Endpoint filter factory was called twice.

[CoreDX9]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Minimal-API's endpoint filter factory was called twice.

Expected Behavior

Minimal-API's endpoint filter factory was called once.

Steps To Reproduce

app.MapGet("/api/a", () => { })
    .AddEndpointFilterFactory((ctx, next) =>
    {
        ctx.ApplicationServices.GetService<ILogger<WebApplication>>()!.LogError("Enter!!!!!!!!!!!!");
        return (ctxf) => next(ctxf);
    });

Exceptions (if any)

No response

.NET Version

No response

Anything else?

• ASP.NET Core version: 8.0 and 9.0.
• VS version: 17.12.1

[oussamatecnique]

I couldn't reproduce it, do you have more details?
also is this affecting the registering of endpoint filters?

[CoreDX9]

The endpoint metadata obtained from the two calls were different objects, so I believe the result of the first call was discarded. This should not affect the registration of endpoint filters.

I think the first call is meaningless. If many endpoints are registered, unnecessary garbage collection and increased startup time may occur.

This is a sample. Both MainWebApplication and MainHostBuilder will output logs twice on .NET 8.0 and 9.0. Browser auto run is closed.

namespace WebApplication1;

public class Program
{
    public const string testStr = "Has a string in endpoint metadata.";
    public static void Main(string[] args)
    {
        MainWebApplication(args);
        //MainHostBuilder(args);
    }

    public static void MainWebApplication(string[] args)
    {
        var builder = WebApplication.CreateBuilder(args);

        var app = builder.Build();

        var endpoint = app.MapGet("/", () => { });

        endpoint.Add(static endpotintBuilder =>
        {
            endpotintBuilder.FilterFactories.Add((ctx, next) =>
            {
                ctx.ApplicationServices.GetService<ILogger<WebApplication>>()!.LogError("Enter!!!!!!!!!!!!");

                if (!endpotintBuilder.Metadata.Any(x => x is testStr))
                {
                    endpotintBuilder.Metadata.Add(testStr);
                    endpotintBuilder.ApplicationServices.GetService<ILogger<WebApplication>>()!.LogError(testStr);

                    return ctxf =>
                    {
                        ctxf.HttpContext.RequestServices.GetService<ILogger<WebApplication>>()!.LogError("A filter with logging added.");
                        return next(ctxf);
                    };
                }

                return (ctxf) => next(ctxf);
            });
        });

        app.Run();
    }

    public static void MainHostBuilder(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        });
}

public class Startup
{
    public void ConfigureServices(IServiceCollection services) { }
    public void Configure(IApplicationBuilder app)
    {
        app.UseRouting();

        app.UseEndpoints(endpoints =>
        {
            var endpoint = endpoints.MapGet("/", () => { });

            endpoint.Add(static endpotintBuilder =>
            {
                endpotintBuilder.FilterFactories.Add((ctx, next) =>
                {
                    ctx.ApplicationServices.GetService<ILogger<WebApplication>>()!.LogError("Enter!!!!!!!!!!!!");

                    if (!endpotintBuilder.Metadata.Any(x => x is Program.testStr))
                    {
                        endpotintBuilder.Metadata.Add(Program.testStr);
                        endpotintBuilder.ApplicationServices.GetService<ILogger<WebApplication>>()!.LogError(Program.testStr);

                        return ctxf =>
                        {
                            ctxf.HttpContext.RequestServices.GetService<ILogger<WebApplication>>()!.LogError("A filter with logging added.");
                            return next(ctxf);
                        };
                    }

                    return (ctxf) => next(ctxf);
                });
            });
        });
    }
}

Output :

info: Microsoft.Hosting.Lifetime[14]
      Now listening on: http://localhost:5219
fail: Microsoft.AspNetCore.Builder.WebApplication[0]
      Enter!!!!!!!!!!!!
fail: Microsoft.AspNetCore.Builder.WebApplication[0]
      Has a string in endpoint metadata.
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
      Content root path: F:\source\repos\WebApplication1\WebApplication1
// Before open browser
// =====================================================================
// After open browser
fail: Microsoft.AspNetCore.Builder.WebApplication[0]
      Enter!!!!!!!!!!!!
fail: Microsoft.AspNetCore.Builder.WebApplication[0]
      Has a string in endpoint metadata.
fail: Microsoft.AspNetCore.Builder.WebApplication[0]
      A filter with logging added.