What are field validators in Django REST Framework serializers?

What are field validators in Django REST Framework serializers?

Field validators in Django REST Framework serializers are functions that validate the data for specific fields in your API. They ensure that the data meets certain criteria before it is saved to the database.

Can you give me an example of a custom field validator?

Sure! Here's a simple example: you can create a validator that checks if a value is positive. You would define a function like this:

from rest_framework import serializers

def validate_positive(value):
    if value <= 0:
        raise serializers.ValidationError('Value must be positive.')

Then, you can use it in your serializer like this:

class MySerializer(serializers.Serializer):
    amount = serializers.IntegerField(validators=[validate_positive])

What happens if the validation fails?

If the validation fails, a ValidationError is raised, and the API will return a 400 Bad Request response along with the error message, indicating what went wrong.

Are there built-in validators I can use?

Yes, Django REST Framework provides several built-in validators, such as UniqueValidator, MaxValueValidator, and MinValueValidator, which you can use directly in your serializers.