Fixes a few bugs.

wpcom-sitemap.php

<?php
/**
 * Generate sitemap files in base XML as well as popular namespace extensions
 *
 * @author Automattic
 * @version 2.0
 * @link http://sitemaps.org/protocol.php Base sitemaps protocol
 * @link http://www.google.com/support/webmasters/bin/answer.py?answer=74288 Google news sitemaps
 */


/**
 * Convert a MySQL datetime string to an ISO 8601 string
 *
 * @link http://www.w3.org/TR/NOTE-datetime W3C date and time formats document
 * @param string $mysql_date UTC datetime in MySQL syntax of YYYY-MM-DD HH:MM:SS
 * @return string ISO 8601 UTC datetime string formatted as YYYY-MM-DDThh:mm:ssTZD where timezone offset is always +00:00
 */
function w3cdate_from_mysql($mysql_date) {
	return str_replace(' ', 'T', $mysql_date).'+00:00';
}

/**
 * Common definition of sitemap cache key for use in getters, setters and clears
 *
 * @returns string cache key
 */
function sitemap_cache_key() {
	return 'sitemap-blog-' . $GLOBALS['blog_id'];
}

/**
 * Get the maximum comment_date_gmt value for approved comments for the given post_id
 *
 * @param int $post_id post identifier
 * @return string datetime MySQL value or null if no comment found
 */
function get_approved_comments_max_datetime( $post_id ) {
	global $wpdb;
	return $wpdb->get_var( $wpdb->prepare( "SELECT MAX(comment_date_gmt) FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_approved = '1' AND comment_type=''", $post_id) );
}

/**
 * Return the content type used to serve a Sitemap XML file
 * Uses text/xml by default, possibly overridden by sitemap_content_type filter
 *
 * @return string Internet media type for the sitemap XML
 */
function sitemap_content_type() {
	return apply_filters( 'sitemap_content_type', 'text/xml' );
}

function wpcom_print_sitemap_item($data) {
	wpcom_print_xml_tag(array('url' => $data));
}

function wpcom_print_xml_tag( $array, $depth = 0 ) {
	$tabs = str_repeat("\t", $depth + 1);
	foreach($array as $key => $value) {
		if ( is_array( $value) ) {
			echo "$tabs\t<$key>\n";
			wpcom_print_xml_tag($value, $depth + 1);
			echo "$tabs\t</$key>\n";
		} else {
			echo "$tabs\t<$key>".wp_specialchars($value)."</$key>\n";
		}
	}
}

/**
 * Convert an array to a SimpleXML child of the passed tree.
 *
 * @param array $data array containing element value pairs, including other arrays, for XML contruction
 * @param SimpleXMLElement A SimpleXMLElement class object used to attach new children
 * @return SimpleXMLElement full tree with new children mapped from array
 */
function wpcom_sitemap_array_to_simplexml($data, &$tree, $namespace = false ) {
	foreach( $data as $key => $value ) {
		if ( is_array($value) )
			// For nodes that need child nodes to be namespaced, pass $key as $namespace
			if ( in_array( $key, array( 'image' ) ) )
				wpcom_sitemap_array_to_simplexml($value, $tree->addChild( $key, null, 'http://www.google.com/schemas/sitemap-image/1.1' ), $key );
			else
				wpcom_sitemap_array_to_simplexml($value, $tree->addChild( $key ) );
		else {
			// Special-case mobile node specified in http://support.google.com/webmasters/bin/answer.py?hl=en&answer=34648
			if ( 'mobile' == $key )
				$tree->addChild( $key, esc_html( $value ), 'http://www.google.com/schemas/sitemap-mobile/1.0' );
			// Special-case image node specified in http://support.google.com/webmasters/bin/answer.py?hl=en&answer=178636
			else if ( in_array( 'image', array( $key, $namespace ) ) )
				$tree->addChild( $key, esc_html( $value ), 'http://www.google.com/schemas/sitemap-image/1.1' );
			else
				$tree->addChild( $key, esc_html( $value ) );
		}
	}
	return $tree;
}

