如何使用 django-rest-framework 将嵌套的 m2m 字段序列化为 self ？

Question

I have a User model that has a m2m relation to itself called friends and I'm trying to serialize it to see and update the pk's of users that are in the relation.

models.py

class User(AbstractBaseUser, PermissionsMixin):
    email = models.EmailField('Email', max_length=254, unique=True)
    name = models.CharField('Full Name', max_length=35, unique=True, null=False, blank=False)

    friends = models.ManyToManyField("User", related_name='user_friends', blank=True)

serializers.py

class UserSerializer(serializers.HyperlinkedModelSerializer):
    password = serializers.CharField( 
        write_only=True,
        required=False,
        help_text='Leave empty if no change needed',
        style={'input_type': 'password', 'placeholder': 'Password'}
    ) #  for setting the password
    
    class Meta:
        model = User
        fields = ('pk', 'email', 'name', 'friends', 'password')

    def create(self, validated_data):
        validated_data['password'] = make_password(validated_data.get('password'))
        return super(UserSerializer, self).create(validated_data)

When I go to my API I see the following:

{
    "user": {
        "pk": 1,
        "email": "user@gmail.com",
        "name": "User",
        "friends": [
            "http://localhost:8000/user_detailAPI/2/"
        ],
    }
}

but I would like for the serializer to display each friend in a list in a manner like this:

{
    "user": {
        "pk": 1,
        "email": "user@gmail.com",
        "name": "User",
        "friends": [
            2
        ],
    }
}

Plus if you could let me know how I would be able to add an object to friends field using POST or PUT request it would be nice because I am new to django-rest-framework and I feel like this is an important problem.

Answer 1

So looks like there is no real way to do that rigth now but there is a workaround which is bascially:

1. Removing m2m field from user model.
2. Creating a helper table called something like FriendRelationship with 2 Foreign Keys to user model.
3. Getting the friends data from the helper table.

This works as there is no m2m relations present and data is easy to extract.