/modules/markdown/easy-markdown.php

<?php 
 
/** 
Plugin Name: Easy Markdown 
Plugin URI: http://automattic.com/ 
Description: Write in Markdown, publish in WordPress 
Version: 0.1 
Author: Matt Wiebe 
Author URI: http://automattic.com/ 
*/ 
 
/** 
 * Copyright (c) Automattic. All rights reserved. 
 * 
 * Released under the GPL license 
 * http://www.opensource.org/licenses/gpl-license.php 
 * 
 * This is an add-on for WordPress 
 * http://wordpress.org/ 
 * 
 * ********************************************************************** 
 * This program is free software; you can redistribute it and/or modify 
 * it under the terms of the GNU General Public License as published by 
 * the Free Software Foundation; either version 2 of the License, or 
 * (at your option) any later version. 
 * 
 * This program is distributed in the hope that it will be useful,  
 * but WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * GNU General Public License for more details. 
 * ********************************************************************** 
 */ 
 
class WPCom_Markdown { 
 
 
  const POST_OPTION = 'wpcom_publish_posts_with_markdown'; 
  const COMMENT_OPTION = 'wpcom_publish_comments_with_markdown'; 
  const POST_TYPE_SUPPORT = 'wpcom-markdown'; 
  const IS_MD_META = '_wpcom_is_markdown'; 
 
  private static $parser; 
  private static $instance; 
 
  // to ensure that our munged posts over xml-rpc are removed from the cache 
  public $posts_to_uncache = array(); 
  private $monitoring = array( 'post' => array(), 'parent' => array() ); 
 
 
  /** 
   * Yay singletons! 
   * @return object WPCom_Markdown instance 
   */ 
  public static function get_instance() { 
      if ( ! self::$instance ) 
          self::$instance = new self(); 
      return self::$instance; 
  } 
 
  /** 
   * Kicks things off on `init` action 
   * @return null 
   */ 
  public function load() { 
      $this->add_default_post_type_support(); 
      $this->maybe_load_actions_and_filters(); 
      if ( defined( 'REST_API_REQUEST' ) && REST_API_REQUEST ) { 
          add_action( 'switch_blog', array( $this, 'maybe_load_actions_and_filters' ), 10, 2 ); 
      } 
      add_action( 'admin_init', array( $this, 'register_setting' ) ); 
      add_action( 'admin_init', array( $this, 'maybe_unload_for_bulk_edit' ) ); 
      if ( current_theme_supports( 'o2' ) || class_exists( 'P2' ) ) { 
          $this->add_o2_helpers(); 
      } 
  } 
 
  /** 
   * If we're in a bulk edit session, unload so that we don't lose our markdown metadata 
   * @return null 
   */ 
  public function maybe_unload_for_bulk_edit() { 
      if ( isset( $_REQUEST['bulk_edit'] ) && $this->is_posting_enabled() ) { 
          $this->unload_markdown_for_posts(); 
      } 
  } 
 
  /** 
   * Called on init and fires on switch_blog to decide if our actions and filters 
   * should be running. 
   * @param int|null $new_blog_id New blog ID 
   * @param int|null $old_blog_id Old blog ID 
   * @return null 
   */ 
  public function maybe_load_actions_and_filters( $new_blog_id = null, $old_blog_id = null ) { 
      // If this is a switch_to_blog call, and the blog isn't changing, we'll already be loaded 
      if ( $new_blog_id && $new_blog_id === $old_blog_id ) { 
          return; 
      } 
 
      if ( $this->is_posting_enabled() ) { 
          $this->load_markdown_for_posts(); 
      } else { 
          $this->unload_markdown_for_posts(); 
      } 
 
      if ( $this->is_commenting_enabled() ) { 
          $this->load_markdown_for_comments(); 
      } else { 
          $this->unload_markdown_for_comments(); 
      } 
  } 
 
