用PHP擷取蝦米音樂網的下載連結

做連結轉換的時候遇到的。蝦米的連結解密有點煩，解法是我看別人的源碼得到的。然後我把他改寫成了PHP的版本。貼出來，有需要的就拿去用~

$mp3_id = '';//音樂IDfunction unescape($str) {    $str = rawurldecode($str);    preg_match_all("/(?:%u.{4}).{4};&#\d+;.+/U",$str,$r);    $ar = $r[0];    foreach($ar as $k=>$v) {        if(substr($v,0,2) == "%u")        {            $ar[$k] = iconv("UCS-2","utf-8//IGNORE",pack("H4",substr($v,-4)));        }        elseif(substr($v,0,3) == "")        {            $ar[$k] = iconv("UCS-2","utf-8",pack("H4",substr($v,3,-1)));        }        elseif(substr($v,0,2) == "&#")        {            echo substr($v,2,-1)."";            $ar[$k] = iconv("UCS-2","utf-8",pack("n",substr($v,2,-1)));        }    }    return join("",$ar);}$x_url="http://www.xiami.com/song/playlist/id/".$mp3_id."/object_name/default/object_id/0";$x_con=file_get_contents($x_url);preg_match_all( "/<location>(.*?)<\/location>/s",$x_con, $locations);$str=$locations[1][0];$num=substr($str, 0,1);$inp=substr($str,1);$iLe=strlen($inp)%$num;$a=0;$ret='';$arr=array();for ($i=0; $i<$num; $i++) {    $arr [$i] = ($iLe>$i?1:0) + (strlen($inp)-$iLe)/$num;}for ($i=0; $i<$arr[1]; $i++)    {        $a=0;        for ($j=0; $j<$num; $j++)        {            $ret .= substr($inp, $a+$i,1);            $a += $arr[$j];        }}$ret_url=unescape($ret);$url=str_replace('^', '0', $ret_url);$url=str_replace('+', ' ', $url);$url=preg_replace('/.mp(.*)/', '.mp3', $url);echo $url;