/**
 * Define an array of attribute value pairs for use inside the root element of an XML document.
 * Intended for mapping namespace and namespace URI values.
 * Passes array through sitemap_ns for other functions to add their own namespaces
 *
 * @return array array of attribute value pairs passed through the sitemap_ns filter
 */
function wpcom_sitemap_namespaces() {
	return apply_filters( 'sitemap_ns', array(
		'xmlns:xsi'=>'http://www.w3.org/2001/XMLSchema-instance',
		'xsi:schemaLocation'=>'http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd',
		'xmlns'=>'http://www.sitemaps.org/schemas/sitemap/0.9',
		// Mobile namespace from http://support.google.com/webmasters/bin/answer.py?hl=en&answer=34648
		'xmlns:mobile' => 'http://www.google.com/schemas/sitemap-mobile/1.0',
		'xmlns:image' => 'http://www.google.com/schemas/sitemap-image/1.1',
	 ) );
}

function wpcom_sitemap_initstr( $charset ) {
	$initstr = '<?xml version="1.0" encoding="' . $charset . '"?>'."\n" . '<!-- generator="wordpress.com" -->' . "\n";
	$initstr .= '<urlset';
	foreach ( wpcom_sitemap_namespaces() as $attribute=>$value ) {
		$initstr .= ' ' . esc_html($attribute) . '="' . esc_attr($value) . '"';
	}
	$initstr .= ' />';
	return $initstr;
}

/**
 * Print an XML sitemap conforming to the Sitemaps.org protocol
 * Outputs an XML list of up to the latest 1000 posts.
 *
 * @link http://sitemaps.org/protocol.php Sitemaps.org protocol
 * @todo set cache and expire on post publish, page publish or approved comment publish
 */
function wpcom_print_sitemap() {
	global $wpdb, $current_blog;
	$key = sitemap_cache_key();
	$xml = wp_cache_get( $key, 'sitemap' );

	$post_types = array( 'post', 'page' );

	if ( empty($xml) ) {

		$post_types_in = array();
		$post_types = apply_filters('wpcom_sitemap_post_types', $post_types);
		foreach( (array) $post_types as $post_type )
			$post_types_in[] = $wpdb->prepare( '%s', $post_type );
		$post_types_in = join( ",", $post_types_in );

		// use direct query instead because get_posts was acting too heavy for our needs
		//$posts = get_posts( array( 'numberposts'=>1000, 'post_type'=>$post_types, 'post_status'=>'published' ) );
		$posts = $wpdb->get_results(
			$wpdb->prepare(
				' SELECT ID, post_type, post_modified_gmt, comment_count' .
				" FROM $wpdb->posts" .
				" WHERE post_status='publish' AND post_type IN ({$post_types_in})" .
				' ORDER BY post_modified_gmt DESC LIMIT 1000',
				null // A warning is raised if a second arg is not passed
				)
			);
		if ( empty($posts) )
			header('HTTP/1.0 404 Not Found', True, 404);
		header('Content-Type: ' . sitemap_content_type());
		$initstr = wpcom_sitemap_initstr( get_bloginfo( 'charset' ) );
		$tree = simplexml_load_string($initstr);
		// If we did not get a valid string, force UTF-8 and try again.
		if( false === $tree ) {
			$initstr = wpcom_sitemap_initstr( 'UTF-8' );
			$tree = simplexml_load_string( $initstr );
		}

		// Acquire necessary attachment data for all of the posts in a performant manner
		$attachment_parents = wp_list_pluck( $posts, 'ID' );
		$post_attachments   = array();
		while ( $sub_posts = array_splice( $attachment_parents, 0, 100 ) ) {
			$post_parents = implode( ',', array_map( 'intval', $sub_posts ) );