  /** 
   * Set up hooks for enabling Markdown conversion on posts 
   * @return null 
   */ 
  public function load_markdown_for_posts() { 
      add_action( 'wp_insert_post', array( $this, 'wp_insert_post' ) ); 
      add_filter( 'wp_insert_post_data', array( $this, 'wp_insert_post_data' ), 10, 2 ); 
      add_filter( 'edit_post_content', array( $this, 'edit_post_content' ), 10, 2 ); 
      add_filter( 'edit_post_content_filtered', array( $this, 'edit_post_content_filtered' ), 10, 2 ); 
      add_action( 'wp_restore_post_revision', array( $this, 'wp_restore_post_revision' ), 10, 2 ); 
      add_filter( '_wp_post_revision_fields', array( $this, '_wp_post_revision_fields' ) ); 
      add_action( 'xmlrpc_call', array( $this, 'xmlrpc_actions' ) ); 
      add_filter( 'content_save_pre', array( $this, 'preserve_code_blocks' ), 1 ); 
      if ( defined( 'XMLRPC_REQUEST' ) && XMLRPC_REQUEST ) { 
          $this->check_for_early_methods(); 
      } 
  } 
 
  /** 
   * Removes hooks to disable Markdown conversion on posts 
   * @return null 
   */ 
  public function unload_markdown_for_posts() { 
      remove_action( 'wp_insert_post', array( $this, 'wp_insert_post' ) ); 
      remove_filter( 'wp_insert_post_data', array( $this, 'wp_insert_post_data' ), 10, 2 ); 
      remove_filter( 'edit_post_content', array( $this, 'edit_post_content' ), 10, 2 ); 
      remove_filter( 'edit_post_content_filtered', array( $this, 'edit_post_content_filtered' ), 10, 2 ); 
      remove_action( 'wp_restore_post_revision', array( $this, 'wp_restore_post_revision' ), 10, 2 ); 
      remove_filter( '_wp_post_revision_fields', array( $this, '_wp_post_revision_fields' ) ); 
      remove_action( 'xmlrpc_call', array( $this, 'xmlrpc_actions' ) ); 
      remove_filter( 'content_save_pre', array( $this, 'preserve_code_blocks' ), 1 ); 
  } 
 
  /** 
   * Set up hooks for enabling Markdown conversion on comments 
   * @return null 
   */ 
  protected function load_markdown_for_comments() { 
      // Use priority 9 so that Markdown runs before KSES, which can clean up 
      // any munged HTML. 
      add_filter( 'pre_comment_content', array( $this, 'pre_comment_content' ), 9 ); 
  } 
 
  /** 
   * Removes hooks to disable Markdown conversion 
   * @return null 
   */ 
  protected function unload_markdown_for_comments() { 
      remove_filter( 'pre_comment_content', array( $this, 'pre_comment_content' ), 9 ); 
  } 
 
  /** 
   * o2 does some of what we do. Let's take precedence. 
   * @return null 
   */ 
  public function add_o2_helpers() { 
      if ( $this->is_posting_enabled() ) { 
          add_filter( 'content_save_pre', array( $this, 'o2_escape_lists' ), 1 ); 
      } 
 
      add_filter( 'o2_preview_post', array( $this, 'o2_preview_post' ) ); 
      add_filter( 'o2_preview_comment', array( $this, 'o2_preview_comment' ) ); 
 
      add_filter( 'wpcom_markdown_transform_pre', array( $this, 'o2_unescape_lists' ) ); 
      add_filter( 'wpcom_untransformed_content', array( $this, 'o2_unescape_lists' ) ); 
  } 
 
  /** 
   * If Markdown is enabled for posts on this blog, filter the text for o2 previews 
   * @param  string $text Post text 
   * @return string       Post text transformed through the magic of Markdown 
   */ 
  public function o2_preview_post( $text ) { 
      if ( $this->is_posting_enabled() ) { 
          $text = $this->transform( $text, array( 'unslash' => false ) ); 
      } 
      return $text; 
  } 
 
  /** 
   * If Markdown is enabled for comments on this blog, filter the text for o2 previews 
   * @param  string $text Comment text 
   * @return string       Comment text transformed through the magic of Markdown 
   */ 
  public function o2_preview_comment( $text ) { 
      if ( $this->is_commenting_enabled() ) { 
          $text = $this->transform( $text, array( 'unslash' => false ) ); 
      } 
      return $text; 
  } 
 
  /** 
   * Escapes lists so that o2 doesn't trounce them 
   * @param  string $text Post/comment text 
   * @return string       Text escaped with HTML entity for asterisk 
   */ 
  public function o2_escape_lists( $text ) { 
      return preg_replace( '/^\\* /um', '* ', $text ); 
  } 
 
  /** 
   * Unescapes the token we inserted on o2_escape_lists 
   * @param  string $text Post/comment text with HTML entities for asterisks 
   * @return string       Text with the HTML entity removed 
   */ 
  public function o2_unescape_lists( $text ) { 
      return preg_replace( '/^[&]\#042; /um', '* ', $text ); 
  } 
 
