Allow for non-blocking continue confirmations in long running php processes on win32 platforms...

confirm_continue.php

/**
 * Allows for asking the user if they want to continue a long running process without blocking PHP if the user doesn't respond on Win32 platforms
 * @param int $duration - number of seconds to wait until we continue anyway
 * @note: Inspired from this stackoverflow post
 * @author http://stackoverflow.com/users/2581/martin
 * @link http://stackoverflow.com/a/9711142
 * @license http://creativecommons.org/licenses/by-sa/3.0/
 */
function confirm_continue($duration = 30)
{
	if (!is_numeric($duration) || $duration > 1000 || $duration < 1)
	{
		throw new Exception("Invalid readline timeout duration, must be numeric and between 1 and 1000");
	}
	
	echo "Press Enter Key to stop processing... ($duration seconds to answer)\n?: ";
	
	while($duration--)
	{
		//Check on STDIN stream
		$read = [STDIN];
		$result = stream_select($read, $write = [], $except = [], 0);
		
		//handle results
		if ($result === false || $result === 0)
		{
			//nothing was entered on stdin so wait another second
			sleep(1);
		}
		else
		{
			//On windows if the cmd prompt process loses focus, we get a false positive response of 1 from stream_select
			//So we ask for a confirmation from the user. If losing focus was unintentional, answering this question will reset the
			//stream_select() result.  In the event that the user had actually pressed Enter to stop the process, the dangling newline
			//character will cascade into this stream_get_line() request and automatically confirm that we should end the process.
			echo "Process interrupted... Are you sure you want to stop this process? [y/n]";
			
			return trim(stream_get_line(STDIN, 1024, PHP_EOL)) == "n" ? true : false;
		}
	}
	
    return true;
}