docs(examples): add more comments to hello server example

seanmonstar · seanmonstar · commit 0331219b40bb · 2019-08-30T14:38:22.000-07:00
diff --git a/examples/hello.rs b/examples/hello.rs
@@ -1,27 +1,32 @@
 #![deny(warnings)]
 
+use std::convert::Infallible;
+
 use hyper::{Body, Request, Response, Server};
 use hyper::service::{make_service_fn, service_fn};
 
-async fn hello(_: Request<Body>) -> Result<Response<Body>, hyper::Error> {
+async fn hello(_: Request<Body>) -> Result<Response<Body>, Infallible> {
     Ok(Response::new(Body::from("Hello World!")))
 }
 
 #[tokio::main]
 pub async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
     pretty_env_logger::init();
 
+    // For every connection, we must make a `Service` to handle all
+    // incoming HTTP requests on said connection.
+    let make_svc = make_service_fn(|_conn| {
+        // This is the `Service` that will handle the connection.
+        // `service_fn` is a helper to convert a function that
+        // returns a Response into a `Service`.
+        async {
+            Ok::<_, Infallible>(service_fn(hello))
+        }
+    });
+
     let addr = ([127, 0, 0, 1], 3000).into();
 
-    let server = Server::bind(&addr)
-        .serve(make_service_fn(|_| {
-            // This is the `Service` that will handle the connection.
-            // `service_fn` is a helper to convert a function that
-            // returns a Response into a `Service`.
-            async {
-                Ok::<_, hyper::Error>(service_fn(hello))
-            }
-        }));
+    let server = Server::bind(&addr).serve(make_svc);
 
     println!("Listening on http://{}", addr);
 