  /** 
   * Preserve code blocks from being munged by KSES before they have a chance 
   * @param  string $text post content 
   * @return string       post content with code blocks escaped 
   */ 
  public function preserve_code_blocks( $text ) { 
      return $this->get_parser()->codeblock_preserve( $text ); 
  } 
 
  /** 
   * Remove KSES if it's there. Store the result to manually invoke later if needed. 
   * @return null 
   */ 
  public function maybe_remove_kses() { 
      // Filters return true if they existed before you removed them 
      if ( $this->is_posting_enabled() ) 
          $this->kses = remove_filter( 'content_filtered_save_pre', 'wp_filter_post_kses' ) && remove_filter( 'content_save_pre', 'wp_filter_post_kses' ); 
  } 
 
  /** 
   * Add our Writing and Discussion settings. 
   * @return null 
   */ 
  public function register_setting() { 
      add_settings_field( self::POST_OPTION, __( 'Markdown', 'jetpack' ), array( $this, 'post_field' ), 'writing' ); 
      register_setting( 'writing', self::POST_OPTION, array( $this, 'sanitize_setting') ); 
      add_settings_field( self::COMMENT_OPTION, __( 'Markdown', 'jetpack' ), array( $this, 'comment_field' ), 'discussion' ); 
      register_setting( 'discussion', self::COMMENT_OPTION, array( $this, 'sanitize_setting') ); 
  } 
 
  /** 
   * Sanitize setting. Don't really want to store "on" value, so we'll store "1" instead! 
   * @param  string $input Value received by settings API via $_POST 
   * @return bool          Cast to boolean. 
   */ 
  public function sanitize_setting( $input ) { 
      return (bool) $input; 
  } 
 
  /** 
   * Prints HTML for the Writing setting 
   * @return null 
   */ 
  public function post_field() { 
      printf( 
          '<label><input name="%s" id="%s" type="checkbox"%s /> %s</label><p class="description">%s</p>',  
          self::POST_OPTION,  
          self::POST_OPTION,  
          checked( $this->is_posting_enabled(), true, false ),  
          esc_html__( 'Use Markdown for posts and pages.', 'jetpack' ),  
          sprintf( '<a href="%s">%s</a>', esc_url( $this->get_support_url() ), esc_html__( 'Learn more about Markdown.', 'jetpack' ) ) 
 ); 
  } 
 
  /** 
   * Prints HTML for the Discussion setting 
   * @return null 
   */ 
  public function comment_field() { 
      printf( 
          '<label><input name="%s" id="%s" type="checkbox"%s /> %s</label><p class="description">%s</p>',  
          self::COMMENT_OPTION,  
          self::COMMENT_OPTION,  
          checked( $this->is_commenting_enabled(), true, false ),  
          esc_html__( 'Use Markdown for comments.', 'jetpack' ),  
          sprintf( '<a href="%s">%s</a>', esc_url( $this->get_support_url() ), esc_html__( 'Learn more about Markdown.', 'jetpack' ) ) 
 ); 
  } 
 
  /** 
   * Get the support url for Markdown 
   * @uses   apply_filters 
   * @return string support url 
   */ 
  protected function get_support_url() { 
      /** 
       * Filter the Markdown support URL. 
       * 
       * @module markdown 
       * 
       * @since 2.8.0 
       * 
       * @param string $url Markdown support URL. 
       */ 
      return apply_filters( 'easy_markdown_support_url', 'http://en.support.wordpress.com/markdown-quick-reference/' ); 
  } 
 
  /** 
   * Is Mardown conversion for posts enabled? 
   * @return boolean 
   */ 
  public function is_posting_enabled() { 
      return (bool) get_option( self::POST_OPTION, '' ); 
  } 
 
  /** 
   * Is Markdown conversion for comments enabled? 
   * @return boolean 
   */ 
  public function is_commenting_enabled() { 
      return (bool) get_option( self::COMMENT_OPTION, '' ); 
  } 
 
  /** 
   * Check if a $post_id has Markdown enabled 
   * @param  int  $post_id A post ID. 
   * @return boolean 
   */ 
  public function is_markdown( $post_id ) { 
      return get_metadata( 'post', $post_id, self::IS_MD_META, true ); 
  } 
 
