Question

I am working on a system that is segmented into yearly sessions. A user can go and change the session to see past sessions

How would I go about passing the users current yearId to every controller?

I was thinking that I could set a users cookie on authentication or when they manually change their session and check the cookie using a global filter like so

public class MyTestAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        HttpCookie cookie = filterContext.HttpContext.Request.Cookies["myCookie"];

        //do something with cookie.Value
        if (cookie!=null) 
        {
           filterContext.ActionParameters["YearId"] = cookie.Value;
        }
        else
        {
           // do something here
        }
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        base.OnActionExecuted(filterContext);
    }
}

Here’s how I’d use the above filter: (or add it as a global filter)

[MyTestAttribute]
public ActionResult Index(int yearId)
{
    //Pass the yearId down the layers
    // _repo.GetData(yearId);
    return View();
}

With this approach, I would have to add yearId to every controller. Any feedback is appreciated.

Answer 1

You could also create a base class for your Controllers that need the parameter as opposed to the filter:

public class MyBaseController : Controller
{
    protected override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        HttpCookie cookie = filterContext.HttpContext.Request.Cookies["myCookie"];

        //do something with cookie.Value
        if (cookie!=null) 
        {
           filterContext.ActionParameters["YearId"] = cookie.Value;
        }
        else
        {
           // do something here
        }
    }
}

Or you could even create a strongly-typed property and make it lazy, so that you don’t have to include it as a parameter to every action method and don’t perform the evaluation unless you access the property:

public class MyBaseController : Controller
{
    private int? _yearId;

    protected int YearId
    {
        get
        {
             // Only evaluate the first time the property is called
             if (!_yearId.HasValue)
             {
                 // HttpContext is accessible directly off of Controller
                 HttpCookie cookie = HttpContext.Request.Cookies["myCookie"];

                 //do something with cookie.Value
                 if (cookie!=null) 
                 {
                      _yearId = int.Parse(cookie.Value);
                 }
                 else
                 {
                      // do something here
                 }
             }

             return _yearId.Value;
        }
    }
}