What is the right way to call an APIRouter endpoint from another in same app

[jintolonappan]

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Question

I'm working on creating an application by following the tutorial. I currently have a structure similar
to below as mentioned in Bigger Applications - Multiple Files section of the tutorial:

.
├── app
│   ├── __init__.py
│   ├── main.py
│   ├── dependencies.py
│   └── routers
│   │   ├── __init__.py
│   │   ├── items.py
│   │   └── users.py
│   └── internal
│       ├── __init__.py
│       └── admin.py

I have a usecase where I need to hit one of the endpoint exposed by one APIRouter (Say, in this example users from the other APIRouter (items from the example).

This is required due to some of the foreign key relationships and wanted to POST the data to referenced table rather than throwing an exception back to the user.
Using above example, the end consumer may send both user data and items data in a single API call and internally, my app needs to hit both users endpoint and items endpoint.

I already looked at the Requests section and thought there must be a better way rather than figuring out client host and manually coming up with the API endpoint.
I also looked at Callback section.

I'm using SQLAlchemy for database connections and is referenced in each APIRouters as Depends.

Environment

• OS: macOS Catalina 10.15.7
• FastAPI Version: 0.63.0
• Python version: Python 3.8.5

[insomnes]

@jintolonappan hello!
Why do you want to call it by HTTP API endpoint request and not by calling some function in app code?
Wrap the desired actions in function somewhere and call it from endpoint handlers.

[ycd]

You can abstract your endpoints logic. Then when you need to call it internally, for example just use the get_user_from_database_by_id function.

async def get_user_from_database_by_id(id: int) -> User:
    ...

@app.get("/user/{id}")
async def get_user_by_id(id: int):
    return await get_user_from_database_by_id(id)
    

[jintolonappan]

Thanks @insomnes @ycd
I implemented the call with function calls. The reason I was a little hesitant to use this option was because I thought I could keep each router on its own without cross-router calls.

[tiangolo]

Thanks for the help here @ycd and @insomnes ! 👏 🙇

Thanks for reporting back and closing the issue @jintolonappan 👍

Sorry for the long delay! 🙈 I wanted to personally address each issue/PR and they piled up through time, but now I'm checking each one in order.