Chrome blocks FastAPI file download using FileResponse due to using HTTP instead of HTTPS

Option 1

You could use HTTPSRedirectMiddleware to enforce all incoming requests to http being redirected to the secure scheme instead.

from fastapi.middleware.httpsredirect import HTTPSRedirectMiddleware
app = FastAPI()
app.add_middleware(HTTPSRedirectMiddleware)

In addition to the above, you could use relative URLs instead of using url_for() in your Jinja2 template; for instance:

<a href="/upload_schedule">Link text</a>

In this way, the scheme of the URL will remain https.

You could have your own url_for custom function to replace the scheme of the URL, similar to the approach demonstrated in Option 2 of this answer.

If you are behind a proxy server, such as Nginx, you may also try passing --proxy-headers parameter to Uvicorn, as described here.