WordPress/wp-includes/feed-atom-comments.php

<?php
/**
 * Atom Feed Template for displaying Atom Comments feed.
 *
 * @package WordPress
 */

header( 'Content-Type: ' . feed_content_type( 'atom' ) . '; charset=' . get_option( 'blog_charset' ), true );
echo '<?xml version="1.0" encoding="' . get_option( 'blog_charset' ) . '" ?' . '>';

/** This action is documented in wp-includes/feed-rss2.php */
do_action( 'rss_tag_pre', 'atom-comments' );
?>
<feed
	xmlns="http://www.w3.org/2005/Atom"
	xml:lang="<?php bloginfo_rss( 'language' ); ?>"
	xmlns:thr="http://purl.org/syndication/thread/1.0"
	<?php
		/** This action is documented in wp-includes/feed-atom.php */
		do_action( 'atom_ns' );

		/**
		 * Fires inside the feed tag in the Atom comment feed.
		 *
		 * @since 2.8.0
		 */
		do_action( 'atom_comments_ns' );
	?>
>
	<title type="text">
	<?php
	if ( is_singular() ) {
		/* translators: Comments feed title. %s: Post title. */
		printf( ent2ncr( __( 'Comments on %s' ) ), get_the_title_rss() );
	} elseif ( is_search() ) {
		/* translators: Comments feed title. 1: Site title, 2: Search query. */
		printf( ent2ncr( __( 'Comments for %1$s searching on %2$s' ) ), get_bloginfo_rss( 'name' ), get_search_query() );
	} else {
		/* translators: Comments feed title. %s: Site title. */
		printf( ent2ncr( __( 'Comments for %s' ) ), get_wp_title_rss() );
	}
	?>
	</title>
	<subtitle type="text"><?php bloginfo_rss( 'description' ); ?></subtitle>

	<updated><?php echo get_feed_build_date( 'Y-m-d\TH:i:s\Z' ); ?></updated>

<?php if ( is_singular() ) : ?>
	<link rel="alternate" type="<?php bloginfo_rss( 'html_type' ); ?>" href="<?php comments_link_feed(); ?>" />
	<link rel="self" type="application/atom+xml" href="<?php echo esc_url( get_post_comments_feed_link( '', 'atom' ) ); ?>" />
	<id><?php echo esc_url( get_post_comments_feed_link( '', 'atom' ) ); ?></id>
<?php elseif ( is_search() ) : ?>
	<link rel="alternate" type="<?php bloginfo_rss( 'html_type' ); ?>" href="<?php echo home_url() . '?s=' . get_search_query(); ?>" />
	<link rel="self" type="application/atom+xml" href="<?php echo get_search_comments_feed_link( '', 'atom' ); ?>" />
	<id><?php echo get_search_comments_feed_link( '', 'atom' ); ?></id>
<?php else : ?>
	<link rel="alternate" type="<?php bloginfo_rss( 'html_type' ); ?>" href="<?php bloginfo_rss( 'url' ); ?>" />
	<link rel="self" type="application/atom+xml" href="<?php bloginfo_rss( 'comments_atom_url' ); ?>" />
	<id><?php bloginfo_rss( 'comments_atom_url' ); ?></id>
<?php endif; ?>
<?php
	/**
	 * Fires at the end of the Atom comment feed header.
	 *
	 * @since 2.8.0
	 */
	do_action( 'comments_atom_head' );
?>
<?php
while ( have_comments() ) :
	the_comment();
	$comment_post    = get_post( $comment->comment_post_ID );
	$GLOBALS['post'] = $comment_post;
	?>
	<entry>
		<title>
		<?php
		if ( ! is_singular() ) {
			$title = get_the_title( $comment_post->ID );
			/** This filter is documented in wp-includes/feed.php */
			$title = apply_filters( 'the_title_rss', $title );
			/* translators: Individual comment title. 1: Post title, 2: Comment author name. */
			printf( ent2ncr( __( 'Comment on %1$s by %2$s' ) ), $title, get_comment_author_rss() );
		} else {
			/* translators: Comment author title. %s: Comment author name. */
			printf( ent2ncr( __( 'By: %s' ) ), get_comment_author_rss() );
		}
		?>
		</title>
		<link rel="alternate" href="<?php comment_link(); ?>" type="<?php bloginfo_rss( 'html_type' ); ?>" />

		<author>
			<name><?php comment_author_rss(); ?></name>
			<?php
			if ( get_comment_author_url() ) {
				echo '<uri>' . get_comment_author_url() . '</uri>';}
			?>

		</author>

		<id><?php comment_guid(); ?></id>
		<updated><?php echo mysql2date( 'Y-m-d\TH:i:s\Z', get_comment_time( 'Y-m-d H:i:s', true, false ), false ); ?></updated>
		<published><?php echo mysql2date( 'Y-m-d\TH:i:s\Z', get_comment_time( 'Y-m-d H:i:s', true, false ), false ); ?></published>

		<?php if ( post_password_required( $comment_post ) ) : ?>
			<content type="html" xml:base="<?php comment_link(); ?>"><![CDATA[<?php echo get_the_password_form(); ?>]]></content>
		<?php else : ?>
			<content type="html" xml:base="<?php comment_link(); ?>"><![CDATA[<?php comment_text(); ?>]]></content>
		<?php endif; // End if post_password_required(). ?>

		<?php
		// Return comment threading information (https://www.ietf.org/rfc/rfc4685.txt).
		if ( 0 == $comment->comment_parent ) : // This comment is top-level.
			?>
			<thr:in-reply-to ref="<?php the_guid(); ?>" href="<?php the_permalink_rss(); ?>" type="<?php bloginfo_rss( 'html_type' ); ?>" />
			<?php
		else : // This comment is in reply to another comment.
			$parent_comment = get_comment( $comment->comment_parent );
			/*
			 * The rel attribute below and the id tag above should be GUIDs,
			 * but WP doesn't create them for comments (unlike posts).
			 * Either way, it's more important that they both use the same system.
			 */
			?>
			<thr:in-reply-to ref="<?php comment_guid( $parent_comment ); ?>" href="<?php echo get_comment_link( $parent_comment ); ?>" type="<?php bloginfo_rss( 'html_type' ); ?>" />
			<?php
		endif;

		/**
		 * Fires at the end of each Atom comment feed item.
		 *
		 * @since 2.2.0
		 *
		 * @param int $comment_id      ID of the current comment.
		 * @param int $comment_post_id ID of the post the current comment is connected to.
		 */
		do_action( 'comment_atom_entry', $comment->comment_ID, $comment_post->ID );
		?>
	</entry>
	<?php
endwhile;
?>
</feed>