Maintain state of the object for same browser session

Question

Following is my ASP.Net Web API controller code. Here as you can see there's a private class object, BL, that is used and both the Get methods implemented. For the first method FetchAllDashboardByUserId(int userId), I pass the user id so that the BL object can be initiated. Within the same browser session, if the second get method is called, then I do not want to pass the userid, since BL should be by default initiated, but currently that's not the case. BL is null for the second method, so I have to add userid to the call to the method - GetCardDataUI(int userId, int dashBoardID, int cardID). My question is how to avoid it. Is my thinking incorrect that:

A single open browser where I make the Consecutive call to the following URLs are a single session:

webapi/ViewR?userId=1

webapi/ViewR?userId=1&dashBoardID=1&cardID=3

I don't want to pass the userId in the second URL. Please note that if I declare class object as static then it works as expected, but that's not what I want, it has to be tied to a user:

public class ViewRController : ApiController
    {
        // BL object for a user
        private static BL accessBL = null;

        // HTTP GET for Webapi/ViewR (Webapi - name of API, ViewR  - Controller with implementation)            

        [AcceptVerbs("Get")]
        public List<DashboardUI> FetchAllDashboardByUserId(int userId)
        {
            if (accessBL == null)
                accessBL = new BL(userId);

            // Use BL object for entity processing
        }

        [AcceptVerbs("Get")]
        public CardDataGetUI GetCardDataUI(int userId, int dashBoardID, int cardID)
        {
            if (accessBL == null)
                accessBL = new BL(userId);

            // Use BL object for entity processing
        }
    }

How I want the second method implementation to be:

[AcceptVerbs("Get")]
            public CardDataGetUI GetCardDataUI(int dashBoardID, int cardID)
            {
               // Use BL class object created in last call for entity processing
               // Should not pass userid again
            }

You will have to store the User Details in Session state. Look at this http://stackoverflow.com/questions/9594229/accessing-session-using-asp-net-web-api — Praveen Reddy, Jun 24 '14 at 18:29
@CodingDawg, thanks This is indeed the solution, it solves the isue for me — Mrinal Kamboj, Jun 25 '14 at 03:30

score 2 · Accepted Answer · answered Jun 24 '14 at 22:32

You can easily store data in Session:

... first request:

Session["userID"] = userID;

... next request:

int userID = (int)Session["userID"];  // should check for null first, but you get the idea...

But keep the following points in mind:

Session variables are stored as objects, so you'll need to cast and/or type-check
Session variables can be null
Session expires after a configurable (in web.config) about of time
Default session state is in-memory, meaning if the app pool is restarted session state is gone - you can store session in files or databases to keep longer
Session doesn't scale out unless you use persistent storage (file, database)
Objects stored in persistent storage must be serializable

It indeed is the solution but needs the post authorization entry in the global.asax as listed in the link above by CodingDawg, otherwise session object is always null — Mrinal Kamboj, Jun 25 '14 at 03:32

Maintain state of the object for same browser session

1 Answers1