在ASP.NET Core中允许Cors Origin

Question

我正在使用Microsoft.ApsNetCore.Cors 2.2

“ CORS策略已阻止从来源“ example.local”访问“ exampleapi.local”处的XMLHttpRequest：在请求的资源上不存在“ Access-Control-Allow-Origin”标头。”

我用这个设定设定

public void ConfigureServices(IServiceCollection services)
        {
            services.AddCors(options =>
            {
                options.AddPolicy("AllowSpecificOrigin",
                        builder =>
                        {
                            builder                            
                            .AllowAnyOrigin()
                            .AllowAnyMethod()
                            .AllowAnyHeader();
                        });
            });

            services.Configure<TokenSettings>(this.Configuration.GetSection("Tokens"));
            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
                .AddJwtBearer(opt =>
                {
                    opt.TokenValidationParameters = new TokenValidationParameters
                    {
                        ValidateIssuer = true,
                        ValidateAudience = true,
                        ValidateLifetime = true,
                        ValidateIssuerSigningKey = true,
                        ValidIssuer = Configuration["Tokens:Issuer"],
                        ValidAudience = Configuration["Tokens:Audience"],
                        IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(Configuration["Tokens:SecurityKey"]))
                    };
                });

            services.AddMvc();
            services.Configure<LdapConfig>(Configuration.GetSection("ldap"));
            services.AddScoped<ILdapAuthenticationService, LdapAuthenticationService>();
            services.AddScoped<IUserService, UserService>();
            services.AddScoped<IProjectService, ProjectService>();
            services.AddScoped<IProjectMembersService, ProjectMembersService>();
            services.AddScoped<IJourneyUsersService, JourneyUsersService>();
            services.AddScoped<IProjectRolesService, ProjectRolesService>();
            services.AddScoped<IPmoGuardianService, PmoGuardianService>();
            services.AddScoped<IHolidaysService, HolidaysService>();
            services.AddScoped<IMailService, MailService>();
            services.AddScoped<INotificationsService, NotificationsService>();
            services.AddScoped<INotificationUsersService, NotificationUsersService>();
            services.Configure<AWSConfigSes>(Configuration.GetSection("AWSSmtp"));
            services.AddDbContext<JourneyContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("JourneyConnection")));
            services.AddDbContext<TSMContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("TSMConnection")));
            services.AddDbContext<PmoGuardianContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("PmoGuardianConnection")));

        }

public void Configure(IApplicationBuilder app, IHostingEnvironment env, IMailService mail, INotificationsService not)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            Recurrence recurrency = Recurrence.GetInstance(not);
            //new TSMClockService(mail);

            app.UseCors("AllowSpecificOrigin");
            app.UseAuthentication();

            app.UseMvc();
        }

[Produces("application/json")]
[Route("api/Mail")]
[EnableCors("AllowSpecificOrigin")]

但这不起作用，总是出现相同的错误

Answer 1

艾米的评论是对的。CORS 标头需要由目标服务器而不是您的服务器设置。

如果您尝试连接到不同端口上的 API，但在同一 IP 地址上本地运行（最常见的示例是 localhost:<> 尝试 ping localhost<> 等），您经常会发现 CORS 问题。

如果您尝试使用 Google Chrome 在本地计算机上运行此程序，您可以下载以下扩展程序，该扩展程序将允许您打开和关闭 CORS 规则，以便您可以在本地进行测试： 允许 CORS：Access-Control-Allow-Origin