docs(examples): add proxy example

Cargo.toml

@@ -104,6 +104,11 @@ name = "params"
 path = "examples/params.rs"
 required-features = ["runtime"]
 
+[[example]]
+name = "proxy"
+path = "examples/proxy.rs"
+required-features = ["runtime"]
+
 [[example]]
 name = "send_file"
 path = "examples/send_file.rs"

examples/README.md

@@ -17,6 +17,8 @@ parses it with serde and outputs the result.
 
 * [`params`](params.rs) - A webserver that accept a form, with a name and a number, checks the parameters are presents and validates the input.
 
+* [`proxy`](proxy.rs) - A webserver that proxies to the hello service above.
+
 * [`send_file`](send_file.rs) - A server that sends back content of files using tokio_fs to read the files asynchronously.
 
 * [`state`](state.rs) - A webserver showing basic state sharing among requests. A counter is shared, incremented for every request, and every response is sent the last count.

examples/proxy.rs

@@ -0,0 +1,44 @@
+#![deny(warnings)]
+extern crate hyper;
+extern crate pretty_env_logger;
+
+use hyper::{Client, Server};
+use hyper::service::service_fn;
+use hyper::rt::{self, Future};
+use std::net::SocketAddr;
+
+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();
+    // new_service is run for each connection, creating a 'service'
+    // to handle requests for that specific connection.
+    let new_service = move || {
+        let client = client_main.clone();
+        // This is the `Service` that will handle the connection.
+        // `service_fn_ok` is a helper to convert a function that
+        // returns a Response into a `Service`.
+        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(new_service)
+        .map_err(|e| eprintln!("server error: {}", e));
+
+    println!("Listening on http://{}", in_addr);
+    println!("Proxying on http://{}", out_addr);
+
+    rt::run(server);
+}