/wp-includes/feed.php

<?php

/**

 * WordPress Feed API

 *

 * Many of the functions used in here belong in The Loop, or The Loop for the

 * Feeds.

 *

 * @package WordPress

 * @subpackage Feed

 */



/**

 * RSS container for the bloginfo function.

 *

 * You can retrieve anything that you can using the get_bloginfo() function.

 * Everything will be stripped of tags and characters converted, when the values

 * are retrieved for use in the feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 1.5.1

 * @uses apply_filters() Calls 'get_bloginfo_rss' hook with two parameters.

 * @see get_bloginfo() For the list of possible values to display.

 *

 * @param string $show See get_bloginfo() for possible values.

 * @return string

 */

function get_bloginfo_rss($show = '') {

	$info = strip_tags(get_bloginfo($show));

	return apply_filters('get_bloginfo_rss', convert_chars($info), $show);

}



/**

 * Display RSS container for the bloginfo function.

 *

 * You can retrieve anything that you can using the get_bloginfo() function.

 * Everything will be stripped of tags and characters converted, when the values

 * are retrieved for use in the feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 0.71

 * @uses apply_filters() Calls 'bloginfo_rss' hook with two parameters.

 * @see get_bloginfo() For the list of possible values to display.

 *

 * @param string $show See get_bloginfo() for possible values.

 */

function bloginfo_rss($show = '') {

	echo apply_filters('bloginfo_rss', get_bloginfo_rss($show), $show);

}



/**

 * Retrieve the default feed.

 *

 * The default feed is 'rss2', unless a plugin changes it through the

 * 'default_feed' filter.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.5

 * @uses apply_filters() Calls 'default_feed' hook on the default feed string.

 *

 * @return string Default feed, or for example 'rss2', 'atom', etc.

 */

function get_default_feed() {

	return apply_filters('default_feed', 'rss2');

}



/**

 * Retrieve the blog title for the feed title.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.2.0

 * @uses apply_filters() Calls 'get_wp_title_rss' hook on title.

 * @uses wp_title() See function for $sep parameter usage.

 *

 * @param string $sep Optional.How to separate the title. See wp_title() for more info.

 * @return string Error message on failure or blog title on success.

 */

function get_wp_title_rss($sep = '&#187;') {

	$title = wp_title($sep, false);

	if ( is_wp_error( $title ) )

		return $title->get_error_message();

	$title = apply_filters('get_wp_title_rss', $title);

	return $title;

}



/**

 * Display the blog title for display of the feed title.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.2.0

 * @uses apply_filters() Calls 'wp_title_rss' on the blog title.

 * @see wp_title() $sep parameter usage.

 *

 * @param string $sep Optional.

 */

function wp_title_rss($sep = '&#187;') {

	echo apply_filters('wp_title_rss', get_wp_title_rss($sep));

}



/**

 * Retrieve the current post title for the feed.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.0.0

 * @uses apply_filters() Calls 'the_title_rss' on the post title.

 *

 * @return string Current post title.

 */

function get_the_title_rss() {

	$title = get_the_title();

	$title = apply_filters('the_title_rss', $title);

	return $title;

}



/**

 * Display the post title in the feed.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 0.71

 * @uses get_the_title_rss() Used to retrieve current post title.

 */

function the_title_rss() {

	echo get_the_title_rss();

}



/**

 * Retrieve the post content for feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.9.0

 * @uses apply_filters() Calls 'the_content_feed' on the content before processing.

 * @see get_the_content()

 *

 * @param string $feed_type The type of feed. rss2 | atom | rss | rdf

 */

function get_the_content_feed($feed_type = null) {

	if ( !$feed_type )

		$feed_type = get_default_feed();



	$content = apply_filters('the_content', get_the_content());

	$content = str_replace(']]>', ']]&gt;', $content);

	return apply_filters('the_content_feed', $content, $feed_type);

}



/**

 * Display the post content for feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.9.0

 * @uses apply_filters() Calls 'the_content_feed' on the content before processing.

 * @see get_the_content()

 *

 * @param string $feed_type The type of feed. rss2 | atom | rss | rdf

 */

function the_content_feed($feed_type = null) {

	echo get_the_content_feed($feed_type);

}



/**

 * Display the post excerpt for the feed.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 0.71

 * @uses apply_filters() Calls 'the_excerpt_rss' hook on the excerpt.

 */

function the_excerpt_rss() {

	$output = get_the_excerpt();

	echo apply_filters('the_excerpt_rss', $output);

}



/**

 * Display the permalink to the post for use in feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.3.0

 * @uses apply_filters() Call 'the_permalink_rss' on the post permalink

 */

function the_permalink_rss() {

	echo esc_url( apply_filters('the_permalink_rss', get_permalink() ));

}



/**

 * Outputs the link to the comments for the current post in an xml safe way

 *

 * @since 3.0.0

 * @return none

 */

function comments_link_feed() {

	echo esc_url( get_comments_link() );

}



/**

 * Display the feed GUID for the current comment.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.5.0

 *

 * @param int|object $comment_id Optional comment object or id. Defaults to global comment object.

