.NET Core微服务之基于Ocelot+IdentityServer实现统一验证与授权

Tip: 此篇已加入.NET Core微服务基础系列文章索引

一、案例结构总览

　　这里，假设我们有两个客户端（一个Web网站，一个移动App），他们要使用系统，需要通过API网关（这里API网关始终作为客户端的统一入口）先向IdentityService进行Login以进行验证并获取Token，在IdentityService的验证过程中会访问数据库以验证。然后再带上Token通过API网关去访问具体的API Service。这里我们的IdentityService基于IdentityServer4开发，它具有统一登录验证和授权的功能。

二、改写API Gateway

　　这里主要基于前两篇已经搭好的API Gateway进行改写，如不熟悉，可以先浏览前两篇文章：Part 1和Part 2。

2.1 配置文件的改动

  ......
  "AuthenticationOptions": {
    "AuthenticationProviderKey": "ClientServiceKey",
    "AllowedScopes": []
  }
  ......
  "AuthenticationOptions": {
    "AuthenticationProviderKey": "ProductServiceKey",
    "AllowedScopes": []
  }
  ......  

　　上面分别为两个示例API Service增加Authentication的选项，为其设置ProviderKey。下面会对不同的路由规则设置的ProviderKey设置具体的验证方式。

2.2 改写StartUp类

    public void ConfigureServices(IServiceCollection services)
    {
        // IdentityServer
        #region IdentityServerAuthenticationOptions => need to refactor
        Action<IdentityServerAuthenticationOptions> isaOptClient = option =>
            {
                option.Authority = Configuration["IdentityService:Uri"];
                option.ApiName = "clientservice";
                option.RequireHttpsMetadata = Convert.ToBoolean(Configuration["IdentityService:UseHttps"]);
                option.SupportedTokens = SupportedTokens.Both;
                option.ApiSecret = Configuration["IdentityService:ApiSecrets:clientservice"];
            };

        Action<IdentityServerAuthenticationOptions> isaOptProduct = option =>
        {
            option.Authority = Configuration["IdentityService:Uri"];
            option.ApiName = "productservice";
            option.RequireHttpsMetadata = Convert.ToBoolean(Configuration["IdentityService:UseHttps"]);
            option.SupportedTokens = SupportedTokens.Both;
            option.ApiSecret = Configuration["IdentityService:ApiSecrets:productservice"];
        };
        #endregion

        services.AddAuthentication()
            .AddIdentityServerAuthentication("ClientServiceKey", isaOptClient)
            .AddIdentityServerAuthentication("ProductServiceKey", isaOptProduct);
        // Ocelot
        services.AddOcelot(Configuration);
        ......
    }

　　这里的ApiName主要对应于IdentityService中的ApiResource中定义的ApiName。这里用到的配置文件定义如下：

  "IdentityService": {
    "Uri": "http://localhost:5100",
    "UseHttps": false,
    "ApiSecrets": {
      "clientservice": "clientsecret",
      "productservice": "productsecret"
    }
  }

　　这里的定义方式，我暂时还没想好怎么重构，不过肯定是需要重构的，不然这样一个一个写比较繁琐，且不利于配置。

三、新增IdentityService

这里我们会基于之前基于IdentityServer的两篇文章，新增一个IdentityService，不熟悉的朋友可以先浏览一下Part 1和Part 2。

3.1 准备工作

　　新建一个ASP.NET Core Web API项目，绑定端口5100，NuGet安装IdentityServer4。配置好证书，并设置其为“较新则复制”，以便能够在生成目录中读取到。

3.2 定义一个InMemoryConfiguration用于测试

    /// <summary>
    /// One In-Memory Configuration for IdentityServer => Just for Demo Use
    /// </summary>
    public class InMemoryConfiguration
    {
        public static IConfiguration Configuration { get; set; }
        /// <summary>
        /// Define which APIs will use this IdentityServer
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<ApiResource> GetApiResources()
        {
            return new[]
            {
                new ApiResource("clientservice", "CAS Client Service"),
                new ApiResource("productservice", "CAS Product Service"),
                new ApiResource("agentservice", "CAS Agent Service")
            };
        }

