Falcon script to server contents of multiple directories on single root path over HTTP for X-Accel-Redirect headers

gooier.py

import falcon
import falcon.asgi
import os

async def diefolt(req, resp, **kwargs):
    _, filename = os.path.split(req.path)
    resp.status = falcon.HTTP_404
    resp.text = f'{filename} Not Found'
    SOURCES = ['/data/ap/beeldbank_images/', '/data/blm/images/']
    for s in SOURCES:
        filepath = os.path.join(s, filename)
        if os.path.exists(filepath):
           resp.set_header('X-Accel-Redirect', filepath.replace('/data', ''))
           resp.status = falcon.HTTP_200
           resp.text = 'Found'

app = falcon.asgi.App()
app.add_sink(diefolt, '/')