docs(examples): update proxy example to async/await

Author: weihanglo

examples/proxy.rs

@@ -0,0 +1,48 @@
+#![feature(async_await)]
+#![deny(warnings)]
+
+use hyper::{Client, Error, Server};
+use hyper::service::{make_service_fn, service_fn};
+use std::net::SocketAddr;
+
+#[hyper::rt::main]
+async fn main() {
+    pretty_env_logger::init();
+
+    let in_addr = ([127, 0, 0, 1], 3001).into();
+    let out_addr: SocketAddr = ([127, 0, 0, 1], 3000).into();
+
+    let client_main = Client::new();
+
+    let out_addr_clone = out_addr.clone();
+
+    // The closure inside `make_service_fn` is run for each connection,
+    // creating a 'service' to handle requests for that specific connection.
+    let make_service = make_service_fn(move |_| {
+        let client = client_main.clone();
+        
+        async move {
+            // This is the `Service` that will handle the connection.
+            // `service_fn` is a helper to convert a function that
+            // returns a Response into a `Service`.
+            Ok::<_, Error>(service_fn(move |mut req| {
+                let uri_string = format!("http://{}/{}",
+                                         out_addr_clone,
+                                         req.uri().path_and_query().map(|x| x.as_str()).unwrap_or(""));
+                let uri = uri_string.parse().unwrap();
+                *req.uri_mut() = uri;
+                client.request(req)
+            }))
+        }
+    });
+
+    let server = Server::bind(&in_addr)
+        .serve(make_service);
+
+    println!("Listening on http://{}", in_addr);
+    println!("Proxying on http://{}", out_addr);
+
+    if let Err(e) = server.await {
+        eprintln!("server error: {}", e);
+    }
+}