Send Custom Error response from serializer in django rest framework?

7
votes

I want to send a custom response from serializers create view to front-end of my application. I tried rest framework Response tutorials but it does not work. My code is:

class UserSerializer(serializers.ModelSerializer):
"""Serializer to serialize user model object"""

    class Meta:
        model = User
        fields = ('id', 'username', 'password', 'first_name', 'last_name')
        extra_kwargs = {'password': {'write_only': True}}

    def create(self, validated_data):
        """create a new user"""

        firstname = self.initial_data['first_name']
        lastname = self.initial_data['last_name']
        fullname = str(firstname) +" "+ str(lastname)
        email = self.initial_data['username'].lower()

        try:
           customer = User.create(
                name=fullname,
                email=email)

        except Error as e:
            error = {'message': e._message or 'Unknown error'}
            return Response(error,status=status.HTTP_400_BAD_REQUEST)
2
djangopython-3.xdjango-modelsdjango-rest-frameworkdjango-serializer

2 Answers

18
votes

serializers.py 

class UserSerializer(serializers.ModelSerializer):
"""Serializer to serialize user model object"""

    class Meta:
        model = User
        fields = ('id', 'username', 'password', 'first_name', 'last_name')
        extra_kwargs = {'password': {'write_only': True}}

    def create(self, validated_data):
        """create a new user"""

        firstname = validated_data['first_name']
        lastname = validated_data['last_name']
        fullname = str(firstname) +" "+ str(lastname)
        email = validated_data['username'].lower()

        try:
           customer = User.objects.create(
                name=fullname,
                email=email)
           return customer

        except Exception as e:
            error = {'message': ",".join(e.args) if len(e.args) > 0 else 'Unknown Error'}
            raise serializers.ValidationError(error)
0
votes

So you want to change the representation of the User (the shape of the JSON response) from this view. To do this you need to change the .to_representation(self, obj) method in the serializer:

class UserSerializer(serializers.ModelSerializer):
    """Serializer to serialize user model object"""
     class Meta:
        model = User
        fields = ('id', 'username', 'password', 'first_name', 'last_name',)
        write_only_fields = ('id', 'password',)

    def to_representation(self, obj):
        return {
            'firstname': obj.first_name,
            'lastname': obj.last_name,
            'fullname': obj.first_name+' '+obj.last_name,
            'email': obj.username.lower()
        }

This should mean that whenever a request is made that uses this serializer the user will only ever see those 4 fields in the JSON, e.g.

{
    "firstname":"Salman",
    "lastname": "Ahmed",
    "fullname": "Salman Ahmed",
    "email": "[email protected]"
}

More details on this is hidden in their docs here.