php - Netbeans Error on $_SERVER -

i have following code:

<?php defined('root') or define('root', $_server['document_root']); ?> 

netbeans returns:

do not acces superglobal $_server array directly. 

i updated netbeans, in previous versions didn't have message, safe ignore it?

print index of $_server array code :

<?php      $keyy=array(); // while(key($_server)){     array_push($keyy,key($_server));     next($_server); } foreach($keyy $ke) echo '<a style="color:red;" >'.$ke.'</a> '.$_server[$ke].' <br>'; ?> 

if print errors don't access $_server on server...
security permission
$_server['remote_addr']
$_server['http_accept_encoding']
$_server['http_host']
$_server['http_user_agent']
enough!!!