Including the get_absolute_url value in JSON output

Question

Just getting into Django Rest Framework.

I have a simple example running where a model is being presented through the REST API. There are no Related fields in the model, just a bunch of strings.

What is the easiest way to present the get_absolute_url() value of that model into the JSON output?

I'm using serializers.HyperlinkedModelSerializer in preparation for moving into more complicated models that do have related fields.

Answer 1

Approach-1 Using a SerializerMethodField:

You can use a SerializerMethodField in your serializer to add the get_absolute_url() value to the serialized representation of the object.

As per the SerializerMethodField docs:

This is a read-only field. It gets its value by calling a method on the serializer class it is attached to. It can be used to add any sort of data to the serialized representation of your object.

We will define a method get_my_abslute_url() for the my_absolute_url field in our serializer which will add the absolute url of the object to the serialized representation.

class MyModelSerializer(serializers.ModelSerializer):

    my_absolute_url = serializers.SerializerMethodField() # define a SerializerMethodField        

    def get_my_absolute_url(self, obj):
        return obj.get_absolute_url() # return the absolute url of the object

Approach-2 Using URLField with source argument:

You can also use a URLField and pass the method get_absolute_url to it. This will call the method get_absolute_url and return that value in the serialized representation.

From DRF docs on source argument:

The name of the attribute that will be used to populate the field. May be a method that only takes a self argument, such as URLField('get_absolute_url'), or may use dotted notation to traverse attributes, such as EmailField(source='user.email').

class MyModelSerializer(serializers.ModelSerializer):

    my_absolute_url = serializers.URLField(source='get_absolute_url', read_only=True) 

I would suggest using the 2nd approach as DRF has explicitly used this in its docs.