clean up client and print server response

examples/client.rs

@@ -1,48 +1,59 @@
-use std::env;
-
 use futures_util::{future, pin_mut, StreamExt};
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use std::env;
+use tokio::{
+    io::{AsyncReadExt, AsyncWriteExt},
+    time::sleep,
+    time::Duration,
+};
 use tokio_tungstenite::{connect_async, tungstenite::protocol::Message};
 
-#[tokio::main]
-async fn main() {
-    let connect_addr = env::args()
-        .nth(1)
-        .unwrap_or_else(|| panic!("this program requires at least one argument"));
-
-    let url = url::Url::parse(&connect_addr).unwrap();
-
-    let (stdin_tx, stdin_rx) = futures_channel::mpsc::unbounded();
-    tokio::spawn(read_stdin(stdin_tx));
-
-    let (ws_stream, _) = connect_async(url).await.expect("Failed to connect");
-    println!("WebSocket handshake has been successfully completed");
-
-    let (write, read) = ws_stream.split();
-
-    let stdin_to_ws = stdin_rx.map(Ok).forward(write);
-    let ws_to_stdout = {
-        read.for_each(|message| async {
-            let data = message.unwrap().into_data();
-            tokio::io::stdout().write_all(&data).await.unwrap();
-        })
-    };
-
-    pin_mut!(stdin_to_ws, ws_to_stdout);
-    future::select(stdin_to_ws, ws_to_stdout).await;
-}
-
 // Our helper method which will read data from stdin and send it along the
 // sender provided.
 async fn read_stdin(tx: futures_channel::mpsc::UnboundedSender<Message>) {
     let mut stdin = tokio::io::stdin();
+
     loop {
         let mut buf = vec![0; 1024];
-        let n = match stdin.read(&mut buf).await {
+        let n = stdin.read(&mut buf).await;
-            Err(_) | Ok(0) => break,
+        buf.truncate(n.unwrap());
-            Ok(n) => n,
-        };
-        buf.truncate(n);
         tx.unbounded_send(Message::binary(buf)).unwrap();
     }
 }
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // sleep to avoid racing the server on startup when using cargo watch
+    sleep(Duration::from_millis(200)).await;
+
+    if let Some(connect_addr) = env::args().nth(1) {
+        let url = url::Url::parse(&connect_addr)?;
+
+        let (stdin_tx, stdin_rx) = futures_channel::mpsc::unbounded();
+        tokio::spawn(read_stdin(stdin_tx));
+
+        let (ws_stream, res) = connect_async(url).await?;
+
+        println!(
+            "WebSocket handshake has been successfully completed\n{:#?}",
+            res
+        );
+
+        let (sink, stream) = ws_stream.split();
+
+        let stdin_to_ws = stdin_rx.map(Ok).forward(sink);
+
+        let ws_to_stdout = {
+            stream.for_each(|message| async {
+                let data = message.unwrap().into_data();
+                tokio::io::stdout().write_all(&data).await.unwrap();
+            })
+        };
+
+        pin_mut!(stdin_to_ws, ws_to_stdout);
+        future::select(stdin_to_ws, ws_to_stdout).await;
+    } else {
+        eprintln!("This program requires at least one argument!")
+    }
+
+    Ok(())
+}