JWT(json web token)是一种基于json的身份验证机制,流程如下:

wKiom1m8rzHhs4TuAAC3ZvZZ67o859.jpg-wh_50

通过登录,来获取Token,再在之后每次请求的Header中追加Authorization为Token的凭据,服务端验证通过即可能获取想要访问的资源。关于JWT的技术,可参考网络上文章,这里不作详细说明,

这篇博文,主要说明在asp.net core 2.0中,基于jwt的web api的权限设置,即在asp.net core中怎么用JWT,再次就是不同用户或角色因为权限问题,即使援用Token,也不能访问不该访问的资源。

基本思路是我们自定义一个策略,来验证用户,和验证用户授权,PermissionRequirement是验证传输授权的参数。在Startup的ConfigureServices注入验证(Authentication),授权(Authorization),和JWT(JwtBearer)

自定义策略:

已封闭成AuthorizeRolicy.JWT nuget包,并发布到nuget上:

https://www.nuget.org/packages/AuthorizePolicy.JWT/

源码如下:

JwtToken.cs

        /// <summary>
        /// 获取基于JWT的Token
        /// </summary>
        /// <param name="username"></param>
        /// <returns></returns>
        public static dynamic BuildJwtToken(Claim[] claims, PermissionRequirement permissionRequirement)
        {
            var now = DateTime.UtcNow;
            var jwt = new JwtSecurityToken(
                issuer: permissionRequirement.Issuer,
                audience: permissionRequirement.Audience,
                claims: claims,
                notBefore: now,
                expires: now.Add(permissionRequirement.Expiration),
                signingCredentials: permissionRequirement.SigningCredentials
            );
            var encodedJwt = new JwtSecurityTokenHandler().WriteToken(jwt);
            var response = new
            {
                Status = true,
                access_token = encodedJwt,
                expires_in = permissionRequirement.Expiration.TotalMilliseconds,
                token_type = "Bearer"
            };
            return response;
        }

Permission.cs

    /// <summary>
    /// 用户或角色或其他凭据实体
    /// </summary>
    public class Permission
    {
        /// <summary>
        /// 用户或角色或其他凭据名称
        /// </summary>
        public virtual string Name
        { get; set; }
        /// <summary>
        /// 请求Url
        /// </summary>
        public virtual string Url
        { get; set; }
    }

PermissionRequirement.cs

    /// <summary>
    /// 必要参数类
    /// </summary>
    public class PermissionRequirement : IAuthorizationRequirement
    {
        /// <summary>
        /// 用户权限集合
        /// </summary>
        public List<Permission> Permissions { get; private set; }
        /// <summary>
        /// 无权限action
        /// </summary>
        public string DeniedAction { get; set; }
        /// <summary>
        /// 认证授权类型
        /// </summary>
        public string ClaimType { internal get; set; }
        /// <summary>
        /// 请求路径
        /// </summary>
        public string LoginPath { get; set; } = "/Api/Login";
        /// <summary>
        /// 发行人
        /// </summary>
        public string Issuer { get; set; }
        /// <summary>
        /// 订阅人
        /// </summary>
        public string Audience { get; set; }
        /// <summary>
        /// 过期时间
        /// </summary>
        public TimeSpan Expiration { get; set; } = TimeSpan.FromMinutes(5000);
        /// <summary>
        /// 签名验证
        /// </summary>
        public SigningCredentials SigningCredentials { get; set; }
        /// <summary>
        /// 构造
        /// </summary>
        /// <param name="deniedAction">无权限action</param>
        /// <param name="userPermissions">用户权限集合</param>
        /// <summary>
        /// 构造
        /// </summary>
        /// <param name="deniedAction">拒约请求的url</param>
        /// <param name="permissions">权限集合</param>
        /// <param name="claimType">声明类型</param>
        /// <param name="issuer">发行人</param>
        /// <param name="audience">订阅人</param>
        /// <param name="signingCredentials">签名验证实体</param>
        public PermissionRequirement(string deniedAction, List<Permission> permissions, string claimType, string issuer, string audience, SigningCredentials signingCredentials)
        {
            ClaimType = claimType;
            DeniedAction = deniedAction;
            Permissions = permissions;
            Issuer = issuer;
            Audience = audience;
            SigningCredentials = signingCredentials;
        }
    }

