Django get_or_create only if form constraints are met - django

Question

I have a form that asks for a song's Artist, Title and Mix. Artist and Title are required fields but Mix is not. The form should only save if Artist, Title and Mix does not exists. If the form has either empty Artist or Title field it should show "This field is required" on submit. The issue I'm having is if the Title field is empty but Artist is populated, it'll still create the Artist object with get_or_create (See ###forms.py below). How do I only create Artist object if the form is valid?
###########models.py
class Artist (models.Model):
name = models.CharField(max_length=100)
class Track (models.Model):
artist = models.ForeignKey(Artist, blank=True, null=True, on_delete=models.SET_NULL, verbose_name="Artist")
user = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.SET_NULL, verbose_name="Submitted by", default=1)
title = models.CharField(max_length=100, verbose_name="Title")
mix = models.CharField(max_length=100, blank=True, verbose_name="Mix")
###########views.py
class TrackCreateView(SuccessMessageMixin, AjaxCreateView):
form_class = ProfileForm
success_message = "Thank you for submitting track: %(artist)s - %(title)s - %(mix)s"
def get_initial(self):
self.initial.update({ 'user': self.request.user })
return self.initial
def get_success_message(self, cleaned_data):
return self.success_message % dict(cleaned_data,
artist=self.object.artist,
title=self.object.title,
)
###########forms.py
class ProfileForm(forms.ModelForm):
class Meta:
model = Track
fields = [
"artist",
"title",
"mix",
]
artist = forms.CharField(widget=forms.TextInput(attrs={'maxlength': '100',}))
def __init__(self, *args, **kwargs):
self.user = kwargs['initial']['user']
super(ProfileForm, self).__init__(*args, **kwargs)
# Set layout for fields.
my_field_text= [
('artist', 'Artist', ''),
('title', 'Title', ''),
('mix', 'Mix', ''),
]
for x in my_field_text:
self.fields[x[0]].label=x[1]
self.fields[x[0]].help_text=x[2]
self.helper = FormHelper()
self.helper.layout = Layout(
Div(
Div('artist', css_class="col-sm-4"),
Div('title', css_class="col-sm-4"),
Div('mix', css_class="col-sm-4"),
css_class = 'row'
),
)
def save(self, commit=True):
obj = super(ProfileForm, self).save(False)
obj.user = self.user
commit and obj.save()
return obj
def clean(self):
cleaned_data = super(ProfileForm, self).clean()
artist = self.cleaned_data.get('artist')
title = self.cleaned_data.get('title')
mix = self.cleaned_data.get('mix')
if artist and title:
title = ' '.join([w.title() if w.islower() else w for w in title.split()])
if mix:
mix = ' '.join([w.title() if w.islower() else w for w in mix.split()])
if Track.objects.filter(artist=artist, title=title, mix=mix).exists():
msg = "Record with Artist and Title already exists."
if mix:
msg = "Record with Artist, Title & Mix already exists."
self.add_error('mix', msg)
self.add_error('artist', msg)
self.add_error('title', msg)
if not artist:
raise forms.ValidationError("Artist is a required field.")
else:
artist, created = Artist.objects.get_or_create(name=artist)
self.cleaned_data['artist'] = artist
self.cleaned_data['title'] = title
self.cleaned_data['mix'] = mix
return self.cleaned_data

Answer 1

How about changing your comparison, by first checking if your form is valid in clean()?
def clean(self):
...
if not artist:
raise ValidationError("artist is a required field")
if not title:
raise ValidationError("title is a required field")
...
The above makes it a two-step process for the user, since if a user leaves both artist and title blank, they ony get the artist notice.
You could make a better (sub) if statement and a combined ValidationError, or solve that by using clean_artist and clean_title, just for raising the ValidationError (not using get_or_create in the field clean methods):
def clean_artist(self):
# no get_or_create here
...
if not artist:
raise ValidationError("artist is a required field")
def clean_title(self):
# no get_or_create here
...
if not title:
raise ValidationError("title is a required field")
def clean(self):
...
if title and artist:
# get_or_create stuff here
...
This way, you should get both errors independently, but the get_or_create is still done in the main clean, only if title and artist are valid.