websocket implemented with dummy send as a toy for test.

README.md

 # Readme for RestAPI
 
 Version 1
-1. /login
+##1. /login
+   
+input 
+    **username** : must be email  
+    **password** : 4-40 chars
+
+output
+
+```json
+{
+  "login": true,
+  "Biukop-Session": "biukop session id",
+  "Biukop-Mid": "biukop machine id"
+}
+```
+
 1. /signup
 2. /logout
 3. /loans?skip=page= GET

apiv1.go

 )
 
 const apiV1Prefix = "/api/v1/"
+const apiV1WebSocket = apiV1Prefix + "ws"
 
 type apiV1HandlerMap struct {
 	Method  string

go.mod

 
 require (
 	biukop.com/sfm/loan v0.0.0-00010101000000-000000000000
-	github.com/VividCortex/mysqlerr v0.0.0-20201215173831-4c396ae82aac
 	github.com/brianvoe/gofakeit/v6 v6.0.1
-	github.com/go-sql-driver/mysql v1.5.0
+	github.com/gorilla/websocket v1.4.2
 	github.com/sirupsen/logrus v1.7.0
 	github.com/stretchr/testify v1.2.2
 )

go.sum

 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
 github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
+github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/sirupsen/logrus v1.7.0 h1:ShrD1U9pZB12TX0cVy0DtePoCH97K8EtX+mg7ZARUtM=

html/index.html

             static url  <a href="test/">/test </a> &#x2192; "./html/test/"
         </li>
 
+
+        <script>
+            let socket = new WebSocket("wss://svr2021.lawipac.com:8080/api/v1/ws");
+            console.log("Attempting Connection...");
+
+            socket.onopen = () => {
+                console.log("Successfully Connected");
+                socket.send("Hi From the Client!");
+                socket.send("send dummy string for 500 times"); //this is a special command server will respond;
+            };
+
+            socket.onclose = event => {
+                console.log("Socket Closed Connection: ", event);
+                socket.send("Client Closed!")
+            };
+
+            socket.onerror = error => {
+                console.log("Socket Error: ", error);
+            };
+
+            socket.onmessage = e => {
+                if(typeof e.data != "string" ) {
+                    console.log("invalid data received ", e)
+                }else{
+                    let server_message = e.data;
+                    console.log("server said: ", server_message)
+                    document.getElementById("socketOutPut").innerHTML= server_message;
+                }
+            }
+
+        </script>
     </ol>
+    <p id="socketOutPut"></p>
 </div>
 
 

main.go

 type httpEntry func(http.ResponseWriter, *http.Request)
 
 var httpEntryMap = map[string]httpEntry{
-	apiV1Prefix: apiV1Main,
-	"/dummy/":   dummyHandler,
+	apiV1Prefix:    apiV1Main,
+	apiV1WebSocket: apiV1WebSocketHandler,
+	"/dummy/":      dummyHandler,
 }
 
 func main() {

websocket.go

+package main
+
+import (
+	"fmt"
+	"github.com/gorilla/websocket"
+	log "github.com/sirupsen/logrus"
+	"net/http"
+	"time"
+)
+
+// We'll need to define an upgradeToWs
+// this will require a Read and Write buffer size
+var upgradeToWs = websocket.Upgrader{
+	ReadBufferSize:  1024,
+	WriteBufferSize: 1024,
+}
+
+func apiV1WebSocketHandler(w http.ResponseWriter, r *http.Request) {
+	upgradeToWs.CheckOrigin = func(r *http.Request) bool { return true }
+	ws, err := upgradeToWs.Upgrade(w, r, nil)
+	if err != nil {
+		log.Println(err)
+	}
+	// helpful log statement to show connections
+	log.Println("Websocket Api/V1: Client Connected")
+
+	wsReader(ws)
+}
+
+func wsReader(conn *websocket.Conn) {
+	for {
+		// read in a message
+		messageType, p, err := conn.ReadMessage()
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		// print out that message for clarity
+		fmt.Println(string(p))
+
+		if err := conn.WriteMessage(messageType, p); err != nil {
+			log.Println(err)
+			return
+		}
+
+		if string(p) == "send dummy string for 500 times" {
+			go wsDummySender(conn)
+		}
+	}
+}
+
+func wsDummySender(conn *websocket.Conn) {
+	//write subsequent 5 copies, each after 1 second
+	log.Info("start sending server data to client ..")
+	p := "dummy string from server "
+	for i := 1; i < 500; i++ {
+		time.Sleep(1 * time.Second)
+		msg := fmt.Sprintf("copy %d, %s", i, p)
+		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
+		}
+	}
+}