Path parameter with List

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Example Code

@app.get(
    V4L2_ROUTE + "controls/{ctrl_list}",
    response_model=List[ControlValue],
    tags=[Tags.controls],
)
def get_controls(
    ctrl_list: List[str],
    params: CommonParams = Depends(),
) -> JSONResponse:
    """Get v4l2 controls"""
    return Camera.get_controls(ctrl_list, params.dev)

Description

When trying to declare a route with a Path parameter which is a List I get the following error: AssertionError: Path params must be of one of the supported types

But from what I can see it should be possible to have Lists in the Path: https://stackoverflow.com/questions/2602043/rest-api-best-practice-how-to-accept-list-of-parameter-values-as-input

Fx: http://our.api.com/Product/101404,7267261

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.85.0

Python Version

Python 3.10.5

Additional Context

No response

[JarroVGIT]

A Path param is always a int or a str. However, you could simply do the conversion yourself. The below example shows how to deal with a list of values like ‘int,int,int’ etc. Using pydantic, I will also perform basic validation, yay!

from fastapi import Depends, FastAPI, HTTPException, Path
from pydantic import BaseModel, ValidationError

app = FastAPI()


class ListOfIds(BaseModel):
    ids: list[int]


def list_path_param(list_of_ids: str = Path()):
    try:
        ids = ListOfIds(ids=list_of_ids.split(","))
    except ValidationError:
        raise HTTPException(400, "IDs must be valid integers.")
    return ids


@app.get("/controls/{list_of_ids}")
async def get_list_of_ids(list_obj: ListOfIds = Depends(list_path_param)):
    return {"count": len(list_obj.ids), "ids": list_obj.ids}


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(app, host="0.0.0.0", port=8000)

This will take the str and will split it (resulting in a list), and construct a Pydantic model with its parts (thus performing validation). The above will run as is.

[tiangolo]

Ah, get it, great!