Can I create a service in fastapi using an imported function from another .py file?-CodePudding

I have written some functions with python in separate files. My task is to transform these functions into services using fastAPI and the services should return a JSON that says if the operation is executed correctly or not (a code and a message).

For example, I have a file sum.py and inside there's a function that sums two numbers and returns the result:

def sum_of_two_numbers(a,b):
    tot = a b
    return tot

Let's say I want to create a service using fastAPI, do you know if I can import sum_of_two_numbers from sum and use TestClient to complete this task without modyfing the code or re-writing it?

In this example the function is short, but have in mind my functions are different. I needed one month to write them all and make the connection to the Oracle db. While reading the documentation of fastAPI, I understood I should modify all the syntax to adapt it for fastAPI.

So, in short can I do this with fastAPI by simply importing the functions and without changing all the functions syntax? Or do you know if is there an easier way to do it?

CodePudding user response：

in a basic fastapi app structure you often have something like this:

Exemple taken from Bastien-BO/fastapi-RBAC-microservice, inspired by Kludex/fastapi-microservices and tiangolo/full-stack-fastapi-postgresql

.
├── app
│   ├── __init__.py
│   ├── main.py
│   ├── dependencies.py
│   └── routers
│   │   ├── __init__.py
│   │   ├── items.py
│   │   └── users.py
│   └── models
│   │   ├── __init__.py
│   │   ├── items.py
│   │   └── users.py
│   └── schemas
│   │   ├── __init__.py
│   │   ├── items.py
│   │   └── users.py
│   └── internal
│   │   ├── __init__.py
│   │   └── crud
|   |   |   └── user.py
|   |   |   └── item.py

Often in your internal files you have functions or classes that you can serve with routes.

exemple of a user route with internal db function call:

# app/routers/users.py
from app.internal.crud.user import crud_user

@router.get("/", response_model=List[UserOut])
async def read_users(offset: int = 0, limit: int = 100, session: Session = Depends(get_db)):
    users = crud_user.get_multi(session, offset=offset, limit=limit)
    return users

# app/internal/crud/user.py

def crud_user():
    #do db stuff here

In this exemple your sum_of_two_numbers function would be in the internal folder and you would wrape it in a route like what is done in read_users.

you should folow the user guide or the advanced user guide (fit better to your need i believe) from fastapi official doc. Also take a look at tiangolo (fastapi creator) Base Project Generator. you will have a good exemple on how to create a strong base for your api.