I’m trying to upload a file along with some credential information that I will save as JSON in the database. I’m using form data to send both the file and credentials. However, I need the credentials to be a dictionary with str type keys and Any type values. Here is the code written in FastAPI:

@router.post('/upload', response_model=SuccessResponse)
async def upload(file: UploadFile = File(...), credential: Dict[str, Any] = Form(...)):
     return response.success(SuccessResponse(data=credential))

Below is the cURL example I’m trying to use:

curl --location '127.0.0.1:8000/api/v1/file/upload' 
--form 'file=@"/Users/hanie/Desktop/example.jpg"' 
--form 'credential[user_id]="2"' 
--form 'credential[page_id]="1"'

However, I keep encountering an error indicating that the credentials are missing:

{"detail": [
    {
        "type": "missing",
        "loc": [
            "body",
            "credential"
        ],
        "msg": "Field required",
        "input": null
    }
]}

I thought about adding a dependency to the credential field and parsing it with a function like this:

async def parse_dict_form(request: Request) -> Dict[str, Any]:
    form_data = await request.form()
    result = {}
    prefix_with_brackets = "credential["
    for key, value in form_data.items():
        if key.startswith(prefix_with_brackets) and key.endswith(']'):
            actual_key = key[len(prefix_with_brackets):-1]
            result[actual_key] = value
    return result

@router.post('/upload', response_model=SuccessResponse)
async def upload(
        file: UploadFile = File(...), 
        credential: Dict[str, Any] = Depends(parse_dict_form)
):
    return response.success(SuccessResponse(data=credential))

This solution works, but it causes issues with the documentation, as it doesn’t correctly identify the credential field.
Documentation before adding the dependency:

Documentation after adding the dependency:

What is the best way to resolve this issue?