        /// <summary>
        /// Define which Apps will use thie IdentityServer
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<Client> GetClients()
        {
            return new[]
            {
                new Client
                {
                    ClientId = "cas.sg.web.nb",
                    ClientName = "CAS NB System MPA Client",
                    ClientSecrets = new [] { new Secret("websecret".Sha256()) },
                    AllowedGrantTypes = GrantTypes.ResourceOwnerPassword,
                    AllowedScopes = new [] { "clientservice", "productservice",
                        IdentityServerConstants.StandardScopes.OpenId,
                        IdentityServerConstants.StandardScopes.Profile }
                },
                new Client
                {
                    ClientId = "cas.sg.mobile.nb",
                    ClientName = "CAS NB System Mobile App Client",
                    ClientSecrets = new [] { new Secret("mobilesecret".Sha256()) },
                    AllowedGrantTypes = GrantTypes.ResourceOwnerPassword,
                    AllowedScopes = new [] { "productservice",
                        IdentityServerConstants.StandardScopes.OpenId,
                        IdentityServerConstants.StandardScopes.Profile }
                },
                new Client
                {
                    ClientId = "cas.sg.spa.nb",
                    ClientName = "CAS NB System SPA Client",
                    ClientSecrets = new [] { new Secret("spasecret".Sha256()) },
                    AllowedGrantTypes = GrantTypes.ResourceOwnerPassword,
                    AllowedScopes = new [] { "agentservice", "clientservice", "productservice",
                        IdentityServerConstants.StandardScopes.OpenId,
                        IdentityServerConstants.StandardScopes.Profile }
                },
                new Client
                {
                    ClientId = "cas.sg.mvc.nb.implicit",
                    ClientName = "CAS NB System MVC App Client",
                    AllowedGrantTypes = GrantTypes.Implicit,
                    RedirectUris = { Configuration["Clients:MvcClient:RedirectUri"] },
                    PostLogoutRedirectUris = { Configuration["Clients:MvcClient:PostLogoutRedirectUri"] },
                    AllowedScopes = new [] {
                        IdentityServerConstants.StandardScopes.OpenId,
                        IdentityServerConstants.StandardScopes.Profile,
                        "agentservice", "clientservice", "productservice"
                    },
                    //AccessTokenLifetime = 3600, // one hour
                    AllowAccessTokensViaBrowser = true // can return access_token to this client
                }
            };
        }

        /// <summary>
        /// Define which IdentityResources will use this IdentityServer
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<IdentityResource> GetIdentityResources()
        {
            return new List<IdentityResource>
            {
                new IdentityResources.OpenId(),
                new IdentityResources.Profile(),
            };
        }
    }

　　这里使用了上一篇的内容，不再解释。实际环境中，则应该考虑从NoSQL或数据库中读取。

3.3 定义一个ResourceOwnerPasswordValidator

　　在IdentityServer中，要实现自定义的验证用户名和密码，需要实现一个接口：IResourceOwnerPasswordValidator

    public class ResourceOwnerPasswordValidator : IResourceOwnerPasswordValidator
    {
        private ILoginUserService loginUserService;

        public ResourceOwnerPasswordValidator(ILoginUserService _loginUserService)
        {
            this.loginUserService = _loginUserService;
        }

        public Task ValidateAsync(ResourceOwnerPasswordValidationContext context)
        {
            LoginUser loginUser = null;
            bool isAuthenticated = loginUserService.Authenticate(context.UserName, context.Password, out loginUser);
            if (!isAuthenticated)
            {
                context.Result = new GrantValidationResult(TokenRequestErrors.InvalidGrant, "Invalid client credential");
            }
            else
            {
                context.Result = new GrantValidationResult(
                    subject : context.UserName,
                    authenticationMethod : "custom",
                    claims : new Claim[] {
                        new Claim("Name", context.UserName),
                        new Claim("Id", loginUser.Id.ToString()),
                        new Claim("RealName", loginUser.RealName),
                        new Claim("Email", loginUser.Email)
                    }
                );
            }

            return Task.CompletedTask;
        }
    }

　　这里的ValidateAsync方法中（你也可以把它写成异步的方式，这里使用的是同步的方式），会调用EF去访问数据库进行验证，数据库的定义如下（密码应该做加密，这里只做demo，没用弄）：

