// nodejs+express+jwt-simple

let jwt = require('jwt-simple');
//秘钥
let secret = "laney";
let time = 10;
let tokenExpiresTime = 1000 * 60 * 60 * 24 * 7; //token过期时间,毫秒为单位， 7天
module.exports = {
  /*
   *检验token合法性
   */
  validate: function (req, res, next) {
    let token = req.headers.token;
    if (token) {
      let decodeToken = null;
      try {
        //防止假冒token解析報錯 
        // decodeToken = jwt.decode(token,secret,'HS256'); 
        decodeToken = jwt.decode(token, secret); //解密
      } catch (err) {
        res.status(401).send("非法访问");
        return;
      }
      let exp = decodeToken.exp;
      if (!exp) {
        res.status(401).send("非法访问");
      }
      // time*60*1000   = > 10分钟
      if (exp < (Date.now() + time * 60 * 1000)) {
        res.send({
          code: '002',
          "errorMsg": "授权超时"
        })
      }
      next();
    } else {
      res.status(401).send("非法访问");
    }
  },
  /* 生成token*/
  makeToken(username) {
    let Token = null;
    //需要加密的对象
    let payload = {
      user: username,
      time: new Date().getTime(),
      exp: Date.now() + tokenExpiresTime
    };
    Token = jwt.encode(payload, secret); //加密
    return Token;
  }
}
// jwt 编码解码方法
// jwt_encode(payload, key, algorithm, options)
// jwt_decode(token, key, noVerify, algorithm)