Validate nested form in Django - django

Question

I have a UserProfile model which is linked OneToOne with Django User model. While adding a user through a form, I wanted to have one form for both of those. I found a snippet that does exactly that, and I didn't have any problem with it, until I wanted to validate the username. The form isn't throwing a ValidationError, like I would like it to, but returns an error page with ValueError: The User could not be created because the data didn't validate..
From what I understand (which obviously could be wrong), the current setup doesn't handle ValidationErrors from the nested form.
Is there any way to add that functionality? If not, how should I tackle the issue of having one form handle to models?
Code:
class CmUserForm(forms.ModelForm):
password = forms.CharField(widget=forms.PasswordInput(),
required=False,
help_text=_("Leave empty if you don't want "
"to change it"))
def clean_password(self):
data = self.cleaned_data['password']
if data.strip():
return make_password(data)
else:
# If password field is empty, then don't change it
return self.instance.password
def clean_username(self):
username = self.cleaned_data['username']
if get_user_model().objects.filter(username=username).exists():
raise forms.ValidationError(_('This username is already in use.'))
return username
class Meta:
model = get_user_model()
fields = ('first_name', 'last_name', 'email', 'username', 'password', 'is_staff', 'is_active')
class CmUserProfileForm(forms.ModelForm):
def __init__(self, *args, **kwargs):
# Take User if updating, None if creating
try:
self.user = kwargs['instance'].user
except AttributeError:
self.user = None
user_kwargs = kwargs.copy()
user_kwargs['instance'] = self.user
self.uf = CmUserForm(*args, **user_kwargs)
super(CmUserProfileForm, self).__init__(*args, **kwargs)
self.fields.update(self.uf.fields)
self.initial.update(self.uf.initial)
class Meta:
model = UserProfile
exclude = ['user']
def save(self, *args, **kwargs):
# Save User and pass it to UserProfile
user = self.uf.save(*args, **kwargs)
self.instance.user = user
return super().save(*args, **kwargs)

Answer 1

i implemented the same today. I learnt this from the this website tango with django. http://www.tangowithdjango.com/book/chapters/login.html. Also i provided my code how i achieved this. Inbuilt user model itself checks if the username already exists or not. hope this is helpful.
class Sam(models.Model):
user = model.OneToOneField(User)
#custom fields apart from the inbuilt User model
region = models.CharField(max_length=10)
designation = models.CharField(max_length=10)
#forms.py form models. Created SamProfileform to capture the custom fields which are specific to One's Profile and SamForm to capture the password and then hash later in the view.
#Please note that i didnt add any username check here. The inbuilt User does it for us. I verified it.
class SamForm(forms.ModelForm):
#form model to capture inbuilt fields of "User" model
password = forms.CharField(widget=PasswordInput())
class Meta:
model = User
fields = ('username', 'email', 'password', 'firstname', 'lastname')
class SamProfileForm(forms.ModelForm):
#form model to built the custom fields in my case region and designation
class Meta:
model = Sam
fields = ('desgination', 'mgr')
def register(request):
registered = False
if request.method == 'POST':
user_form = SamForm(data=request.POST)
profile_form = SamProfileForm(request.POST)
if user_form.is_valid() and profile_form.is_valid():
user = user_form.save()
user.set_password(user.password)
user.save()
profile = profile_form.save(commit=False)
profile.user = user
profile.save()
registered = True
else:
print user_form.errors, profile_form.errors
else:
user_form = SamForm()
profile_form = SamProfileForm()
template = loader.get_template('sam/register.html')
context = RequestContext(request, {
'user_form' : user_form, 'profile_form' : profile_form, 'registered' : registered,
})
return HttpResponse(template.render(context))