微服务系列之授权认证(二) identity server 4

1.简介

　　IdentityServer4 是为ASP.NET Core系列量身打造的一款基于 OpenID Connect 和 OAuth 2.0 认证授权框架。
　　　　官方文档：https://identityserver4.readthedocs.io/en/latest/

　　　　框架源码：https://github.com/IdentityServer/IdentityServer4　

　　IdentityServer主要使用场景:

　　1)基于中台认证中心的saas系统/pass系统的单点登录或者做为统一认证授权入口(授权模式:授权码模式Authorization Code或者混合模式hybrid)；

　　2)用于API服务与API服务之间的固定token通讯，或者某业务系统服务群集与其他业务系统的服务群集之间通信，或者某业务系统群集服务与中台服务群集之间通信,所使用的授权模式为客户端模式Client Credential;

　　3)用于移动客户端与API服务之间通信，授权码模式为自定义授权码。

　　4)用于给第三方客户端授权使用平台数据资源，类似微信、支付宝等用户授权给。主要授权模式为权码模式Authorization Code

2.Identity Server入门demo

　新建.net core 3.1项目，nuget安装IdentityServer4，我这里是3.14版本

　　

正常来说，商业业务，Api资源、Client客户端、Identity资源、User等数据存储在数据库,token可以存储在数据库也可以存储到redis，这里为了入门演示，使用内存模式，快速搭建。

定义一个类，创建API资源，客户端client，我们这里只使用客户端模式授权，篇幅问题，其他授权方式就不一一写了，基本都差不多

public class TestConfig
    {
        /// <summary>
        /// Api资源
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<ApiResource> GetApiResources()
        {
            return new List<ApiResource>
            {
                new ApiResource(){
                    Name = "myapi",
                    ApiSecrets= new List<Secret>(){
                        new Secret(){
                            Description = "secret",
                            Value = "secret".Sha256()
                        }
                    },
                    Scopes = new List<Scope>(){
                        new Scope(){
                            Name = "apim"
                        }
                    }
                },
            };
        }

        /// <summary>
        /// client
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<Client> GetClients()
        {

            return new List<Client>
            {
               new Client()
               {
                   ClientId="client",//定义客户端ID

                   //AllowedGrantTypes = new List<string>()
                   //{
                   //    GrantTypes.ResourceOwnerPassword.FirstOrDefault(),
                   //    GrantType.ClientCredentials,
                   //    GrantType.Hybrid
                   //},
                   //必须是单个指定授权类型，可能是内存模式问题。
                   AllowedGrantTypes = GrantTypes.ClientCredentials,
                   // 用于认证的密码
                    ClientSecrets =
                    {
                        new Secret("secret".Sha256())
                    },
                   AllowedScopes= {"apim"},
                   AccessTokenLifetime = 360000000
               },
             };
        }

        public static List<TestUser> GetTestUsers()
        {
            return new List<TestUser>
            {
                new TestUser()
                {
                     SubjectId = "1",
                     Username = "test",
                     Password = "123456"
                }
            };
        }
    }　　

在启动类注入

  public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages();
            #region 内存方式
            services.AddIdentityServer()
                .AddDeveloperSigningCredential()//添加证书加密方式，执行该方法，会先判断tempkey.rsa证书文件是否存在，如果不存在的话，就创建一个新的tempkey.rsa证书文件，如果存在的话，就使用此证书文件。
                .AddInMemoryApiResources(TestConfig.GetApiResources())//把受保护的Api资源添加到内存中
                .AddInMemoryClients(TestConfig.GetClients())//客户端配置添加到内存中
                .AddTestUsers(TestConfig.GetTestUsers())//测试的用户添加进来
            .AddDeveloperSigningCredential();
            #endregion
        }

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
            }

            app.UseStaticFiles();

            app.UseRouting();
　　　　　　　　//添加中间件
   　　　　　　//这个必须在UseRouting和UseEndpoints中间。如果IdentityServer服务端和API端要写在一起，
            //那么这个必须在UseAuthorization和UseAuthentication的上面。
            app.UseIdentityServer();
            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapRazorPages();
            });
        }

