargs())

because the form_class will always be AuthenticationForm or am I missing something? Why should form_class be passed as a parameter in the get_form method? I am really confused on this.

anyone?

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points

In the default mode, form_class would not be provided as an argument, thus the get_form_class would return AuthenticationForm. However, if one wanted to provide an alternative form, then it could be passed to the get_form method.

It looks like the code was borrowed from the FormMixin class get_form method.

get_form(form_class=None) โ€” Instantiate an instance of form_class using get_form_kwargs(). If form_class isnโ€™t provided get_form_class() will be used.

ForumMixin.get_form source code:

    def get_form(self, form_class=None):
        """Return an instance of the form to be used in this view."""
        if form_class is None:
            form_class = self.get_form_class()
        return form_class(**self.get_form_kwargs())