Django Rest Framework Serializer format - django

Question

I have two serializers: one for the Restaurant model, another for the MainMenu model:
class RestaurantSerializer(serializers.ModelSerializer):
class Meta:
model = Restaurant
class MainMenuSerializer(serializers.ModelSerializer):
restaurant = RestaurantSerializer()
main_menu_items = serializers.StringRelatedField(many=True)
class Meta:
model = MenuMain
fields = ('id', 'restaurant', 'main_menu_items')
The current output of the MainMenuSerializer is
[
{
"id": 1,
"restaurant": {
"id": 1,
"name": "Restaurant A",
"location": "Street B"
},
"main_menu_items": [
"Fried Rice"
]
},
{
"id": 2,
"restaurant": {
"id": 1,
"name": "Restaurant A",
"location": "Street B",
},
"main_menu_items": [
"Noodles"
]
}
]
But I want the RestaurantSerializer to only output once, something like this:
[
{
"restaurant": {
"id": 1,
"name": "Restaurant A",
"location": "Street B"
}
},
[
{
"id": 1,
"main_menu_items": [
"Fried Rice",
"Meat Balls"
]
},
{
"id": 2,
"main_menu_items": [
"Noodles"
]
}
]
]
EDIT:
models used
class Restaurant(models.Model):
name = models.CharField(max_length=100, default='')
location = models.CharField(max_length=100, default='')
class MenuMain(models.Model):
price = models.IntegerField()
restaurant = models.ForeignKey(Restaurant, related_name='main_menus')
class MenuMainItems(models.Model):
menu_main = models.ForeignKey(MenuMain, related_name='main_menu_items')
item = models.CharField(max_length=150, default='')

Answer 1

The more "Django REST" way of doing this is to set up a url node for each restaurant that returns all the menu items in the restaurant. For instance,
urls.py
url(r'restaurant-menu/(?P<pk>[0-9]+)$', MenuItemViewset.as_view())
In your viewset class
class MenuItemViewset(viewsets.ModelViewSet):
serializer_class = MainMenuSerializer
def retrieve(self, request, pk=None):
return Restaurant.objects.get(pk=pk).menumain_set.all()[0].menumainitems_set.all()
This of course assumes one menu per restaurant. If there are multiple menus and you want to get all of them, it's probably best practice to break it up into two calls: one for the restaurant's menu, and to get a particular menu's items. Otherwise too many assumptions are being made about the organization of the data, and that's a rather fragile design pattern.
Link to docs on fetching related objects
If you still are intent on getting a response like you originally asked for, you just need to reverse the serializer nesting, i.e. add a menu field to the RestaurantSerializer.

Answer 2

Here is the very simplest approach I came with. I know this can be improved.
Please comment if you have any query or improvement suggestion.
class RestaurantSerializer(serializers.ModelSerializer):
menu = serializers.SerializerMethodField()
def get_menu(self, obj):
dict_l = {}
res = MainMenu.objects.all() # filter as per your requirement
'''
flds = MainMenu._meta.local_fields
for ins in res:
for f in flds:
print f.name
'''
for ins in res:
dict_l['id'] = ins.id
dict_l['name'] = ins.name
dict_l['restaurant'] = ins.restaurant_id
# return {1: 1, 2: 2}
return dict_l
class Meta:
model = Restaurant
fields = ('id', 'name', 'menu',)