WordPress/wp-includes/rss.php

<?php
/**
 * MagpieRSS: a simple RSS integration tool
 *
 * A compiled file for RSS syndication
 *
 * @author Kellan Elliott-McCrea <kellan@protest.net>
 * @version 0.51
 * @license GPL
 *
 * @package External
 * @subpackage MagpieRSS
 */

/**
 * Deprecated. Use SimplePie (class-simplepie.php) instead.
 */
_deprecated_file( basename( __FILE__ ), '3.0', WPINC . '/class-simplepie.php' );

/*
 * Hook to use another RSS object instead of MagpieRSS
 */
do_action('load_feed_engine');

/** RSS feed constant. */
define('RSS', 'RSS');
define('ATOM', 'Atom');
define('MAGPIE_USER_AGENT', 'WordPress/' . $GLOBALS['wp_version']);

class MagpieRSS {
	var $parser;
	var $current_item	= array();	// item currently being parsed
	var $items			= array();	// collection of parsed items
	var $channel		= array();	// hash of channel fields
	var $textinput		= array();
	var $image			= array();
	var $feed_type;
	var $feed_version;

	// parser variables
	var $stack				= array(); // parser stack
	var $inchannel			= false;
	var $initem 			= false;
	var $incontent			= false; // if in Atom <content mode="xml"> field
	var $intextinput		= false;
	var $inimage 			= false;
	var $current_field		= '';
	var $current_namespace	= false;

	//var $ERROR = "";

	var $_CONTENT_CONSTRUCTS = array('content', 'summary', 'info', 'title', 'tagline', 'copyright');

	function MagpieRSS ($source) {

		# if PHP xml isn't compiled in, die
		#
		if ( !function_exists('xml_parser_create') )
			trigger_error( "Failed to load PHP's XML Extension. http://www.php.net/manual/en/ref.xml.php" );

		$parser = @xml_parser_create();

		if ( !is_resource($parser) )
			trigger_error( "Failed to create an instance of PHP's XML parser. http://www.php.net/manual/en/ref.xml.php");

		$this->parser = $parser;

		# pass in parser, and a reference to this object
		# set up handlers
		#
		xml_set_object( $this->parser, $this );
		xml_set_element_handler($this->parser,
				'feed_start_element', 'feed_end_element' );

		xml_set_character_data_handler( $this->parser, 'feed_cdata' );

		$status = xml_parse( $this->parser, $source );

		if (! $status ) {
			$errorcode = xml_get_error_code( $this->parser );
			if ( $errorcode != XML_ERROR_NONE ) {
				$xml_error = xml_error_string( $errorcode );
				$error_line = xml_get_current_line_number($this->parser);
				$error_col = xml_get_current_column_number($this->parser);
				$errormsg = "$xml_error at line $error_line, column $error_col";

				$this->error( $errormsg );
			}
		}

		xml_parser_free( $this->parser );

		$this->normalize();
	}

	function feed_start_element($p, $element, &$attrs) {
		$el = $element = strtolower($element);
		$attrs = array_change_key_case($attrs, CASE_LOWER);

		// check for a namespace, and split if found
		$ns	= false;
		if ( strpos( $element, ':' ) ) {
			list($ns, $el) = split( ':', $element, 2);
		}
		if ( $ns and $ns != 'rdf' ) {
			$this->current_namespace = $ns;
		}

		# if feed type isn't set, then this is first element of feed
		# identify feed from root element
		#
		if (!isset($this->feed_type) ) {
			if ( $el == 'rdf' ) {
				$this->feed_type = RSS;
				$this->feed_version = '1.0';
			}
			elseif ( $el == 'rss' ) {
				$this->feed_type = RSS;
				$this->feed_version = $attrs['version'];
			}
			elseif ( $el == 'feed' ) {
				$this->feed_type = ATOM;
				$this->feed_version = $attrs['version'];
				$this->inchannel = true;
			}
			return;
		}

		if ( $el == 'channel' )
		{
			$this->inchannel = true;
		}
		elseif ($el == 'item' or $el == 'entry' )
		{
			$this->initem = true;
			if ( isset($attrs['rdf:about']) ) {
				$this->current_item['about'] = $attrs['rdf:about'];
			}
		}