 */

function comment_guid($comment_id = null) {

	echo esc_url( get_comment_guid($comment_id) );

}



/**

 * Retrieve the feed GUID for the current comment.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.5.0

 *

 * @param int|object $comment_id Optional comment object or id. Defaults to global comment object.

 * @return bool|string false on failure or guid for comment on success.

 */

function get_comment_guid($comment_id = null) {

	$comment = get_comment($comment_id);



	if ( !is_object($comment) )

		return false;



	return get_the_guid($comment->comment_post_ID) . '#comment-' . $comment->comment_ID;

}



/**

 * Display the link to the comments.

 *

 * @since 1.5.0

 */

function comment_link() {

	echo esc_url( get_comment_link() );

}



/**

 * Retrieve the current comment author for use in the feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.0.0

 * @uses apply_filters() Calls 'comment_author_rss' hook on comment author.

 * @uses get_comment_author()

 *

 * @return string Comment Author

 */

function get_comment_author_rss() {

	return apply_filters('comment_author_rss', get_comment_author() );

}



/**

 * Display the current comment author in the feed.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 1.0.0

 */

function comment_author_rss() {

	echo get_comment_author_rss();

}



/**

 * Display the current comment content for use in the feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 1.0.0

 * @uses apply_filters() Calls 'comment_text_rss' filter on comment content.

 * @uses get_comment_text()

 */

function comment_text_rss() {

	$comment_text = get_comment_text();

	$comment_text = apply_filters('comment_text_rss', $comment_text);

	echo $comment_text;

}



/**

 * Retrieve all of the post categories, formatted for use in feeds.

 *

 * All of the categories for the current post in the feed loop, will be

 * retrieved and have feed markup added, so that they can easily be added to the

 * RSS2, Atom, or RSS1 and RSS0.91 RDF feeds.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.1.0

 * @uses apply_filters()

 *

 * @param string $type Optional, default is the type returned by get_default_feed().

 * @return string All of the post categories for displaying in the feed.

 */

function get_the_category_rss($type = null) {

	if ( empty($type) )

		$type = get_default_feed();

	$categories = get_the_category();

	$tags = get_the_tags();

	$the_list = '';

	$cat_names = array();



	$filter = 'rss';

	if ( 'atom' == $type )

		$filter = 'raw';



	if ( !empty($categories) ) foreach ( (array) $categories as $category ) {

		$cat_names[] = sanitize_term_field('name', $category->name, $category->term_id, 'category', $filter);

	}



	if ( !empty($tags) ) foreach ( (array) $tags as $tag ) {

		$cat_names[] = sanitize_term_field('name', $tag->name, $tag->term_id, 'post_tag', $filter);

	}



	$cat_names = array_unique($cat_names);



	foreach ( $cat_names as $cat_name ) {

		if ( 'rdf' == $type )

			$the_list .= "\t\t<dc:subject><![CDATA[$cat_name]]></dc:subject>\n";

		elseif ( 'atom' == $type )

			$the_list .= sprintf( '<category scheme="%1$s" term="%2$s" />', esc_attr( apply_filters( 'get_bloginfo_rss', get_bloginfo( 'url' ) ) ), esc_attr( $cat_name ) );

		else

			$the_list .= "\t\t<category><![CDATA[" . @html_entity_decode( $cat_name, ENT_COMPAT, get_option('blog_charset') ) . "]]></category>\n";

	}



	return apply_filters('the_category_rss', $the_list, $type);

}



/**

 * Display the post categories in the feed.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 0.71

 * @see get_the_category_rss() For better explanation.

 *

 * @param string $type Optional, default is the type returned by get_default_feed().

 */

function the_category_rss($type = null) {

	echo get_the_category_rss($type);

}



/**

 * Display the HTML type based on the blog setting.

 *

 * The two possible values are either 'xhtml' or 'html'.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.2.0

 */

function html_type_rss() {

	$type = get_bloginfo('html_type');

	if (strpos($type, 'xhtml') !== false)

		$type = 'xhtml';

	else

		$type = 'html';

	echo $type;

}



/**

 * Display the rss enclosure for the current post.

 *

 * Uses the global $post to check whether the post requires a password and if

 * the user has the password for the post. If not then it will return before

 * displaying.

 *

 * Also uses the function get_post_custom() to get the post's 'enclosure'

 * metadata field and parses the value to display the enclosure(s). The

 * enclosure(s) consist of enclosure HTML tag(s) with a URI and other

 * attributes.

 *

 * @package WordPress

 * @subpackage Template

 * @since 1.5.0

 * @uses apply_filters() Calls 'rss_enclosure' hook on rss enclosure.

 * @uses get_post_custom() To get the current post enclosure metadata.

