CODEWITHSUNDEEP
pythondjangodjango-rest-frameworkforeign-keys
Serghey Hmeli
Serghey Hmeli

Reputation: 63

How to get a value from the foreign key id?

I recently started to learn django, so I am not even sure how to ask this question. I want to build an api and I am using django rest framework. Now I have two main models Product and Category.

class Category(models.Model):
    id = models.CharField(max_length=100, primary_key=True)
    name = models.CharField(max_length=100)


class Product(models.Model):
    id = models.CharField(max_length=100, primary_key=True)
    title = models.CharField(max_length=100)
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    price = models.FloatField(default=0.0)

And I have some functions

@api_view(['GET'])
def productList(request):
    products = Product.objects.all()
    serializer = ProductSerializer(products, many=True)
    return Response(serializer.data)

@api_view(['POST'])
def addProduct(request):
    serializer = ProductSerializer(data=request.data)

    if serializer.is_valid():
        serializer.save()

    return Response(serializer.data)

All of these seems to works fine and I am getting a response from an api that looks something like this:

{id: "1", title: "banana", price: 3, category: "1"}

As you can see response does not include category name that I need. Can you please help me figure this out? Thank you

Upvotes: 0

Views: 200

Answers (1)

henriquesalvaro
henriquesalvaro

Reputation: 1272

You can update the to_representation method of your serializer, to include the name of the category, or to use a nested representation. If you'd like to return the name of the category:

class ProductSerializer(serializers.ModelSerializer):

    def to_representation(self, instance):
        data = super().to_representation(instance)
        data['category'] = instance.category.name
        return data

and if you'd like to return a nested representation of the category, you could do something like:

class CategorySerializer(serializers.ModelSerializer):
    
    class Meta:
        model = Category
        fields = ('id', 'name',)


class ProductSerializer(serializers.ModelSerializer):

    def to_representation(self, instance):
        data = super().to_representation(instance)
        data['category'] = CategorySerializer(instance.category).data
        return data

Keep in mind that this is for the case where you're using the same serializer for both creating and listing the products, and where you're creating the product by receiving the category's id (write), while also wanting to send it as another representation.

Upvotes: 1

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