zDWSI/blankBackend/main.go

package main

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
	"net/http"
	"os"
)

var ListenAddress string

var upGrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

func ping(c *gin.Context) {
	ws, err := upGrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		return
	}
	defer ws.Close()
	for {
		mt, message, err := ws.ReadMessage()
		if err != nil {
			break
		}
		if string(message) == "ping" {
			message = []byte("pong")
		}
		err = ws.WriteMessage(mt, message)
		if err != nil {
			break
		}
	}
}

func main() {
	ListenAddress = os.Getenv("listen")
	if ListenAddress == "" {
		fmt.Println("No environment variable 'listen', use default value ':9090'")
		ListenAddress = ":9090"
	}
	r := gin.Default()
	r.GET("/api/ws/ping", ping)
	r.GET("/api/hello", hello)
	r.Run(ListenAddress)
}

func hello(context *gin.Context) {
	context.Writer.WriteString("hello")
	context.Status(200)
}