generate random id

gistfile1.php

function getShortenForm($url){
	$ignore = array('I','0','O','1');
	$alphabet = array_merge(range('A','Z'),array_map(function($i){return (string)$i;},range(0,9)));
	$parsing_url = md5($url.'-'.rand().'-'.rand().'-'.microtime(true));
	$parsing_url = substr($parsing_url, strlen($parsing_url)/2-1,strlen($parsing_url)).substr($parsing_url, 0,strlen($parsing_url)/2);
	$shorten = strtoupper(substr(base_convert($parsing_url,16, 36),0,self::MAX_CHARS));
	$cleaned = array_diff($alphabet, $ignore);
	$cleaned = array_values($cleaned);
	$replaceble = array();
	array_walk($ignore,function($val,$key) use (&$replaceble,$cleaned){
		array_push($replaceble,$cleaned[rand(0, count($cleaned)-1)]);
	});
	$returnShorten = str_replace($ignore, $replaceble, $shorten);
	return $returnShorten;
}