FastAPI equivalent of Flask's request.form, for agnostic forms

I try to migrate from Flask to FastAPI, and I was wondering if there is something similar to Flask's:

payload = request.form.to_dict(flat=False)
payload = {key:payload[key][0] for key in payload}

for FastAPI.

Until now I've found only some hacks, were you still had to implement one-by-one all the form's arguments to a function:

from pydantic import BaseModel
class FormData(BaseModel):
    alfa: str=Form(...)
    vita: str=Form(...)
async def Home(request: Request, form_data:FormData)

This example is of course better in readability than the standard form handling:

async def Home(username: str = Form(...), something_else: str = Form(...)):

But still it's quite restricting, due to the necessary declaration of all form fields.

Is there any other more agnostic & elegant approach?

Solution

You can get the underlying starlette request and use its request.form() method. It requires python-multipart to work:

from fastapi import FastAPI, Request

app = FastAPI()

@app.post("/example")
async def example(request: Request):
    form_data = await request.form()
    return form_data

Example of calling it:

C:\>curl -X POST "http://localhost:8000/example" -d "hello=there&another=value"
{"hello":"there","another":"value"}