Implement Sink trait based upon work in tide-websockets PRs http-rs#3 …

…and http-rs#9.

Cargo.toml

@@ -26,3 +26,4 @@ async-std = "1.9.0"
 [dev-dependencies]
 env_logger = "0.8.3"
 async-std = { version = "1.9.0", features = ["attributes"] }
+futures = "0.3.12"

examples/futures_select.rs

@@ -0,0 +1,181 @@
+use async_std::channel::{unbounded, Sender};
+use futures::{SinkExt, StreamExt};
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex};
+use tide::http::mime;
+use tide::log::*;
+use tide::Response;
+use tide_websockets::{Message, WebSocket};
+
+struct State {
+    connections: HashMap<u32, Sender<Message>>,
+    tick_count: u32,
+    next_id: u32,
+}
+impl State {
+    fn add_connection(&mut self, connection_tx: Sender<Message>) {
+        self.connections.insert(self.next_id, connection_tx);
+        self.next_id += 1;
+    }
+}
+#[async_std::main]
+async fn main() -> Result<(), std::io::Error> {
+    env_logger::init();
+
+    let state = Arc::new(Mutex::new(State {
+        connections: HashMap::new(),
+        tick_count: 0,
+        next_id: 0,
+    }));
+
+    let mut app = tide::with_state(Arc::clone(&state));
+
+    async_std::task::spawn(app_loop(state));
+
+    app.at("/").get(|_| async move {
+        Ok(Response::builder(200)
+            .body(INDEX_HTML)
+            .content_type(mime::HTML)
+            .build())
+    });
+
+    app.at("/ws").get(WebSocket::new(
+        |request: tide::Request<Arc<Mutex<State>>>, stream| async move {
+            info!("new websocket opened");
+            let state = request.state();
+
+            // Channel for outgoing WebSocket messages from other threads
+            let (send_ws_msg_tx, send_ws_msg_rx) = unbounded::<Message>();
+            let mut send_ws_msg_rx = send_ws_msg_rx.fuse();
+
+            state.lock().unwrap().add_connection(send_ws_msg_tx);
+
+            let mut stream = stream.fuse();
+            loop {
+                let ws_msg = futures::select! {
+
+                         ws_msg = stream.select_next_some() => {
+                             match ws_msg {
+                                //  _ => None,
+                                 Ok(Message::Close(_)) => {
+                                     println!("peer disconnected");
+                                     break
+                                 },
+                                 Ok(Message::Ping(data)) => Some(Message::Pong(data)),
+                                 Ok(Message::Pong(_)) => None,
+                                 Ok(Message::Binary(_)) => None,
+                                 Ok(Message::Text(text)) => {
+                                     println!("Message received: {}",text);
+                                     None
+                                 },
+                                 Err(_) =>{
+                                     // done
+                                     None
+                                 }
+                             }
+                         },
+
+                         // Handle WebSocket messages we created asynchronously
+                         // to send them out now
+                         ws_msg = send_ws_msg_rx.select_next_some() => Some(ws_msg),
+
+                         // Once we're done, break the loop and return
+                         complete => break,
+
+                };
+
+                // If there's a message to send out, do so now
+                if let Some(ws_msg) = ws_msg {
+                    stream.send(ws_msg).await?;
+                }
+            }
+
+            // TODO: socket closed or errored, delete from remote handles
+
+            Ok(())
+        },
+    ));
+
+    app.listen("127.0.0.1:8080").await?;
+
+    Ok(())
+}
+
+async fn app_loop(state: Arc<Mutex<State>>) -> () {
+    loop {
+        let (tick_count, connections) = {
+            let mut state = state.lock().unwrap();
+            println!(
+                "Tick #{}. Connection count is {}",
+                state.tick_count,
+                state.connections.len()
+            );
+            let tick_count = state.tick_count;
+            state.tick_count += 1;
+
+            let connections = state.connections.clone();
+            (tick_count, connections)
+        };
+        let connection_count = connections.len();
+
+        for conn in connections {
+            match conn
+                .1
+                .send(Message::Text(format!(
+                    r#"{{ "ticks": {}, "connections": {} }}"#,
+                    tick_count, connection_count
+                )))
+                .await
+            {
+                Ok(_) => (),
+                Err(_e) => {
+                    //println!("error: {}", e);
+                    state.lock().unwrap().connections.remove(&conn.0);
+                }
+            }
+        }
+        std::thread::sleep(std::time::Duration::from_millis(1000));
+    }
+}
+
+const INDEX_HTML: &str = r##"
+<!DOCTYPE html>
+<html>
+<head>
+    <title>futures::select!() example</title>
+    <script type="text/javascript">
+        var count;
+        var tick;
+        var websocketConnection;
+        function onServerMessage(event) {
+            var msg;
+            try {
+                msg = JSON.parse(event.data);
+            } catch (e) {
+                console.log("bad: " + e);
+                return;
+            }
+            count.innerText = msg.connections;
+            tick.innerText = msg.ticks;
+            websocketConnection.send("Hello there.");
+        }
+        window.onload = function () {
+            count = document.getElementById("count");
+            tick = document.getElementById("tick");
+            var wsHost = window.location.hostname;
+            var wsPort = window.location.port;
+            if (wsPort)
+                wsPort = ":" + wsPort;
+            var wsUrl = "ws://" + wsHost + wsPort + "/ws";
+            console.log("ws url:" + wsUrl);
+
+            websocketConnection = new WebSocket(wsUrl);
+            websocketConnection.addEventListener("message", onServerMessage);
+        };
+    </script>
+</head>
+<body>
+    connection count: <span id="count">?</span> tick: <span id="tick">?</span>
+</body>
+</html>
+"##;

src/websocket_connection.rs

@@ -3,6 +3,7 @@ use std::pin::Pin;
 use async_dup::{Arc, Mutex};
 use async_std::task;
 use async_tungstenite::WebSocketStream;
+use futures_util::sink::Sink;
 use futures_util::stream::{SplitSink, SplitStream, Stream};
 use futures_util::{SinkExt, StreamExt};
 
@@ -59,6 +60,35 @@ impl Stream for WebSocketConnection {
     }
 }
 
+impl Sink<Message> for WebSocketConnection {
+    type Error = async_tungstenite::tungstenite::Error;
+
+    fn poll_ready(
+        self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+    ) -> task::Poll<Result<(), Self::Error>> {
+        Pin::new(&mut *self.0.lock()).poll_ready(cx)
+    }
+
+    fn start_send(self: Pin<&mut Self>, item: Message) -> Result<(), Self::Error> {
+        Pin::new(&mut *self.0.lock()).start_send(item)
+    }
+
+    fn poll_flush(
+        self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+    ) -> task::Poll<Result<(), Self::Error>> {
+        Pin::new(&mut *self.0.lock()).poll_flush(cx)
+    }
+
+    fn poll_close(
+        self: Pin<&mut Self>,
+        cx: &mut task::Context<'_>,
+    ) -> task::Poll<Result<(), Self::Error>> {
+        Pin::new(&mut *self.0.lock()).poll_close(cx)
+    }
+}
+
 impl From<WebSocketStream<Connection>> for WebSocketConnection {
     fn from(ws: WebSocketStream<Connection>) -> Self {
         Self::new(ws)