Add amp-live-list comments

amp.php

@@ -88,7 +88,8 @@ function amp_after_setup_theme() {
 	}
 
 	add_action( 'init', 'amp_init' );
-	add_action( 'widgets_init', 'AMP_Theme_Support::register_widgets' );
+	add_action( 'widgets_init', 'AMP_Theme_Support::register_widgets' ); // @todo Let this be called by AMP_Theme_Support::init().
+	add_action( 'init', 'AMP_Theme_Support::setup_commenting' ); // @todo Let this be called by AMP_Theme_Support::init().
 	add_action( 'admin_init', 'AMP_Options_Manager::register_settings' );
 	add_filter( 'amp_post_template_analytics', 'amp_add_custom_analytics' );
 	add_action( 'wp_loaded', 'amp_post_meta_box' );
@@ -102,8 +103,10 @@ function amp_after_setup_theme() {
  * Init AMP.
  *
  * @since 0.1
+ * @global string $pagenow
  */
 function amp_init() {
+	global $pagenow;
 
 	/**
 	 * Triggers on init when AMP plugin is active.
@@ -123,7 +126,10 @@ function amp_init() {
 	add_filter( 'old_slug_redirect_url', 'amp_redirect_old_slug_to_new_url' );
 
 	if ( class_exists( 'Jetpack' ) && ! ( defined( 'IS_WPCOM' ) && IS_WPCOM ) ) {
-		require_once( AMP__DIR__ . '/jetpack-helper.php' );
+		require_once AMP__DIR__ . '/jetpack-helper.php';
+	}
+	if ( isset( $pagenow ) && 'wp-comments-post.php' === $pagenow ) {
+		amp_prepare_comment_post();
 	}
 }
 

includes/amp-helper-functions.php

@@ -223,15 +223,56 @@ function amp_get_content_sanitizers( $post = null ) {
 		array(
 			'AMP_Style_Sanitizer'             => array(),
 			'AMP_Img_Sanitizer'               => array(),
+			'AMP_Form_Sanitizer'              => array(),
+			'AMP_Comments_Sanitizer'          => array(),
 			'AMP_Video_Sanitizer'             => array(),
 			'AMP_Audio_Sanitizer'             => array(),
 			'AMP_Playbuzz_Sanitizer'          => array(),
 			'AMP_Iframe_Sanitizer'            => array(
 				'add_placeholder' => true,
 			),
-			'AMP_Form_Sanitizer'              => array(),
 			'AMP_Tag_And_Attribute_Sanitizer' => array(), // Note: This whitelist sanitizer must come at the end to clean up any remaining issues the other sanitizers didn't catch.
 		),
 		$post
 	);
 }
+
+/**
+ * Hook into a comment submission of an AMP XHR post request.
+ *
+ * This only runs on wp-comments-post.php.
+ *
+ * @since 0.7.0
+ */
+function amp_prepare_comment_post() {
+	if ( ! isset( $_GET['__amp_source_origin'] ) ) { // WPCS: CSRF ok. Beware of AMP_Theme_Support::purge_amp_query_vars().
+		return;
+	}
+
+	// Add amp comment hooks.
+	add_filter( 'comment_post_redirect', function() {
+		// We don't need any data, so just send a success.
+		wp_send_json_success();
+	}, PHP_INT_MAX, 2 );
+
+	// Add die handler for AMP error display.
+	add_filter( 'wp_die_handler', function() {
+		/**
+		 * New error handler for AMP form submission.
+		 *
+		 * @param WP_Error|string $error The error to handle.
+		 */
+		return function( $error ) {
+			status_header( 400 );
+			if ( is_wp_error( $error ) ) {
+				$error = $error->get_error_message();
+			}
+			$error = strip_tags( $error, 'strong' );
+			wp_send_json( compact( 'error' ) );
+		};
+	} );
+
+	// Send AMP header.
+	$origin = esc_url_raw( wp_unslash( $_GET['__amp_source_origin'] ) ); // WPCS: CSRF ok.
+	header( 'AMP-Access-Control-Allow-Source-Origin: ' . $origin, true );
+}

