Dependency injection data model in FastAPI

Question

I’m very new to FastAPI. I have a request which looks something like this:

@router.post("/", response_model=EducationInResp)
async def create_Education_account(
        education_in: EducationCreation,
        current_user=Depends(get_current_user),
        has_perm=Depends(user_has_create_perms),
):

Now, the EducationCreation data model has a field called customer_id. I want to check if the customer_id exists in the database. Now, I know that I can manually do that within the function itself and it is not recommended to do database related validation in Schema. Is there any way to check if the customer_id exists in the database using dependencies? Is there something like this:

async def check_customer_exist(some_val):
    # some operation here to check and raise exception

@router.post("/", response_model=EducationInResp)
async def create_Education_account(
        education_in: EducationCreation = Depends(check_customer_exist),
        current_user=Depends(get_current_user),
        has_perm=Depends(user_has_create_perms),
):

Asked By: Koushik Das

||

Source

Answer 1

You could do that by declaring the parameter in the dependency function, as described in the documentation. If the customer_id exists in the database, then return the data to the route. If not, you could then raise an HTTPException, or handle it as desired.

from fastapi.exceptions import HTTPException
  
customer_ids = [1, 2, 3]

async def check_customer_exist(education_in: EducationCreation):
    if education_in.customer_id not in customer_ids:  # here, check if the customer id exists in the database. 
        raise HTTPException(status_code=404, detail="Customer ID not found")
    else:
        return education_in

@router.post("/", response_model=EducationInResp)
async def create_Education_account(
        education_in: EducationCreation = Depends(check_customer_exist),
        current_user=Depends(get_current_user),
        has_perm=Depends(user_has_create_perms),
):

Answered By: Chris

Dependency injection data model in FastAPI

Question:

Answers: