Untitled

use futures::{future, Stream};
use hyper::{Body, Method, Request, Response, Server, StatusCode};
use hyper::rt::Future;
use hyper::service::service_fn;

type BoxFut = Box<dyn Future<Item=Response<Body>, Error=hyper::Error> + Send>;

fn echo(req: Request<Body>) -> BoxFut {
  let mut response = Response::new(Body::empty());
  match (req.method(), req.uri().path()) {
    (&Method::GET, "/") => {
      *response.body_mut() = Body::from("Try POSTing data to /echo");
    },
    (&Method::POST, "/echo") => {
      *response.body_mut() = req.into_body();
    },
    (&Method::POST, "/echo/uppercase") => {
      let mapping = req.into_body()
        .map(|chunk| {
          chunk.iter()
            .map(|byte| byte.to_ascii_uppercase())
            .collect::<Vec<u8>>()
        });
      *response.body_mut() = Body::wrap_stream(mapping);
    },
    // Yet another route inside our match block...
    (&Method::POST, "/echo/reverse") => {
      // This is actually a new `Future`, waiting on `concat`...
      let reversed = req
        .into_body()
        // A future of when we finally have the full body...
        .concat2()
        // `move` the `Response` into this future...
        .map(move |chunk| {
            let body = chunk.iter()
                .rev()
                .cloned()
                .collect::<Vec<u8>>();
            *response.body_mut() = Body::from(body);
            response
        });
      // We can't just return the `Response` from this match arm,
      // because we can't set the body until the `concat` future
      // completed...
      //
      // However, `reversed` is actually a `Future` that will return
      // a `Response`! So, let's return it immediately instead of
      // falling through to the default return of this function.
      return Box::new(reversed)
    },
    _ => {
      *response.status_mut() = StatusCode::NOT_FOUND;
    },
  }
  Box::new(future::ok(response))
}