How can I validate data using Django serializers?

How can I validate data using Django serializers?

You can validate data in Django serializers by defining validation methods in your serializer class. For example, you can override the validate_<field_name> method to add custom validation logic.

Can you show me an example of a custom validation method?

Sure! Here's a simple example:

from rest_framework import serializers

class UserSerializer(serializers.Serializer):
    username = serializers.CharField(max_length=100)

    def validate_username(self, value):
        if ' ' in value:
            raise serializers.ValidationError('Username should not contain spaces.')
        return value

What happens if the validation fails?

If the validation fails, a ValidationError is raised, and the serializer will return an error response with the details of the validation issues.

Can I validate multiple fields at once?

Yes, you can override the validate method in your serializer to validate multiple fields together. This allows you to implement complex validation logic.