go-examples/authcookie/main.go

package main

import (
	"html/template"
	"log"
	"net/http"

	"github.com/gorilla/sessions"
)

type AuthCookie struct {
	templates *template.Template
	store     *sessions.CookieStore
}

func (app *AuthCookie) HomePage(res http.ResponseWriter, req *http.Request) {
	app.templates.ExecuteTemplate(res, "home.html", app.CurrentSession(res, req).Values)
}
func (app *AuthCookie) LoginPage(res http.ResponseWriter, req *http.Request) {
	formErr := make(map[string]string)
	switch req.Method {
	case "POST":
		username := req.FormValue("username")
		if username == "" {
			formErr["username"] = "Empty username"
		}
		password := req.FormValue("password")
		if password == "" {
			formErr["password"] = "Empty password"
		}
		if len(formErr) == 0 {
			app.SaveUsername(username, res, req)
			RedirectHome(res, req)
			return
		}
		fallthrough
	case "GET":
		app.templates.ExecuteTemplate(res, "login.html", formErr)
	}
}
func (app *AuthCookie) LogoutPage(res http.ResponseWriter, req *http.Request) {
	app.SaveUsername("", res, req)
	RedirectHome(res, req)
}
func (app *AuthCookie) CurrentSession(res http.ResponseWriter, req *http.Request) *sessions.Session {
	session, _ := app.store.Get(req, "session")
	return session
}
func (app *AuthCookie) SaveUsername(username string, res http.ResponseWriter, req *http.Request) {
	session := app.CurrentSession(res, req)
	session.Values["username"] = username
	session.Save(req, res)
}
func RedirectHome(res http.ResponseWriter, req *http.Request) {
	http.Redirect(res, req, "/", http.StatusSeeOther)
}

/*
Create an http application that supports at least 2 endpoints:
login and logout. login should accept a form and save a cookie.
(with at least the username) logout should clear the cookie.
*/
func main() {
	tpl, err := template.ParseGlob("templates/*.html")
	if err != nil {
		log.Fatalln(err)
	}
	app := AuthCookie{
		templates: tpl,
		store:     sessions.NewCookieStore([]byte("flQ6QzM/c3Jtdl9ycDx6OXRIfFgK")),
	}
	http.HandleFunc("/", app.HomePage)
	http.HandleFunc("/login", app.LoginPage)
	http.HandleFunc("/logout", app.LogoutPage)
	http.ListenAndServeTLS(":9443", "../cert.pem", "../key.pem", nil)
}