.net Core Jwt登录验证刷新Token

使用 jwt做登录验证的时候，token的过期时间的固定的， 也就是只要经过了一定的时间肯定会过期。有可能用户用着系统就突然提示登录失效了。这里通过在行为结果过滤器Result Filter中刷新Token。例如设置token失效时间为20分钟， 那么只要用户在20分钟之内没有访问后台接口，token将失效。

代码只是个范例，不严谨。小伙伴们自己修改吧！别报空引用哦~~~

 public class MyResultFilter : IResultFilter
    {
        public void OnResultExecuted(ResultExecutedContext context)
        {
            Console.WriteLine("AddHeaderResultFilter:OnResultExecuted");
        }
        /// <summary>
        /// 在结果过滤器中刷新jwt的token
        /// </summary>
        /// <param name="context"></param>
        public void OnResultExecuting(ResultExecutingContext context)
        {
            //获取当前请求的Token
            string tokenOld =  context.HttpContext.Request.Headers["Authorization"].FirstOrDefault().Split(' ')[1];

            var tokens = new JwtSecurityTokenHandler().ReadJwtToken(tokenOld);
            var temp = tokens.Claims;

            var claims = new List<Claim>();
            claims.AddRange(temp.Where(t => t.Type != JwtRegisteredClaimNames.Iat));
            //重置token的发布时间为当前时间
            string time = DateTimeOffset.Now.ToUnixTimeSeconds().ToString();
            claims.Add(new Claim(JwtRegisteredClaimNames.Iat, time, ClaimValueTypes.Integer64));

            var now = DateTime.UtcNow;
            var jwtSecurityToken = new JwtSecurityToken(
                issuer: "111",
                audience: "222",
                claims: claims,
                notBefore: now,
                expires: now.Add(TimeSpan.FromDays(1)),
                signingCredentials: new SigningCredentials(new SymmetricSecurityKey(Encoding.ASCII.GetBytes("333")), SecurityAlgorithms.HmacSha256)
            );

            string tokenNew = new JwtSecurityTokenHandler().WriteToken(jwtSecurityToken);
            //在响应头中返回新的Token
            context.HttpContext.Response.Headers.Add("TokenNew", tokenNew);

        }
    }

配置过滤器全局生效

    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }
        public IConfiguration Configuration { get; }
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc(options =>
            {
                options.Filters.Add<MyResultFilter>(); //配置过滤器
            });
        }