http - 如何在 Rust 中使用 hyper、tokio 和 futures 为 HTTP 请求设置超时？

Question

如何使用异步 Hyper (>= 0.11) 为 HTTP 请求设置超时？

下面是没有超时的代码示例:

extern crate hyper;
extern crate tokio_core;
extern crate futures;

use futures::Future;
use hyper::Client;
use tokio_core::reactor::Core;

fn main() {
    let mut core = Core::new().unwrap();
    let client = Client::new(&core.handle());

    let uri = "http://stackoverflow.com".parse().unwrap();
    let work = client.get(uri).map(|res| {
        res.status()
    });

    match core.run(work) {
        Ok(status) => println!("Status: {}", status),
        Err(e) => println!("Error: {:?}", e)
    }
}

Answer 1

根据 seanmonstar 提供的指向 Hyper Guide / General Timeout 的链接，用工作代码示例回答我自己的问题:

extern crate hyper;
extern crate tokio_core;
extern crate futures;

use futures::Future;
use futures::future::Either;
use hyper::Client;
use tokio_core::reactor::Core;
use std::time::Duration;
use std::io;

fn main() {
    let mut core = Core::new().unwrap();
    let handle = core.handle();
    let client = Client::new(&handle);

    let uri: hyper::Uri = "http://stackoverflow.com".parse().unwrap();
    let request = client.get(uri.clone()).map(|res| res.status());

    let timeout = tokio_core::reactor::Timeout::new(Duration::from_millis(170), &handle).unwrap();

    let work = request.select2(timeout).then(|res| match res {
        Ok(Either::A((got, _timeout))) => Ok(got),
        Ok(Either::B((_timeout_error, _get))) => {
            Err(hyper::Error::Io(io::Error::new(
                io::ErrorKind::TimedOut,
                "Client timed out while connecting",
            )))
        }
        Err(Either::A((get_error, _timeout))) => Err(get_error),
        Err(Either::B((timeout_error, _get))) => Err(From::from(timeout_error)),
    });

    match core.run(work) {
        Ok(status) => println!("OK: {:?}", status),
        Err(e) => println!("Error: {:?}", e)
    }
}