		// if we're in the default namespace of an RSS feed,
		//  record textinput or image fields
		elseif (
			$this->feed_type == RSS and
			$this->current_namespace == '' and
			$el == 'textinput' )
		{
			$this->intextinput = true;
		}

		elseif (
			$this->feed_type == RSS and
			$this->current_namespace == '' and
			$el == 'image' )
		{
			$this->inimage = true;
		}

		# handle atom content constructs
		elseif ( $this->feed_type == ATOM and in_array($el, $this->_CONTENT_CONSTRUCTS) )
		{
			// avoid clashing w/ RSS mod_content
			if ($el == 'content' ) {
				$el = 'atom_content';
			}

			$this->incontent = $el;

		}

		// if inside an Atom content construct (e.g. content or summary) field treat tags as text
		elseif ($this->feed_type == ATOM and $this->incontent )
		{
			// if tags are inlined, then flatten
			$attrs_str = join(' ',
					array_map(array('MagpieRSS', 'map_attrs'),
					array_keys($attrs),
					array_values($attrs) ) );

			$this->append_content( "<$element $attrs_str>"  );

			array_unshift( $this->stack, $el );
		}

		// Atom support many links per containging element.
		// Magpie treats link elements of type rel='alternate'
		// as being equivalent to RSS's simple link element.
		//
		elseif ($this->feed_type == ATOM and $el == 'link' )
		{
			if ( isset($attrs['rel']) and $attrs['rel'] == 'alternate' )
			{
				$link_el = 'link';
			}
			else {
				$link_el = 'link_' . $attrs['rel'];
			}

			$this->append($link_el, $attrs['href']);
		}
		// set stack[0] to current element
		else {
			array_unshift($this->stack, $el);
		}
	}

	function feed_cdata ($p, $text) {

		if ($this->feed_type == ATOM and $this->incontent)
		{
			$this->append_content( $text );
		}
		else {
			$current_el = join('_', array_reverse($this->stack));
			$this->append($current_el, $text);
		}
	}

	function feed_end_element ($p, $el) {
		$el = strtolower($el);

		if ( $el == 'item' or $el == 'entry' )
		{
			$this->items[] = $this->current_item;
			$this->current_item = array();
			$this->initem = false;
		}
		elseif ($this->feed_type == RSS and $this->current_namespace == '' and $el == 'textinput' )
		{
			$this->intextinput = false;
		}
		elseif ($this->feed_type == RSS and $this->current_namespace == '' and $el == 'image' )
		{
			$this->inimage = false;
		}
		elseif ($this->feed_type == ATOM and in_array($el, $this->_CONTENT_CONSTRUCTS) )
		{
			$this->incontent = false;
		}
		elseif ($el == 'channel' or $el == 'feed' )
		{
			$this->inchannel = false;
		}
		elseif ($this->feed_type == ATOM and $this->incontent  ) {
			// balance tags properly
			// note:  i don't think this is actually neccessary
			if ( $this->stack[0] == $el )
			{
				$this->append_content("</$el>");
			}
			else {
				$this->append_content("<$el />");
			}

			array_shift( $this->stack );
		}
		else {
			array_shift( $this->stack );
		}

		$this->current_namespace = false;
	}

	function concat (&$str1, $str2="") {
		if (!isset($str1) ) {
			$str1="";
		}
		$str1 .= $str2;
	}

	function append_content($text) {
		if ( $this->initem ) {
			$this->concat( $this->current_item[ $this->incontent ], $text );
		}
		elseif ( $this->inchannel ) {
			$this->concat( $this->channel[ $this->incontent ], $text );
		}
	}

	// smart append - field and namespace aware
	function append($el, $text) {
		if (!$el) {
			return;
		}
		if ( $this->current_namespace )
		{
			if ( $this->initem ) {
				$this->concat(
					$this->current_item[ $this->current_namespace ][ $el ], $text);
			}
			elseif ($this->inchannel) {
				$this->concat(
					$this->channel[ $this->current_namespace][ $el ], $text );
			}
			elseif ($this->intextinput) {
				$this->concat(
					$this->textinput[ $this->current_namespace][ $el ], $text );
			}
			elseif ($this->inimage) {
				$this->concat(
					$this->image[ $this->current_namespace ][ $el ], $text );
			}
		}
		else {
			if ( $this->initem ) {
				$this->concat(
					$this->current_item[ $el ], $text);
			}
			elseif ($this->intextinput) {
				$this->concat(
					$this->textinput[ $el ], $text );
			}
			elseif ($this->inimage) {
				$this->concat(
					$this->image[ $el ], $text );
			}
			elseif ($this->inchannel) {
				$this->concat(
					$this->channel[ $el ], $text );
			}

