Django Rest Framework receive primary key value in POST and return model object as nested serializer

user_923323 0
Viewed 13820

I'm not completely sure that the title of my question is as specific as I wanted it to be, but this is the case:

I have a HyperlinkedModelSerializer that looks like this:

class ParentArrivalSerializer(serializers.HyperlinkedModelSerializer):
    carpool = SchoolBuildingCarpoolSerializer()

    class Meta:
        model = ParentArrival

As you can see the carpool is defined as a nested serializer object and what I want is to be able to make a POST request to create a ParentArrival in this way (data as application/json):

{
    ...
    "carpool": "http://localhost:8000/api/school-building-carpools/10/"
    ...
}

And receive the data in this way:

{
    "carpool": {
        "url": "http://localhost:8000/api/school-building-carpools/10/"
        "name": "Name of the carpool",
        ...
    }
}

Basically, I'm looking for a way to deal with nested serializers without having to send data as an object (but id or url in this case) in POST request, but receiving the object as nested in the serialized response.

django-rest-framework serialization django python json
4 Answers

It's simple. As you know, Django appends "_id" to the field name in the ModelClass, and you can achieve it in the SerializerClass, and the original filed can also be achieved. All you have to do is like this

class ParentArrivalSerializer(serializers.HyperlinkedModelSerializer):
    # ...
    carpool_id = serializers.IntegerField(write_only=True)
    carpool = SchoolBuildingCarpoolSerializer(read_only=True)
    # ...
    class Meta:
        fields = ('carpool_id', 'carpool', ...)

And use carpool_id in POST request.

user_75555270

How about overriding the to_representation method?

class YourSerializer(serializers.ModelSerializer):

    class Meta:
        model = ModelClass
        fields = ["id", "foreignkey"]

    def to_representation(self, instance):
        data = super(YourSerializer, self).to_representation(instance)
        data['foreignkey'] = YourNestedSerializer(instance.foreignkey).data
        return data
user_36016540
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