I use the AddService() method to inject a things on occasion but its not used heavily. For lightweight apps I'll spin up things like a shared SQLiteConnection and inject it for all resources to use.

The DI pattern is simple & clean at this scale. In my top-level program I define my routes like:

  app.Map("/", Home.HandleRequest);
  app.Map("/login", Login.HandleRequest);
  app.Map("/account/new", NewAccount.HandleRequest);
  app.Map("/{owner}", OwnerHome.HandleRequest);

And then I have HandleRequest implementations like:

  static async Task HandleRequest(HttpContext context, SQLiteConnection sql)
  static async Task HandleRequest(HttpContext context, SQLiteConnection sql, string owner)
  etc...

The actual HandleRequest() method can do anything, including concerns like directly accepting and handling web socket connections.