　然后启动服务，使用postman访问identity server 4默认的endpoint地址发现文档：

使用identityServer4的发现文档中的token_endpoint获取token

token已经获取了，可以使用发现文档里的introspection_endpoint来验证token

上图可见，我们已经为client客户端，创建了一个拥有访问scope为apim权限的token

接下来，创建一个受保护的api服务，同样创建一个.net core 3.1服务，并nuget包安装Microsoft.AspNetCore.Authentication.JwtBearer，选择3.14版本，根据.net core版本来

在启动类中，配置认证和授权DI,和添加认证授权中间件：

public class Startup
    {
        // This method gets called by the runtime. Use this method to add services to the container.
        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
        readonly string MyAllowSpecificOrigins = "_myAllowSpecificOrigins";
        public void ConfigureServices(IServiceCollection services)
        {
            //配置认证
            services.AddAuthentication("Bearer")
                .AddJwtBearer(options =>
                {
                    options.Authority = "http://localhost:5000";//刚才启动的授权认证服务
                    options.RequireHttpsMetadata = false;
                    options.TokenValidationParameters = new TokenValidationParameters //不验证jwt的aud信息
                    {
                        ValidateAudience = false
                    };

                });
            // 配置授权策略
            services.AddAuthorization(options =>
            {
                //定义授权策略，这个名字可以随便起
                options.AddPolicy("ApiScope", policy =>
                {
                    policy.RequireAuthenticatedUser();
                    //
                    policy.RequireClaim("scope", "apim");//策略需要scope有apim
                });
                options.AddPolicy("ApiScope2", policy =>
                {
                    policy.RequireAuthenticatedUser();
                    //
                    policy.RequireClaim("scope", "apim2");
                });
            });
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services
            .AddCors(options =>
            {
                options.AddPolicy(MyAllowSpecificOrigins,
                builder => builder.AllowAnyOrigin()
                .WithMethods("GET", "POST", "HEAD", "PUT", "DELETE", "OPTIONS")
                );
            }).AddMvc();
            services.AddControllers();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            app.Use((context, next) =>
            {
                context.Request.EnableBuffering();
                return next();
            });
            app.UseRouting();
            //跨域设置
            app.UseCors(MyAllowSpecificOrigins);

            //身份验证中间件 （身份验证必须在授权的前面）
            app.UseAuthentication();

            //授权验证中间件
            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapGet("/", async context =>
                {
                    await context.Response.WriteAsync("Hello World!");
                });
            });
        }
    }

　　写2个接口

注意，Authorize标签可生效于类或者方法上，，根据不同的授权策略来合理安排需要保护的资源。最后，可以用刚才的token来访问这个API,，如果token错误会401，如果根据授权策略的不同，比如mytwo接口受到apiScope2策略保护，apiScope2策略需要apim2这个scope权限，因为刚才我们获取的token只包含apim这个scope权限，所以访问会返回403权限不足，大家可以去试试，我试过了就不贴图。

至此demo结束，大家可以去试试其他模式的获取token方式

3.IdentityServer4的数据存储

　　商业级项目，授权资源是需要持久化存储的，官方已经提供了基于ef core的来维护我们授权资源和token的管理模型、上下文、仓储接口等，具体我就不写了，推荐参考这篇文章.net core 3.1 Identity Server4 (EntityFramework Core 配置) - 尘叶心繁的专栏 - TNBLOG。下面贴几张基于Identity Server4 EFCore包管理的APIResource、Client、Identity资源、Token的相关代码简介

services.AddIdentityServer()
                    .AddConfigurationStore(options =>  //注入idenity相关资源上下文
                    {
                        options.ResolveDbContextOptions = (provider, builder) =>
                        {
                            builder.UseSqlServer(Configuration.GetSection("Database:ConnectString").Value,
                                sql => sql.MigrationsAssembly(migrationsAssembly));
                        };
                    })
                    .AddOperationalStore(options =>  //注入Token管理上下文
                    {
                        options.ConfigureDbContext = builder =>
                            builder.UseSqlServer(Configuration.GetSection("Database:ConnectString").Value,
                                sql => sql.MigrationsAssembly(migrationsAssembly));
                        options.EnableTokenCleanup = true;
                        options.TokenCleanupInterval = 3600;
                    })
                   .AddDeveloperSigningCredential();

