How to use django model clean() method?

Question

class Restaurant(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=120, unique=True, verbose_name="Name")
    direction = models.CharField(max_length=120, verbose_name="Direction")
    phone = models.IntegerField()
    slug = models.SlugField(blank=True)

    def __str__(self):
        return self.name
    
    def get_absolute_url(self):
        return f'/res/{self.slug}'

    @property
    def full_name(self):
        return self.name   
    
    
    def clean(self):
        from django.core.exceptions import ValidationError        
       
        if len(str(self.phone))<=5:
            raise ValidationError({'phone':('Enter Correct number.')})
        

clean() method is not working. My view.py code is as follow :

class RestaurantView(generics.ListCreateAPIView):
    queryset=Restaurant.objects.all()
    serializer_class=RestaurantSerializer

    def get(self,request):
        query=self.get_queryset()        
        serializer=RestaurantSerializer(query,many=True)        
        return Response(serializer.data)

    def post(self,request):
        serializer  =   RestaurantSerializer(data=request.POST)
        if serializer.is_valid(raise_exception=True):
            name=serializer.validated_data.get('name')
            direction=serializer.validated_data.get('direction')
            phone=serializer.validated_data.get('phone')
            r=Restaurant()
            r.name=name,
            r.direction=direction,
            r.phone=phone
            r.save()
            response={'msg':'Data Saved Successfully'}
            return Response(response)

How can I handle the clean() method validation? I'm also validating data in serializer.py file but still i want to validate data in models clean() method.Thankx in advance.

Answer 1

Validation of django objects (docs):

There are three steps involved in validating a model:

• Validate the model fields - Model.clean_fields()
• Validate the model as a whole - Model.clean()
• Validate the field uniqueness - Model.validate_unique()

All three steps are performed when you call a model’s full_clean() method.

So your method clean() is correct, you just need to call it before saving your model instance (it is not automatically called).

This can be done be just calling r.clean(), or you can do a full validation (the 3 steps mentioned above) by calling r.full_clean().

So in your code add the validation call before r.save():

...
r = Restaurant()
...
r.full_clean()
r.save()
...