using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Web;namespace Rk.JWT
{public class Jwt{//参考自 阮一峰 jwt介绍  http://www.ruanyifeng.com/blog/2018/07/json_web_token-tutorial.htmlpublic static string SALT = "OXpcRP8jmCfMKumY";/// <summary>////// </summary>/// <param name="ExraPayload">额外的信息</param>/// <returns></returns>public static string Create(Dictionary<string,object> ExraPayload){var Header = new Dictionary<string, string>();Header.Add("tp", "MD5");var Payload = new Dictionary<string, object>();//JWT 规定了7个官方字段，供选用。Payload.Add("iss", "signBy"); //颁发人Payload.Add("jti", Guid.NewGuid().ToString()); //jwt的idPayload.Add("exp",System.DateTime.Now.AddMinutes(20));//过期时间Payload.Add("nbf", System.DateTime.Now);//生效时间Payload.Add("iat", System.DateTime.Now);//签发时间Payload.Add("sub", "subject");//主题Payload.Add("aud", "audience");//受众foreach (var item in ExraPayload){if (Payload.ContainsKey(item.Key)){throw new Exception($"{item.Key}键值已被占用 不能使用 ");}else{Payload.Add(item.Key, item.Value);}}string base64Header = Base64Url(Newtonsoft.Json.JsonConvert.SerializeObject(Header));string base64Payload = Base64Url(Newtonsoft.Json.JsonConvert.SerializeObject(Payload));string tmp = base64Header + "." + base64Payload;string sign = Md5(tmp+ SALT);//加盐，重要return base64Header+"."+ base64Payload+"."+ sign;}//校验是否合法，是否过期public static bool Check(string token){string base64Header = token.Split('.')[0];string base64Payload = token.Split('.')[1];string sign = token.Split('.')[2];string tmp = base64Header + "." + base64Payload;var signCheck = Md5(base64Header + "." + base64Payload + SALT);if(signCheck!= sign){return false;}var dic = Newtonsoft.Json.JsonConvert.DeserializeObject<Dictionary<string, object>>(Base64UrlDecode(base64Payload));if(  Convert.ToDateTime(dic["exp"])<System.DateTime.Now){//过期了return false;}return true;}//校验是否合法，是否过期public static Dictionary<string,object> GetPayLoad(string token){string base64Payload = token.Split('.')[1];var dic = Newtonsoft.Json.JsonConvert.DeserializeObject<Dictionary<string, object>>(Base64UrlDecode(base64Payload));return dic;}public static string Base64Url(string input){//JWT 作为一个令牌（token），有些场合可能会放到 URL（比如 api.example.com/?token=xxx）。//Base64 有三个字符+、/和=，在 URL 里面有特殊含义，所以要被替换掉：=被省略、+替换成-，/替换成_ 。string output = "";byte[] bytes = Encoding.UTF8.GetBytes(input);try{output = Convert.ToBase64String(bytes).Replace('+', '-').Replace('/', '_').TrimEnd('=') ;}catch (Exception e){throw e;}return output;}public static string Base64UrlDecode(string input){string output = "";input = input.Replace('-', '+').Replace('_', '/');switch (input.Length % 4){case 2:input += "==";break;case 3:input += "=";break;}byte[] bytes = Convert.FromBase64String(input);try{output = Encoding.UTF8.GetString(bytes);}catch{output = input;}return output;}public static string Md5(string input,int bit=16){MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider();byte[] hashedDataBytes;hashedDataBytes = md5Hasher.ComputeHash(Encoding.GetEncoding("gb2312").GetBytes(input));StringBuilder tmp = new StringBuilder();foreach (byte i in hashedDataBytes){tmp.Append(i.ToString("x2"));}if (bit == 16)return tmp.ToString().Substring(8, 16);elseif (bit == 32) return tmp.ToString();//默认情况else return string.Empty;}}}

public class HomeController : BaseController{public ActionResult Login(string username, string pwd){/// 1, todo 验证用户名密码正确//2,//在token中加入用户id,创建tokenvar dic = new Dictionary<string, object>();dic.Add("userid", "20125521225858");string token = JWT.Jwt.Create(dic);//验证token是否正确是否过期var isChecked = JWT.Jwt.Check(token);return Content("");}}