Where to put logic in ASP.NET MVC app so its always fired (just once) per page request?

Question

I have an ASP.NET MVC application and I want to be able to perform some logic 'just once' per page request. More specifically, I need to check details surrounding the logged in users role 'just once', each time they request a page within the application. I need to check the DB to see if their role has been changed since (flag in the db) and if so, log them out and redirect them back to the login screen.

I started off by creating a Base Controller and putting this logic inside the base class Initialize method, which works fine. The problem is that this particular initialize code is getting fired multiple times per page request (as there are numerous controllers in the application, many of which can get instantiated with any given page request.

I only want/need my logic (currently inside the base controller Initialize method) to occur once per page request though.

What approach would be recommended for this?

Use Global.asax and Application events http://weblog.west-wind.com/posts/2009/Jun/18/How-do-ASPNET-Application-Events-Work Or implement an `IHttpModule` — VMAtm, Apr 21 '15 at 10:40
Look at the IsPostback Property of a page, this might help: http://stackoverflow.com/questions/760912/what-is-the-difference-between-page-ispostback-and-page-iscallback — Schuere, Apr 21 '15 at 10:41

score 2 · Answer 1 · answered Apr 21 '15 at 10:42

2

You can create an action filter (https://msdn.microsoft.com/en-us/library/gg416513%28VS.98%29.aspx) and override the OnActionExecuting method.

In it you only execute your logic if: - it is a GET - it is not an AJAX initiated request

answered Apr 21 '15 at 10:42

Stefano Altieri

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Zeeshan · Accepted Answer · 2015-04-21T10:51:59.143

BaseController is the right place. You need to use OnActionExecuting filter. override it in BaseController, and put logic inside

roughly like:

      public override void OnActionExecuting(ActionExecutingContext filterContext)
      {
           if(roleChanged)
            {
                 context.Result = new RedirectToRouteResult(new RouteValueDictionary(new
                  {
                     controller = "Home",
                     action = "Logout"
                  }));
             }
      }

You can further utilize filterContext instance to place checks on specific calls by determining Action and Controller for each request. (eg, i usually need this in case of ajax call)

This has worked for me, in conjunction with doing 'if (ControllerContext.IsChildAction ) return; to prevent it hitting my logic multiple times per page request. Thanks. — marcusstarnes, Apr 21 '15 at 11:29

score 1 · Answer 3 · answered Apr 21 '15 at 10:46

Filter ajax request and child actions in base controller in Initialize method.

    protected override void Initialize(RequestContext requestContext) {
        if (requestContext.HttpContext.Request.IsAjaxRequest() || ControllerContext.IsChildAction)
            return;
    }

Where to put logic in ASP.NET MVC app so its always fired (just once) per page request?

3 Answers3