Django Rest Framework override model fields in modelserialzer

Question

Let's say I have this serializer:

class DashboardItemSerializer(ModelSerializer):
    offer = serializers.SerializerMethodField()
    cart_item = serializers.SerializerMethodField()
    stock_details = serializers.SerializerMethodField()

    class Meta:
        model = OrderItem
        fields = ('uuid', 'seller', 'total', 'tax', 'offer', 'shipping_address', 'cart_item', 'stock_details')

    def offer(self, obj):
        return 123

    def cart_item(self, obj):
        return 123

    def stock_details(self, obj):
        return 123

these fields offer, cart_item and stock_details are model fields, and I would like to override it with to return different values, but looks like DRF ignores the customized fields and return the original value in obj.

If I don't put them in the fields list, the data will simply not include those fields.

class DashboardItemSerializer(ModelSerializer):
    offer = serializers.SerializerMethodField()
    cart_item = serializers.SerializerMethodField()
    stock_details = serializers.SerializerMethodField()

    class Meta:
        model = OrderItem
        fields = ('uuid', 'seller', 'total', 'tax', 'shipping_address')

    def offer(self, obj):
        return 123

    def cart_item(self, obj):
        return 123

    def stock_details(self, obj):
        return 123

One way to do it is to define fields explicitly, but I wonder if there is a easier way.

Answer 1

It is also possible to pass the method name as an optional parameter to each serializers.SerializerMethodField() and specify the custom method name you want to use for each custom/overridden field. This way you can omit the get_ prefix in the resolver method names inside the serializer class.

Answer 2

You forgot to add get_ prefix. Your methods names should have get_ prefix as it is mentioned in SerializerMethodField docs

def get_offer(self, obj):
    return 123

def get_cart_item(self, obj):
    return 123

def get_stock_details(self, obj):
    return 123