Question

Consider I have defined the following models:

class Tag(models.Model):
  name = models.CharField(max_length=20)

class Entry(models.Model):
  title = models.CharField(max_length=100)
  date = models.DateField()
  tags = models.ManyToManyField(Tag)

and the following model form:

class EntryForm(forms.ModelForm):
  tags =  CharField(max_length=100, label='Tags', required=False)
  class Meta:
    model = Entry

Basically I have an entry with tags. The tags are not necessarily already created. I need to receive a filled entry form and save it with tags.

I can do that easily if I don’t have the ManyToMany relation in the Entry. But with it I first need to save the tags, then add the saved tags to the entry and then save the entry. Which means I have to override the EntryForm’s save() method.

I saw this question already, but it looks different. In my case I need to save only the tags, and the rest should be able use ModelForm’s default save().

I presented a simplified example. In real one I have much more fields in the Entry.
What is your recommendation for writing EntryForm’s save() method in a django way?

Answer 1

The best and correct option here would be to add the clean_tags method to the form, not to override the save() in the model.

def clean_tags(self):
    tags = self.cleaned_data.get('tags', None)

    clean_tags = []


    tags = [tag.strip() for tag in tags.split(',') if tags]

    for tag in tags:
        t, created = Tag.objects.get_or_create(title=tag)
        t.count = F('count') + 1
        t.user.add(self.cleaned_data['user'])
        t.save()
        clean_tags.append(t)

    return clean_tags