Metadata of Endpoints in ASPNET Core

Metadata of Endpoints

Some, not all, routes need a daily downtime between 17 hrs to 18 hrs. So they have to be shut during that period so that no requests are processed. Any request has to be redirected to another page or a website, say, hoven.in. How should that be implemented?

Solution

Keep the visual studio template as it is. Edit the Startup class like this

public class Startup
{

  public void ConfigureServices(IServiceCollection services)
  {

    services.AddMvc();

  }

  public void Configure(IApplicationBuilder app)
  {

    app.UseRouting();

    // insert a middleware between 
    // UseRouting and UseEndpoints 
    app.Use(next => context =>

    {

      // get the endpoint 
      var endPoint = context.GetEndpoint();

      // if it exists 
      if (null != endPoint)
      {

        // obtain the Limited attribute 
        var limAttr = endPoint.Metadata.GetMetadata<LimitedAttribute>();

        // if it is not serving, redirect 
        if ((null != limAttr) && limAttr.IsServing)
        {

          context.Response.Redirect("http://hoven.in");

          // and short circuit 
          return Task.CompletedTask;

        }

      }

      // pass to the next component 
      return next(context);

    });

    app.UseEndpoints(endpoints =>

    {

      endpoints.MapControllerRoute
      (
      pattern: "/{controller}/{action}/{id?}",
      defaults: new { controller = "Hoven", action = "Index" },
      constraints: new { id = "int" },
      name: "MyRoute"
      );

    });

  }

}

[AttributeUsage(AttributeTargets.Method)]
public class LimitedAttribute : Attribute
{

  public bool IsServing { get; private set; }
  public LimitedAttribute()
  {

    int hour = DateTime.UtcNow.Hour;

    IsServing = (hour < 17) || (hour > 18);

  }

}

public class HovenController : Controller
{

  [Limited]
  public IActionResult Index(int? id)
  {

    return new ObjectResult("Hello, MVC!");

  }

}

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