JWT in Golang

jwt-example.go

package main

import (
	"fmt"
	"net/http"
	"time"

	"github.com/go-zoo/bone"
	"github.com/go-zoo/claw"
	mw "github.com/go-zoo/claw/middleware"

	jwt "github.com/dgrijalva/jwt-go"
)

var (
	privateKey []byte
)

func init() {
	privateKey = []byte("secret")
}

func main() {
	muxx := bone.New()
	clw := claw.New(mw.Logger)

	muxx.GetFunc("/login/:user", loginHandler)
	muxx.GetFunc("/private", privateHandler)

	http.ListenAndServe(":8080", clw.Merge(muxx))
}

func loginHandler(rw http.ResponseWriter, req *http.Request) {
	username := bone.GetValue(req, "user")
	if username != "" {
		token := jwt.New(jwt.GetSigningMethod("HS256"))
		token.Claims["ID"] = username
		token.Claims["EXP"] = time.Now().Add(time.Minute * 5).Unix()

		tokenString, err := token.SignedString(privateKey)
		if err != nil {
			rw.WriteHeader(http.StatusInternalServerError)
			fmt.Fprintf(rw, "Internal Error %s \n", err)
			return
		}
		rw.Header().Add("Authorization", fmt.Sprintf("Bearer %s", tokenString))
		fmt.Fprintf(rw, "Token : %s \n", tokenString)
		return
	}
	fmt.Fprintf(rw, "[x] You need to provide a valid username !\n")
	return
}

func privateHandler(rw http.ResponseWriter, req *http.Request) {
	token, err := jwt.ParseFromRequest(req, func(t *jwt.Token) (interface{}, error) {
		return privateKey, nil
	})
	if err == nil && token.Valid {
		fmt.Fprintf(rw, "[+] You [%s] have access to the private section !!\n", token.Claims["ID"].(string))
		return
	}
	fmt.Fprintf(rw, "[x] Access Denied !!\n")
	return
}