Question

I have User form in which there is a username field. The fields in the form are initialized from the data in the db.

class PersonEditForm(forms.ModelForm):

    username = forms.RegexField(label=_("Username"), max_length=30, regex=r'^[\w.@+-]+$',
    help_text = _("Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only."),
    error_messages = {'invalid': _("This value may contain only letters, numbers and @/./+/-/_ characters.")})


class Meta:
    model = User

view.py

@login_required
def edit(request, template_name):

    if request.user.is_authenticated():
        if request.method == 'POST':
            form = PersonEditForm(request.POST)
            if form.is_valid():
                form.save(instance = request.POST, user = request.user)
                return HttpResponseRedirect(reverse('/success/'))

        else:
            user = User.objects.get(username = request.user)
            form = PersonEditForm(instance = user, initial = {'username': request.user.username})

            return render_to_response(template_name, {"form": form },
                              context_instance = RequestContext(request))

The logged in user can edit the username. The problem is while writing the clean_username method I would require the request.user, to check:

1. if username == request.user.username #return true

2. elif username != request.user.username

   a) User.objects.get(username = username) #if returns something then raise forms.ValidationError(_(“Username already taken.”))

   b) else user.username = username

How can I achieve this?

Answer 1

You can get it in self.instance

class PersonEditForm(forms.ModelForm):
    def clean_username(self):
        # self.instance is your current user

    ...

A view should look like this

if request.user.is_authenticated():
    if request.method == 'POST':
        form = PersonEditForm(request.POST, instance=request.user)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('/success/'))

    else:
        form = PersonEditForm(instance=request.user, initial={'username': request.user.username})

    return render_to_response(template_name, {"form": form },
                          context_instance = RequestContext(request))