pong-game/PongGame/Program.cs

using MessagePack;
using PongGame.Hubs;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorPages();
builder.Services.AddSingleton<PongLobby>(services
    => new(services.GetRequiredService<ILogger<PongLobby>>()));
builder.Services.AddSignalR()
    .AddMessagePackProtocol();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment()) {
    app.UseExceptionHandler("/Error");
}
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.UseEndpoints(endpoints => {
    endpoints.MapRazorPages();
    endpoints.MapHub<PongHub>("/pong/hub");
});

app.Run();