		}
	}

	function normalize () {
		// if atom populate rss fields
		if ( $this->is_atom() ) {
			$this->channel['descripton'] = $this->channel['tagline'];
			for ( $i = 0; $i < count($this->items); $i++) {
				$item = $this->items[$i];
				if ( isset($item['summary']) )
					$item['description'] = $item['summary'];
				if ( isset($item['atom_content']))
					$item['content']['encoded'] = $item['atom_content'];

				$this->items[$i] = $item;
			}
		}
		elseif ( $this->is_rss() ) {
			$this->channel['tagline'] = $this->channel['description'];
			for ( $i = 0; $i < count($this->items); $i++) {
				$item = $this->items[$i];
				if ( isset($item['description']))
					$item['summary'] = $item['description'];
				if ( isset($item['content']['encoded'] ) )
					$item['atom_content'] = $item['content']['encoded'];

				$this->items[$i] = $item;
			}
		}
	}

	function is_rss () {
		if ( $this->feed_type == RSS ) {
			return $this->feed_version;
		}
		else {
			return false;
		}
	}

	function is_atom() {
		if ( $this->feed_type == ATOM ) {
			return $this->feed_version;
		}
		else {
			return false;
		}
	}

	function map_attrs($k, $v) {
		return "$k=\"$v\"";
	}

	function error( $errormsg, $lvl = E_USER_WARNING ) {
		// append PHP's error message if track_errors enabled
		if ( isset($php_errormsg) ) {
			$errormsg .= " ($php_errormsg)";
		}
		if ( MAGPIE_DEBUG ) {
			trigger_error( $errormsg, $lvl);
		} else {
			error_log( $errormsg, 0);
		}
	}

}

if ( !function_exists('fetch_rss') ) :
/**
 * Build Magpie object based on RSS from URL.
 *
 * @since 1.5.0
 * @package External
 * @subpackage MagpieRSS
 *
 * @param string $url URL to retrieve feed
 * @return bool|MagpieRSS false on failure or MagpieRSS object on success.
 */
function fetch_rss ($url) {
	// initialize constants
	init();

	if ( !isset($url) ) {
		// error("fetch_rss called without a url");
		return false;
	}

	// if cache is disabled
	if ( !MAGPIE_CACHE_ON ) {
		// fetch file, and parse it
		$resp = _fetch_remote_file( $url );
		if ( is_success( $resp->status ) ) {
			return _response_to_rss( $resp );
		}
		else {
			// error("Failed to fetch $url and cache is off");
			return false;
		}
	}
	// else cache is ON
	else {
		// Flow
		// 1. check cache
		// 2. if there is a hit, make sure it's fresh
		// 3. if cached obj fails freshness check, fetch remote
		// 4. if remote fails, return stale object, or error

		$cache = new RSSCache( MAGPIE_CACHE_DIR, MAGPIE_CACHE_AGE );

		if (MAGPIE_DEBUG and $cache->ERROR) {
			debug($cache->ERROR, E_USER_WARNING);
		}

		$cache_status 	 = 0;		// response of check_cache
		$request_headers = array(); // HTTP headers to send with fetch
		$rss 			 = 0;		// parsed RSS object
		$errormsg		 = 0;		// errors, if any

		if (!$cache->ERROR) {
			// return cache HIT, MISS, or STALE
			$cache_status = $cache->check_cache( $url );
		}

		// if object cached, and cache is fresh, return cached obj
		if ( $cache_status == 'HIT' ) {
			$rss = $cache->get( $url );
			if ( isset($rss) and $rss ) {
				$rss->from_cache = 1;
				if ( MAGPIE_DEBUG > 1) {
				debug("MagpieRSS: Cache HIT", E_USER_NOTICE);
			}
				return $rss;
			}
		}

		// else attempt a conditional get

		// set up headers
		if ( $cache_status == 'STALE' ) {
			$rss = $cache->get( $url );
			if ( isset($rss->etag) and $rss->last_modified ) {
				$request_headers['If-None-Match'] = $rss->etag;
				$request_headers['If-Last-Modified'] = $rss->last_modified;
			}
		}