 自定义策略类PermissionHandler.cs

    /// <summary>
    /// 权限授权Handler
    /// </summary>
    public class PermissionHandler : AuthorizationHandler<PermissionRequirement>
    {    
        /// <summary>
        /// 验证方案提供对象
        /// </summary>
        public IAuthenticationSchemeProvider Schemes { get; set; }
        /// <summary>
        /// 自定义策略参数
        /// </summary>
        public PermissionRequirement Requirement
        { get; set; }
        /// <summary>
        /// 构造
        /// </summary>
        /// <param name="schemes"></param>
        public PermissionHandler(IAuthenticationSchemeProvider schemes)
        {
            Schemes = schemes;
        }  
        protected override async Task HandleRequirementAsync(AuthorizationHandlerContext context, PermissionRequirement requirement)
        {
            ////赋值用户权限       
            Requirement = requirement;
            //从AuthorizationHandlerContext转成HttpContext,以便取出表求信息
            var httpContext = (context.Resource as Microsoft.AspNetCore.Mvc.Filters.AuthorizationFilterContext).HttpContext;
            //请求Url
            var questUrl = httpContext.Request.Path.Value.ToLower();  
            //判断请求是否停止
            var handlers = httpContext.RequestServices.GetRequiredService<IAuthenticationHandlerProvider>();
            foreach (var scheme in await Schemes.GetRequestHandlerSchemesAsync())
            {
                var handler = await handlers.GetHandlerAsync(httpContext, scheme.Name) as IAuthenticationRequestHandler;
                if (handler != null && await handler.HandleRequestAsync())
                {
                    context.Fail();
                    return;
                }
            }
            //判断请求是否拥有凭据,即有没有登录
            var defaultAuthenticate = await Schemes.GetDefaultAuthenticateSchemeAsync();
            if (defaultAuthenticate != null)
            {
                var result = await httpContext.AuthenticateAsync(defaultAuthenticate.Name);
                //result?.Principal不为空即登录成功
                if (result?.Principal != null)
                {
                    httpContext.User = result.Principal;
                    //权限中是否存在请求的url
                    if (Requirement.Permissions.GroupBy(g => g.Url).Where(w => w.Key.ToLower() == questUrl).Count() > 0)
                    {
                        var name = httpContext.User.Claims.SingleOrDefault(s => s.Type == requirement.ClaimType).Value;
                        //验证权限
                        if (Requirement.Permissions.Where(w => w.Name == name && w.Url.ToLower() == questUrl).Count() <= 0)
                        {
                            //无权限跳转到拒绝页面
                            httpContext.Response.Redirect(requirement.DeniedAction);
                        }
                    }
                    context.Succeed(requirement);
                    return;
                }
            }
            //判断没有登录时,是否访问登录的url,并且是Post请求,并助是form表单提交类型,否则为失败
            if (!questUrl.Equals(Requirement.LoginPath.ToLower(), StringComparison.Ordinal) && (!httpContext.Request.Method.Equals("POST")
               || !httpContext.Request.HasFormContentType))
            {
                context.Fail();
                return;
            }
            context.Succeed(requirement);     
        }
    }

  

新建asp.net core 2.0的web api项目,并在项目添加AuthorizePolicy.JWT如图

wKiom1m8r1bwEC5rAAERXf_Bgk0510.png-wh_50

先设置配置文件,用户可以定义密匙和发生人,订阅人

  "Audience": {

    "Secret": "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890",

    "Issuer": "gsw",

    "Audience": "everone"

