[add] websocket proxy example

examples/websocket-proxy/main.go

@@ -0,0 +1,76 @@
+package main
+
+import (
+	"errors"
+	"github.com/gorilla/websocket"
+	"github.com/telanflow/mps"
+	"log"
+	"net/http"
+	"net/url"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+var (
+	upgrader = websocket.Upgrader{}
+	endPointAddr = "localhost:9990"
+)
+
+// run a endPoint websocket server
+func runWebsocketServer() {
+	http.ListenAndServe(endPointAddr, http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		c, err := upgrader.Upgrade(rw, req, nil)
+		if err != nil {
+			return
+		}
+		defer c.Close()
+		for {
+			mt, message, err := c.ReadMessage()
+			if err != nil {
+				break
+			}
+			err = c.WriteMessage(mt, message)
+			if err != nil {
+				break
+			}
+		}
+	}))
+}
+
+// A simple proxy websocket server
+func main() {
+	// quit signal
+	quitSignChan := make(chan os.Signal)
+	signal.Notify(quitSignChan, syscall.SIGINT, syscall.SIGKILL, syscall.SIGTERM, syscall.SIGQUIT)
+
+	// start endPoint websocket server
+	go runWebsocketServer()
+
+	// start proxy websocket server
+	websocketHandler := mps.NewWebsocketHandler()
+	websocketHandler.Transport().Proxy = func(request *http.Request) (*url.URL, error) {
+		// endPoint websocket server
+		return url.Parse("ws://" + endPointAddr)
+	}
+	srv := &http.Server{
+		Addr:    "localhost:8080",
+		Handler: websocketHandler,
+	}
+	go func() {
+		log.Printf("WebsocketProxy started listen: ws://%s", srv.Addr)
+		err := srv.ListenAndServe()
+		if errors.Is(err, http.ErrServerClosed) {
+			return
+		}
+		if err != nil {
+			quitSignChan <- syscall.SIGKILL
+			log.Fatalf("WebsocketProxy start fail: %v", err)
+		}
+	}()
+
+	<-quitSignChan
+	_ = srv.Close()
+	log.Fatal("WebsocketProxy server stop!")
+}
+