diff --git a/examples/echo.rs b/examples/echo.rs index 994fa2aa..d0303cf1 100644 --- a/examples/echo.rs +++ b/examples/echo.rs @@ -6,19 +6,32 @@ use hyper::rt::{Future, Stream}; use hyper::service::service_fn; use hyper::{Body, Method, Request, Response, Server, StatusCode}; +/// We need to return different futures depending on the route matched, +/// and we can do that with an enum, such as `futures::Either`, or with +/// trait objects. +/// +/// A boxed Future (trait object) is used as it is easier to understand +/// and extend with more types. Advanced users could switch to `Either`. type BoxFut = Box, Error = hyper::Error> + Send>; +/// This is our service handler. It receives a Request, routes on its +/// path, and returns a Future of a Response. fn echo(req: Request) -> BoxFut { let mut response = Response::new(Body::empty()); match (req.method(), req.uri().path()) { - (&Method::GET, "/") => { + // Serve some instructions at / + (Method::GET, "/") => { *response.body_mut() = Body::from("Try POSTing data to /echo"); } - (&Method::POST, "/echo") => { + + // Simply echo the body back to the client. + (Method::POST, "/echo") => { *response.body_mut() = req.into_body(); } - (&Method::POST, "/echo/uppercase") => { + + // Convert to uppercase before sending back to client. + (Method::POST, "/echo/uppercase") => { let mapping = req.into_body().map(|chunk| { chunk .iter() @@ -28,7 +41,14 @@ fn echo(req: Request) -> BoxFut { *response.body_mut() = Body::wrap_stream(mapping); } - (&Method::POST, "/echo/reversed") => { + + // Reverse the entire body before sending back to the client. + // + // Since we don't know the end yet, we can't simply stream + // the chunks as they arrive. So, this returns a different + // future, waiting on concatenating the full body, so that + // it can be reversed. Only then can we return a `Response`. + (Method::POST, "/echo/reversed") => { let reversed = req.into_body().concat2().map(move |chunk| { let body = chunk.iter().rev().cloned().collect::>(); *response.body_mut() = Body::from(body); @@ -37,6 +57,8 @@ fn echo(req: Request) -> BoxFut { return Box::new(reversed); } + + // The 404 Not Found route... _ => { *response.status_mut() = StatusCode::NOT_FOUND; } @@ -52,6 +74,6 @@ fn main() { .serve(|| service_fn(echo)) .map_err(|e| eprintln!("server error: {}", e)); - println!("The magic happens on port {}", addr.port()); + println!("Listening on http://{}", addr); hyper::rt::run(server); }