  /** 
   * Set Markdown as enabled on a post_id. We skip over update_postmeta so we 
   * can sneakily set metadata on post revisions, which we need. 
   * @param int    $post_id A post ID. 
   * @return bool  The metadata was successfully set. 
   */ 
  protected function set_as_markdown( $post_id ) { 
      return update_metadata( 'post', $post_id, self::IS_MD_META, true ); 
  } 
 
  /** 
   * Get our Markdown parser object, optionally requiring all of our needed classes and 
   * instantiating our parser. 
   * @return object WPCom_GHF_Markdown_Parser instance. 
   */ 
  public function get_parser() { 
 
      if ( ! self::$parser ) { 
          jetpack_require_lib( 'markdown' ); 
          self::$parser = new WPCom_GHF_Markdown_Parser; 
      } 
 
      return self::$parser; 
  } 
 
  /** 
   * We don't want Markdown conversion all over the place. 
   * @return null 
   */ 
  public function add_default_post_type_support() { 
      add_post_type_support( 'post', self::POST_TYPE_SUPPORT ); 
      add_post_type_support( 'page', self::POST_TYPE_SUPPORT ); 
      add_post_type_support( 'revision', self::POST_TYPE_SUPPORT ); 
  } 
 
  /** 
   * Figure out the post type of the post screen we're on 
   * @return string Current post_type 
   */ 
  protected function get_post_screen_post_type() { 
      global $pagenow; 
      if ( 'post-new.php' === $pagenow ) 
          return ( isset( $_GET['post_type'] ) ) ? $_GET['post_type'] : 'post'; 
      if ( isset( $_GET['post'] ) ) { 
          $post = get_post( (int) $_GET['post'] ); 
          if ( is_object( $post ) && isset( $post->post_type ) ) 
              return $post->post_type; 
      } 
      return 'post'; 
  } 
 
  /** 
   * Swap post_content and post_content_filtered for editing 
   * @param  string $content Post content 
   * @param  int $id         post ID 
   * @return string          Swapped content 
   */ 
  public function edit_post_content( $content, $id ) { 
      if ( $this->is_markdown( $id ) ) { 
          $post = get_post( $id ); 
          if ( $post && ! empty( $post->post_content_filtered ) ) { 
              $post = $this->swap_for_editing( $post ); 
              return $post->post_content; 
          } 
      } 
      return $content; 
  } 
 
  /** 
   * Swap post_content_filtered and post_content for editing 
   * @param  string $content Post content_filtered 
   * @param  int $id         post ID 
   * @return string          Swapped content 
   */ 
  public function edit_post_content_filtered( $content, $id ) { 
      // if markdown was disabled, let's turn this off 
      if ( ! $this->is_posting_enabled() && $this->is_markdown( $id ) ) { 
          $post = get_post( $id ); 
          if ( $post && ! empty( $post->post_content_filtered ) ) 
              $content = ''; 
      } 
      return $content; 
  } 
 
  /** 
   * Magic happens here. Markdown is converted and stored on post_content. Original Markdown is stored 
   * in post_content_filtered so that we can continue editing as Markdown. 
   * @param  array $post_data  The post data that will be inserted into the DB. Slashed. 
   * @param  array $postarr    All the stuff that was in $_POST. 
   * @return array             $post_data with post_content and post_content_filtered modified 
   */ 
  public function wp_insert_post_data( $post_data, $postarr ) { 
      // $post_data array is slashed! 
      $post_id = isset( $postarr['ID'] ) ? $postarr['ID'] : false; 
      // bail early if markdown is disabled or this post type is unsupported. 
      if ( ! $this->is_posting_enabled() || ! post_type_supports( $post_data['post_type'], self::POST_TYPE_SUPPORT ) ) { 
          // it's disabled, but maybe this *was* a markdown post before. 
          if ( $this->is_markdown( $post_id ) && ! empty( $post_data['post_content_filtered'] ) ) { 
              $post_data['post_content_filtered'] = ''; 
          } 
          // we have no context to determine supported post types in the `post_content_pre` hook,  
          // which already ran to sanitize code blocks. Undo that. 
          $post_data['post_content'] = $this->get_parser()->codeblock_restore( $post_data['post_content'] ); 
          return $post_data; 
      } 
      // rejigger post_content and post_content_filtered 
      // revisions are already in the right place, except when we're restoring, but that's taken care of elsewhere 
      if ( 'revision' !== $post_data['post_type'] ) { 
          /** 
           * Filter the original post content passed to Markdown. 
           * 
           * @module markdown 
           * 
           * @since 2.8.0 
           * 
           * @param string $post_data['post_content'] Untransformed post content. 
           */ 
          $post_data['post_content_filtered'] = apply_filters( 'wpcom_untransformed_content', $post_data['post_content'] ); 
          $post_data['post_content'] = $this->transform( $post_data['post_content'], array( 'id' => $post_id ) ); 
          /** This filter is already documented in core/wp-includes/default-filters.php */ 
          $post_data['post_content'] = apply_filters( 'content_save_pre', $post_data['post_content'] ); 
      } elseif ( 0 === strpos( $post_data['post_name'], $post_data['post_parent'] . '-autosave' ) ) { 
          // autosaves for previews are weird 
          $post_data['post_content'] = $this->transform( $post_data['post_content'], array( 'id' => $post_data['post_parent'] ) ); 
          /** This filter is already documented in core/wp-includes/default-filters.php */ 
          $post_data['post_content'] = apply_filters( 'content_save_pre', $post_data['post_content'] ); 
      } 
 