  }

在ConfigureServices中注入验证(Authentication),授权(Authorization),和JWT(JwtBearer)

Startup.cs

        public void ConfigureServices(IServiceCollection services)
        {
            //读取配置文件
            var audienceConfig = Configuration.GetSection("Audience");
            var symmetricKeyAsBase64 = audienceConfig["Secret"];
            var keyByteArray = Encoding.ASCII.GetBytes(symmetricKeyAsBase64);
            var signingKey = new SymmetricSecurityKey(keyByteArray);
            var tokenValidationParameters = new TokenValidationParameters
            {
                ValidateIssuerSigningKey = true,
                IssuerSigningKey = signingKey,
                ValidateIssuer = true,
                ValidIssuer = audienceConfig["Issuer"],
                ValidateAudience = true,
                ValidAudience = audienceConfig["Audience"],
                ValidateLifetime = true,
                ClockSkew = TimeSpan.Zero
            };
            var signingCredentials = new SigningCredentials(signingKey, SecurityAlgorithms.HmacSha256);
            services.AddAuthorization(options =>
            {
                //这个集合模拟用户权限表,可从数据库中查询出来
                var permission = new List<Permission> {
                              new Permission {  Url="/", Name="admin"},
                              new Permission {  Url="/api/values", Name="admin"},
                              new Permission {  Url="/", Name="system"},
                              new Permission {  Url="/api/values1", Name="system"}
                          };
                //如果第三个参数,是ClaimTypes.Role,上面集合的每个元素的Name为角色名称,如果ClaimTypes.Name,即上面集合的每个元素的Name为用户名
                var permissionRequirement = new PermissionRequirement("/api/denied", permission, ClaimTypes.Role, audienceConfig["Issuer"], audienceConfig["Audience"], signingCredentials);
                options.AddPolicy("Permission",
                          policy => policy.Requirements.Add(permissionRequirement));
            }).AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
            })
            .AddJwtBearer(o =>
            {
                //不使用https
                o.RequireHttpsMetadata = false;
                o.TokenValidationParameters = tokenValidationParameters;
            });
            //注入授权Handler
            services.AddSingleton<IAuthorizationHandler, PermissionHandler>();
            services.AddMvc();
        }

 在需要授的Controller上添加授权特性

    [Authorize("Permission")]

PermissionController类有两个方法,一个是登录,验证用户名和密码是否正确,如果正确就发放Token,如果失败,验证失败,别一个成功登后的无权限导航action。

    [Authorize("Permission")]
    public class PermissionController : Controller
    {
        /// <summary>
        /// 自定义策略参数
        /// </summary>
        PermissionRequirement _requirement;
        public PermissionController(IAuthorizationHandler authorizationHander)
        {
            _requirement = (authorizationHander as PermissionHandler).Requirement;
        }
        [AllowAnonymous]
        [HttpPost("/api/login")]
        public IActionResult Login(string username,string password,string role)
        { 
            var isValidated = username == "gsw" && password == "111111";
            if (!isValidated)
            {
                return new JsonResult(new
                {
                    Status = false,
                    Message = "认证失败"
                });
            }
            else
            { 
                //如果是基于角色的授权策略,这里要添加用户;如果是基于角色的授权策略,这里要添加角色
                var claims =new Claim[]{ new Claim(ClaimTypes.Name, username),new Claim(ClaimTypes.Role, role) };
                //用户标识
                var identity = new ClaimsIdentity(JwtBearerDefaults.AuthenticationScheme); 
                identity.AddClaims(claims);
                //登录
                HttpContext.SignInAsync(JwtBearerDefaults.AuthenticationScheme, new ClaimsPrincipal(identity));
                var token = JwtToken.BuildJwtToken(claims, _requirement);
                return new JsonResult(token);
            }
        }
        [AllowAnonymous]
        [HttpGet("/api/denied")]
        public IActionResult Denied()
        {
            return new JsonResult(new
            {
                Status = false,
                Message = "你无权限访问"
            });
        }
    }