   private ConfigurationDbContext _dbContext;
        private PersistedGrantDbContext _grantdbContext; //这个就是identity资源上下文
        private IOptions<IdentityOption> _identityOption; //这个就是token上下文
        private IMediator _mediator;
        public ClientManager(ConfigurationDbContext dbContext, IOptions<IdentityOption> identityOption, PersistedGrantDbContext grantdbContext, IMediator mediator)
        {
            _dbContext = dbContext;
            _identityOption = identityOption;
            _grantdbContext = grantdbContext;
            _mediator = mediator;
        }

下面是部分Client客户端管理代码

public async Task<Client> CreateClient(ClientEntity clientEntity)
        {
            if (_dbContext.Clients.Any(m => m.ClientName == clientEntity.ClientName))
                throw new Exception("clientName Duplicate");
            if (_dbContext.Clients.Any(m => m.ClientId == clientEntity.ClientId))
                throw new Exception("clientId Duplicate");
            IdentityServer4.EntityFramework.Entities.Client client = new IdentityServer4.EntityFramework.Entities.Client()
            {
                ClientId = clientEntity.ClientId,
                ClientSecrets = new List<IdentityServer4.EntityFramework.Entities.ClientSecret>()
                        {
                            new IdentityServer4.EntityFramework.Entities.ClientSecret(){
                                 Value=clientEntity.Sha256Secret,
                                 Description=clientEntity.Secret
                            }
                        },
                ClientName = clientEntity.ClientName,
                // ClientUri = clientEntity.ClientUri,
                Description = clientEntity.Description,
                AccessTokenType = 1,
                RequireConsent = clientEntity.RequireConsent,
                AccessTokenLifetime = clientEntity.AccessTokenLifetime,
                AllowOfflineAccess = true,
                RedirectUris = new List<IdentityServer4.EntityFramework.Entities.ClientRedirectUri>(),
                PostLogoutRedirectUris = new List<IdentityServer4.EntityFramework.Entities.ClientPostLogoutRedirectUri>(),
                AllowedGrantTypes = new List<IdentityServer4.EntityFramework.Entities.ClientGrantType>(),
                Claims = new List<IdentityServer4.EntityFramework.Entities.ClientClaim>()
            };

            if (clientEntity.RedirectUris.Count > 0)
            {
                foreach (var url in clientEntity.RedirectUris)
                {
                    client.RedirectUris.Add(new IdentityServer4.EntityFramework.Entities.ClientRedirectUri()
                    {
                        RedirectUri = url
                    });
                }

            }
            if (clientEntity.PostLogoutRedirectUris.Count > 0)
            {
                foreach (var url in clientEntity.PostLogoutRedirectUris)
                {
                    client.PostLogoutRedirectUris.Add(new IdentityServer4.EntityFramework.Entities.ClientPostLogoutRedirectUri()
                    {
                        PostLogoutRedirectUri = url
                    });
                }

            }

            //平台默认开放这三个类型
            var typeList = new List<string>() { "hybrid", "client_credentials", "delegation" };
            typeList.ForEach(type =>
            {
                client.AllowedGrantTypes.Add(new IdentityServer4.EntityFramework.Entities.ClientGrantType()
                {
                    GrantType = type
                });
            });

            var res = await _dbContext.Clients.AddAsync(client);
            await _dbContext.SaveChangesAsync();
            return res.Entity;
        }

