docs(examples): update send_file example to async/await

2019-07-16 06:26:15 +08:00
parent 524a453b6f
commit e8c19fea4c
4 changed files with 83 additions and 80 deletions
--- a/examples/send_file.rs
+++ b/examples/send_file.rs
@@ -0,0 +1,82 @@
+#![feature(async_await)]
+#![deny(warnings)]
+
+use tokio::io::AsyncReadExt;
+use tokio_fs::file::File;
+
+use hyper::{Body, Method, Result, Request, Response, Server, StatusCode};
+use hyper::service::{make_service_fn, service_fn};
+
+static INDEX: &str = "examples/send_file_index.html";
+static INTERNAL_SERVER_ERROR: &[u8] = b"Internal Server Error";
+static NOTFOUND: &[u8] = b"Not Found";
+
+#[hyper::rt::main]
+async fn main() {
+    pretty_env_logger::init();
+
+    let addr = "127.0.0.1:1337".parse().unwrap();
+
+    let make_service = make_service_fn(|_| async {
+        Ok::<_, hyper::Error>(service_fn(response_examples))
+    });
+
+    let server = Server::bind(&addr)
+        .serve(make_service);
+
+    println!("Listening on http://{}", addr);
+
+    if let Err(e) = server.await {
+        eprintln!("server error: {}", e);
+    }
+}
+
+async fn response_examples(req: Request<Body>) -> Result<Response<Body>> {
+    match (req.method(), req.uri().path()) {
+        (&Method::GET, "/") |
+        (&Method::GET, "/index.html") |
+        (&Method::GET, "/big_file.html") => {
+            simple_file_send(INDEX).await
+        }
+        (&Method::GET, "/no_file.html") => {
+            // Test what happens when file cannot be be found
+            simple_file_send("this_file_should_not_exist.html").await
+        }
+        _ => Ok(not_found())
+    }
+}
+
+/// HTTP status code 404
+fn not_found() -> Response<Body> {
+    Response::builder()
+        .status(StatusCode::NOT_FOUND)
+        .body(NOTFOUND.into())
+        .unwrap()
+}
+
+/// HTTP status code 500
+fn internal_server_error() -> Response<Body> {
+    Response::builder()
+        .status(StatusCode::INTERNAL_SERVER_ERROR)
+        .body(INTERNAL_SERVER_ERROR.into())
+        .unwrap()
+}
+
+async fn simple_file_send(f: &str) -> Result<Response<Body>> {
+    // Serve a file by asynchronously reading it entirely into memory.
+    // Uses tokio_fs to open file asynchronously, then tokio::io::AsyncReadExt
+    // to read into memory asynchronously.
+
+    let filename = f.to_string(); // we need to copy for lifetime issues
+
+    if let Ok(mut file) = File::open(filename).await {
+        let mut buf = Vec::new();
+        if let Ok(_) = file.read_to_end(&mut buf).await {
+            return Ok(Response::new(buf.into()));
+        }
+
+        return Ok(internal_server_error());
+    }
+
+    return Ok(not_found());
+}
--- a/examples/send_file_index.html
+++ b/examples/send_file_index.html
@@ -0,0 +1,11 @@
+<html>
+  <head>
+    <title>Hyper responding example</title>
+  </head>
+  <body>
+    <h1>Hyper responding example</h1>
+    <a href="index.html">index.html</a> Top Level<br>
+    <a href="big_file.html">big_file.html</a> This page, streamed in chunks<br>
+    <a href="no_file.html">no_file.html</a> A 404 test, the requested file does not exist<br>
+  </body>
+</html>