 下面定义一个控制台(.NetFramewrok)程序,用RestSharp来访问我们定义的web api,其中1为admin角色登录,2为system角色登录,3为错误用户密码登录,4是一个查询功能,在startup.cs中,admin角色是具有查询/api/values的权限的,所以用admin登录是能正常访问的,用system登录,能成功登录,但没有权限访问/api/values,用户名密码错误,访问/aip/values,直接是没有授权的

  class Program
    {
        /// <summary>
        /// 访问Url
        /// </summary>
        static string _url = "http://localhost:39286";
        static void Main(string[] args)
        {
            dynamic token = null;
            while (true)
            {
                Console.WriteLine("1、登录【admin】 2、登录【system】 3、登录【错误用户名密码】 4、查询数据 ");
                var mark = Console.ReadLine();
                var stopwatch = new Stopwatch();
                stopwatch.Start();
                switch (mark)
                {
                    case "1":
                        token = AdminLogin();
                        break;
                    case "2":
                        token = SystemLogin();
                        break;
                    case "3":
                        token = NullLogin();
                        break;
                    case "4":
                        AdminInvock(token);
                        break;
                }
                stopwatch.Stop();
                TimeSpan timespan = stopwatch.Elapsed;
                Console.WriteLine($"间隔时间:{timespan.TotalSeconds}");
            }
        }
        static dynamic NullLogin()
        {
            var loginClient = new RestClient(_url);
            var loginRequest = new RestRequest("/api/login", Method.POST);
            loginRequest.AddParameter("username", "gswaa");
            loginRequest.AddParameter("password", "111111");
            //或用用户名密码查询对应角色
            loginRequest.AddParameter("role", "system");
            IRestResponse loginResponse = loginClient.Execute(loginRequest);
            var loginContent = loginResponse.Content;
            Console.WriteLine(loginContent);
            return Newtonsoft.Json.JsonConvert.DeserializeObject(loginContent);
        }
        static dynamic SystemLogin()
        {
            var loginClient = new RestClient(_url);
            var loginRequest = new RestRequest("/api/login", Method.POST);
            loginRequest.AddParameter("username", "gsw");
            loginRequest.AddParameter("password", "111111");
            //或用用户名密码查询对应角色
            loginRequest.AddParameter("role", "system");
            IRestResponse loginResponse = loginClient.Execute(loginRequest);
            var loginContent = loginResponse.Content;
            Console.WriteLine(loginContent);
            return Newtonsoft.Json.JsonConvert.DeserializeObject(loginContent);
        }
        static dynamic AdminLogin()
        {
            var loginClient = new RestClient(_url);
            var loginRequest = new RestRequest("/api/login", Method.POST);
            loginRequest.AddParameter("username", "gsw");
            loginRequest.AddParameter("password", "111111");
            //或用用户名密码查询对应角色
            loginRequest.AddParameter("role", "admin");
            IRestResponse loginResponse = loginClient.Execute(loginRequest);
            var loginContent = loginResponse.Content;
            Console.WriteLine(loginContent);
            return Newtonsoft.Json.JsonConvert.DeserializeObject(loginContent);
        }
        static void AdminInvock(dynamic token)
        {
            var client = new RestClient(_url);
            //这里要在获取的令牌字符串前加Bearer
            string tk = "Bearer " + Convert.ToString(token?.access_token);
            client.AddDefaultHeader("Authorization", tk);
            var request = new RestRequest("/api/values", Method.GET);
            IRestResponse response = client.Execute(request);
            var content = response.Content;
            Console.WriteLine($"状态:{response.StatusCode}  返回结果:{content}");
        }
    }

 运行结果:

wKioL1m8r0WiZPFBAAJPTV9tao8984.jpg-wh_50

 

源码:https://github.com/axzxs2001/AuthorizePolicy.JWT