如何使用 futures “0.3” 和 hyper “0.13.0-alpha.4” 编写一个简单的 Rust 异步代理？

Question

我正在尝试通过迁移到 :

来重写代理书 example of Asynchronous Programming in Rust

futures-preview = { version = "0.3.0-alpha.19", features = ["async-await"]}`
hyper = "0.13.0-alpha.4"`

来自：

futures-preview = { version = "=0.3.0-alpha.17", features = ["compat"] }`
hyper = "0.12.9"

当前示例将返回的 Future 从 futures 0.3 转换为 futures 0.1，因为 hyper = "0.12.9" 与 futures 0.3 的 async/await。

我的代码：

use {
    futures::future::{FutureExt, TryFutureExt},
    hyper::{
        rt::run,
        service::{make_service_fn, service_fn},
        Body, Client, Error, Request, Response, Server, Uri,
    },
    std::net::SocketAddr,
    std::str::FromStr,
};

fn forward_uri<B>(forward_url: &'static str, req: &Request<B>) -> Uri {
    let forward_uri = match req.uri().query() {
        Some(query) => format!("{}{}?{}", forward_url, req.uri().path(), query),
        None => format!("{}{}", forward_url, req.uri().path()),
    };

    Uri::from_str(forward_uri.as_str()).unwrap()
}

async fn call(
    forward_url: &'static str,
    mut _req: Request<Body>,
) -> Result<Response<Body>, hyper::Error> {
    *_req.uri_mut() = forward_uri(forward_url, &_req);
    let url_str = forward_uri(forward_url, &_req);
    let res = Client::new().get(url_str).await;
    res
}

async fn run_server(forward_url: &'static str, addr: SocketAddr) {
    let forwarded_url = forward_url;
    let serve_future = service_fn(move |req| call(forwarded_url, req).boxed());

    let server = Server::bind(&addr).serve(serve_future);
    if let Err(err) = server.await {
        eprintln!("server error: {}", err);
    }
}

fn main() {
    // Set the address to run our socket on.
    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
    let url = "http://127.0.0.1:9061";
    let futures_03_future = run_server(url, addr);
    run(futures_03_future);
}

首先，我在 run_server 函数中收到 server 的错误：

the trait tower_service::Service<&'a hyper::server::tcp::addr_stream::AddrStream> is not implemented for hyper::service::service::ServiceFn<[closure@src/main.rs:35:35: 35:78 forwarded_url:_], hyper::body::body::Body>

此外，我不能使用 hyper::rt::run，因为它在 hyper = 0.13.0-alpha.4 中的实现可能有所不同。

如果您告诉我您的修复方法，我将不胜感激。

Answer 1

通过这个 issue, to create a new service for each connection you need to create MakeService 在 hyper = "0.13.0-alpha.4" 中。您可以使用 make_service_fn 创建带有闭包的 MakeService。

Also, I cannot use hyper::rt::run because it might have been implemented differently in hyper = 0.13.0-alpha.4.

正确，在后台 hyper::rt::run 正在调用 tokio::run，它已从 api 中删除，但目前我不知道原因。您可以通过自己调用 tokio::run 或使用 #[tokio::main] 注释来运行您的未来。为此，您需要将 tokio 添加到您的货物中：

#this is the version of tokio inside hyper "0.13.0-alpha.4"
tokio = "=0.2.0-alpha.6"

然后像这样更改您的 run_server：

async fn run_server(forward_url: &'static str, addr: SocketAddr) {
    let server = Server::bind(&addr).serve(make_service_fn(move |_| {
        async move { Ok::<_, Error>(service_fn(move |req| call(forward_url, req))) }
    }));
    if let Err(err) = server.await {
        eprintln!("server error: {}", err);
    }
}

和main：

#[tokio::main]
async fn main() -> () {
    // Set the address to run our socket on.
    let addr = SocketAddr::from(([127, 0, 0, 1], 3000));
    let url = "http://www.google.com:80"; // i have tested with google 

    run_server(url, addr).await
}

如何使用 futures “0.3” 和 hyper “0.13.0-alpha.4” 编写一个简单的 Rust 异步代理？

How to write a simple Rust asynchronous proxy using futures "0.3" and hyper "0.13.0-alpha.4"?

asynchronous

rust

async-await

future

hyper