package auth

import (

"crypto/hmac"

"crypto/sha256"

"encoding/base64"

"encoding/json"

"errors"

"fmt"

"io"

"reflect"

"strings"

)

var ErrToken = errors.New("jwt token error")

var ErrTokenExpired = errors.New("jwt token expired")

// 使用jwt 认证

const header = `{'typ': 'JWT',

'alg': 'HS256'

}`

// 创建jwt , 已废弃 请使用 github.com/dgrijalva/jwt-go

func MakeJwt(salt string, tk interface{}) (string, error) {

payload, err := json.Marshal(tk)

if err != nil {

return "", err

}

s := base64.StdEncoding.EncodeToString([]byte(header))

p := base64.StdEncoding.EncodeToString([]byte(payload))

pre := s + "." + p

token := pre + "." + getHc(pre, salt)

return token, nil

}

// 获取hc

func getHc(b, salt string) string {

h := hmac.New(sha256.New, []byte(salt))

io.WriteString(h, b)

return fmt.Sprintf("%x", h.Sum(nil))

}

// 检查jwt, must be a point , 已废弃 请使用 github.com/dgrijalva/jwt-go

func GetJwt(jwt, salt string, token interface{}) error {

if reflect.TypeOf(token).Kind() != reflect.Ptr {

return errors.New("token must be a pointer")

}

js := strings.Split(jwt, ".")

if len(js) < 3 {

return errors.New("invalid jwt")

}

b, err := base64.StdEncoding.DecodeString(js[1])

if err != nil {

return err

}

err = json.Unmarshal(b, token)

// err = json.NewDecoder(bytes.NewReader(b)).Decode(token)

if err != nil {

return err

}

// // 检查过期时间

pre := js[0] + "." + js[1]

if getHc(pre, salt) == js[2] {

return nil

}

return ErrToken

}