			// Get the attachment IDs for all posts. We need to see how many
			// attachments each post parent has and limit it to 5.
			$query = $wpdb->prepare(
				' SELECT ID, post_parent' .
				" FROM {$wpdb->posts}" .
				" WHERE post_parent IN ({$post_parents}) AND post_type='attachment' AND post_mime_type='image/jpeg'" .
				' LIMIT 0,1000',
				null // A warning is raised if a second arg is not passed
				);
			$all_attachments      = $wpdb->get_results( $query );
			$selected_attachments = array();
			$attachment_count     = array();

			foreach ( $all_attachments as $attachment ) {

				// Prevent an out of bounds error
				if ( array_key_exists( $attachment->post_parent, $attachment_count ) ) {
					// Skip this particular attachment if we already have 5 for the post
					if ( $attachment_count[ $attachment->post_parent ] >= 5 ) {
						continue;
					}

					$attachment_count[$attachment->post_parent]++;
				}

				$selected_attachments[] = $attachment->ID;

			}

			// bail if there weren't any attachments to avoid an extra query
			if ( empty( $selected_attachments ) )
				continue;

			// Get more of the attachment object for the attachments we actually care about
			$attachment_ids   = implode( ',', array_map( 'intval', $selected_attachments ) );
			$query = $wpdb->prepare(
				' SELECT p.ID, p.post_parent, p.post_title, p.post_excerpt, p.guid' .
				" FROM {$wpdb->posts} as p" .
				" WHERE p.ID IN ({$attachment_ids}) AND p.post_type='attachment' AND p.post_mime_type='image/jpeg'" .
				' LIMIT 500',
				null // A warning is raised if a second arg is not passed
				);
			$attachments      = $wpdb->get_results( $query );
			$post_attachments = array_merge( $post_attachments, $attachments );
		}

		unset( $initstr );
		$latest_mod = '';
		foreach ( $posts as $post ) {

			// Add in filter to allow skipping specific posts
			if ( apply_filters( 'sitemap_skip_post', false, $post ) )
				continue;

			$post_latest_mod = null;
			$url             = array( 'loc'=> esc_url( get_permalink( $post->ID ) ) );

			// Mobile node specified in http://support.google.com/webmasters/bin/answer.py?hl=en&answer=34648
			$url['mobile']   = '';

			// Image node specified in http://support.google.com/webmasters/bin/answer.py?hl=en&answer=178636
			// These attachments were produced with batch SQL earlier in the script
			if ( $attachments = wp_filter_object_list( $post_attachments, array( 'post_parent' => $post->ID ) ) ) {

				$url['image'] = array();

				foreach ( $attachments as $attachment ) {
					$attachment_url = false;
					if ( $attachment->guid ) {

						// Copied from core's wp_get_attachment_url(). We already
						// have the guid value, so we don't want to get it again.
						// Note: we're using the WP.com version of the function.

						$attachment_url = apply_filters( 'get_the_guid', $attachment->guid );

						// If we don't have an attachment URL, don't include this image
						$attachment_url = apply_filters( 'wp_get_attachment_url', $attachment_url, $attachment->ID );

						if ( ! $attachment_url ) {
							unset( $url['image'] );
							continue;
						}

						$url['image']['loc'] = esc_url( $attachment_url );
					}

					// Only include title if not empty
					if ( $attachment_title = apply_filters( 'the_title_rss', $attachment->post_title ) ) {
						$url['image']['title'] = esc_html( $attachment_title );
					}

					// Only include caption if not empty
					if ( $attachment_caption = apply_filters( 'the_excerpt_rss', $attachment->post_excerpt ) ) {
						$url['image']['caption'] = esc_html( $attachment_caption );
					}
				}
			}

