Improve client disconnect detection

ws-server/connection.go

@@ -3,12 +3,14 @@ package main
 import (
 	"log"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/gorilla/websocket"
 )
 
 type WSConnection struct {
+	id           int32
 	conn         *websocket.Conn
 	writeLock    sync.Mutex
 	alive        bool
@@ -21,6 +23,7 @@ type WSConnection struct {
 
 func NewConn(conn *websocket.Conn, server *WSServer) *WSConnection {
 	wsconn := &WSConnection{
+		id:           server.clientId,
 		conn:         conn,
 		alive:        true,
 		IdleTimeout:  server.IdleTimeout,
@@ -29,6 +32,7 @@ func NewConn(conn *websocket.Conn, server *WSServer) *WSConnection {
 		WriteChan:    make(chan string, 1024),
 		ErrorChan:    make(chan error, 1),
 	}
+	atomic.AddInt32(&server.clientId, 1)
 
 	return wsconn
 }
@@ -36,11 +40,16 @@ func NewConn(conn *websocket.Conn, server *WSServer) *WSConnection {
 func (ws *WSConnection) Open() {
 	go ws.messageReader()
 	go ws.messageSender()
-	// go ws.pinger()
+	go ws.pinger()
+	ws.conn.SetPongHandler(func(string) error {
+		// log.Printf("Client %d: Pong OK", ws.id)
+		ws.conn.SetReadDeadline(time.Now().Add(ws.IdleTimeout))
+		return nil
+	})
 }
 
 func (ws *WSConnection) messageReader() {
-	log.Printf("Reading messages")
+	log.Printf("Client %d: Reading messages", ws.id)
 	for {
 		_, message, err := ws.conn.ReadMessage()
 		if !ws.alive {
@@ -51,48 +60,52 @@ func (ws *WSConnection) messageReader() {
 			ws.ErrorChan <- err
 			return
 		}
-		log.Printf("Received: %s, %d in output channel", message, len(ws.ReadChan))
+		log.Printf("Client %d: Received: %s, %d in output channel", ws.id, message, len(ws.ReadChan))
 		ws.ReadChan <- string(message)
 	}
 }
 
 func (ws *WSConnection) messageSender() {
-	log.Printf("Sending messages")
+	log.Printf("Client %d: Sending messages", ws.id)
 	for {
-		msg := <-ws.WriteChan
-		if !ws.alive {
+		func() {
+			msg, ok := <-ws.WriteChan
+			if !ok || !ws.alive {
 				return
 			}
 			ws.writeLock.Lock()
+			defer ws.writeLock.Unlock()
 	
 			ws.conn.SetWriteDeadline(time.Now().Add(ws.IdleTimeout))
-		log.Printf("Sending: %s, %d in input channel", msg, len(ws.WriteChan))
+			log.Printf("Client %d: Sending: %s, %d in input channel", ws.id, msg, len(ws.WriteChan))
 			err := ws.conn.WriteMessage(websocket.TextMessage, []byte(msg))
 			if err != nil {
-			log.Printf("Error during message writing: %v", err)
+				log.Printf("Client %d: Error during message writing: %v", ws.id, err)
 				ws.ErrorChan <- err
 				return
 			}
-		ws.writeLock.Unlock()
+		}()
 	}
 }
 
-// func (ws *WSConnection) pinger() {
-// 	log.Printf("Starting pinger, sleeping for %v", ws.PingInterval)
-// 	for {
-// 		time.Sleep(ws.PingInterval)
-// 		if !ws.alive {
-// 			return
-// 		}
+func (ws *WSConnection) pinger() {
+	log.Printf("Client %d: Starting pinger, sleeping for %v", ws.id, ws.PingInterval)
+	for {
+		time.Sleep(ws.PingInterval)
+		if !ws.alive {
+			return
+		}
 
-// 		log.Printf("Ping")
-// 		ws.writeLock.Lock()
-// 		err := ws.conn.WriteMessage(websocket.PingMessage, nil)
-// 		if err != nil {
-// 			log.Println("Error during ping:", err)
-// 			ws.ErrorChan <- err
-// 			return
-// 		}
-// 		ws.writeLock.Unlock()
-// 	}
-// }
+		// log.Printf("Client %d: Ping", ws.id)
+		ws.writeLock.Lock()
+		err := ws.conn.WriteMessage(websocket.PingMessage, nil)
+		if err != nil {
+			log.Printf("Client %d: Error during ping: %+v", ws.id, err)
+			ws.ErrorChan <- err
+			return
+		}
+		ws.conn.SetWriteDeadline(time.Now().Add(ws.IdleTimeout))
+		ws.writeLock.Unlock()
+		// log.Printf("Client %d: Ping OK", ws.id)
+	}
+}

ws-server/main.go

@@ -43,9 +43,11 @@ func handleDownload(responseWriter http.ResponseWriter, request *http.Request) {
 	server.Broadcast <- req.Link
 }
 
-func main() {
-	log.SetFlags(log.Lmicroseconds)
+func init() {
+	log.SetFlags(log.Lmicroseconds | log.Lshortfile)
+}
 
+func main() {
 	http.HandleFunc("/ws", wsHandler)
 	http.HandleFunc("/download", handleDownload)
 	log.Println("Server starting on :8080")

ws-server/server.go

@@ -9,6 +9,7 @@ import (
 
 type WSServer struct {
 	connections  map[*WSConnection]bool
+	clientId     int32
 	Upgrader     websocket.Upgrader
 	Broadcast    chan string
 	IdleTimeout  time.Duration
@@ -42,9 +43,12 @@ func (server *WSServer) HandleNew(conn *websocket.Conn) {
 	server.connections[wsconn] = true
 
 	go func() {
-		<-wsconn.ErrorChan
+		err := <-wsconn.ErrorChan
 		wsconn.alive = false
+		close(wsconn.ReadChan)
+		close(wsconn.WriteChan)
+		close(wsconn.ErrorChan)
+		log.Printf("Client %d: disconnected due to %+v, now %d clients", wsconn.id, err, len(server.connections))
 		delete(server.connections, wsconn)
-		log.Printf("Client disconnected, now %d clients", len(server.connections))
 	}()
 }