1 files changed, 65 insertions, 0 deletions
diff --git a/src/api.rs b/src/api.rs
new file mode 100644
index 00000000..9ee17047
--- /dev/null
+++ b/src/api.rs
@@ -0,0 +1,65 @@
+use futures_util::TryStreamExt;
+use hyper::service::{make_service_fn, service_fn};
+use hyper::{Body, Method, Request, Response, Server, StatusCode};
+use futures::future::Future;
+
+use crate::error::Error;
+use crate::System;
+
+/// This is our service handler. It receives a Request, routes on its
+/// path, and returns a Future of a Response.
+async fn echo(req: Request<Body>) -> Result<Response<Body>, Error> {
+    match (req.method(), req.uri().path()) {
+        // Serve some instructions at /
+        (&Method::GET, "/") => Ok(Response::new(Body::from(
+            "Try POSTing data to /echo such as: `curl localhost:3000/echo -XPOST -d 'hello world'`",
+        ))),
+
+        // Simply echo the body back to the client.
+        (&Method::POST, "/echo") => Ok(Response::new(req.into_body())),
+
+        // Convert to uppercase before sending back to client using a stream.
+        (&Method::POST, "/echo/uppercase") => {
+            let chunk_stream = req.into_body().map_ok(|chunk| {
+                chunk
+                    .iter()
+                    .map(|byte| byte.to_ascii_uppercase())
+                    .collect::<Vec<u8>>()
+            });
+            Ok(Response::new(Body::wrap_stream(chunk_stream)))
+        }
+
+        // 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 as we did with the above uppercase endpoint.
+        // So here we do `.await` on the future, waiting on concatenating the full body,
+        // then afterwards the content can be reversed. Only then can we return a `Response`.
+        (&Method::POST, "/echo/reversed") => {
+            let whole_body = hyper::body::to_bytes(req.into_body()).await?;
+
+            let reversed_body = whole_body.iter().rev().cloned().collect::<Vec<u8>>();
+            Ok(Response::new(Body::from(reversed_body)))
+        }
+
+        // Return the 404 Not Found for other routes.
+        _ => {
+            let mut not_found = Response::default();
+            *not_found.status_mut() = StatusCode::NOT_FOUND;
+            Ok(not_found)
+        }
+    }
+}
+
+pub async fn run_api_server(sys: &System, api_port: u16, shutdown_signal: impl Future<Output=()>) -> Result<(), hyper::Error> {
+    let addr = ([0, 0, 0, 0], api_port).into();
+
+    let service = make_service_fn(|_| async { Ok::<_, Error>(service_fn(echo)) });
+
+    let server = Server::bind(&addr).serve(service);
+
+	let graceful = server.with_graceful_shutdown(shutdown_signal);
+    println!("Listening on http://{}", addr);
+
+	graceful.await
+}