Filter to log request headers using Warp framework

warp_log_headers.rs

// [dependencies]
// tokio = { version = "0.2", features = ["macros"] }
// warp = "0.2.2"

use warp::Filter;
use warp::http::HeaderMap;
use std::convert::Infallible;

#[tokio::main]
async fn main() {

    let port: u16 = 8080;

    let api = warp::any()
        .and(log_headers())
        .and_then(handle);
    
    let server_future = warp::serve(api).run(([0, 0, 0, 0], port.clone()));

    server_future.await;
}

fn log_headers() -> impl Filter<Extract = (), Error = Infallible> + Copy {
    warp::header::headers_cloned()
        .map(|headers: HeaderMap| {
            for (k, v) in headers.iter() {
                // Error from `to_str` should be handled properly
                println!("{}: {}", k, v.to_str().expect("Failed to print header value"))
            }
        })
        .untuple_one()
}

async fn handle() -> Result<impl warp::Reply, warp::Rejection> {
    Ok(warp::reply::reply())
}