gjerokrsteski/pimf-framework

<?php
/**
 * Util
 *
 * @copyright Copyright (c)  Gjero Krsteski (http://krsteski.de)
 * @license   http://opensource.org/licenses/MIT MIT License
 */
namespace Pimf\Util\Character;

/**
 * String
 *
 * @package Util_String
 * @author  Gjero Krsteski <gjero@krsteski.de>
 */
class Sanitize
{

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function removeNullCharacters($string)
    {
        return preg_replace(array('/\0+/', '/(\\\\0)+/'), '', $string);
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function validateStandardCharacterEntities($string)
    {
        return preg_replace('#(&\#*\w+)[\x00-\x20]+;#u', "\\1;", $string);
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function validateUTF16TwoByteEncoding($string)
    {
        return preg_replace('#(&\#x*)([0-9A-F]+);*#iu', "\\1\\2;", $string);
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function strangeThingsAreSubmitted($string)
    {
        return preg_replace(array("/%u0([a-z0-9]{3})/i", "/%([a-z0-9]{2})/i"), "&#x\\1;", $string);
    }

    /**
     * @param string $string  String to check
     * @param string $charset Character set (default ISO-8859-1)
     *
     * @return mixed
     */
    public static function convertCharacterEntitiesToASCII($string, $charset)
    {
        $matches = array();

        if (preg_match_all("/<(.+?)>/si", $string, $matches)) {

            $count = count($matches['0']);

            for ($i = 0; $i < $count; $i++) {
                $string = str_replace(
                    $matches['1'][$i],
                    html_entity_decode($matches['1'][$i], ENT_COMPAT, $charset),
                    $string
                );
            }
        }

        return $string;
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function convertAllTabsToSpaces($string)
    {
        return preg_replace("#\t+#", " ", $string);
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function makesPhpTagsSafe($string)
    {
        return str_replace(
            array('<?php', '<?PHP', '<?', '?>'),
            array('&lt;?php', '&lt;?PHP', '&lt;?', '?&gt;'),
            $string
        );
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function compactAnyExplodedWords($string)
    {
        $words = array('javascript', 'vbscript', 'script', 'applet', 'alert', 'document', 'write', 'cookie', 'window');
        foreach ($words as $word) {
            $temp = '';
            $len = strlen($word);
            for ($i = 0; $i < $len; $i++) {
                $temp .= substr($word, $i, 1) . "\s*";
            }
            $temp = substr($temp, 0, -3);
            $string = preg_replace('#' . $temp . '#s', $word, $string);
            $string = preg_replace('#' . ucfirst($temp) . '#s', ucfirst($word), $string);
        }

        return $string;
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function removeDisallowedJavaScriptInLinksOrImgTags($string)
    {
        $string = preg_replace(
            "#<a.+?href=.*?(alert\(|alert&\#40;|javascript\:|window\.|document\.|\.cookie|<script|<xss).*?\>.*?</a>#si",
            "",
            $string
        );
        $string = preg_replace(
            "#<img.+?src=.*?(alert\(|alert&\#40;|javascript\:|window\.|document\.|\.cookie|<script|<xss).*?\>#si",
            "",
            $string
        );

        return preg_replace("#<(script|xss).*?\>#si", "", $string);
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function removeJavaScriptEventHandlers($string)
    {
        return preg_replace(
            '#(<[^>]+.*?)(onblur|onchange|onclick|onfocus|onload|onmouseover|onmouseup|'
            . 'onmousedown|onselect|onsubmit|onunload|onkeypress|onkeydown|onkeyup|onresize)[^>]*>#iU',
            "\\1>",
            $string
        );
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function healNaughtyHTMLElements($string)
    {
        return preg_replace(
            '#<(/*\s*)(alert|applet|basefont|base|behavior|bgsound|'
            . 'blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input'
            . '|layer|link|meta|object|plaintext|style|script|textarea|title|xml|xss)([^>]*)>#is',
            "&lt;\\1\\2\\3&gt;",
            $string
        );
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function healNaughtyScriptingElements($string)
    {
        return preg_replace(
            '#(alert|cmd|passthru|eval|exec|system|fopen|fsockopen|'
            . 'file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si',
            "\\1\\2&#40;\\3&#41;",
            $string
        );
    }

    /**
     * @param string $string String to check
     *
     * @return mixed
     */
    public static function removeJavaScriptHardRedirects($string)
    {
        $bad = array(
            'document.cookie' => '',
            'document.write'  => '',
            'window.location' => '',
            "javascript\s*:"  => '',
            "Redirect\s+302"  => '',
            '<!--'            => '&lt;!--',
            '-->'             => '--&gt;'
        );
        foreach ($bad as $key => $val) {
            $string = preg_replace("#" . $key . "#i", $val, $string);
        }

        return $string;
    }
}