/home/kueuepay/public_html/vendor/ezyang/htmlpurifier/library/HTMLPurifier/AttrDef/URI/IPv6.php
<?php

/**
 * Validates an IPv6 address.
 * @author Feyd @ forums.devnetwork.net (public domain)
 * @note This function requires brackets to have been removed from address
 *       in URI.
 */
class HTMLPurifier_AttrDef_URI_IPv6 extends HTMLPurifier_AttrDef_URI_IPv4
{

    /**
     * @param string $aIP
     * @param HTMLPurifier_Config $config
     * @param HTMLPurifier_Context $context
     * @return bool|string
     */
    public function validate($aIP, $config, $context)
    {
        if (!$this->ip4) {
            $this->_loadRegex();
        }

        $original = $aIP;

        $hex = '[0-9a-fA-F]';
        $blk = '(?:' . $hex . '{1,4})';
        $pre = '(?:/(?:12[0-8]|1[0-1][0-9]|[1-9][0-9]|[0-9]))'; // /0 - /128

        //      prefix check
        if (strpos($aIP, '/') !== false) {
            if (preg_match('#' . $pre . '$#s', $aIP, $find)) {
                $aIP = substr($aIP, 0, 0 - strlen($find[0]));
                unset($find);
            } else {
                return false;
            }
        }

        //      IPv4-compatiblity check
        if (preg_match('#(?<=:' . ')' . $this->ip4 . '$#s', $aIP, $find)) {
            $aIP = substr($aIP, 0, 0 - strlen($find[0]));
            $ip = explode('.', $find[0]);
            $ip = array_map('dechex', $ip);
            $aIP .= $ip[0] . $ip[1] . ':' . $ip[2] . $ip[3];
            unset($find, $ip);
        }

        //      compression check
        $aIP = explode('::', $aIP);
        $c = count($aIP);
        if ($c > 2) {
            return false;
        } elseif ($c == 2) {
            list($first, $second) = $aIP;
            $first = explode(':', $first);
            $second = explode(':', $second);

            if (count($first) + count($second) > 8) {
                return false;
            }

            while (count($first) < 8) {
                array_push($first, '0');
            }

            array_splice($first, 8 - count($second), 8, $second);
            $aIP = $first;
            unset($first, $second);
        } else {
            $aIP = explode(':', $aIP[0]);
        }
        $c = count($aIP);

        if ($c != 8) {
            return false;
        }

        //      All the pieces should be 16-bit hex strings. Are they?
        foreach ($aIP as $piece) {
            if (!preg_match('#^[0-9a-fA-F]{4}$#s', sprintf('%04s', $piece))) {
                return false;
            }
        }
        return $original;
    }
}

// vim: et sw=4 sts=4
Best Practice

Best Practices

To ensure a smooth integration process and optimal performance, follow these best practices:

  1. Use secure HTTPS connections for all API requests.
  2. Implement robust error handling to handle potential issues gracefully.
  3. Regularly update your integration to stay current with any API changes or enhancements.