LoginSystem/main.go

package main

import (
	"flag"
	"log"
	"net/http"
)

var loggedIn bool = false

func checklogin() []byte {
	if loggedIn == true {
		return []byte(`{"loggedIn": true}`)
	} else {
		return []byte(`{"loggedIn": false}`)
	}
}

func loginHandler(rw http.ResponseWriter, req *http.Request) {
	if req.Method == "GET" {
		password := req.FormValue("password")
		log.Println("The typed password is:" + password)
		if password == "admin" {
			log.Println("Password is correct")
			rw.Write([]byte("true"))
			loggedIn = true
			log.Println("Logged in")
		} else {
			log.Println("WRONG password!!")
		}
	}
}

func logoutHandler(rw http.ResponseWriter, req *http.Request) {
	loggedIn = false
	http.Redirect(rw, req, "/login.html", http.StatusSeeOther)
	log.Println("Logged out successfully")
}

func checkloginHandler(rw http.ResponseWriter, req *http.Request) {
	rw.Write(checklogin())
	log.Println("Check button is clicked")
}

func main() {
	portPointer := flag.String("port", "8000", "An integer")
	flag.Parse()
	log.Println("Port Number: " + *portPointer)
	httpFileServer := http.FileServer(http.Dir("./files"))
	http.Handle("/", httpFileServer)

	http.HandleFunc("/login", loginHandler)
	http.HandleFunc("/logout", logoutHandler)
	http.HandleFunc("/checklogin", checkloginHandler)

	log.Printf("Listening http://localhost:%s\n", *portPointer)
	if error := http.ListenAndServe(":"+*portPointer, nil); error != nil {
		log.Printf("Error: %s\n", error)
	}
}