PHP防止两次包含相同的文件

Question

Hi I have following files:
login.php, index.php, header.php, footer.php, restrictaccess.php

restrictaccess.php has following code:

<?php
session_start();
if (!(isset($_SESSION['user']) && $_SESSION['user'] != ''))
if (!(isset($_SESSION['access']) && $_SESSION['access'] != '')) 
{
header ("Location: login.php");
exit();
}


if($_SESSION['access']=="2" ) {
     echo 'You are logged on as Manager';

}
if($_SESSION['access']=="1" ) {
     echo 'You are logged on as Restricted user';
}
?>

restrictaccess.php, header.php and footer.php is included on every page accept login.php.
Both header and footer also includes restrictaccess.php; will this cause any problem ? Is there anyway so that such includes will only be loaded once ?

Currently when someone logon the message "You are loged on as Manager/Restricted user" is displayed thrice.

Your help will be much appreciated, thank you.

Answer 1

Try using require_once() to include your file. This method checks wether the file was already included.

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