root/tags/1.3/wpmu-settings.php

<?php
if( $current_site && $current_blog )
    return;

// depreciated
$wpmuBaseTablePrefix = $table_prefix;

$domain = addslashes( $_SERVER['HTTP_HOST'] );
if( substr( $domain, 0, 4 ) == 'www.' )
    $domain = substr( $domain, 4 );
if( strpos( $domain, ':' ) ) {
    if( substr( $domain, -3 ) == ':80' ) {
        $domain = substr( $domain, 0, -3 );
        $_SERVER['HTTP_HOST'] = substr( $_SERVER['HTTP_HOST'], 0, -3 );
    } else {
        die( 'WPMU only works without the port number in the URL.' );
    }
}
$domain = preg_replace('/:.*$/', '', $domain); // Strip ports
if( substr( $domain, -1 ) == '.' )
    $domain = substr( $domain, 0, -1 );

$path = preg_replace( '|([a-z0-9-]+.php.*)|', '', $_SERVER['REQUEST_URI'] );
$path = str_replace ( '/wp-admin/', '/', $path );
$path = preg_replace( '|(/[a-z0-9-]+?/).*|', '$1', $path );

function wpmu_current_site() {
    global $wpdb, $current_site, $domain, $path, $sites;
    $path = substr( $_SERVER[ 'REQUEST_URI' ], 0, 1 + strpos( $_SERVER[ 'REQUEST_URI' ], '/', 1 ) );
    if( constant( 'VHOST' ) == 'yes' ) {
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='$path'" );
        if( $current_site != null )
            return $current_site;
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='/'" );
        if( $current_site != null ) {
            $path = '/';
            return $current_site;
        }
        $sitedomain = substr( $domain, 1 + strpos( $domain, '.' ) );
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$sitedomain' AND path='$path'" );
        if( $current_site != null )
            return $current_site;
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$sitedomain' AND path='/'" );
        if( $current_site == null && defined( "WP_INSTALLING" ) == false ) {
            if( count( $sites ) == 1 ) {
                $current_site = $sites[0];
                die( "That blog does not exist. Please try <a href='http://{$current_site->domain}{$current_site->path}'>http://{$current_site->domain}{$current_site->path}</a>" );
            } else {
                die( "No WPMU site defined on this host. If you are the owner of this site, please check <a href='http://trac.mu.wordpress.org/wiki/DebuggingWpmu'>Debugging WPMU</a> for further assistance." );
            }
        } else {
            $path = '/';
        }
    } else {
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='$path'" );
        if( $current_site != null )
            return $current_site;
        $current_site = $wpdb->get_row( "SELECT * FROM $wpdb->site WHERE domain = '$domain' AND path='/'" );
        if( $current_site == null && defined( "WP_INSTALLING" ) == false ) {
            if( count( $sites ) == 1 ) {
                $current_site = $sites[0];
                die( "That blog does not exist. Please try <a href='http://{$current_site->domain}{$current_site->path}'>http://{$current_site->domain}{$current_site->path}</a>" );
            } else {
                die( "No WPMU site defined on this host. If you are the owner of this site, please check <a href='http://trac.mu.wordpress.org/wiki/DebuggingWpmu'>Debugging WPMU</a> for further assistance." );
            }
        } else {
            $path = '/';
        }
    }
    return $current_site;
}

$wpdb->hide_errors();
$sites = $wpdb->get_results( "SELECT * FROM $wpdb->site" ); // usually only one site
if( count( $sites ) == 1 ) {
    $current_site = $sites[0];
    $path = $current_site->path;
} else {
    $current_site = wpmu_current_site();
}


if( constant( 'VHOST' ) == 'yes' ) {
    $current_blog = $wpdb->get_row("SELECT * FROM $wpdb->blogs WHERE domain = '$domain'");
    if( $current_blog != null ) {
        $current_site = $wpdb->get_row("SELECT * FROM $wpdb->site WHERE id='{$current_blog->site_id}'");
    } else {
        $blogname = substr( $domain, 0, strpos( $domain, '.' ) );
    }
} else {
    $blogname = htmlspecialchars( substr( $_SERVER[ 'REQUEST_URI' ], strlen( $path ) ) );
    if( strpos( $blogname, '/' ) )
        $blogname = substr( $blogname, 0, strpos( $blogname, '/' ) );
    if( strpos( " ".$blogname, '?' ) )
        $blogname = substr( $blogname, 0, strpos( $blogname, '?' ) );
    $blognames = array( 'page', 'comments', 'blog', 'wp-admin', 'wp-includes', 'wp-content', 'files', 'feed' );
    if( $blogname == '' || in_array( $blogname, $blognames ) || is_file( $blogname ) || is_blogname_page( $blogname ) ) {
        $current_blog = $wpdb->get_row("SELECT * FROM $wpdb->blogs WHERE domain = '$domain' AND path = '$path'");
    } else {
        $current_blog = $wpdb->get_row("SELECT * FROM $wpdb->blogs WHERE domain = '$domain' AND path = '{$path}{$blogname}/'");
    }
}

if( defined( "WP_INSTALLING" ) == false ) {
    if( $current_site && $current_blog == null ) {
        header( "Location: http://{$current_site->domain}{$current_site->path}wp-signup.php?new=" . urlencode( $blogname ) );
        die();
    }
    if( $current_blog == false || $current_site == false )
        is_installed();
}

function is_blogname_page( $blogname ) {
    global $wpdb, $table_prefix, $domain, $path;