		$resp = _fetch_remote_file( $url, $request_headers );

		if (isset($resp) and $resp) {
			if ($resp->status == '304' ) {
				// we have the most current copy
				if ( MAGPIE_DEBUG > 1) {
					debug("Got 304 for $url");
				}
				// reset cache on 304 (at minutillo insistent prodding)
				$cache->set($url, $rss);
				return $rss;
			}
			elseif ( is_success( $resp->status ) ) {
				$rss = _response_to_rss( $resp );
				if ( $rss ) {
					if (MAGPIE_DEBUG > 1) {
						debug("Fetch successful");
					}
					// add object to cache
					$cache->set( $url, $rss );
					return $rss;
				}
			}
			else {
				$errormsg = "Failed to fetch $url. ";
				if ( $resp->error ) {
					# compensate for Snoopy's annoying habbit to tacking
					# on '\n'
					$http_error = substr($resp->error, 0, -2);
					$errormsg .= "(HTTP Error: $http_error)";
				}
				else {
					$errormsg .=  "(HTTP Response: " . $resp->response_code .')';
				}
			}
		}
		else {
			$errormsg = "Unable to retrieve RSS file for unknown reasons.";
		}

		// else fetch failed

		// attempt to return cached object
		if ($rss) {
			if ( MAGPIE_DEBUG ) {
				debug("Returning STALE object for $url");
			}
			return $rss;
		}

		// else we totally failed
		// error( $errormsg );

		return false;

	} // end if ( !MAGPIE_CACHE_ON ) {
} // end fetch_rss()
endif;

/**
 * Retrieve URL headers and content using WP HTTP Request API.
 *
 * @since 1.5.0
 * @package External
 * @subpackage MagpieRSS
 *
 * @param string $url URL to retrieve
 * @param array $headers Optional. Headers to send to the URL.
 * @return Snoopy style response
 */
function _fetch_remote_file($url, $headers = "" ) {
	$resp = wp_remote_request($url, array('headers' => $headers, 'timeout' => MAGPIE_FETCH_TIME_OUT, 'reject_unsafe_urls' => true ));
	if ( is_wp_error($resp) ) {
		$error = array_shift($resp->errors);

		$resp = new stdClass;
		$resp->status = 500;
		$resp->response_code = 500;
		$resp->error = $error[0] . "\n"; //\n = Snoopy compatibility
		return $resp;
	}

	// Snoopy returns headers unprocessed.
	// Also note, WP_HTTP lowercases all keys, Snoopy did not.
	$return_headers = array();
	foreach ( wp_remote_retrieve_headers( $resp ) as $key => $value ) {
		if ( !is_array($value) ) {
			$return_headers[] = "$key: $value";
		} else {
			foreach ( $value as $v )
				$return_headers[] = "$key: $v";
		}
	}

	$response = new stdClass;
	$response->status = wp_remote_retrieve_response_code( $resp );
	$response->response_code = wp_remote_retrieve_response_code( $resp );
	$response->headers = $return_headers;
	$response->results = wp_remote_retrieve_body( $resp );

	return $response;
}

/**
 * Retrieve
 *
 * @since 1.5.0
 * @package External
 * @subpackage MagpieRSS
 *
 * @param unknown_type $resp
 * @return unknown
 */
function _response_to_rss ($resp) {
	$rss = new MagpieRSS( $resp->results );

	// if RSS parsed successfully
	if ( $rss && (!isset($rss->ERROR) || !$rss->ERROR) ) {

		// find Etag, and Last-Modified
		foreach( (array) $resp->headers as $h) {
			// 2003-03-02 - Nicola Asuni (www.tecnick.com) - fixed bug "Undefined offset: 1"
			if (strpos($h, ": ")) {
				list($field, $val) = explode(": ", $h, 2);
			}
			else {
				$field = $h;
				$val = "";
			}

			if ( $field == 'etag' ) {
				$rss->etag = $val;
			}

			if ( $field == 'last-modified' ) {
				$rss->last_modified = $val;
			}
		}

		return $rss;
	} // else construct error message
	else {
		$errormsg = "Failed to parse RSS file.";

		if ($rss) {
			$errormsg .= " (" . $rss->ERROR . ")";
		}
		// error($errormsg);

		return false;
	} // end if ($rss and !$rss->error)
}

/**
 * Set up constants with default values, unless user overrides.
 *
 * @since 1.5.0
 * @package External
 * @subpackage MagpieRSS
 */
function init () {
	if ( defined('MAGPIE_INITALIZED') ) {
		return;
	}
	else {
		define('MAGPIE_INITALIZED', 1);
	}

