CORS in .NET Core

Question

I am trying to enable CORS in .NET Core in this way:

    public IConfigurationRoot Configuration { get; }

    public void ConfigureServices(IServiceCollecti         


        

Answer 1

I just fixed my problem with Cors in Core 3.1. I was following almost every example and documentation out there. Unfortunately nothing worked until I did .Build() for the builder inside the AddPolicy portion.

        services.AddCors(options => {
            options.AddPolicy(
                name: OrginPolicyKey, 
                builder => builder.WithOrigins("http://localhost:3000")
                    .AllowAnyHeader()
                    .AllowAnyMethod()
                    .Build() // <--- This right here
            );
        });

Also, other people were mentioning about calling the UseCors(OrginPolicyKey) before the rest of your routing and UseMvc stuff. That is correct and I saw that Putting UseCors after the route part broke it. Below is how mine is setup.

        app.UseCors(OrginPolicyKey); // <--- First

        // Then routing stuff..
        app.UseRouting();
        app.UseEndpoints(endpoints =>
        {
            endpoints
                .MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}"
                );
        });

Who knew a builder needs to be built ;D