　　

　　至于EF部分，则是一个典型的简单的Service调用Repository的逻辑，下面只贴Repository部分：

    public class LoginUserRepository : RepositoryBase<LoginUser, IdentityDbContext>, ILoginUserRepository
    {
        public LoginUserRepository(IdentityDbContext dbContext) : base(dbContext)
        {
        }

        public LoginUser Authenticate(string _userName, string _userPassword)
        {
            var entity = DbContext.LoginUsers.FirstOrDefault(p => p.UserName == _userName &&
                p.Password == _userPassword);

            return entity;
        }
    }

　　其他具体逻辑请参考示例代码。

3.4 改写StarUp类

    public void ConfigureServices(IServiceCollection services)
    {
        // IoC - DbContext
        services.AddDbContextPool<IdentityDbContext>(
            options => options.UseSqlServer(Configuration["DB:Dev"]));
        // IoC - Service & Repository
        services.AddScoped<ILoginUserService, LoginUserService>();
        services.AddScoped<ILoginUserRepository, LoginUserRepository>();
        // IdentityServer4
        string basePath = PlatformServices.Default.Application.ApplicationBasePath;
        InMemoryConfiguration.Configuration = this.Configuration;
        services.AddIdentityServer()
            .AddSigningCredential(new X509Certificate2(Path.Combine(basePath,
                Configuration["Certificates:CerPath"]),
                Configuration["Certificates:Password"]))
            //.AddTestUsers(InMemoryConfiguration.GetTestUsers().ToList())
            .AddInMemoryIdentityResources(InMemoryConfiguration.GetIdentityResources())
            .AddInMemoryApiResources(InMemoryConfiguration.GetApiResources())
            .AddInMemoryClients(InMemoryConfiguration.GetClients())
            .AddResourceOwnerValidator<ResourceOwnerPasswordValidator>()
            .AddProfileService<ProfileService>();
        ......
    }

　　这里高亮的是新增的部分，为了实现自定义验证。关于ProfileService的定义如下：

    public class ProfileService : IProfileService
    {
        public async Task GetProfileDataAsync(ProfileDataRequestContext context)
        {
            var claims = context.Subject.Claims.ToList();
            context.IssuedClaims = claims.ToList();
        }

        public async Task IsActiveAsync(IsActiveContext context)
        {
            context.IsActive = true;
        }
    }

3.5 新增统一Login入口

　　这里新增一个LoginController:

    [Produces("application/json")]
    [Route("api/Login")]
    public class LoginController : Controller
    {
        private IConfiguration configuration;
        public LoginController(IConfiguration _configuration)
        {
            configuration = _configuration;
        }

        [HttpPost]
        public async Task<ActionResult> RequestToken([FromBody]LoginRequestParam model)
        {
            Dictionary<string, string> dict = new Dictionary<string, string>();
            dict["client_id"] = model.ClientId;
            dict["client_secret"] = configuration[$"IdentityClients:{model.ClientId}:ClientSecret"];
            dict["grant_type"] = configuration[$"IdentityClients:{model.ClientId}:GrantType"];
            dict["username"] = model.UserName;
            dict["password"] = model.Password;

            using (HttpClient http = new HttpClient())
            using (var content = new FormUrlEncodedContent(dict))
            {
                var msg = await http.PostAsync(configuration["IdentityService:TokenUri"], content);
                if (!msg.IsSuccessStatusCode)
                {
                    return StatusCode(Convert.ToInt32(msg.StatusCode));
                }

                string result = await msg.Content.ReadAsStringAsync();
                return Content(result, "application/json");
            }
        }
    }

　　这里假设客户端会传递用户名，密码以及客户端ID(ClientId，比如上面InMemoryConfiguration中的cas.sg.web.nb或cas.sg.mobile.nb)。然后构造参数再调用connect/token接口进行身份验证和获取token。这里将client_secret等机密信息封装到了服务器端，无须客户端传递（对于机密信息一般也不会让客户端知道）：