      // set as markdown on the wp_insert_post hook later 
      if ( $post_id ) 
          $this->monitoring['post'][ $post_id ] = true; 
      else 
          $this->monitoring['content'] = wp_unslash( $post_data['post_content'] ); 
      if ( 'revision' === $postarr['post_type'] && $this->is_markdown( $postarr['post_parent'] ) ) 
          $this->monitoring['parent'][ $postarr['post_parent'] ] = true; 
 
      return $post_data; 
  } 
 
  /** 
   * Calls on wp_insert_post action, after wp_insert_post_data. This way we can 
   * still set postmeta on our revisions after it's all been deleted. 
   * @param  int $post_id The post ID that has just been added/updated 
   * @return null 
   */ 
  public function wp_insert_post( $post_id ) { 
      $post_parent = get_post_field( 'post_parent', $post_id ); 
      // this didn't have an ID yet. Compare the content that was just saved. 
      if ( isset( $this->monitoring['content'] ) && $this->monitoring['content'] === get_post_field( 'post_content', $post_id ) ) { 
          unset( $this->monitoring['content'] ); 
          $this->set_as_markdown( $post_id ); 
      } 
      if ( isset( $this->monitoring['post'][$post_id] ) ) { 
          unset( $this->monitoring['post'][$post_id] ); 
          $this->set_as_markdown( $post_id ); 
      } elseif ( isset( $this->monitoring['parent'][$post_parent] ) ) { 
          unset( $this->monitoring['parent'][$post_parent] ); 
          $this->set_as_markdown( $post_id ); 
      } 
  } 
 
  /** 
   * Run a comment through Markdown. Easy peasy. 
   * @param  string $content 
   * @return string 
   */ 
  public function pre_comment_content( $content ) { 
      return $this->transform( $content, array( 
          'id' => $this->comment_hash( $content ),  
 ) ); 
  } 
 
  protected function comment_hash( $content ) { 
      return 'c-' . substr( md5( $content ), 0, 8 ); 
  } 
 
  /** 
   * Markdown conversion. Some DRYness for repetitive tasks. 
   * @param  string $text  Content to be run through Markdown 
   * @param  array  $args  Arguments, with keys: 
   *                       id: provide a string to prefix footnotes with a unique identifier 
   *                       unslash: when true, expects and returns slashed data 
   *                       decode_code_blocks: when true, assume that text in fenced code blocks is already 
   *                         HTML encoded and should be decoded before being passed to Markdown, which does 
   *                         its own encoding. 
   * @return string        Markdown-processed content 
   */ 
  public function transform( $text, $args = array() ) { 
      $args = wp_parse_args( $args, array( 
          'id' => false,  
          'unslash' => true,  
          'decode_code_blocks' => ! $this->get_parser()->use_code_shortcode 
 ) ); 
      // probably need to unslash 
      if ( $args['unslash'] ) 
          $text = wp_unslash( $text ); 
 
