Parsing JSON from POST request using Python and FastAPI - python-3.x

Question

I'm trying to parse a JSON that came from a POST request from user to my API made with FastAPI. I have a nested JSON that can receive multiple values and my problem is: How can I parse it and get the values from this nested JSON?
The JSON is like this:
{
"recipe": [
{
"ingredient": "rice",
"quantity": 1.5
},
{
"ingredient": "carrot",
"quantity": 1.8
},
{
"ingredient": "beans",
"quantity": 1.8
}
]
}
I must grab the all values from the list recipe separated, as I have a database with this ingredient and will query all of this and do some calculates with the quantity given from user. But I don't even know how I can parse this JSON from the POST request.
I already have a 2 classes with Pydantic validating this values like:
class Ingredientes(BaseModel):
ingredient: str
quantity: float
class Receita(BaseModel):
receita: List[Ingredientes] = []
Edit 1: I tried to include it in my function that recieve this POST request and didn't work like:
#app.post('/calcul', status_code=200)
def calculate_table(receita: Receita):
receipe = receita["receita"]
for ingredient in receipe:
return f'{ingredient["ingredient"]}: {ingredient["quantity"]}'
Edit 2: Fixed the issue with the code bellow(Thanks MatsLindh):
#app.post('/calcul', status_code=200)
def calculate_table(receita: Receita):
receipe = receita.receita
for ingredient in receipe:
return f'{ingredient.ingrediente}: {ingredient.quantidade}'

Answer 1

To parse a JSON-formatted string (from the POST request, for example) into a dictionary, use the loads function from the json module, like this:
import json
s = """{
"recipe": [
{
"ingredient": "rice",
"quantity": 1.5
},
{
"ingredient": "carrot",
"quantity": 1.8
},
{
"ingredient": "beans",
"quantity": 1.8
}
]
}
"""
recipe = json.loads(s)["recipe"]
for ingredient in recipe:
print(f"{ingredient['ingredient']}: {ingredient['quantity']}")