warp_test.rs

use futures::Future;
use warp::Filter;

#[tokio::main]
async fn main() {
    let r1 = warp::path("index").and_then(route1);

    let r2 = warp::path::param().and_then(route2);

    let routes = r1.recover(recover).or(r2.recover(recover));

    warp::serve(routes).run(([127, 0, 0, 1], 3020)).await;
}

fn route1() -> impl Future<Output = Result<impl warp::Reply, warp::Rejection>> {
    dbg!("was here");
    futures::future::err::<String, warp::Rejection>(warp::reject::custom(
        std::io::Error::from(std::io::ErrorKind::ConnectionAborted),
    ))
}

fn route2(_param: String) -> impl Future<Output = Result<impl warp::Reply, warp::Rejection>> {
    futures::future::ok("hello world")
}

async fn recover(err: warp::Rejection) -> Result<impl warp::Reply, warp::Rejection> {
    Ok(warp::reply::with_status("an error happened", warp::http::StatusCode::BAD_REQUEST))
}