includes/class-amp-autoloader.php

@@ -30,6 +30,7 @@ class AMP_Autoloader {
 	 */
 	private static $_classmap = array(
 		'AMP_Theme_Support'                           => 'includes/class-amp-theme-support',
+		'AMP_Comment_Walker'                          => 'includes/class-amp-comment-walker',
 		'AMP_WP_Styles'                               => 'includes/class-amp-wp-styles',
 		'AMP_Template_Customizer'                     => 'includes/admin/class-amp-customizer',
 		'AMP_Post_Meta_Box'                           => 'includes/admin/class-amp-post-meta-box',
@@ -69,6 +70,7 @@ class AMP_Autoloader {
 		'AMP_Blacklist_Sanitizer'                     => 'includes/sanitizers/class-amp-blacklist-sanitizer',
 		'AMP_Iframe_Sanitizer'                        => 'includes/sanitizers/class-amp-iframe-sanitizer',
 		'AMP_Img_Sanitizer'                           => 'includes/sanitizers/class-amp-img-sanitizer',
+		'AMP_Comments_Sanitizer'                      => 'includes/sanitizers/class-amp-comments-sanitizer',
 		'AMP_Form_Sanitizer'                          => 'includes/sanitizers/class-amp-form-sanitizer',
 		'AMP_Playbuzz_Sanitizer'                      => 'includes/sanitizers/class-amp-playbuzz-sanitizer',
 		'AMP_Style_Sanitizer'                         => 'includes/sanitizers/class-amp-style-sanitizer',

includes/class-amp-comment-walker.php

@@ -0,0 +1,121 @@
+<?php
+/**
+ * Class AMP_Comment_Walker
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Comment_Walker
+ *
+ * Walker to wrap comments in mustache tags for amp-template.
+ */
+class AMP_Comment_Walker extends Walker_Comment {
+
+	/**
+	 * The original comments arguments.
+	 *
+	 * @since 0.7
+	 * @var array
+	 */
+	public $args;
+
+	/**
+	 * Holds the timestamp of the most reacent comment in a thread.
+	 *
+	 * @since 0.7
+	 * @var array
+	 */
+	private $comment_thread_age = array();
+
+	/**
+	 * Starts the element output.
+	 *
+	 * @since 0.7.0
+	 *
+	 * @see Walker::start_el()
+	 * @see wp_list_comments()
+	 * @global int        $comment_depth
+	 * @global WP_Comment $comment
+	 *
+	 * @param string     $output Used to append additional content. Passed by reference.
+	 * @param WP_Comment $comment Comment data object.
+	 * @param int        $depth Optional. Depth of the current comment in reference to parents. Default 0.
+	 * @param array      $args Optional. An array of arguments. Default empty array.
+	 * @param int        $id Optional. ID of the current comment. Default 0 (unused).
+	 */
+	public function start_el( &$output, $comment, $depth = 0, $args = array(), $id = 0 ) {
+
+		$new_out = '';
+		parent::start_el( $new_out, $comment, $depth, $args, $id );
+
+		if ( 'div' === $args['style'] ) {
+			$tag = '<div';
+		} else {
+			$tag = '<li';
+		}
+		$new_tag = $tag . ' data-sort-time="' . esc_attr( strtotime( $comment->comment_date ) ) . '"';
+
+		if ( ! empty( $this->comment_thread_age[ $comment->comment_ID ] ) ) {
+			$new_tag .= ' data-update-time="' . esc_attr( $this->comment_thread_age[ $comment->comment_ID ] ) . '"';
+		}
+
+		$output .= $new_tag . substr( ltrim( $new_out ), strlen( $tag ) );
+
+	}
+
+	/**
+	 * Output amp-list template code and place holder for comments.
+	 *
+	 * @since 0.7
+	 * @see Walker::paged_walk()
+	 *
+	 * @param WP_Comment[] $elements List of comment Elements.
+	 * @param int          $max_depth The maximum hierarchical depth.
+	 * @param int          $page_num The specific page number, beginning with 1.
+	 * @param int          $per_page Per page counter.
+	 *
+	 * @return string XHTML of the specified page of elements.
+	 */
+	public function paged_walk( $elements, $max_depth, $page_num, $per_page ) {
+		if ( empty( $elements ) || $max_depth < -1 ) {
+			return '';
+		}
+
+		$this->build_thread_latest_date( $elements );
+
+		$args = array_slice( func_get_args(), 4 );
+
+		return parent::paged_walk( $elements, $max_depth, $page_num, $per_page, $args[0] );
+	}
+
+	/**
+	 * Find the timestamp of the latest child comment of a thread to set the updated time.
+	 *
+	 * @since 0.7
+	 *
+	 * @param WP_Comment[] $elements The list of comments to get thread times for.
+	 * @param int          $time $the timestamp to check against.
+	 * @param bool         $is_child Flag used to set the the value or return the time.
+	 * @return int Latest time.
+	 */
+	protected function build_thread_latest_date( $elements, $time = 0, $is_child = false ) {
+
+		foreach ( $elements as $element ) {
+
+			$children  = $element->get_children();
+			$this_time = strtotime( $element->comment_date );
+			if ( ! empty( $children ) ) {
+				$this_time = $this->build_thread_latest_date( $children, $this_time, true );
+			}
+			if ( $this_time > $time ) {
+				$time = $this_time;
+			}
+			if ( false === $is_child ) {
+				$this->comment_thread_age[ $element->comment_ID ] = $time;
+			}
+		}
+
+		return $time;
+	}
+}