        public async Task<Client> UpdateClient(ClientEntity clientEntity)
        {
            if (_dbContext.Clients.Any(m => m.ClientName == clientEntity.ClientName && m.Id != clientEntity.Id))
                throw new Exception("clientName Duplicate");
            var client = await _dbContext.Clients
                                            .Include(x => x.AllowedGrantTypes)
                                            .Include(x => x.RedirectUris)
                                            .Include(x => x.PostLogoutRedirectUris)
                                            .Include(x => x.AllowedScopes)
                                            .Include(x => x.ClientSecrets)
                                            .Include(x => x.Claims)
                                            .Include(x => x.IdentityProviderRestrictions)
                                            .Include(x => x.AllowedCorsOrigins)
                                            .Include(x => x.Properties)
                                            .FirstOrDefaultAsync(x => x.Id == clientEntity.Id);
            if (client == null)
                throw new Exception("Client Not Exists!");
            client.ClientName = clientEntity.ClientName;
            client.Description = clientEntity.Description;
            client.AccessTokenLifetime = clientEntity.AccessTokenLifetime;
            client.RequireConsent = clientEntity.RequireConsent;
            client.Enabled = clientEntity.Enabled;
            client.RedirectUris = new List<IdentityServer4.EntityFramework.Entities.ClientRedirectUri>();
            client.PostLogoutRedirectUris = new List<IdentityServer4.EntityFramework.Entities.ClientPostLogoutRedirectUri>();
            client.AllowedScopes = new List<IdentityServer4.EntityFramework.Entities.ClientScope>();
            client.AllowedGrantTypes = new List<IdentityServer4.EntityFramework.Entities.ClientGrantType>();

            if (clientEntity.RedirectUris.Count > 0)
            {
                foreach (var url in clientEntity.RedirectUris)
                {
                    client.RedirectUris.Add(new IdentityServer4.EntityFramework.Entities.ClientRedirectUri { RedirectUri = url });
                }
            }

            if (clientEntity.PostLogoutRedirectUris.Count > 0)
            {
                foreach (var url in clientEntity.PostLogoutRedirectUris)
                {
                    client.PostLogoutRedirectUris.Add(new IdentityServer4.EntityFramework.Entities.ClientPostLogoutRedirectUri { PostLogoutRedirectUri = url });
                }

            }

            foreach (string scope in clientEntity.AllowedScopes)
            {
                client.AllowedScopes.Add(new IdentityServer4.EntityFramework.Entities.ClientScope { Scope = scope });
            }

            foreach (string key in clientEntity.AllowedGrantTypes)
            {
                client.AllowedGrantTypes.Add(new IdentityServer4.EntityFramework.Entities.ClientGrantType { GrantType = key });
            }

            var res = _dbContext.Clients.Update(client);
            await _dbContext.SaveChangesAsync();
            return res.Entity;
        }

下面以部分token管理代码

 public async Task<string> GenerateToken(int id, string nickName, string projectGroup, string contact, string useReason)
        {
            var client = await _dbContext.Clients
                                            .Include(x => x.AllowedGrantTypes)
                                            .Include(x => x.RedirectUris)
                                            .Include(x => x.PostLogoutRedirectUris)
                                            .Include(x => x.AllowedScopes)
                                            .Include(x => x.ClientSecrets)
                                            .Include(x => x.Claims)
                                            .Include(x => x.IdentityProviderRestrictions)
                                            .Include(x => x.AllowedCorsOrigins)
                                            .Include(x => x.Properties)
                                            .FirstOrDefaultAsync(x => x.Id == id);
            if (client == null)
                throw new Exception("Client Not Exists!");
            //初始化连接IdentityServer客户端，这也是人家封装好的http请求
            var discoveryClient = new DiscoveryClient(_identityOption.Value.Host)
            {
                Policy = new DiscoveryPolicy { RequireHttps = _identityOption.Value.Https, ValidateIssuerName = false }
            };
            //获取endpint
            var discoveryResponse = await discoveryClient.GetAsync();
            //连接获取token那个endpoint
            var tokenClient = new TokenClient(discoveryResponse.TokenEndpoint,
                                                  client.ClientId,
                                                  client.ClientSecrets.FirstOrDefault().Description);
            #region 计算当前client的拥有的API资源SCOPE
            var allScopes = client.AllowedScopes.Select(p => p.Scope).ToList();
            var apiResourceScopes = new List<string>();
            _dbContext.ApiResources.Include("Scopes").ToList().ForEach(api =>
            {
                if (api.Scopes.Count > 0)
                    apiResourceScopes.AddRange(api.Scopes.Select(p => p.Name).ToList());
            });
            var inScopes = apiResourceScopes.Intersect(allScopes);
            #endregion
            var scope = string.Join(" ", inScopes);
            //请求生成客户端模式的token
            var tokenResponse = await tokenClient.RequestCustomGrantAsync("client_credentials", scope);