	if ( !defined('MAGPIE_CACHE_ON') ) {
		define('MAGPIE_CACHE_ON', 1);
	}

	if ( !defined('MAGPIE_CACHE_DIR') ) {
		define('MAGPIE_CACHE_DIR', './cache');
	}

	if ( !defined('MAGPIE_CACHE_AGE') ) {
		define('MAGPIE_CACHE_AGE', 60*60); // one hour
	}

	if ( !defined('MAGPIE_CACHE_FRESH_ONLY') ) {
		define('MAGPIE_CACHE_FRESH_ONLY', 0);
	}

		if ( !defined('MAGPIE_DEBUG') ) {
		define('MAGPIE_DEBUG', 0);
	}

	if ( !defined('MAGPIE_USER_AGENT') ) {
		$ua = 'WordPress/' . $GLOBALS['wp_version'];

		if ( MAGPIE_CACHE_ON ) {
			$ua = $ua . ')';
		}
		else {
			$ua = $ua . '; No cache)';
		}

		define('MAGPIE_USER_AGENT', $ua);
	}

	if ( !defined('MAGPIE_FETCH_TIME_OUT') ) {
		define('MAGPIE_FETCH_TIME_OUT', 2);	// 2 second timeout
	}

	// use gzip encoding to fetch rss files if supported?
	if ( !defined('MAGPIE_USE_GZIP') ) {
		define('MAGPIE_USE_GZIP', true);
	}
}

function is_info ($sc) {
	return $sc >= 100 && $sc < 200;
}

function is_success ($sc) {
	return $sc >= 200 && $sc < 300;
}

function is_redirect ($sc) {
	return $sc >= 300 && $sc < 400;
}

function is_error ($sc) {
	return $sc >= 400 && $sc < 600;
}

function is_client_error ($sc) {
	return $sc >= 400 && $sc < 500;
}

function is_server_error ($sc) {
	return $sc >= 500 && $sc < 600;
}

class RSSCache {
	var $BASE_CACHE;	// where the cache files are stored
	var $MAX_AGE	= 43200;  		// when are files stale, default twelve hours
	var $ERROR 		= '';			// accumulate error messages

	function RSSCache ($base='', $age='') {
		$this->BASE_CACHE = WP_CONTENT_DIR . '/cache';
		if ( $base ) {
			$this->BASE_CACHE = $base;
		}
		if ( $age ) {
			$this->MAX_AGE = $age;
		}

	}

/*=======================================================================*\
	Function:	set
	Purpose:	add an item to the cache, keyed on url
	Input:		url from wich the rss file was fetched
	Output:		true on sucess
\*=======================================================================*/
	function set ($url, $rss) {
		$cache_option = 'rss_' . $this->file_name( $url );

		set_transient($cache_option, $rss, $this->MAX_AGE);

		return $cache_option;
	}

/*=======================================================================*\
	Function:	get
	Purpose:	fetch an item from the cache
	Input:		url from wich the rss file was fetched
	Output:		cached object on HIT, false on MISS
\*=======================================================================*/
	function get ($url) {
		$this->ERROR = "";
		$cache_option = 'rss_' . $this->file_name( $url );

		if ( ! $rss = get_transient( $cache_option ) ) {
			$this->debug(
				"Cache doesn't contain: $url (cache option: $cache_option)"
			);
			return 0;
		}

		return $rss;
	}

/*=======================================================================*\
	Function:	check_cache
	Purpose:	check a url for membership in the cache
				and whether the object is older then MAX_AGE (ie. STALE)
	Input:		url from wich the rss file was fetched
	Output:		cached object on HIT, false on MISS
\*=======================================================================*/
	function check_cache ( $url ) {
		$this->ERROR = "";
		$cache_option = 'rss_' . $this->file_name( $url );

		if ( get_transient($cache_option) ) {
			// object exists and is current
				return 'HIT';
		} else {
			// object does not exist
			return 'MISS';
		}
	}

/*=======================================================================*\
	Function:	serialize
\*=======================================================================*/
	function serialize ( $rss ) {
		return serialize( $rss );
	}

/*=======================================================================*\
	Function:	unserialize
\*=======================================================================*/
	function unserialize ( $data ) {
		return unserialize( $data );
	}