  "IdentityClients": {
    "cas.sg.web.nb": {
      "ClientSecret": "websecret",
      "GrantType": "password"
    },
    "cas.sg.mobile.nb": {
      "ClientSecret": "mobilesecret",
      "GrantType": "password"
    }
  }

3.6 加入API网关中

　　在API网关的Ocelot配置文件中加入配置，配置如下（这里我是开发用，所以没有用服务发现，实际环境建议采用服务发现）：

    // --> Identity Service Part
    {
      "UseServiceDiscovery": false, // do not use Consul service discovery in DEV env
      "DownstreamPathTemplate": "/api/{url}",
      "DownstreamScheme": "http",
      "DownstreamHostAndPorts": [
        {
          "Host": "localhost",
          "Port": ""
        }
      ],
      "ServiceName": "CAS.IdentityService",
      "LoadBalancerOptions": {
        "Type": "RoundRobin"
      },
      "UpstreamPathTemplate": "/api/identityservice/{url}",
      "UpstreamHttpMethod": [ "Get", "Post" ],
      "RateLimitOptions": {
        "ClientWhitelist": [ "admin" ], // 白名单
        "EnableRateLimiting": true, // 是否启用限流
        "Period": "1m", // 统计时间段：1s, 5m, 1h, 1d
        "PeriodTimespan": , // 多少秒之后客户端可以重试
        "Limit":  // 在统计时间段内允许的最大请求数量
      },
      "QoSOptions": {
        "ExceptionsAllowedBeforeBreaking": , // 允许多少个异常请求
        "DurationOfBreak": , // 熔断的时间，单位为秒
        "TimeoutValue":  // 如果下游请求的处理时间超过多少则视如该请求超时
      },
      "HttpHandlerOptions": {
        "UseTracing": false // use butterfly to tracing request chain
      },
      "ReRoutesCaseSensitive": false // non case sensitive
    }

四、改写业务API Service

4.1 ClientService

　　（1）安装IdentityServer4.AccessTokenValidation

NuGet>Install-Package IdentityServer4.AccessTokenValidation

　　（2）改写StartUp类

    public IServiceProvider ConfigureServices(IServiceCollection services)
    {
        ......

        // IdentityServer
        services.AddAuthentication(Configuration["IdentityService:DefaultScheme"])
            .AddIdentityServerAuthentication(options =>
            {
                options.Authority = Configuration["IdentityService:Uri"];
                options.RequireHttpsMetadata = Convert.ToBoolean(Configuration["IdentityService:UseHttps"]);
            });

        ......
    }

　　这里配置文件的定义如下：

  "IdentityService": {
    "Uri": "http://localhost:5100",
    "DefaultScheme":  "Bearer",
    "UseHttps": false,
    "ApiSecret": "clientsecret"
  }

4.2 ProductService

　　与ClientService一致，请参考示例代码。

五、测试

5.1 测试Client: cas.sg.web.nb

　　（1）统一验证&获取token （by API网关）

　　

　　（2）访问clientservice （by API网关）

　　

　　（3）访问productservice（by API网关）

　　

5.2 测试Client: cas.sg.mobile.nb

　　由于在IdentityService中我们定义了一个mobile的客户端，但是其访问权限只有productservice，所以我们来测试一下：

　　（1）统一验证&获取token

　　

　　（2）访问ProductService（by API网关）

　　

　　（3）访问ClientService（by API网关） => 401 Unauthorized

　　

六、小结

　　本篇主要基于前面Ocelot和IdentityServer的文章的基础之上，将Ocelot和IdentityServer进行结合，通过建立IdentityService进行统一的身份验证和授权，最后演示了一个案例以说明如何实现。不过，本篇实现的Demo还存在诸多不足，比如需要重构的代码较多如网关中各个Api的验证选项的注册，没有对各个请求做用户角色和权限的验证等等，相信随着研究和深入的深入，这些都可以逐步解决。后续会探索一下数据一致性的基本知识以及框架使用，到时再做一些分享。

示例代码

　　Click Here => 点我进入GitHub

参考资料

　　杨中科，《.NET Core微服务介绍课程》

　　

作者：周旭龙

出处：http://edisonchou.cnblogs.com

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