			if ( $post->post_modified_gmt && $post->post_modified_gmt != '0000-00-00 00:00:00' )
				$post_latest_mod = $post->post_modified_gmt;
			if ( $post->comment_count > 0 ) {
				// last modified based on last comment
				$latest_comment_datetime = get_approved_comments_max_datetime( $post->ID );
				if ( !empty( $latest_comment_datetime ) ) {
					if ( is_null($post_latest_mod) || $latest_comment_datetime > $post_latest_mod )
						$post_latest_mod = $latest_comment_datetime;
				}
				unset( $latest_comment_datetime );
			}
			if ( !empty( $post_latest_mod ) ) {
				$latest_mod = max($latest_mod, $post_latest_mod);
				$url['lastmod'] = w3cdate_from_mysql( $post_latest_mod );
			}
			unset( $post_latest_mod );
			if ( $post->post_type == 'page' ) {
				$url['changefreq'] = 'weekly';
				$url['priority'] = '0.6'; // set page priority above default priority of 0.5
			} else {
				$url['changefreq'] = 'monthly';
			}
			wpcom_sitemap_array_to_simplexml( array( 'url' => apply_filters( 'sitemap_url', $url, $post->ID ) ), $tree );
			unset( $url );
		}
		$blog_home = array(
			'loc'=>esc_url( get_bloginfo('siteurl').'/' ),
			'changefreq' => 'daily',
			'priority' => '1.0'
		);
		if ( !empty( $latest_mod ) ) {
			$blog_home['lastmod'] = w3cdate_from_mysql($latest_mod);
			header( 'Last-Modified:' . mysql2date('D, d M Y H:i:s', $latest_mod, 0).' GMT' );
		}
		wpcom_sitemap_array_to_simplexml( array( 'url'=> apply_filters( 'sitemap_url_home', $blog_home ) ), $tree );
		unset( $blog_home );

		$tree = apply_filters( 'wpcom_print_sitemap', $tree, $latest_mod );

		$xml = $tree->asXML();
		unset($tree);
		if ( !empty($xml) ) {
			wp_cache_set( $key, $xml, 'sitemap', 24*60*60 );  // cache for 24 hours
			echo $xml;
		}
	} else {
		header('Content-Type: ' . sitemap_content_type(), True);
		echo $xml;
	}
	die();
}

function wpcom_print_news_sitemap($format) {
	global $wpdb;
	$limit = apply_filters( 'wpcom_sitemap_news_sitemap_count', 1000 );
	$cur_datetime = current_time( 'mysql', true );
	$query = $wpdb->prepare( "
		SELECT p.ID, p.post_title, p.post_type, p.post_date, p.post_name, p.post_date_gmt, GROUP_CONCAT(t.name SEPARATOR ', ') AS keywords
		FROM
			$wpdb->posts AS p LEFT JOIN $wpdb->term_relationships AS r ON p.ID = r.object_id
			LEFT JOIN $wpdb->term_taxonomy AS tt ON r.term_taxonomy_id = tt.term_taxonomy_id AND tt.taxonomy = 'post_tag'
			LEFT JOIN $wpdb->terms AS t ON tt.term_id = t.term_id
		WHERE
			post_status='publish' AND post_type='post' AND post_date_gmt > (%s - INTERVAL 2 DAY)
		GROUP BY p.ID
		ORDER BY p.post_date_gmt DESC LIMIT %d", $cur_datetime, $limit );

	header('Content-Type: application/xml');
	echo '<?xml version="1.0" encoding="UTF-8"?>'."\n";
?>
<!-- generator="wordpress.com" -->
<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd"
	xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
	xmlns:n="http://www.google.com/schemas/sitemap-news/0.9"
	xmlns:image="http://www.google.com/schemas/sitemap-image/1.1"
	>
<?php
	$posts = $wpdb->get_results( $query );
	foreach ( $posts as $post ):
		$GLOBALS['post'] = $post;
		$url = array();
		$url['loc'] = get_permalink($post->ID);
		$news = array();
		$news['n:publication']['n:name'] = get_bloginfo( 'name' );
		if ( function_exists( 'get_blog_lang_code' ) )
			$news['n:publication']['n:language'] = get_blog_lang_code() ;
		$news['n:publication_date'] = w3cdate_from_mysql($post->post_date_gmt);
		$news['n:title'] = ent2ncr( $post->post_title );
		if ( $post->keywords ) $news['n:keywords'] = $post->keywords;
		$url['n:news'] = $news;

		// Add image to sitemap
		if ( current_theme_supports( 'post-thumbnails' ) && has_post_thumbnail( $post->ID ) ) {
			$post_thumbnail_id = get_post_thumbnail_id( $post_id );
			$post_thumbnail_src = wp_get_attachment_image_src( $post_thumbnail_id );
			if ( $post_thumbnail_src )
				$url['image:image'] = array( 'image:loc' => esc_url( $post_thumbnail_src[0] ) );
		}

