1. Open the Cargo.toml file that has been generated for you
2. Under [dependencies], if you didn't do so in the last recipe, add the following lines:

futures = "0.1.18"
hyper = "0.11.21"

3. If you want, you can go to futures' (https://crates.io/crates/futures) and hyper's (https://crates.io/crates/hyper) crates.io pages to check for the newest version and use that one instead
4. In the folder src/bin, create a file called echo_server_with_routing.rs
5. Add the following code and run it with cargo run --bin echo_server_with_routing:

1   extern crate hyper;
2
3   use hyper::{Method, StatusCode};
4   use hyper::server::{const_service, service_fn, Http, Request, 
    Response};
5   use hyper::header::{ContentLength, ContentType};
6   use std::net::SocketAddr;
7
8   fn main() {
9     let addr = "[::1]:3000".parse().expect("Failed to parse 
      address");
10    run_echo_server(&addr).expect("Failed to run web server");
11  }
12
13  fn run_echo_server(addr: &SocketAddr) -> Result<(),  
    hyper::Error> {
14    let echo_service = const_service(service_fn(|req: Request| {
15      // An easy way to implement routing is
16      // to simply match the request's path
17      match (req.method(), req.path()) {
18        (&Method::Get, "/") => handle_root(),
19        (&Method::Post, "/echo") => handle_echo(req),
20        _ => handle_not_found(),
21      }
22    }));
23
24    let server = Http::new().bind(addr, echo_service)?;
25    server.run()
26  }

The functions are handling the routes:

28  type ResponseResult = Result<Response, hyper::Error>;
29  fn handle_root() -> ResponseResult {
30    const MSG: &str = "Try doing a POST at /echo";
31    Ok(Response::new()
32      .with_header(ContentType::plaintext())
33      .with_header(ContentLength(MSG.len() as u64))
34      .with_body(MSG))
35  }
36
37  fn handle_echo(req: Request) -> ResponseResult {
38    // The echoing is implemented by setting the response's
39    // body to the request's body
40    Ok(Response::new().with_body(req.body()))
41  }
42
43  fn handle_not_found() -> ResponseResult {
44    // Return a 404 for every unsupported route
45    Ok(Response::new().with_status(StatusCode::NotFound))
46  }