/*=======================================================================*\
	Function:	file_name
	Purpose:	map url to location in cache
	Input:		url from wich the rss file was fetched
	Output:		a file name
\*=======================================================================*/
	function file_name ($url) {
		return md5( $url );
	}

/*=======================================================================*\
	Function:	error
	Purpose:	register error
\*=======================================================================*/
	function error ($errormsg, $lvl=E_USER_WARNING) {
		// append PHP's error message if track_errors enabled
		if ( isset($php_errormsg) ) {
			$errormsg .= " ($php_errormsg)";
		}
		$this->ERROR = $errormsg;
		if ( MAGPIE_DEBUG ) {
			trigger_error( $errormsg, $lvl);
		}
		else {
			error_log( $errormsg, 0);
		}
	}
			function debug ($debugmsg, $lvl=E_USER_NOTICE) {
		if ( MAGPIE_DEBUG ) {
			$this->error("MagpieRSS [debug] $debugmsg", $lvl);
		}
	}
}

if ( !function_exists('parse_w3cdtf') ) :
function parse_w3cdtf ( $date_str ) {

	# regex to match wc3dtf
	$pat = "/(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})(:(\d{2}))?(?:([-+])(\d{2}):?(\d{2})|(Z))?/";

	if ( preg_match( $pat, $date_str, $match ) ) {
		list( $year, $month, $day, $hours, $minutes, $seconds) =
			array( $match[1], $match[2], $match[3], $match[4], $match[5], $match[7]);

		# calc epoch for current date assuming GMT
		$epoch = gmmktime( $hours, $minutes, $seconds, $month, $day, $year);

		$offset = 0;
		if ( $match[11] == 'Z' ) {
			# zulu time, aka GMT
		}
		else {
			list( $tz_mod, $tz_hour, $tz_min ) =
				array( $match[8], $match[9], $match[10]);

			# zero out the variables
			if ( ! $tz_hour ) { $tz_hour = 0; }
			if ( ! $tz_min ) { $tz_min = 0; }

			$offset_secs = (($tz_hour*60)+$tz_min)*60;

			# is timezone ahead of GMT?  then subtract offset
			#
			if ( $tz_mod == '+' ) {
				$offset_secs = $offset_secs * -1;
			}

			$offset = $offset_secs;
		}
		$epoch = $epoch + $offset;
		return $epoch;
	}
	else {
		return -1;
	}
}
endif;

if ( !function_exists('wp_rss') ) :
/**
 * Display all RSS items in a HTML ordered list.
 *
 * @since 1.5.0
 * @package External
 * @subpackage MagpieRSS
 *
 * @param string $url URL of feed to display. Will not auto sense feed URL.
 * @param int $num_items Optional. Number of items to display, default is all.
 */
function wp_rss( $url, $num_items = -1 ) {
	if ( $rss = fetch_rss( $url ) ) {
		echo '<ul>';

		if ( $num_items !== -1 ) {
			$rss->items = array_slice( $rss->items, 0, $num_items );
		}

		foreach ( (array) $rss->items as $item ) {
			printf(
				'<li><a href="%1$s" title="%2$s">%3$s</a></li>',
				esc_url( $item['link'] ),
				esc_attr( strip_tags( $item['description'] ) ),
				esc_html( $item['title'] )
			);
		}

		echo '</ul>';
	} else {
		_e( 'An error has occurred, which probably means the feed is down. Try again later.' );
	}
}
endif;

if ( !function_exists('get_rss') ) :
/**
 * Display RSS items in HTML list items.
 *
 * You have to specify which HTML list you want, either ordered or unordered
 * before using the function. You also have to specify how many items you wish
 * to display. You can't display all of them like you can with wp_rss()
 * function.
 *
 * @since 1.5.0
 * @package External
 * @subpackage MagpieRSS
 *
 * @param string $url URL of feed to display. Will not auto sense feed URL.
 * @param int $num_items Optional. Number of items to display, default is all.
 * @return bool False on failure.
 */
function get_rss ($url, $num_items = 5) { // Like get posts, but for RSS
	$rss = fetch_rss($url);
	if ( $rss ) {
		$rss->items = array_slice($rss->items, 0, $num_items);
		foreach ( (array) $rss->items as $item ) {
			echo "<li>\n";
			echo "<a href='$item[link]' title='$item[description]'>";
			echo esc_html($item['title']);
			echo "</a><br />\n";
			echo "</li>\n";
		}
	} else {
		return false;
	}
}
endif;