Django Rest Framework many to many with extra fields serialization - django

Question

class Item(models.Model):
name = models.CharField(max_length=20)
class Meals(models.Model):
name = models.CharField(max_length=50)
ingredients = models.ManyToManyField(Item, through='MealRecipe')
class Menu(models.Model):
name = models.CharField(max_length=50)
meals = models.ManyToManyField(Meals,through='CompMenu')
class CompMenu(models.Model):
TYPE_COMP = (
('B', 'Breakfast'),
('L', 'Lunch'),
('D', 'Dinner')
)
menu = models.ForeignKey(Menu)
meal = models.ForeignKey(Meals)
type = models.CharField(max_length=1, choices=TYPE_COMP)
class MealRecipe(models.Model):
meal = models.ForeignKey(Meal)
item = models.ForeignKey(Item)
qty = models.IntegerField()
If i need to serialze queryset how can i do it, there is no documentation about it, i need a JSON with Item_id, Item_name, MealRecipe_qty. Do i have to serialze all models ? I need this to manipualte the recipe quantities on the front end based on the selected menu.
receipes = MealRecipe.objects.filter(meal__in=meals_of_menu)
for receipe in receipes:
name = receipe.item.name
qty = receipe.qty
OR
MealRecipe.objects.filter(meal__menu=some_menu_instance).distinct()
I cannot figure out how to pass the result o this query to the front end

Answer 1

For your requirements of Item_id, Item_name, MealRecipe_qty, you will need to serialize the MealRecipe model and the Item model.
Also give a related name to item in MealRecipe model
class MealRecipe(models.Model):
meal = models.ForeignKey(Meal)
item = models.ForeignKey(Item,related_name='qty')
qty = models.IntegerField()
And your serializers will be
class MealRecipeSerializer(serializers.ModelSerializer):
class Meta:
model = MealRecipe
fields = ('qty')
class ItemSerializer(serializers.ModelSerializer):
qty = MealRecipeSerializer()
class Meta:
model = Item
fields = ('id','name','qty')
Also if you are passing a queryset to a serializer do it as, MealRecipeSerializer(many=True)