source: trunk/wp-includes/links-update-xml.php @ 1355

<?php
// Links weblogs.com grabber
// Copyright (C) 2003 Mike Little -- [email protected]

// Get the path of our parent directory:
$parentpath = dirname(dirname(__FILE__));

require_once($parentpath.'/wp-config.php');

// globals to hold state
$updated_timestamp = 0;
$all_links = array();

/**
 ** preload_links()
 ** Pre-load the visible, non-blank, links into an associative array $all_links
 ** key is url, value is array of link_id and update_time
 ** Note: update time is initialised to 0. That way we only have to update (in
 ** the db) the ones which have been updated (on weblogs.com).
 **/
function preload_links() {
        global $all_links, $wpdb;
        $links = $wpdb->get_results("SELECT link_id, link_url FROM $wpdb->links WHERE link_visible = 'Y' AND link_url <> ''");
        foreach ($links as $link) {
                $link_url = transform_url($link->link_url);
                $all_links[$link_url] = array($link->link_id, 0);
        }
}

/**
 ** update_links()
 ** Update in the db the links which have been updated ($all_links[url][1] != 0)
 **/
function update_links() {
        global $all_links, $wpdb;
        reset($all_links);
        while (list($id, $val) = each($all_links)) {
                if ($val[1]) {
                        $wpdb->query("UPDATE $wpdb->links SET link_updated = '$val[1]' WHERE link_id = $val[0]");
                }
        } // end while
}

/**
 ** get_weblogs_updatedfile()
 ** Retrieves and caches a copy of the weblogs.com changed blogs xml file.
 ** If the file exists check it's age, get new copy if old.
 ** If a new or updated file has been written return true (needs processing)
 ** otherwise return false (nothing to do)
 **/
function get_weblogs_updatedfile() {
        global $ignore_weblogs_cache;
        $update = false;
        $file = ABSPATH . 'wp-content/links-update-cache.xml';
        if ($ignore_weblogs_cache) {
                $update = true;
        } else {
                if (file_exists($file)) {
                        // is it old?
                        $modtime = filemtime($file);
                        if ((time() - $modtime) > (get_settings('weblogs_cacheminutes') * 60)) {
                                $update = true;
                        }
                } else { // doesn't exist
                        $update = true;
                }
        }

        if ($update) {
                // get a new copy
                $a = @file(get_settings('weblogs_xml_url'));
                if ($a != false && count($a) && $a[0]) {
                        $contents = implode('', $a);

                        // Clean up the input, because weblogs.com doesn't output clean XML     
                        $contents = preg_replace("/'/",'&#39;',$contents);
                        $contents = preg_replace('|[^[:space:][:punct:][:alpha:][:digit:]]|','',$contents);

                        $cachefp = fopen(ABSPATH . 'wp-content/links-update-cache.xml', "w");
                        fwrite($cachefp, $contents);
                        fclose($cachefp);
                } else {
                        return false; //don't try to process
                }
        }
        return $update;
}

/**
 ** startElement()
 ** Callback function. Called at the start of a new xml tag.
 **/
function startElement($parser, $tagName, $attrs) {
        global $updated_timestamp, $all_links;
        if ($tagName == 'WEBLOGUPDATES') {
                //convert 'updated' into php date variable
                $updated_timestamp = strtotime($attrs['UPDATED']);
                //echo('got timestamp of ' . gmdate('F j, Y, H:i:s', $updated_timestamp) . "\n");
        } else if ($tagName == 'WEBLOG') {
                // is this url in our links?
                $link_url = transform_url($attrs['URL']);
                if (isset($all_links[$link_url])) {
                        $all_links[$link_url][1] = date('YmdHis', $updated_timestamp - $attrs['WHEN']);
                        //echo('set link id ' . $all_links[$link_url][0] . ' to date ' . $all_links[$link_url][1] . "\n");
                }
        }
}

/**
 ** endElement()
 ** Callback function. Called at the end of an xml tag.
 **/
function endElement($parser, $tagName) {
        // nothing to do.
}

/**
 ** transform_url()
 ** Transforms a url to a minimal identifier.
 **
 ** Remove www, remove index.* or default.*, remove
 ** trailing slash
 **/
function transform_url($url) {
        //echo("transform_url(): $url ");
        $url = str_replace('www.', '', $url);
        $url = str_replace('WWW.', '', $url);
        $url = preg_replace('/(?:index|default)\.[a-z]{2,}/i', '', $url);
        if (substr($url, -1, 1) == '/') {
                $url = substr($url, 0, -1);
        }
        //echo(" now equals $url\n");
        return $url;
} // end transform_url

// get/update the cache file.
// true return means new copy
if (get_weblogs_updatedfile()) {
        //echo('<pre>');
        // pre-load the links
        preload_links();

        // Create an XML parser
        $xml_parser = xml_parser_create();

        // Set the functions to handle opening and closing tags
        xml_set_element_handler($xml_parser, "startElement", "endElement");

        // Open the XML file for reading
        $fp = fopen(ABSPATH . 'wp-content/links-update-cache.xml', "r")
                  or die("Error reading XML data.");

        // Read the XML file 16KB at a time
        while ($data = fread($fp, 16384)) {
                // Parse each 4KB chunk with the XML parser created above
                xml_parse($xml_parser, $data, feof($fp))
                                or die(sprintf("XML error: %s at line %d",
                                        xml_error_string(xml_get_error_code($xml_parser)),
                                        xml_get_current_line_number($xml_parser)));
        }

        // Close the XML file
        fclose($fp);

        // Free up memory used by the XML parser
        xml_parser_free($xml_parser);

        // now update the db with latest times
        update_links();

        //echo('</pre>');
} // end if updated cache file

?>