Django Rest Framework中的多对多嵌套关系作为列表

Question

I'm building an API using the Django Rest Framework and I have two models that share a many to many relationship. The models are Contacts and Tasks. A Task can be shared with several Contacts and a Contact can have many Tasks shared with it. I'm also using a manual join table, rather than Django's built-in many-to-many relationship.

In the API, I'd like to have the method for retrieving Tasks include a list of Contacts with whom the Task has been shared. I have a way of accomplishing this currently, but it isn't great. The serialized Task has an attribute shared_with , which is a related field that goes through the SharedWithSerializer class (which is the version of the ContactTaskJoin serializer for this side of the relationship). So the output is quite clunky. The SharedWithSerializer has just one attribute— contact —which references the ContactSerializer class. An example Task returned by the API:

{
 'id': 100,
 'shared_with': [
    {
       'contact': {
          'id': 1,
          'name': 'Alice'
       }
    },
    {
       'contact': {
          'id': 2,
          'name': 'Bob'
       }
    }
 ]
}

What I would like is to just have a plain list of the Contacts with whom the Task was shared. Something like:

 {
 'id': 100,
 'shared_with': [
    {
       'id': 1,
       'name': 'Alice'
    },
    {
       'id': 2,
       'name': 'Bob'
    },
 ]
}

Any suggestions would be much appreciated.

Answer 1

You could override to_representation on the SharedWithSerializer to flatten the contact fields one level up

For example

class SharedWithSerializer(serializers.ModelSerializer):

    def to_representation(self, obj):
        representation = super().to_representation(obj)
        shared_with = representation.pop('shared_with')
        representation['shared_with'] = [entry['contact'] for entry in shared_with]
        return representation

I hope this helps resolve you issue. If you could also post your models.py and serializers.py I can provide a more tailored answer, if necessary.