Coalesce outbound messages in chat example

Author: garyburd

examples/chat/conn.go

@@ -5,10 +5,12 @@
 package main
 
 import (
-"github.com/gorilla/websocket"
+"bytes"
 "log"
 "net/http"
 "time"
+
+"github.com/gorilla/websocket"
 )
 
 const (
@@ -25,6 +27,11 @@ const (
 maxMessageSize = 512
 )
 
+var (
+newline = []byte{'\n'}
+space = []byte{' '}
+)
+
 var upgrader = websocket.Upgrader{
 ReadBufferSize: 1024,
 WriteBufferSize: 1024,
@@ -56,6 +63,7 @@ func (c *Conn) readPump() {
 }
 break
 }
+message = bytes.TrimSpace(bytes.Replace(message, newline, space, -1))
 hub.broadcast <- message
 }
 }
@@ -77,10 +85,26 @@ func (c *Conn) writePump() {
 select {
 case message, ok := <-c.send:
 if !ok {
+// The hub closed the channel.
 c.write(websocket.CloseMessage, []byte{})
 return
 }
-if err := c.write(websocket.TextMessage, message); err != nil {
+
+c.ws.SetWriteDeadline(time.Now().Add(writeWait))
+w, err := c.ws.NextWriter(websocket.TextMessage)
+if err != nil {
+return
+}
+w.Write(message)
+
+// Add queued chat messages to the current websocket message.
+n := len(c.send)
+for i := 0; i < n; i++ {
+w.Write(newline)
+w.Write(<-c.send)
+}
+
+if err := w.Close(); err != nil {
 return
 }
 case <-ticker.C:

examples/chat/home.html

@@ -36,7 +36,10 @@
  appendLog($("<div><b>Connection closed.</b></div>"));
  };
  conn.onmessage = function (evt) {
- appendLog($("<div/>").text(evt.data));
+ var messages = evt.data.split('\n')
+ for (var i = 0; i < messages.length; i++) {
+ appendLog($("<div/>").text(messages[i]));
+ }
  };
  } else {
  appendLog($("<div><b>Your browser does not support WebSockets.</b></div>"));