python - Serialize multiple models and send all in one json response django rest framework

Question

This question is being asked to expand and fill in the holes from this one: Return results from multiple models with Django REST Framework

my goal is to return a json object that I will use to dynamically populate the options in various select statements in my html code.

so I want to grab a attribute from model a, another from model b etc

then I want all the values from attribute a and b and c etc

to be in a value as a JSON array to a key so

json = {
    modelA: {'atter1, atter2, atter3}
    modelB: {'atter1, atter2, atter3}
    model..:{you get the point}
}

this part from the post referenced above makes sense:

class TimelineViewSet(viewsets.ModelViewSet):
    """
    API endpoint that lists all tweet/article objects in rev-chrono.
    """
    queryset = itertools.chain(Tweet.objects.all(), Article.objects.all())
    serializer_class = TimelineSerializer

what doesn't is this:

class TimelineSerializer(serializers.Serializer):
    pk = serializers.Field()
    title = serializers.CharField()
    author = serializers.RelatedField()
    pub_date = serializers.DateTimeField()

how do I set the the seperate model attributes to the correct json key?

I assume its something similar to a serializer relation but these values aren't related to eachother via onetoone, onetomany, or many to many. I just want to grab all this info at once instead of creating an api for each value.

I am a lost little girl and I am asking you to help me find my way home.

Answer 1

You'll find things easier in Django REST Framework if you design your response format rationally.

It seems a bit vague at the moment, but I would suggest something like:

{
    "tweets": [
        {"tweet_attr_A": value_1, ...},  // first tweet
        {"tweet_attr_A": value_2, ...},  // second tweet
        //etc
    ],
    "articles": [
        {"id": 1, ...},  // first article
        {"id": 2, ...},  // second article
        //etc
    ]
}

We can express this with three serializers, like:

class TweetSerializer(serializers.ModelSerializer):
    class Meta:
        model = Tweet

class ArticleSerializer(serializers.ModelSerializer):
    class Meta:
        model = Article

class TimelineSerializer(serializers.Serializer):
    tweets = TweetSerializer(many=True)
    articles = ArticleSerializer(many=True)

http://www.django-rest-framework.org/api-guide/serializers/#dealing-with-nested-objects

Then, because we're using more than one model, it's easiest just to define your own custom viewset rather than trying to shoe-horn this into DRF's magic ModelViewSet type.
http://www.django-rest-framework.org/api-guide/viewsets/#example

First we need an object type to pass into our TimelineSerializer. It should have two attributes: tweets and articles

from collections import namedtuple

Timeline = namedtuple('Timeline', ('tweets', 'articles'))

Then we'll define the custom viewset to fetch the tweets and articles, instantiate a Timeline object and return the TimelineSerializer data:

class TimelineViewSet(viewsets.ViewSet):
    """
    A simple ViewSet for listing the Tweets and Articles in your Timeline.
    """
    def list(self, request):
        timeline = Timeline(
            tweets=Tweet.objects.all(),
            articles=Article.objects.all(),
        )
        serializer = TimelineSerializer(timeline)
        return Response(serializer.data)