    $blog_id = $wpdb->get_var("SELECT blog_id FROM $wpdb->blogs WHERE domain = '$domain' AND path = '$path'");

    // is the request for a page of the main blog? We need to cache this information somewhere to save a request
    $pages = $wpdb->get_col( "SELECT LOWER(post_name) FROM {$table_prefix}{$blog_id}_posts WHERE post_type='page'" ); 

    if( is_array( $pages ) == false ) 
        return false;

    if( in_array( strtolower( $blogname ), $pages ) ) {
        return true;
    } else {
        return false;
    }
}

$blog_id = $current_blog->blog_id;
$public  = $current_blog->public;
$site_id = $current_blog->site_id;

if( $site_id == 0 )
    $site_id = 1;

$current_site->site_name = $wpdb->get_var( "SELECT meta_value FROM $wpdb->sitemeta WHERE site_id = '$site_id' AND meta_key = 'site_name'" );
if( $current_site->site_name == null )
    $current_site->site_name = ucfirst( $current_site->domain );

if( $blog_id == false ) {
    // no blog found, are we installing? Check if the table exists.
    if ( defined('WP_INSTALLING') ) {
    $query = "SELECT blog_id FROM ".$wpdb->blogs." limit 0,1";
    $blog_id = $wpdb->get_var( $query );
    if( $blog_id == false ) {
        // table doesn't exist. This is the first blog
        $blog_id = 1;
    } else {
        // table exists
        // don't create record at this stage. we're obviously installing so it doesn't matter what the table vars below are like.
        // default to using the "main" blog.
        $blog_id = 1;
    }
    } else {
    $check = $wpdb->get_results( "SELECT * FROM $wpdb->site" );
    if( $check == false ) {
        $msg = ': DB Tables Missing';
    } else {
        $msg = '';
    }
    die( "No Blog by that name on this system." . $msg );
    }
}

$wpdb->show_errors();

if( '0' == $current_blog->public ) {
    // This just means the blog shouldn't show up in google, etc. Only to registered members
}

function is_installed() {
    global $wpdb, $domain, $path;
    $base = stripslashes( $base );
    if( defined( "WP_INSTALLING" ) == false ) {
        $check = $wpdb->get_results( "SELECT * FROM $wpdb->site" );
        $msg = "If your blog does not display, please contact the owner of this site.<br /><br />If you are the owner of this site please check that MySQL is running properly and all tables are error free.<br /><br />";
        if( $check == false ) {
            $msg .= "<strong>Database Tables Missing.</strong><br />Database tables are missing. This means that MySQL is either not running, WPMU was not installed properly, or someone deleted {$wpdb->site}. You really <em>should</em> look at your database now.<br />";
        } else {
            $msg .= '<strong>Could Not Find Blog!</strong><br />';
            $msg .= "Searched for <em>" . $domain . $path . "</em> in " . DB_NAME . "::" . $wpdb->blogs . " table. Is that right?<br />";
        }
        $msg .= "<br />\n<h1>What do I do now?</h1>";
        $msg .= "Read the <a target='_blank' href='http://trac.mu.wordpress.org/wiki/DebuggingWpmu'>bug report</a> page. Some of the guidelines there may help you figure out what went wrong.<br />";
        $msg .= "If you're still stuck with this message, then check that your database contains the following tables:<ul>
            <li> $wpdb->blogs </li>
            <li> $wpdb->users </li>
            <li> $wpdb->usermeta </li>
            <li> $wpdb->site </li>
            <li> $wpdb->sitemeta </li>
            <li> $wpdb->sitecategories </li>
            </ul>";
        $msg .= "If you suspect a problem please report it to the support forums but you must include the information asked for in the <a href='http://trac.mu.wordpress.org/wiki/DebuggingWpmu'>WPMU bug reporting guidelines</a>!<br /><br />";
        if( is_file( 'release-info.txt' ) ) {
            $msg .= 'Your bug report must include the following text: "';
            $info = file( 'release-info.txt' );
            $msg .= $info[ 4 ] . '"';
        }

        die( "<h1>Fatal Error</h1> " . $msg );
    }
}

$table_prefix = $table_prefix . $blog_id . '_';

?>