root/trunk/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();
}

/**
 * Display the post content for the feed.
 *
 * For encoding the html or the $encode_html parameter, there are three possible
 * values. '0' will make urls footnotes and use make_url_footnote(). '1' will
 * encode special characters and automatically display all of the content. The
 * value of '2' will strip all HTML tags from the content.
 *
 * Also note that you cannot set the amount of words and not set the html
 * encoding. If that is the case, then the html encoding will default to 2,
 * which will strip all HTML tags.
 *
 * To restrict the amount of words of the content, you can use the cut
 * parameter. If the content is less than the amount, then there won't be any
 * dots added to the end. If there is content left over, then dots will be added
 * and the rest of the content will be removed.
 *
 * @package WordPress
 * @subpackage Feed
 * @since 0.71
 * @uses apply_filters() Calls 'the_content_rss' on the content before processing.
 * @see get_the_content() For the $more_link_text, $stripteaser, and $more_file
 *        parameters.
 *
 * @param string $more_link_text Optional. Text to display when more content is available but not displayed.
 * @param int|bool $stripteaser Optional. Default is 0.
 * @param string $more_file Optional.
 * @param int $cut Optional. Amount of words to keep for the content.
 * @param int $encode_html Optional. How to encode the content.
 */
function the_content_rss($more_link_text='(more...)', $stripteaser=0, $more_file='', $cut = 0, $encode_html = 0) {
    $content = get_the_content($more_link_text, $stripteaser, $more_file);
    $content = apply_filters('the_content_rss', $content);
    if ( $cut && !$encode_html )
        $encode_html = 2;
    if ( 1== $encode_html ) {
        $content = wp_specialchars($content);
        $cut = 0;
    } elseif ( 0 == $encode_html ) {
        $content = make_url_footnote($content);
    } elseif ( 2 == $encode_html ) {
        $content = strip_tags($content);
    }
    if ( $cut ) {
        $blah = explode(' ', $content);
        if ( count($blah) > $cut ) {
            $k = $cut;
            $use_dotdotdot = 1;
        } else {
            $k = count($blah);
            $use_dotdotdot = 0;
        }

        /** @todo Check performance, might be faster to use array slice instead. */
        for ( $i=0; $i<$k; $i++ )
            $excerpt .= $blah[$i].' ';
        $excerpt .= ($use_dotdotdot) ? '...' : '';
        $content = $excerpt;
    }
    $content = str_replace(']]>', ']]&gt;', $content);
    echo $content;
}

/**
 * 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 apply_filters('the_permalink_rss', get_permalink());
}

/**
 * Display the feed GUID for the current comment.
 *
 * @package WordPress
 * @subpackage Feed
 * @since unknown
 */
function comment_guid() {
    echo get_comment_guid();
}

/**
 * Retrieve the feed GUID for the current comment.
 *
 * @package WordPress
 * @subpackage Feed
 * @since unknown
 *
 * @return bool|string false on failure or guid for comment on success.
 */
function get_comment_guid() {
    global $comment;

    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 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 $type Optional, default is 'rss'. Either 'rss', 'atom', or 'rdf'.
 * @return string All of the post categories for displaying in the feed.
 */
function get_the_category_rss($type = 'rss') {
    $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 )
            $the_list .= "\n\t\t<dc:subject><![CDATA[$cat_name]]></dc:subject>\n";
        elseif ( 'atom' == $type )
            $the_list .= sprintf( '<category scheme="%1$s" term="%2$s" />', attribute_escape( apply_filters( 'get_bloginfo_rss', get_bloginfo( 'url' ) ) ), attribute_escape( $cat_name ) );
        else
            $the_list .= "\n\t\t<category><![CDATA[" . html_entity_decode( $cat_name ) . "]]></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 $type Optional, default is 'rss'. Either 'rss', 'atom', or 'rdf'.
 */
function the_category_rss($type = 'rss') {
    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 = split("\n", $enc);
                
                //only get the the first element eg, audio/mpeg from 'audio/mpeg mpga mp2 mp3'
                $t = split('[ \t]', trim($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() {
    echo clean_url( 
        'http'
        . ( (isset($_SERVER['https']) && $_SERVER['https'] == 'on') ? 's' : '' ) . '://'
        . $_SERVER['HTTP_HOST']
        . stripslashes($_SERVER['REQUEST_URI'])
        );
}

?>