		$url = apply_filters( 'wpcom_sitemap_news_sitemap_item', $url, $post );

		if ( empty( $url ) )
			continue;

		wpcom_print_sitemap_item($url);
	endforeach;
?>
</urlset>
<?php
	die();
}

/**
 * Absolute URL of the current blog's sitemap
 *
 * @return string sitemap URL
 */
function sitemap_uri() {
	global $current_blog;
	$domain = $current_blog->primary_redirect ? $current_blog->primary_redirect : $current_blog->domain;
	return 'http://' . $domain . '/sitemap.xml';
}

/**
 * A list or HTTP endpoints for a sitemap ping
 *
 * Note: disabled ping to http://submissions.ask.com/ping?sitemap=
 * See http://systemattic.wordpress.com/2010/02/11/sitemap-jobs-queue-showed-up-in-nagios/
 *
 * @return array List of endpoints waiting for a URI append
 */
function sitemap_endpoints() {
	return apply_filters( 'sitemap_ping_uris', array(
		'www.google.com/webmasters/tools/ping?sitemap=',
	  	'http://search.yahooapis.com/SiteExplorerService/V1/updateNotification?appid=' . urlencode(WPAS__YAHOO_UPDATES_APPLICATION_ID) . '&url=', // appid is WPCOM id
  		'http://www.bing.com/webmaster/ping.aspx?siteMap='
	));
}

/**
 * Ping all registered HTTP endpoints for sitemap URIs
 */
function do_sitemap_pings( $job ) {
	if ( empty($job->data->sitemap_uri) )
		return;

	$sitemap_uri = urlencode( $job->data->sitemap_uri );
	$headers = array( 'From'=>'pings@wordpress.com' );
	foreach ( $job->data->sitemap_endpoints as $endpoint ) {
		wp_remote_head( $endpoint . $sitemap_uri , array('httpversion'=>'1.1', 'headers'=>$headers, 'timeout'=>3, 'blocking'=>false, 'redirection'=>0) );
	}
}
add_action( 'pings_sitemap', 'do_sitemap_pings', 10, 1 );

/**
 * Output the master sitemap URLs for the current blog context
 */
function sitemap_discovery() {
	echo 'Sitemap: ' . sitemap_uri() . "\n\n";
}

/**
 * Clear the sitemap cache when a sitemap action has changed
 * Add a job to the pings queue to send out update notifications
 *
 * @param int $post_id unique post identifier. not used.
 */
function sitemap_handle_update( $post_id ) {
	global $current_blog;
	wp_cache_delete( sitemap_cache_key(), 'sitemap' );

	if ( function_exists( 'queue_pings_job' ) ) {
		$data = new stdClass();
		$data->sitemap_uri = sitemap_uri();
		$data->sitemap_endpoints = sitemap_endpoints();
		$data->origin_ip = $_SERVER['REMOTE_ADDR'];
		$data->blog_id = $current_blog->blog_id;
		$data->post_id = $post_id;
		queue_pings_job( $data, 'sitemap', (int)wpcom_is_vip(), 2 );
	}
}

if ( ! function_exists( 'is_publicly_available' ) || is_publicly_available() ) {
	add_action( 'do_robotstxt', 'sitemap_discovery', 5, 0 );

	add_action( 'publish_post', 'sitemap_handle_update', 12, 1 );
	add_action( 'publish_page', 'sitemap_handle_update', 12, 1 );
	add_action( 'trash_post', 'sitemap_handle_update', 12, 1 );
	add_action( 'deleted_post', 'sitemap_handle_update', 12, 1 );

	if ( false !== strpos( $_SERVER['REQUEST_URI'], '/sitemap.xml' ) )
		add_action( 'init', 'wpcom_print_sitemap', 99 ); // run later so things like custom post types have been registered
	elseif ( false !== strpos( $_SERVER['REQUEST_URI'], '/news-sitemap.xml' ) )
		add_action( 'init', 'wpcom_print_news_sitemap', 99 ); // run later so things like custom post types have been registered
}