根据官方文档，Asp.net Core 3.0 CORS 无法工作

Question

我想通过 Asp.Net Core 3.0 API 项目启用 CORS。这是生成的基本 Asp.Net Core Api 模板。一切都是模板中的默认设置，除了我从文档中添加了 CORS 设置：在 ASP.NET Core 中启用跨源请求 (CORS)

这是我的 Startup.cs

public class Startup
{
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
            services.AddCors(options =>
            {
                options.AddPolicy("CorsPolicy",
                    builder => builder.WithOrigins("localhost", "www.google.com")
                    .AllowAnyMethod()
                    .AllowAnyHeader()
                    .AllowCredentials());
            });
        }

        // 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.UseHttpsRedirection();

            app.UseRouting();

            app.UseCors("CorsPolicy");
            app.UseAuthorization();

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

这些是我的响应标题：

我应该设置什么才能在响应中获取正确的 CORS 标头？

这是我的 fetch api 测试：

Answer 1

哎呀，我成功解决了这个问题。

这种组合对我来说是唯一有效的组合：

public class Startup
{
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();
            services.AddCors(); //This needs to let it default
        }

        // 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.UseHttpsRedirection();

            app.UseRouting();

            app.UseCors(
                options => options.SetIsOriginAllowed(x => _ = true).AllowAnyMethod().AllowAnyHeader().AllowCredentials()
            ); //This needs to set everything allowed

            app.UseAuthorization();

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