Сервер

import (
    "io"
    "log"
    "net/http"
    "fmt"
)

func main() {

    // Функции
    http.HandleFunc("/ok/", sayHello)
    http.HandleFunc("/bye", sayBye)
    http.HandleFunc("/",    StaticPage)                          // Link to static page

    fmt.Println("Server is started!")
    err := http.ListenAndServe(":5555", nil)
    if err != nil {
        log.Fatal(err)
    }
}


func sayHello(w http.ResponseWriter, r *http.Request) {
    io.WriteString(w, "Hello world, this is version 1.")
}

func sayBye(w http.ResponseWriter, r *http.Request) {
    io.WriteString(w, "Bye bye, this is version 1.")
}



/********************************************************************************************************************************
 *
 *   Статические странички
 *   c установкой разрешений и доступов на операции
 *
 *   http.HandleFunc("/static/", func(w http.ResponseWriter, r *http.Request) {http.ServeFile(w, r, r.URL.Path[1:])})
 *   http.HandleFunc("/static/", func(w http.ResponseWriter, r *http.Request) {http.FileServer(http.Dir("/static/"))})
 *
 *   /static/....
 *
 *********************************************************************************************************************************/
func StaticPage(w http.ResponseWriter, r *http.Request) {
    // Allows
    w.Header().Set("Access-Control-Allow-Origin", "*")

    /* Allows
          if origin := r.Header().Get("Origin"); origin != "" {
             w.Header().Set("Access-Control-Allow-Origin", origin)
             w.Header().Set("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE")
             w.Header().Set("Access-Control-Allow-Headers",  "Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization")
             w.Header().Set("Access-Control-Max-Age", "86400") // 24 hours
            }
    */

    //  File static page
    http.ServeFile(w, r, r.URL.Path[1:])
}