Delete a Question Object from Database after 3 days if it is not answered

Question

I'm working on a web application project using .net core and I want to self-close(delete) a Question object from the database(MySQL in my case) if it has been posted for 3 days with no answer. I believe I can use Worker Services but I'm not sure how to use it and if it's logical to have so many background services running in the background (1 service/timer for each question). Thank you.

Answer 1

You need just one background service for this job.

I Assume that you already have a service interface:

public interface IQuestionService {
    Task<IEnumerable<Question>> GetQuestionsToClose();
    Task CloseQuestions(IEnumerable<Question> questions);
}

Than you need to implement your background service:

public CloseQuestionsBackgroundService : BackgroundService
{
    private readonly IQuestionService questionService;
    public CloseQuestionsBackgroundService(IQuestionService questionService)
    {
        this.questionService = questionService;
    }
    protected override async Task ExecuteAsync(CancellationToken stopToken)
    {
      while (!stopToken.IsCancellationRequested)
      {
          var questionsToClose = questionService.GetQuestionsToClose().ConfigureAwait(false);
          if (questionsToClose.Any())
          {
               await questionService.CloseQuestions(questionsToClose).ConfigureAwait(false);
          }
          await Task.Delay(Timespan.FromSeconds(10)).ConfigureAwait(false); // choose how much time between iterations
      }
   }
}

Now you just have to register the background service in the ConfigureService method of your Startup.cs

 services.AddHostedService<CloseQuestionsBackgroundService>();