/inc/plugins/google_seo/404.php

<?php
/**
 * This file is part of Google SEO plugin for MyBB.
 * Copyright (C) 2008-2011 Andreas Klauer <Andreas.Klauer@metamorpher.de>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

// Disallow direct access to this file for security reasons
if(!defined("IN_MYBB"))
{
    die("Direct initialization of this file is not allowed.<br /><br />
         Please make sure IN_MYBB is defined.");
}

/**
 * Hooks are called too late, so this is done before hooks:
 *
 * Define NO_ONLINE if it looks like we're going to show an 404 error,
 * unless the user explicitely wants these errors to show in the WOL.
 */

global $mybb;

if(THIS_SCRIPT == "misc.php"
   && $mybb->input['google_seo_error'] == "404")
{
    if($mybb->settings['google_seo_404_wol_show'])
    {
        // Set the 404 error location
        $location = 'misc.php?google_seo_error=404';

        if($mybb->settings['google_seo_404_wol_show'] == 2)
        {
            // Include the URI for debugging purposes
            $location .= '&amp;uri='.urlencode($_SERVER['REQUEST_URI']);
        }

        $location = substr($location, 0, 150);

        global $google_seo_location;
        $google_seo_location = $location;
    }

    else
    {
        @define("NO_ONLINE", 1);
    }
}

/* --- Hooks: --- */

// Set HTTP 404 status code, add widget to error pages:
$plugins->add_hook("error", "google_seo_404");
$plugins->add_hook("no_permission", "google_seo_404_no_permission");

// Custom 404 error page:
$plugins->add_hook("misc_start", "google_seo_404_page");

// WOL extension for custom page:
$plugins->add_hook("build_friendly_wol_location_end", "google_seo_404_wol");

/* --- 404 helpers: --- */

/**
 * Sort function: longest strings first, patterns last
 */
function google_seo_404_status_cmp($a, $b)
{
    return strlen($b) - strlen($a);
}

/**
 * Parse the 404 status setting
 */
function google_seo_404_status($label)
{
    global $settings;

    $patterns = array('*' => '404 Not Found');

    if(is_string($settings['google_seo_404_status']))
    {
        $lines = explode("\n", $settings['google_seo_404_status']);

        foreach($lines as $line)
        {
            $fields = explode("=", $line);

            if(count($fields) == 2)
            {
                $status = trim($fields[0]);
                $values = explode(",", $fields[1]);

                if(strpos($status, (int)$status.' ') === 0)
                {
                    foreach($values as $value)
                    {
                        $value = trim($value);

                        if($value === $label)
                        {
                            return $status;
                        }

                        else if(strpos($value, '*') !== false)
                        {
                            $patterns[$value] = $status;
                        }
                    }
                }
            }
        }
    }

    // Sort patterns by length.
    uksort($patterns, 'google_seo_404_status_cmp');

    // Find the first matching pattern
    foreach($patterns as $pattern => $status)
    {
        $pattern = preg_quote($pattern, '#');
        $pattern = str_replace('\\*', '.*', $pattern);

        if(preg_match("#^{$pattern}\$#", $label))
        {
            return $status;
        }
    }
}

/* --- 404 error handling: --- */

/**
 * Set the 404 header, add Google 404 widget, if enabled.
 *
 * @param string Error message, which may be modified.
 */
function google_seo_404(&$error)
{
    global $mybb, $lang, $settings;
    global $google_seo_404_label;

    if($mybb->input['ajax'])
    {
        // don't mess with ajax
        return;
    }

    // Reverse language lookup hack. Might fail for dynamic {1} elements.
    // Thanks to Cayo / HTTP Status plugin for this idea.
    $keys = array_keys((array)$lang, $error);

    if(count($keys) > 0)
    {
        sort($keys); // try to be deterministic in case of dupes
        $label = $keys[0];

        // Most labels start with error_, shorten it.
        if(strpos($label, "error_") === 0)
        {
            $label = substr($label, 6);
        }
    }

    else if($google_seo_404_label)
    {
        $label = $google_seo_404_label;
    }

    else
    {
        $label = 'NULL';
    }

    if($label && $settings['google_seo_404_debug'])
    {
        $label = htmlspecialchars($label);
        $error .= "<p>(Error label: '<b>{$label}</b>')</p>";
    }

    $status = google_seo_404_status($label);

    if($status)
    {
        @header("HTTP/1.1 {$status}");

        if($status[0] == '4' && $settings['google_seo_404_widget'])
        {
            $error .= $lang->sprintf($lang->googleseo_404_widget,
                                     $settings['bburl']);
        }
    }
}

function google_seo_404_no_permission()
{
    global $google_seo_404_label;
    $google_seo_404_label = "no_permission";
}

/* ---  Custom 404 error page --- */

/**
 * Create a custom 404 error page for errors that occur outside of MyBB.
 *
 */
function google_seo_404_page()
{
    global $mybb, $lang;

    if($mybb->input['google_seo_error'] == 404)
    {
        error($lang->googleseo_404_notfound);
    }
}

/* --- WOL --- */

/**
 * Extend WOL for users on the 404 page.
 *
 */
function google_seo_404_wol(&$p)
{
    global $lang, $user, $settings;

    // Check if this user is on a 404 page.
    if(strpos($p['user_activity']['location'], "misc.php?google_seo_error=404") === 0)
    {
        $p['user_activity']['activity'] = 'google_seo_404';
        $location = $p['user_activity']['location'];
        $p['location_name'] = $lang->sprintf($lang->googleseo_404_wol,
                                             $location);
    }
}

/* --- End of file. --- */
?>