WebApi中添加Jwt鉴权

前言

JSON Web Token（JWT）是一个非常轻巧的规范。这个规范允许我们使用 JWT 在用户和服务器之间传递安全可靠的信息。一个 JWT 实际上就是一个字符串，它由三部分组成，头部、载荷与签名。前两部分需要经过 Base64 编码，后一部分通过前两部分 Base64 编码后再加密而成。针对前后端分离的项目，大多是通过 token 进行身份认证来进行交互，今天将介绍一种简单的创建和验证token 的方式。

项目介绍

项目框架：.NET Core 3.1

项目依赖：

Swashbuckle.AspNetCore
JWT

项目架构：

项目核心代码

JWT帮助类

  /// <summary>
    /// JWT获取和验证帮助类
    /// </summary>
    public class JwtHelper
    {
        /// <summary>
        /// 日志
        /// </summary>
       private static Logger  _logger = new Logger();

        /// <summary>
        /// 私钥appsettings.json中配置
        /// </summary>
        private static string secret =  ConfigHelper.GetSectionValue("TokenSecret");

        /// <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)
        {
            try
            {
                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;
            }
            catch (System.Exception ex)
            {
                _logger.Error(ex.Message);
                return null;
            }

        }

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

        }

    }

过滤器Filter

 /// <summary>
    /// 授权认证
    /// </summary>
    public class AuthorizeFilter : Attribute, IActionFilter
    {

        public void OnActionExecuted(ActionExecutedContext context)
        {

        }

        public void OnActionExecuting(ActionExecutingContext context)
        {
            var controller = context.RouteData.Values["controller"].ToString();
            //var action = context.RouteData.Values["action"].ToString();
            if (controller == "User" || controller == "Jwt")
            {
                //登录接口不验证
            }
            else
            {
                var authHeader = context.HttpContext.Request.Headers["Authorization"];
                if (string.IsNullOrWhiteSpace(authHeader))
                {
                    //此接口必须携带token访问！
                    context.Result = new JsonResult(new OperationResult(OperationResultType.Error, "此接口必须携带token访问，请登录携带Token访问"));
                }
                else //字段值不为空
                {
                    authHeader = authHeader.ToString().Replace("Bearer", "").Trim();//去掉Bearer字串
                    if (authHeader == "")
                    {
                        context.Result = new JsonResult(new OperationResult(OperationResultType.Error, "token验证失败：您没有权限调用此接口，请登录重新获取Token"));
                    }
                    else
                    {
                        LoginUserInfo LoginInfo = JwtHelper.GetJwtDecode(authHeader);
                        if (LoginInfo != null)
                        {
                            context.Result = new JsonResult(new OperationResult(OperationResultType.Error, "Token验证失败"));
                        }
                        string UserName = LoginInfo.username;
                        string PassWord = LoginInfo.pwd;
                        string ExpireTimeStamp = LoginInfo.exp;
                        //var cacheToken = Cache.Get(UserName);
                        if (isTokenExpire(ExpireTimeStamp)) //这里应该验证有效期
                        {
                            context.Result = new JsonResult(new OperationResult(OperationResultType.Error, "token验证失败：您没有权限调用此接口，请登录重新获取Token"));
                        }
                    }

                }
            }
        }

        /// <summary>
        /// 时间戳字符串
        /// </summary>
        /// <param name="timestampstr"></param>
        /// <returns></returns>
        private bool isTokenExpire(string timestampstr)
        {
            try
            {
                double timestamp = double.Parse(timestampstr);
                System.DateTime startTime = TimeZone.CurrentTimeZone.ToLocalTime(new System.DateTime(1970, 1, 1));//当地时区
                var expireTime = startTime.AddSeconds(timestamp);
                if (expireTime > DateTime.Now)
                {
                    return false;//未过期
                }
                else
                {
                    return true;//已过期
                }
            }
            catch (Exception ex)
            {
                return true;
            }
        }

    }