            if (tokenResponse.IsError)
            {
                throw new Exception(tokenResponse.Error);
            }
            else
            {
                //发送事件
                var _key = string.Format("{0}:reference_token", tokenResponse.AccessToken).ToSha256();
                var tokenEntity = new TokenEntity(_key, nickName, projectGroup, contact, useReason, client.ClientId, tokenResponse.AccessToken);
                await _mediator.Publish<GenerateTokenEvent>(new GenerateTokenEvent(tokenEntity));
                return tokenResponse.AccessToken;
            }
        }

下面还有一段关于修改token过期时间的代码

 public async Task<bool> AddExpiration(string token, DateTime date)
        {
            if (!_dbContext.TokenEntities.Any(p => p.Token == token))
                throw new Exception("manage token not exsits");
            //这个key是经过一定格式后进行sha256加密后，作为数据库表PersistedGrants一个唯一标识
            var _key = string.Format("{0}:reference_token", token).ToSha256();
            var persistedGrant = _grantdbContext.PersistedGrants.FirstOrDefault(p => p.Key == _key);
            if (persistedGrant == null)
                throw new Exception("token不存在或者TOKEN已过期");
            var data = JObject.Parse(persistedGrant.Data);
            var creation = data.Value<DateTime>("CreationTime");
            var lifetime = data.Value<int>("Lifetime");

            data["Lifetime"] = (int)((date - creation).TotalSeconds);

            persistedGrant.Expiration = date;
            persistedGrant.Data = data.ToString(Newtonsoft.Json.Formatting.None);

            _grantdbContext.PersistedGrants.Update(persistedGrant);
            await _grantdbContext.SaveChangesAsync();
            return true;
        }

再来一段自定义授权模式代码

public class DelegationGrantValidator : IExtensionGrantValidator//需要继承一下类型验证扩展接口
    {
        private readonly ITokenValidator _validator;//identity框架已实现的token验证服务，直接注入使用

        public DelegationGrantValidator(ITokenValidator validator)
        {
            _validator = validator;
        }

        public string GrantType => "delegation";//自定义的授权类型，我这实现的是一个token交换token的类型

        public async Task ValidateAsync(ExtensionGrantValidationContext context)
        {
            var userToken = context.Request.Raw.Get("token");//获取被交换token

            if (string.IsNullOrEmpty(userToken))
            {
                context.Result = new GrantValidationResult(TokenRequestErrors.InvalidGrant);
                return;
            }

            var result = await _validator.ValidateAccessTokenAsync(userToken);//直接使用人家实现好的token验证服务验证传来的token
            if (result.IsError)
            {
                context.Result = new GrantValidationResult(TokenRequestErrors.InvalidGrant);
                return;
            }

            //声明获取用户，如果有用户，说明要换取用户token
            var sub = result.Claims.FirstOrDefault(c => c.Type == "sub")?.Value;
            if (sub != null)
            {
                context.Result = new GrantValidationResult(sub, GrantType);//换取用户token,
                return;
            }

            // 声明中获取客户端ID，如果有clientId,说明换取客户端token
            var client_id = result.Claims.FirstOrDefault(c => c.Type == "client_id")?.Value;
            if (client_id != null)
            {
                //context.Result = new GrantValidationResult(client_id, GrantType);
                context.Result = new GrantValidationResult();//换取客户端token
                return;
            }

            context.Result = new GrantValidationResult(TokenRequestErrors.InvalidRequest);
        }
    }

builder.AddExtensionGrantValidator<DelegationGrantValidator>();注入DI。

IdentityServer4还可以扩展endpoint,但是扩展完后，在发现文档不显示，但是可以作为http使用，以下代码截图供参考

4.结尾

　　identityServer4要写的东西实在太多，整体的把握理解还是有一定的复杂性的，我之前公司一个pass平台项目，是基于认证中心，其他业务系统实现快速集成，我当时负责的就是授权资源、token管理，还有对IDP的授权类型、endpoint一些扩展，现在总结成博客，写的不是很细，希望对后来者带来一些帮助和参考意义。