foregroundProcInfo.js

// You need to `npm install ref ffi` for the following code to run.
// What it does basically is get the foreground window in windows and fetch its
// title and the path of the .exe that launched it.

var ref    = require('ref');
var ffi    = require('ffi');

var stringPtr = ref.refType('string');
var voidPtr   = ref.refType('void');
var intPtr    = ref.refType('int');


var user32 = new ffi.Library('user32', {
   'GetForegroundWindow'      : [voidPtr, []], // HWND
   'GetWindowTextA'           : ['int32', ['pointer', stringPtr, 'int32']],
   'GetWindowThreadProcessId' : ['int32', ['pointer', intPtr]],
});

var kernel32 = new ffi.Library('kernel32', {
   'OpenProcess': [voidPtr, ['int32', 'int32', 'int32']],
   'CloseHandle': ['int32', [voidPtr]],
});

var psapi = new ffi.Library('psapi', {
   'GetModuleFileNameExA': ['int32', [voidPtr, voidPtr, stringPtr, 'int32']],
});

var i = 0;
var str = '';
for (i = 0; i < 1024; i++) {
   str += ' ';
}

// reusable buffers.
var buf = ref.allocCString(str, 'ucs2');
var pid = ref.alloc('int');

function processInfo() {
   var res = {};

   // handle to the currently focused window
   var handle = user32.GetForegroundWindow();

   // Get the currently focused window title.
   user32.GetWindowTextA(handle, buf, buf.length);
   res.title = ref.readCString(buf, 0);

   // Get the PID of the process to query its name later on.
   user32.GetWindowThreadProcessId(handle, pid);
   res.pid = pid.deref();

   // QUERY_INFORMATION | VM_READ
   var process = kernel32.OpenProcess(0x0400 | 0x0010, false, pid.deref());
   // Get the process path
   psapi.GetModuleFileNameExA(process, null, buf, buf.length);
   res.process = ref.readCString(buf, 0);

   // free the memory of the handle.
   kernel32.CloseHandle(handle);

   return res;
}

setTimeout(function () {
   console.log(processInfo());
}, 2000);

exports.getProcessInfo = processInfo;