 */

function rss_enclosure() {

	if ( post_password_required() )

		return;



	foreach ( (array) get_post_custom() as $key => $val) {

		if ($key == 'enclosure') {

			foreach ( (array) $val as $enc ) {

				$enclosure = explode("\n", $enc);



				//only get the the first element eg, audio/mpeg from 'audio/mpeg mpga mp2 mp3'

				$t = preg_split('/[ \t]/', trim($enclosure[2]) );

				$type = $t[0];



				echo apply_filters('rss_enclosure', '<enclosure url="' . trim(htmlspecialchars($enclosure[0])) . '" length="' . trim($enclosure[1]) . '" type="' . $type . '" />' . "\n");

			}

		}

	}

}



/**

 * Display the atom enclosure for the current post.

 *

 * Uses the global $post to check whether the post requires a password and if

 * the user has the password for the post. If not then it will return before

 * displaying.

 *

 * Also uses the function get_post_custom() to get the post's 'enclosure'

 * metadata field and parses the value to display the enclosure(s). The

 * enclosure(s) consist of link HTML tag(s) with a URI and other attributes.

 *

 * @package WordPress

 * @subpackage Template

 * @since 2.2.0

 * @uses apply_filters() Calls 'atom_enclosure' hook on atom enclosure.

 * @uses get_post_custom() To get the current post enclosure metadata.

 */

function atom_enclosure() {

	if ( post_password_required() )

		return;



	foreach ( (array) get_post_custom() as $key => $val ) {

		if ($key == 'enclosure') {

			foreach ( (array) $val as $enc ) {

				$enclosure = split("\n", $enc);

				echo apply_filters('atom_enclosure', '<link href="' . trim(htmlspecialchars($enclosure[0])) . '" rel="enclosure" length="' . trim($enclosure[1]) . '" type="' . trim($enclosure[2]) . '" />' . "\n");

			}

		}

	}

}



/**

 * Determine the type of a string of data with the data formatted.

 *

 * Tell whether the type is text, html, or xhtml, per RFC 4287 section 3.1.

 *

 * In the case of WordPress, text is defined as containing no markup,

 * xhtml is defined as "well formed", and html as tag soup (i.e., the rest).

 *

 * Container div tags are added to xhtml values, per section 3.1.1.3.

 *

 * @link http://www.atomenabled.org/developers/syndication/atom-format-spec.php#rfc.section.3.1

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.5

 *

 * @param string $data Input string

 * @return array array(type, value)

 */

function prep_atom_text_construct($data) {

	if (strpos($data, '<') === false && strpos($data, '&') === false) {

		return array('text', $data);

	}



	$parser = xml_parser_create();

	xml_parse($parser, '<div>' . $data . '</div>', true);

	$code = xml_get_error_code($parser);

	xml_parser_free($parser);



	if (!$code) {

		if (strpos($data, '<') === false) {

			return array('text', $data);

		} else {

			$data = "<div xmlns='http://www.w3.org/1999/xhtml'>$data</div>";

			return array('xhtml', $data);

		}

	}



	if (strpos($data, ']]>') == false) {

		return array('html', "<![CDATA[$data]]>");

	} else {

		return array('html', htmlspecialchars($data));

	}

}



/**

 * Display the link for the currently displayed feed in a XSS safe way.

 *

 * Generate a correct link for the atom:self element.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.5

 */

function self_link() {

	$host = @parse_url(home_url());

	$host = $host['host'];

	echo esc_url(

		'http'

		. ( (isset($_SERVER['https']) && $_SERVER['https'] == 'on') ? 's' : '' ) . '://'

		. $host

		. stripslashes($_SERVER['REQUEST_URI'])

		);

}



/**

 * Return the content type for specified feed type.

 *

 * @package WordPress

 * @subpackage Feed

 * @since 2.8.0

 */

function feed_content_type( $type = '' ) {

	if ( empty($type) )

		$type = get_default_feed();



	$types = array(

		'rss'  => 'application/rss+xml',

		'rss2' => 'application/rss+xml',

		'rss-http'  => 'text/xml',

		'atom' => 'application/atom+xml',

		'rdf'  => 'application/rdf+xml'

	);



	$content_type = ( !empty($types[$type]) ) ? $types[$type] : 'application/octet-stream';



	return apply_filters( 'feed_content_type', $content_type, $type );

}



/**

 * Build SimplePie object based on RSS or Atom feed from URL.

 *

 * @since 2.8

 *

 * @param string $url URL to retrieve feed

 * @return WP_Error|SimplePie WP_Error object on failure or SimplePie object on success

 */

function fetch_feed($url) {

	require_once (ABSPATH . WPINC . '/class-feed.php');



	$feed = new SimplePie();

	$feed->set_feed_url($url);

	$feed->set_cache_class('WP_Feed_Cache');

	$feed->set_file_class('WP_SimplePie_File');

	$feed->set_cache_duration(apply_filters('wp_feed_cache_transient_lifetime', 43200, $url));

	do_action_ref_array( 'wp_feed_options', array( &$feed, $url ) );

	$feed->init();

	$feed->handle_content_type();



	if ( $feed->error() )

		return new WP_Error('simplepie-error', $feed->error());



	return $feed;

}