Reading All Users Session
Introduction :
InProc Session is the widely used state management. Storing the session state Inproc is also the fastest method and is well-suited to small amounts of volatile data. Reading and writing current user Session is very easy. But some times we need to read all users session before taking a decision or sometimes we may need to check which users are currently active with the help of Session. But unfortunately there is no class in .Net Framework (i don't found myself) to read all user InProc Session Data. In this article i will use reflection to read all user Inproc Session.
Description :
There is slight difference in code depending ASP.NET version( 2.0 and 3.5).
This code will work equally in both MVC and webform, but for demonstration i will use a simple webform example. So let's create a simple Website and Add two aspx pages, Default.aspx and Default2.aspx. In Default.aspx just add a link to navigate to Default2.aspx and in Default.aspx.cs just add a Session.
Default.aspx:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<a href="Default2.aspx" mce_href="Default2.aspx">Click to navigate to next page</a>
</div>
</form>
</body>
</html>
Default.aspx.cs:
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Session["User"] = "User" + DateTime.Now;
}
}
Now when every user click this link will navigate to Default2.aspx where all the magic appears.
Default2.aspx.cs(2.0):
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Reflection;
using System.Web.SessionState;
public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
object obj = typeof(HttpRuntime).GetProperty("CacheInternal", BindingFlags.NonPublic | BindingFlags.Static).GetValue(null, null);
Hashtable c2 = (Hashtable)obj.GetType().GetField("_entries", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(obj);
foreach (DictionaryEntry entry in c2)
{
object o1 = entry.Value.GetType().GetProperty("Value", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(entry.Value, null);
if (o1.GetType().ToString() == "System.Web.SessionState.InProcSessionState")
{
SessionStateItemCollection sess = (SessionStateItemCollection)o1.GetType().GetField("_sessionItems", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(o1);
if (sess != null)
{
if (sess["User"] != null)
{
Label1.Text += sess["User"] + " is Active.
";
}
}
}
}
}
}
Default2.aspx.cs(3.5):
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Reflection;
using System.Web.SessionState;public partial class Default2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
object obj = typeof(HttpRuntime).GetProperty("CacheInternal", BindingFlags.NonPublic | BindingFlags.Static).GetValue(null, null);
object[] obj2 = (object[])obj.GetType().GetField("_caches", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(obj);
for (int i = 0; i < obj2.Length; i++)
{
Hashtable c2 = (Hashtable)obj2[i].GetType().GetField("_entries", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(obj2[i]);
foreach (DictionaryEntry entry in c2)
{
object o1 = entry.Value.GetType().GetProperty("Value", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(entry.Value, null);
if (o1.GetType().ToString() == "System.Web.SessionState.InProcSessionState")
{
SessionStateItemCollection sess = (SessionStateItemCollection)o1.GetType().GetField("_sessionItems", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(o1);
if (sess != null)
{
if (sess["User"] != null)
{
Label1.Text += sess["User"] + " is Active.
";
}
}
}
}
}
}
}
Now just open more than one browsers or more than one browser instance and then navigate to Default.aspx and click the link, you will see all the user's Session data.
How this works :
InProc session data is stored in the HttpRuntime’s internal cache in an implementation of ISessionStateItemCollection that implements ICollection. In this code, first of all i got CacheInternal Static Property of HttpRuntime class and then with the help of this object i got _entries private member which is of type ICollection. Then simply enumerate this dictionary and only take object of type System.Web.SessionState.InProcSessionState and finaly got SessionStateItemCollection for each user.
Summary :
In this article, I shows you how you can get all current user Sessions. However one thing you will find when executing this code is that it will not show the current user Session which is set in the current request context because Session will be saved after all the Page Events.