Custom Nested serializer and lookups - django-rest-framework

Question

I have a Category model and a Menu Model and I want to display the JSON data as follows:
{
"category":{
"category": "Something",
"menu": [
{
"id": 1,
"dish": "Sample Dish",
"price": 150,
"restaurant": 1
},
{
"id": 1,
"dish": "Sample Dish",
"price": 150,
"restaurant": 1
},
}
}
Here are the models:
class Menu(models.Model):
dish = models.CharField(max_length=250)
category = models.ForeignKey('Menu_Category',on_delete=models.CASCADE,related_name='menu')
price = models.IntegerField()
restaurant = models.ForeignKey('Restaurant',on_delete=models.CASCADE,related_name='menu')
def __str__(self):
return self.dish
class Menu_Category(models.Model):
category = models.CharField(max_length=255,default='')
def __str__(self):
return self.category
class Meta:
verbose_name = 'Menu Category'
verbose_name_plural = 'Menu Categories'
and here is the seriailizer:
class MenuSerializer(serializers.Serializer):
class Meta:
model = Menu
fields =['dish','price','restaurant']
class MenuCategorySerializer(serializers.Serializer):
menu = MenuSerializer(read_only=True,many=True)
class Meta:
model = Menu_Category
fields = ['category','menu']
I have tried building up some custom nested serializers as well and cant seem to get the JSON data right.

Answer 1

You should be able to do this by creating the property on the category model that returns it's related menus. Just FYI(You can also use self.menu_set.all()). See below for the model change
class Menu_Category(models.Model):
category = models.CharField(max_length=255,default='')
def __str__(self):
return self.category
class Meta:
verbose_name = 'Menu Category'
verbose_name_plural = 'Menu Categories'
#property
def menu(self):
return Menu.objects.filter(category=self)
In the serializer, change the serializer inheritence to ModelSerializer. You shouldn't need to change anything else unless your property name in models.py is different to the serializer fieldname
Sources in Rest framework serializers
class MenuCategorySerializer(serializers.ModelSerializer):
menu = MenuSerializer(read_only=True,many=True, source='menu') # -- Source must be the same as declared in models.py property
class Meta:
model = Menu_Category
fields = ['category','menu']

Answer 2

You have to add id to MenuSerializer fields and you can use reverse relation menu_set with source parameter in serializer like below
class MenuSerializer(serializers.Serializer):
class Meta:
model = Menu
fields =['id', 'dish','price','restaurant']
class MenuCategorySerializer(serializers.Serializer):
menu = MenuSerializer(read_only=True,many=True, source='menu_set')
class Meta:
model = Menu_Category
fields = ['category','menu']