Sharing sessions across applications using the ASP.NET Session State Service

I am trying to share sessions between two web applications, both hosted on the same server. One is a .net 2.0 web forms application the other is as .net 3.5 MVC2 application.

Both apps have their session set up like this:

<sessionState
      mode="StateServer"
      stateConnectionString="tcpip=127.0.0.1:42424"
      />

In the webform application I am posting the the session key to the MVC app:

protected void LinkButton1_Click(object sender, EventArgs e)
{
	Session["myvariable"] = "dan"; 
	string sessionKey = HttpContext.Current.Session.SessionID;
          
	//Followed by some code that posts sessionKey to the other application    
}

I then recieve it in the MVC application and try use the same session like this:

[HttpPost]
public  void Recieve(string sessionKey )
{
    var manager = new SessionIDManager();

    bool redirected;
    bool IsAdded;

     manager.SaveSessionID(HttpContext.ApplicationInstance.Context, Id, out redirected, out IsAdded);
     var myVar = Session["myvariable"];

}

The key is being posted but the session does not seem to get loaded in the MVC app, i.e. sessionKey is null. Can what I am trying to do be done?

I did it this way:

Basically the idea is both apps use native .net sessionState stored in sqlserver. By using the same machine key and making a small tweak to a stored procedure – both apps can share any session keys and/or forms authenication.

Both apps would do something like this in their web.config:

<sessionState mode="SQLServer" sqlConnectionString="Data Source=.\SQLEXPRESS;User Id=test;Password=test;Application Name=AppName"  />
    <machineKey
validationKey="SOMEKEY"
validation="SHA1" decryption="AES"
/>

Session state db would need to be set up on a database server, that both apps can see.

Docs for doing this: http://msdn.microsoft.com/en-us/library/ms229862(VS.80).aspx

Command that would need to be run: C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\bin>aspnet_regsql.exe -E -ssadd --sstype p -S .\SQLEXPRESS

Stored procedure (TempGetAppID) tweak to:

 @appId int OUTPUT
AS

    -- start change

    -- Use the application name specified in the connection for the appname if specified
    -- This allows us to share session between sites just by making sure they have the
    -- the same application name in the connection string.
    DECLARE @connStrAppName nvarchar(50)
    SET @connStrAppName = APP_NAME()

    -- .NET SQLClient Data Provider is the default application name for .NET apps
    IF (@connStrAppName <> '.NET SQLClient Data Provider')
        SET @appName = @connStrAppName

    -- end change

SET @appName = LOWER(@appName)

The problem is that session keys are scoped to the applications, so two applications having the same session key in fact have separate sessions.

You can do one of two things:

1. Put both applications as a virtual directory under a common IIS Application. I don't think this is a good idea, but it will work.

2. Roll your own session data solution for the data you want to share. Possibly using the backend database as the common storage, if you have one that is.

Based on Justin's comment, just to clarify option 2 is not refering to the SQL state managemet for out of process sessions. I mean for you to actually manually manage the shared data for the two sessions, possibly using a database.

You can use a common Machine key to generate same Session ID inside both applications for a given user. Additionally, you should also plan on storing sessions of both applications in a common store such as ASP.NET State Service or a distributed cache.

You can use NCache distributed cache which takes provides session sharing feature between different applications. You specify same Application ID tag for both apps inside session state settings which allows you to share session object provided you have same Session ID generated for both applications.