QuickBooks/MerchantService.php
protected function _transRequestID($type, $Obj, $amount, $force_new_transaction = true)
	{
		$rand = '';
		if ($force_new_transaction)
		{
			$rand = mt_rand() . microtime();
		}
		
		return md5($type . '-' . serialize($Obj) . '-' . $amount . '-' . $rand);
	}
protected function _transRequestID($type, $Obj, $amount, $force_new_transaction = true)
	{
		$rand = '';
		if ($force_new_transaction)
		{
			$rand = mt_rand() . microtime();
		}
		
		return md5($type . '-' . serialize($Obj) . '-' . $amount . '-' . $rand);
	}
Create a unique transaction requestID from a set of parameters

@param string $type
@param object $Obj
@param float $amount
@param boolean $force_new_transaction
@return string