How do I fetch and send Data from multiple models in Django?

Question

I'm Trying to send data about all the available retailers and their prices for a particular product . How should I approach creating the view for it?

Here are my models:

class Product(models.Model):
    name = models.CharField(max_length=30,null=True,blank=True)
    brand = models.CharField(max_length=20,null=True,blank=True)
    image = models.ImageField(null=True,blank=True)
    _id = models.AutoField(primary_key=True, editable=False)

    def __str__(self):
        return self.name

class Retailer(models.Model):
    name = models.CharField(max_length=20,null=True,blank=True)
    image = models.ImageField(null=True,blank=True)
    _id = models.AutoField(primary_key=True, editable=False)

    def __str__(self):
        return self.name

class RetailerProduct(models.Model):
    url = models.CharField(max_length=300,null=True,blank=True) 
    price =  models.DecimalField(default=0.00,max_digits=8,decimal_places=2,null=True,blank=True)
    difference = models.DecimalField(default=0.00,max_digits=8,decimal_places=2,null=True,blank=True)
    retailer = models.ForeignKey(Retailer, on_delete=models.CASCADE)
    available = models.BooleanField(default=False)
    _id = models.AutoField(primary_key=True, editable=False)
    product = models.ForeignKey(Product, on_delete=models.CASCADE)

    def __str__(self):
        return self.retailer.name + " - " + self.product.name 

Here is the JSON data I would like to send.

 {
        '_id': '2',
        'name': 'ProductName',
        'image': '/images/ProductName.jpg',
        'description':'',
        'brand': 'brandname',
        'category': 'categoryname',
        'price': 599.99,
        'Instock': False,
        'ranking': 10,
        'numSources': 4,
        'sources':[{'Retailer':'Amazon', 'Price':'799.99'}, {'Retailer':'Onbuy', 'Price':'599.99'}, {'Retailer':'Ebay', 'Price':'599.99'}, {'Retailer':'NewEgg', 'Price':'499.99'}],
      },

Here Is my current view for getting a specific product:

class getProduct(APIView):
     def get(self, request,pk):
        product = Product.objects.get(_id=pk)
        serializer = ProductSerializer(product,many=False)
        return Response(serializer.data)

The serializer just has field = '__all__'

Any help would be much appreciated.

Answer 1

There are several ways to do it:

• You could use nested serializer to render the source field
• You could start from a Product ModelSerializer where you override the to_representation in order to generate and return the source content