Project ActivityMonitoring

From Frederick Chapleau Wiki

Great, but... why?

In clear, just to know if I'm too much in front of my screens just like my mother was doing when I was 8.

The real question is more: In which circumstances that can be usefull? To be a Big Brother? Maybe, to automatically launch a program after a delay? Yes, more in that way.

The Solution

It's a Windows Service that is using some Windows API to calculate time elapsed since the last user interaction. After a pre-defined amount of time, it is calling a web service that is using a SQL Server database to store the actions.

By the way, a little hint: if you want to monitor a computer globally for inputs, just use the Windows Service via the Local System account. This will also monitor the RDP Connections.

The Code

Let's begin with the 20% code that is used 80% of the time.

The bigest challenges were setting or deducting the types. The MSDN documenation did not have the right types neither the right code to access the API.

Monitoring Code

        [StructLayout(LayoutKind.Sequential)]
        public struct LASTINPUTINFO
        {
            public uint cbSize;
            public uint dwTime;
        };
 
        [DllImport("USER32.DLL")]
        private static extern bool GetLastInputInfo(ref LASTINPUTINFO ii);
 
 
        public long GetIdleTime()
        {
            LASTINPUTINFO lastInPut = new LASTINPUTINFO();
            lastInPut.cbSize = (uint)System.Runtime.InteropServices.Marshal.SizeOf(lastInPut);
 
            if (GetLastInputInfo(ref lastInPut))
            {
                long el = lastInPut.dwTime;
                long ui = (Environment.TickCount - el);
 
                // Overflow
                if (ui < 0)
                    ui = ui + uint.MaxValue + 1;
 
                return ui;
            }
            else
            {
                throw new ApplicationException("Timespan");
            }
 
        }
 
        public TimeSpan GetIdleTimeSpan()
        {
            return new TimeSpan(GetIdleTime() * 10000);
        }

RDP Sessions State

Check out the RoyalTS Source Code for great RDP Wrappers.

Session 0 Isolation

There is a problem with Windows Vista that introducte Session 0 isolation. With this "feature", you can monitor globally idle time, without spanning a process inside each session, that return the result.

As a workaround, my activity monitoring tiny client was refactored as a standard Windows UI, so that it can run on the current session.