AddCors, AddPolicy, AllowSpecificOrigin asp.net core api

Startup.cs

 public void ConfigureServices(IServiceCollection services)
  {
      services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

      services.AddCors(options =>
      {
          options.AddPolicy("AllowSpecificOrigin",
                            builder => builder.WithOrigins("http://example.com"));
      });
  }