在 Django Rest 框架中发布外键 ID

Question

I'm working on a Django API using Django Rest Framework. I have two related entities, Event and Venue . An Event takes place in a Venue.

By using nested serialization I'm able to return the following to my API users:

{
  "id": "1234",
  "name": "My event",
  "venue": {
    "id": "5678",
    "name": "My venue"
  }
}

This is all as expected. However, I'm now trying to POST an event and reference the venue as a parameter:

POST /api/events/

{
  "name": "My new event",
  "venue_id": "5678"
}

But I'm struggling to make this work. I'm trying both venue_id and venue as attribute names (I'd prefer _id as it would be more correct, but it wouldn't be a big deal).

I'm using the following serializers:

class VenueSerializer(serializers.ModelSerializer):
    class Meta:
        model = Venue
        fields = ['id', 'name', 'created_at', 'updated_at']

class EventSerializer(serializers.ModelSerializer):
    venue = VenueSerializer()

    class Meta:
        model = Event
        fields = ['id', 'name', 'venue', 'created_at', 'updated_at']

What would be the correct approach to achieve this?

Answer 1

If you are using PrimaryKey(the venue_id) instead of the whole model object, you may use PrimaryKeyRelatedField instead of a nested serializer.

In your example, it would look like:

class EventCreateSerializer(serializers.ModelSerializer):
    venue = PrimaryKeyRelatedField(queryset=Venue.objects.all())

    class Meta:
        model = Event
        fields = ['id', 'name', 'venue', 'created_at', 'updated_at']

And you shall use the request:

{
  "name": "My new event",
  "venue": "5678"
}