If you are new to PHP or just need to refresh your skills, this is the place to start. This series of tutorials will give you the basic knowledge you will need to create a simple PHP website.

PHP is a reflective programming language originally designed for producing dynamic web pages.[1] PHP is used mainly in server-side scripting, but can be used from a command line interface or in standalone graphical applications. Textual User Interfaces can also be created using ncurses.

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Chapter 62. Miscellaneous Questions

There can be some questions we can't put into other categories. Here you can find them.

1. How can I handle the bz2 compressed manuals on Windows?
2. What does & beside argument mean in function declaration of e.g. asort()?
3. How do I deal with register_globals?

1. How can I handle the bz2 compressed manuals on Windows?

If you don't have an archiver-tool to handle bz2 files download the command line tool from Redhat (please find further information below).

If you would not like to use a command line tool, you can try free tools like Stuffit Expander, UltimateZip, 7-Zip, or Quick Zip. If you have tools like WinRAR or Power Archiver, you can easily decompress the bz2 files with it. If you use Total Commander (formerly Windows Commander), a bz2 plugin for that program is available freely from the Total Commander site.

The bzip2 command line tool from Redhat:

Win2k Sp2 users grab the latest version 1.0.2, all other Windows user should grab version 1.00. After downloading rename the executable to bzip2.exe. For convenience put it into a directory in your path, e.g. C:\Windows where C represents your Windows installation drive.

Note: lang stands for your language and x for the desired format, e.g.: pdf. To uncompress the php_manual_lang.x.bz2 follow these simple instructions:

open a command prompt window
cd to the folder where you stored the downloaded php_manual_lang.x.bz2
invoke bzip2 -d php_manual_lang.x.bz2, extracting php_manual_lang.x in the same folder

In case you downloaded the php_manual_lang.tar.bz2 with many html-files in it, the procedure is the same. The only difference is that you got a file php_manual_lang.tar. The tar format is known to be treated with most common archivers on Windows like e.g. WinZip.

2. What does & beside argument mean in function declaration of e.g. asort()?

It means that the argument is passed by reference and the function will likely modify it corresponding to the documentation. You can pass only variables this way and you don't need to pass them with & in function call (it's even deprecated).

3. How do I deal with register_globals?

For information about the security implications of register_globals, read the security chapter on Using register_globals.

It's preferred to use superglobals, rather than relying upon register_globals being on.

If you are on a shared host with register_globals turned off and need to use some legacy applications, which require this option to be turned on, or you are on some hosting server, where this feature is turned on, but you would like to eliminate security risks, you might need to emulate the opposite setting with PHP. It is always a good idea to first ask if it would be possible to change the option somehow in PHP's configuration, but if it is not possible, then you can use these compatibility snippets.

Example 62-1. Emulating Register Globals

This will emulate register_globals On. If you altered your variables_order directive, consider changing the $superglobals accordingly.


<?php
// Emulate register_globals on
if (!ini_get('register_globals')) {
    $superglobals = array($_SERVER, $_ENV,
        $_FILES, $_COOKIE, $_POST, $_GET);
    if (isset($_SESSION)) {
        array_unshift($superglobals, $_SESSION);
    }
    foreach ($superglobals as $superglobal) {
        extract($superglobal, EXTR_SKIP);
    }
}
?>

This will emulate register_globals Off. Keep in mind, that this code should be called at the very beginning of your script, or after session_start() if you use it to start your session.


<?php
// Emulate register_globals off
function unregister_GLOBALS()
{
    if (!ini_get('register_globals')) {
        return;
    }

    // Might want to change this perhaps to a nicer error
    if (isset($_REQUEST['GLOBALS']) || isset($_FILES['GLOBALS'])) {
        die('GLOBALS overwrite attempt detected');
    }

    // Variables that shouldn't be unset
    $noUnset = array('GLOBALS',  '_GET',
                     '_POST',    '_COOKIE',
                     '_REQUEST', '_SERVER',
                     '_ENV',     '_FILES');

    $input = array_merge($_GET,    $_POST,
                         $_COOKIE, $_SERVER,
                         $_ENV,    $_FILES,
                         isset($_SESSION) && is_array($_SESSION) ? $_SESSION : array());
    
    foreach ($input as $k => $v) {
        if (!in_array($k, $noUnset) && isset($GLOBALS[$k])) {
            unset($GLOBALS[$k]);
        }
    }
}

unregister_GLOBALS();

?>

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Chapter 62. Miscellaneous Questions