Django Rest Framework - Custom error messages - Serializer vs. Model

Question

:) Hello!

I'm currently facing a problem that I am not being able to solve by searching the documentation or other questions, if someone can help I would be very grateful.

The problem is relatively of simple: I am adding custom messages for validation errors that come up when posting a new object, but I'd like to do it in one place only: inside model OR inside serializer.

For the sake of this example and my use case, I am talking only about unique and max_length validations.

• Defining error_messages=errors_dict inside the model fields currently only changes the unique validation error message, displaying the default for max_length.

• The opposite happens when I set it inside the serializer, using extra_kwargs inside Meta. It only changes the max_length validation error message.

Does anyone know what I am missing here? Is it possible to set the error_messages in only one place?

Thank you!

---

Here are some code snippets, if it helps:

errors in the below examples is the same dictionary, containing both keys (unique and max_length).

• Inside Model, working only for the unique validation:

class User(AbstractUser, SplintModel):
    (...)
    cpf = models.CharField('CPF', blank=False, max_length=11, unique=True, error_messages=errors)

• Inside Serializer, working only for the max_length validation:

class UserSerializer(serializers.ModelSerializer):
    (...)
    class Meta:
        model = User
        (...)

        extra_kwargs = {
            "cpf": {"error_messages": errors}
        }

Answer 1

try this in your serializers.py:

from rest_framework.validators import UniqueValidator

    extra_kwargs = {
       'cpf': { 
                {
                  'error_messages' : {"max_length": "your error"},
                  'validators': [
                      UniqueValidator(
                         queryset=User.objects.all(),
                         message="write your error message here"
                )
             ]
        }
     }