Option<Path<T>> extractor does not return None

[demhadais]

• [ x ] I have looked for existing issues (including closed) about this

Bug Report

Platform

Darwin Ahmeds-MacBook-Air.local 24.2.0 Darwin Kernel Version 24.2.0: Fri Dec 6 18:51:28 PST 2024; root:xnu-11215.61.5~2/RELEASE_ARM64_T8112 arm64

Description

I tried for a long time to get this to work, and I'm fairly confident I'm misunderstanding how this extractor is meant to be used and/or the expected result. Anyways, the issue is that with the following code, theOption<Path<T>> extractor doesn't actually ever return the None variant.

use axum::{extract::Path, routing::get, Router};
use tokio::net::TcpListener;

#[tokio::main]
async fn main() {
    let app = Router::new().route("/{name}", get(handler));
    let listener = TcpListener::bind("localhost:8080").await.unwrap();

    axum::serve(listener, app).await.unwrap();
}

async fn handler(name: Option<Path<String>>) -> String {
    match name {
        Some(Path(name)) => format!("{name}\n"),
        None => "hello\n".to_string(),
    }
}

Here are some snippets from my command-line:
No path - I expect this to error

$ curl -i http://localhost:8080
HTTP/1.1 404 Not Found
content-length: 0
date: Sun, 02 Feb 2025 04:37:43 GMT

Just a slash - I expect this to show hello\n, but instead it errors too

$ curl -i http://localhost:8080/
HTTP/1.1 404 Not Found
content-length: 0
date: Sun, 02 Feb 2025 04:37:43 GMT

A path parameter - This works

$ curl -i http://localhost:8080/some-random-string
HTTP/1.1 200 OK
content-type: text/plain; charset=utf-8
content-length: 19
date: Sun, 02 Feb 2025 04:43:03 GMT

some-random-string

Version

├── axum v0.8.1
│   ├── axum-core v0.5.0

[jplatte]

We should probably improve the documentation for this. Option<Path<T>> is for when you wsnt to have multiple routes that use the same handler function, where one has parameters and the other one not. Since you only have one route in your example, you always get the same behavior. Try adding .route("/", get(handler)).

[demhadais]

Oh wow I should have definitely figured that out lol. Thanks for your help! I'd be happy to submit a PR with a small addition to the docs if it'd help