How to dynamically specify fields for nested serialization - django

Question

When working with Django rest-framework, and object relationships, I often encounter situations in which I want to return different fields from a serializer depending on the context in which I'm calling that serializier. To provide an example, lets say I have some models representing artiste and album
class Artiste(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
name = models.CharField(max_length=30)
songs = models.ManyToManyField(Song, related_name='artiste')
albums = models.ManyToManyField(Album, related_name='artiste')
class Album(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
title = models.CharField(max_length=30)
description = models.TextField(blank=True, null=True)
These models being serialized by these serializers, which include field from the many to many relationship
class AlbumSerializer(serializers.ModelSerializer):
artiste = ArtisteSerializer(many=True)
class Meta:
model = Album
fields = ('id','title','description','artiste')
class ArtisteSerializer(serializers.ModelSerializer):
class Meta:
model = Artiste
fields = ('id', 'name', 'albums')
A request to my album endpoint might produce an object like this
"id": "5807bd12-254f-4508-b76f-02dc0740e809",
"title": "Test",
"description": "",
"artiste": [
{
"id": "31f09ef0-50ce-48b1-96a6-a6c234930ce5",
"name": "Alec Benjamin",
"albums": [
"5807bd12-254f-4508-b76f-02dc0740e809"
]
}
]
As you can see, using nested serialization ends up giving me more information that I actually want in this context. Given that I had more data for example, when looking at the information for an artiste, I'd love to have the information regarding all the albums that the artiste has made, but when looking at my album endpoint, I'd rather not have this information be included, especially here where the only album the artiste has made is the one I'm currently looking at anyways. As the system gets larger, this problem gets worse as i include songs, playlists etc
What I want to do, is to be able to specify what serialzier fields I want depending on the context in which I'm calling that serializer, as opposed to defining my serializer once and then always getting the same information even when its not needed.
my current approach to this is to use a SerializerMethodField and adding this to my album serializer
artiste = serializers.SerializerMethodField('get_artiste')
def get_artiste(self, obj):
return [(i.id ,i.name)for i in obj.artiste.all()]
Doing this allows me to explicitly state what I want to return in the context of my album serializer but this makes my artiste field read only, meaning that when trying to create an album, I cannot specify what artiste it belongs to. This issue also seems to be the case with StringRelatedField etc.
What is your approach to doing nested serialization? Is there any way to specify what fields should be returned from serialization in a specific situation without rewriting the serializer or making the field read only?
Sorry for the lengthy, probably stupid question and thanks for your help.

Answer 1

according to documentation serializers classes is very like regular django form classes so you only need to specify which fields you want that serializer to show and it will be done in your example it will be :
class ArtisteSerializer(serializers.ModelSerializer):
class Meta:
model = Artiste
fields = ('id', 'name')
and now this serializer will only show the related 'id' and 'name' of the given artiste model.
and there is much more that you can do here like special fields = '__all__'
which will show all fields of a given model or instead of using fields you can use exclude = ('album',) that just removes these fields from serializer .
also you can use django's models relationship here as well.
update :
to be able to use these serializers in different endpoints it is better to use python class inheritance create a base serializer and use different attributes on childs
class BaseArtisteSerializer(serializers.ModelSerializer):
class Meta:
model = Artiste
fields = ('id', 'name', 'artist')
class ArtisteSerializer(BaseArtisteSerializer):
class Meta(BaseArtisteSerializer.Meta):
fields = ('id', 'name')