added websocket and using flex engine

.gitignore

+/cert/

api1ws.go

 import (
 	"fmt"
 	"github.com/gorilla/websocket"
-	"log"
+	log "github.com/sirupsen/logrus"
 	"net/http"
+	"time"
 )
 
 const apiV1WebSocket = apiV1Prefix + "ws"
 			return
 		}
 
-		WsEchoIncomingMessage(conn, string(p), messageType)
-		//switch messageType {
-		//case websocket.TextMessage:
-		//	WsProcessingTxtMessage(conn, string(p))
-		//	break
-		//case websocket.BinaryMessage:
-		//	WsProcessingBinaryMessage(conn, p)
-		//	break
-		//case websocket.PingMessage:
-		//	break
-		//case websocket.PongMessage:
-		//	break
-		//}
+		switch messageType {
+		case websocket.TextMessage:
+			WsProcessingTxtMessage(conn, string(p))
+			break
+		case websocket.BinaryMessage:
+			WsProcessingBinaryMessage(conn, p)
+			break
+		case websocket.PingMessage:
+			break
+		case websocket.PongMessage:
+			break
+		}
+	}
+}
+
+func WsProcessingTxtMessage(conn *websocket.Conn, str string) {
+	if str == "send dummy string for 500 times" {
+		go wsDummySender(conn)
+	} else {
+		WsEchoIncomingMessage(conn, str, websocket.TextMessage)
 	}
+
+}
+
+func WsProcessingBinaryMessage(conn *websocket.Conn, data []byte) {
+	return
 }
 
 func WsEchoIncomingMessage(conn *websocket.Conn, msg string, messageType int) {
 		return
 	}
 }
+
+func wsDummySender(conn *websocket.Conn) {
+	//write subsequent 5 copies, each after 1 second
+	log.Info("start sending server data to client ..")
+	p := "From server "
+	for i := 1; i < 500; i++ {
+		time.Sleep(1 * time.Second)
+		n := time.Now()
+		s := n.Format("2006-01-02 15:04:05")
+		p1 := p + s
+		//msg := fmt.Sprintf("copy %d, %s, %s", i, p, wsDummyString()) // 4M long string no issue
+		msg := fmt.Sprintf("copy %d, %s ", i, p1)
+		log.Info("dummy sender is working, ", msg)
+		if err := conn.WriteMessage(websocket.TextMessage, []byte(msg)); err != nil {
+			log.Println("wsDummySender stopped on error: ", err)
+			return
+		}
+	}
+}

app.yaml

-runtime: go115
+runtime: go1.15
+env: flex

config.json

   "Host":"0.0.0.0",
   "Port":"8080",
   "DSN": "sp:sp@tcp(192.168.1.70:3306)/syd_credit?parseTime=true&loc=Australia%2FSydney&collation=utf8mb4_0900_ai_ci",
-  "TlsCert": "fullchain.pem",
-  "TlsKey": "privkey.pem",
+  "TlsCert": "cert/fullchain.pem",
+  "TlsKey": "cert/privkey.pem",
   "Debug": true,
   "Static": [
     {

html/index.html

 
 
         <script>
-            let socket = new WebSocket("wss://svr2021.lawipac.com:8080/api/v1/ws");
+            let host = window.location.hostname;
+            let protocol = window.location.protocol;
+            let socket = null;
+            if ( protocol.toLowerCase() == 'http:' ){
+                socket = new WebSocket("ws://" + host + ":" + location.port + "/api1/ws");
+            }else{ // https
+                socket = new WebSocket("wss://" + host + ":" + location.port + "/api1/ws");
+            }
+
             console.log("Attempting Connection...");
 
             socket.onopen = () => {

http_handler.go

 
 	log.Printf("Server started at %s:%s\n", config.Host, config.Port)
 	log.Fatal(http.ListenAndServe(config.Host+":"+config.Port, nil))
-	// log.Fatal(http.ListenAndServeTLS(config.Host+":"+config.Port, config.TlsCert, config.TlsKey, nil))
+	//log.Fatal(http.ListenAndServeTLS(config.Host+":"+config.Port, config.TlsCert, config.TlsKey, nil))
 }