asp.net core IdentityServer4 实现 resource owner password credentials(密码凭证)

   public class Config
    {
        /// <summary>
        ///     定义要保护的资源
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<ApiResource> GetApiResources() {
            return new List<ApiResource>
            {
               new ApiResource("api1","MyApi")
            };
        }
        /// <summary>
        ///     定义授权客户端
        /// </summary>
        /// <returns></returns>
        public static IEnumerable<Client> GetClients() {
            return new List<Client>
            {
                new Client(){ 
                    ClientId="client",
                    AllowedGrantTypes=GrantTypes.ResourceOwnerPassword,
                    ClientSecrets=
                    {
                      new Secret("secret".Sha256())
                    },
                    AllowedScopes={ "api1",IdentityServerConstants.StandardScopes.OfflineAccess //如果要获取refresh_tokens ,必须在scopes中加上OfflineAccess
                    },
                    AllowOfflineAccess=true// 主要刷新refresh_token,
        
                }
            };
        }
    }

   public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
            services.AddIdentityServer()
                .AddDeveloperSigningCredential()
                .AddInMemoryApiResources(Config.GetApiResources())
                .AddInMemoryClients(Config.GetClients())
                .AddResourceOwnerValidator<ResourceOwnerPasswordValidator>();//注入自定义登录验证

        }

    public class ResourceOwnerPasswordValidator : IResourceOwnerPasswordValidator
    {
        public Task ValidateAsync(ResourceOwnerPasswordValidationContext context)
        {
            if (context.UserName == "test" && context.Password == "test")
            {
                context.Result = new GrantValidationResult(
                 subject: context.UserName,
                 authenticationMethod: OidcConstants.AuthenticationMethods.Password);
            }
            else
            {
                //验证失败
                context.Result = new GrantValidationResult(
                    TokenRequestErrors.InvalidGrant,
                    "invalid custom credential"
                    );
            }
            return Task.FromResult(0);
        }
    }

      public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
            services.AddAuthentication("Bearer")
              .AddIdentityServerAuthentication(options =>
              {
                  options.Authority = "http://localhost:5000";//授权服务器地址
                   options.RequireHttpsMetadata = false;//不需要https    
                   options.ApiName = "api1";
              });
        }