jwt在ASP.NET MVC下的token用法

[转载]Json Web Token(jwt)   

          一种不错的身份验证及授权方案，与 Session 相反，Jwt 将用户信息存放在 Token 的 payload 字段保存在客户端，通过 RSA 加密的方式，保证数据不会被篡改，验证数据有效性。

详细请参考jwt.io。

本文在转载文上做了一些修改，避免初学者走弯路，以下文章中有介绍设置过期时间，还有，token仔细看会发现每次请求到的新token字符串会有细微变化，而不是一成不变的。 

1. 开发环境如下

vs2017+ASP.NET MVC 5+.NET FrameWork4.5

2. 在nuget上先添加封装了jwt使用的框架

因为环境是.NET FrameWork4.5  所以我采用3.0.0版本 注意版本问题

3.封装一个JWT帮助类

创建实体类  UserInfo   

public string UserName { get; set; }

public string Pwd { get; set; }

public class JwtHelp
    {

        //私钥  web.config中配置
        //"GQDstcKsx0NHjPOuXOYg5MbeJ1XT0uFiwDVvVBrk";
        private static string secret = ConfigurationManager.AppSettings["Secret"].ToString();

        /// <summary>
        /// 生成JwtToken
        /// </summary>
        /// <param name="payload">不敏感的用户数据</param>
        /// <returns></returns>
        public static string SetJwtEncode(Dictionary<string, object> payload)
        {

            //格式如下
            //var payload = new Dictionary<string, object>
            //{
            //    { "username","admin" },
            //    { "pwd", "claim2-value" }
            //};

            IJwtAlgorithm algorithm = new HMACSHA256Algorithm();
            IJsonSerializer serializer = new JsonNetSerializer();
            IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
            IJwtEncoder encoder = new JwtEncoder(algorithm, serializer, urlEncoder);

            var token = encoder.Encode(payload, secret);
            return token;
        }

        /// <summary>
        /// 根据jwtToken  获取实体
        /// </summary>
        /// <param name="token">jwtToken</param>
        /// <returns></returns>
        public static UserInfo GetJwtDecode(string token)
        {
            IJsonSerializer serializer = new JsonNetSerializer();
            IDateTimeProvider provider = new UtcDateTimeProvider();
            IJwtValidator validator = new JwtValidator(serializer, provider);
            IBase64UrlEncoder urlEncoder = new JwtBase64UrlEncoder();
            IJwtDecoder decoder = new JwtDecoder(serializer, validator, urlEncoder);
            var userInfo = decoder.DecodeToObject<UserInfo>(token, secret, verify: true);//token为之前生成的字符串
            return userInfo;
        }

        public class UserInfo
        {
            public string username{ get; set; }
            public string pwd{ get; set; }
        }

        public class tokenResult
        {
            public string Token { get; set; }
            public bool Success { get; set; }
            public string Message { get; set; }
        }
    }
}

 

4.创建JwtController  生成jwtToken看看效果 

Get 请求需要改成这样

return Json(result,JsonRequestBehavior.AllowGet);

public class JwtController : Controller
    {
        // GET: Jwt
        public ActionResult Index()
        {
            return View();
        }

        /// <summary>
        /// 创建jwtToken
        /// </summary>
        /// <param name="username"></param>
        /// <param name="pwd"></param>
        /// <returns></returns>
        public ActionResult CreateToken(string username, string pwd)
        {

            tokenResult result = new tokenResult();

            //假设用户名为"admin"，密码为"123"  
            if (username == "admin" && pwd == "123")
            {

                IDateTimeProvider provider = new UtcDateTimeProvider();
                var now = provider.GetNow();
                var unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
                var secondsSinceEpoch = Math.Round((now - unixEpoch).TotalSeconds);
                var payload = new Dictionary<string, object>
                {
                    { "username",username },
                    { "pwd", pwd },
                    { "exp", secondsSinceEpoch + 60*30} //失效时间 秒 30分钟
                };

                result.Token = JwtHelp.SetJwtEncode(payload);
                result.Success = true;
                result.Message = "成功";
            }
            else
            {
                result.Token = "";
                result.Success = false;
                result.Message = "生成token失败";
            }

            return Json(result);
            //get请求需要修改成这样
　　　　　　　//return Json(result,JsonRequestBehavior.AllowGet);
        }

    }

5.我喜欢postMan测试神器   你值得拥有

 6.AuthorizeAttribute

接下来，我们需要编写有关权限控制及token解析有关的代码。

所有操作都在Home里面  将受限Action或Controller打上标签, 所有访问都想先权限验证通过后才能访问

编写一个继承AuthorizeAttribute实现类，根据实体类是否相等。

我先简单描述下程序执行过程

1.进入验证入口->验证核心代码->

1.返回false进入验证处理失败

2.返回true进入访问的controller/action里面

public class MyAuthorizeAttribute : AuthorizeAttribute
    {
        /// <summary>
        /// 验证入口
        /// </summary>
        /// <param name="filterContext"></param>
        public override void OnAuthorization(AuthorizationContext filterContext)
        {
            base.OnAuthorization(filterContext);
        }

        /// <summary>
        /// 验证核心代码
        /// </summary>
        /// <param name="httpContext"></param>
        /// <returns></returns>
        protected override bool AuthorizeCore(HttpContextBase httpContext)
        {


            //前端请求api时会将token存放在名为"auth"的请求头中
            var authHeader = httpContext.Request.Headers["auth"];
            if (authHeader == null)
            {
                httpContext.Response.StatusCode = 403;
                return false;
            }


            var userinfo = JwtHelp.GetJwtDecode(authHeader);
            //举个例子  生成jwtToken 存入redis中    
            //这个地方用jwtToken当作key 获取实体val   然后看看jwtToken根据redis是否一样
            if (userinfo.UserName == "admin" && userinfo.Pwd == "123")
                return true;

            httpContext.Response.StatusCode = 403;
            return false;
        }

        /// <summary>
        /// 验证失败处理
        /// </summary>
        /// <param name="filterContext"></param>
        protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
        {

            base.HandleUnauthorizedRequest(filterContext);
            if (filterContext.HttpContext.Response.StatusCode == 403)
            {
                filterContext.Result = new RedirectResult("/Error");
                filterContext.HttpContext.Response.Redirect("/Home/Error");
            }
        }
    }