sample-go-session-count-up.md

package main

import (
	"github.com/gorilla/sessions"
	"net/http"
	"html/template"
	"github.com/labstack/echo"
	"github.com/labstack/echo-contrib/session"
	"io"
)

func countUp(c echo.Context) int {
	sess, _ := session.Get("session", c)
	sess.Options = &sessions.Options{
		Path:     "/",
		MaxAge:   86400 * 7,
		HttpOnly: true,
	}
	cnt := 0
	if v, ok := sess.Values["cnt"]; ok {
		if c, ok := v.(int); ok {
			cnt = c + 1
		}
	}
	sess.Values["cnt"] = cnt
	sess.Save(c.Request(), c.Response())
	return cnt
}

func topPage(c echo.Context) error {
	cnt := countUp(c)
	return c.Render(http.StatusOK, "index", map[string]interface{}{
		"Cnt": cnt,
	})
}

type Renderer struct {
	templates *template.Template
}

func (r *Renderer) Render(w io.Writer, name string, data interface{}, c echo.Context) error {
	return r.templates.ExecuteTemplate(w, name, data)
}

func tAdd(a, b int64) int64 {
	return a + b
}

func tRange(a, b int64) []int64 {
	r := make([]int64, b-a+1)
	for i := int64(0); i <= (b - a); i++ {
		r[i] = a + i
	}
	return r
}

func main() {
	e := echo.New()
	funcs := template.FuncMap{
		"add":    tAdd,
		"xrange": tRange,
	}
	e.Renderer = &Renderer{
		templates: template.Must(template.New("").Funcs(funcs).ParseGlob("views/*.html")),
	}
	e.Use(session.Middleware(sessions.NewCookieStore([]byte("secret"))))
	e.GET("/", topPage)
	e.Start(":5000")
}