php处理替换链接参数

<?php
$url = 'http://www.baidu.com/index.php?m=content&c=index&a=lists&catid=6&area=0&author=0&h=0&region=0&s=1&page=1';
$arr = parse_url($url);
print_r($arr);
$arr_query = convertUrlQuery($arr['query']);
print_r(getUrlQuery($arr_query));
/**
* 将字符串参数变为数组
* @param $query
* @return array array (size=10)
                    'm' => string 'content' (length=7)
                    'c' => string 'index' (length=5)
                    'a' => string 'lists' (length=5)
                    'catid' => string '6' (length=1)
                    'area' => string '0' (length=1)
                    'author' => string '0' (length=1)
                    'h' => string '0' (length=1)
                    'region' => string '0' (length=1)
                    's' => string '1' (length=1)
                    'page' => string '1' (length=1)
*/
function convertUrlQuery($query)
{
    $queryParts = explode('&', $query);
    $params = array();
    foreach ($queryParts as $param) {
        $item = explode('=', $param);
        $params[$item[0]] = $item[1];
    }
    return $params;
}
/**
* 将参数变为字符串
* @param $array_query
* @return string string 'm=content&c=index&a=lists&catid=6&area=0&author=0&h=0&region=0&s=1&page=1' (length=73)
*/
function getUrlQuery($array_query)
{
    $tmp = array();
    foreach($array_query as $k=>$param)
    {
        if($k=='ali_trackid'){
            $tmp[] = $k.'='.'2:mm_58345187_23388879_77836075:1495808287_3k6_1652169695';
        }else{
            $tmp[] = $k.'='.$param;
        }
    }
    $params = implode('&',$tmp);
    return $params;
}