docs(examples): add comments to the echo example

This commit is contained in:
Sean McArthur
2018-06-05 12:27:33 -07:00
parent 53f4c9dca1
commit 41291346d0

View File

@@ -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<Future<Item = Response<Body>, 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<Body>) -> 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<Body>) -> 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::<Vec<u8>>();
*response.body_mut() = Body::from(body);
@@ -37,6 +57,8 @@ fn echo(req: Request<Body>) -> 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);
}