Question

I’m using PostSharp with the TraceAttribute on each class in order to write to log files. A new requirement is to be able to prepend each log entry with the SessionID.

PostSharp doesn’t seem to be able to work this way though. I’ve tried the two approaches that made sense to me and neither work.

Try #1

I added a string parameter to the TraceAttribute constructor to be passed in and used by the OnEntry, OnExit and OnException methods.

private readonly string _sessionID;

public TraceAttribute(string sessionID)
{
    _sessionID = sessionID;
    logger = new Logger();
}

public override void OnExit(MethodExecutionArgs args)
{
    logger.LogMethodExit(string.Format("Session {0} Exiting {1}.{2}", _sessionID, args.Method.DeclaringType.FullName, args.Method.Name));
}

My controllers were decorated with the [Trace] attribute originally and I modified to this approach…

[Trace(HttpContext.Session.SessionID)]

This doesn’t work as the HttpContext is not available in a static context.

So that idea is out the window.

Try #2

So my next try was to simply create the sessionId variable locally to each method in the TraceAttribute…

public override void OnEntry(MethodExecutionArgs args)
{
    var sessionID = HttpContext.Current.Session.SessionID;
    logger.LogMethodEntry(string.Format("Session {0} Entering {1}.{2}", sessionID, args.Method.DeclaringType.FullName, args.Method.Name));
}

This doesn’t work either as again, the HttpContext is not yet available and is a null object at runtime as soon I run the solution..

Try #3

public override void OnEntry(MethodExecutionArgs args)
{
    string sessionID = "Not initialized";
    if (HttpContext.Current.Session.SessionID != null)
        sessionID = HttpContext.Current.Session.SessionID;
    logger.LogMethodEntry(string.Format("Session {0} Entering {1}.{2}", sessionID, args.Method.DeclaringType.FullName, args.Method.Name));
}

Is there any way to get the session information into a TraceAttribute that is weaved with PostSharp in this manner? Some workaround that can accomplish this goal?

Answer 1

Got it working, I was missing my session being turned in in web.config.

Added this line to config and it works fine now.

<sessionState mode="InProc" cookieless="false" timeout="20"/>