      /** 
       * Filter the content to be run through Markdown, before it's transformed by Markdown. 
       * 
       * @module markdown 
       * 
       * @since 2.8.0 
       * 
       * @param string $text Content to be run through Markdown 
       * @param array $args Array of Markdown options. 
       */ 
      $text = apply_filters( 'wpcom_markdown_transform_pre', $text, $args ); 
      // ensure our paragraphs are separated 
      $text = str_replace( array( '</p><p>', "</p>\n<p>" ), "</p>\n\n<p>", $text ); 
      // visual editor likes to add <p>s. Buh-bye. 
      $text = $this->get_parser()->unp( $text ); 
      // sometimes we get an encoded > at start of line, breaking blockquotes 
      $text = preg_replace( '/^>/m', '>', $text ); 
      // prefixes are because we need to namespace footnotes by post_id 
      $this->get_parser()->fn_id_prefix = $args['id'] ? $args['id'] . '-' : ''; 
      // If we're not using the code shortcode, prevent over-encoding. 
      if ( $args['decode_code_blocks'] ) { 
          $text = $this->get_parser()->codeblock_restore( $text ); 
      } 
      // Transform it! 
      $text = $this->get_parser()->transform( $text ); 
      // Fix footnotes - kses doesn't like the : IDs it supplies 
      $text = preg_replace( '/((id|href)="#?fn(ref)?):/', "$1-", $text ); 
      // Markdown inserts extra spaces to make itself work. Buh-bye. 
      $text = rtrim( $text ); 
      /** 
       * Filter the content to be run through Markdown, after it was transformed by Markdown. 
       * 
       * @module markdown 
       * 
       * @since 2.8.0 
       * 
       * @param string $text Content to be run through Markdown 
       * @param array $args Array of Markdown options. 
       */ 
      $text = apply_filters( 'wpcom_markdown_transform_post', $text, $args ); 
 
      // probably need to re-slash 
      if ( $args['unslash'] ) 
          $text = wp_slash( $text ); 
 
      return $text; 
  } 
 
  /** 
   * Shows Markdown in the Revisions screen, and ensures that post_content_filtered 
   * is maintained on revisions 
   * @param  array $fields  Post fields pertinent to revisions 
   * @return array          Modified array to include post_content_filtered 
   */ 
  public function _wp_post_revision_fields( $fields ) { 
      $fields['post_content_filtered'] = __( 'Markdown content', 'jetpack' ); 
      return $fields; 
  } 
 
  /** 
   * Do some song and dance to keep all post_content and post_content_filtered content 
   * in the expected place when a post revision is restored. 
   * @param  int $post_id        The post ID have a restore done to it 
   * @param  int $revision_id    The revision ID being restored 
   * @return null 
   */ 
  public function wp_restore_post_revision( $post_id, $revision_id ) { 
      if ( $this->is_markdown( $revision_id ) ) { 
          $revision = get_post( $revision_id, ARRAY_A ); 
          $post = get_post( $post_id, ARRAY_A ); 
          $post['post_content'] = $revision['post_content_filtered']; // Yes, we put it in post_content, because our wp_insert_post_data() expects that 
          // set this flag so we can restore the post_content_filtered on the last revision later 
          $this->monitoring['restore'] = true; 
          // let's not make a revision of our fixing update 
          add_filter( 'wp_revisions_to_keep', '__return_false', 99 ); 
          wp_update_post( $post ); 
          $this->fix_latest_revision_on_restore( $post_id ); 
          remove_filter( 'wp_revisions_to_keep', '__return_false', 99 ); 
      } 
  } 
 
  /** 
   * We need to ensure the last revision has Markdown, not HTML in its post_content_filtered 
   * column after a restore. 
   * @param  int $post_id The post ID that was just restored. 
   * @return null 
   */ 
  protected function fix_latest_revision_on_restore( $post_id ) { 
      global $wpdb; 
      $post = get_post( $post_id ); 
      $last_revision = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_type = 'revision' AND post_parent = %d ORDER BY ID DESC", $post->ID ) ); 
      $last_revision->post_content_filtered = $post->post_content_filtered; 
      wp_insert_post( (array) $last_revision ); 
  } 
 
  /** 
   * Kicks off magic for an XML-RPC session. We want to keep editing Markdown 
   * and publishing HTML. 
   * @param  string $xmlrpc_method The current XML-RPC method 
   * @return null 
   */ 
  public function xmlrpc_actions( $xmlrpc_method ) { 
      switch ( $xmlrpc_method ) { 
          case 'metaWeblog.getRecentPosts': 
          case 'wp.getPosts': 
          case 'wp.getPages': 
              add_action( 'parse_query', array( $this, 'make_filterable' ), 10, 1 ); 
              break; 
          case 'wp.getPost': 
              $this->prime_post_cache(); 
              break; 
      } 
  } 
 
  /** 
   * metaWeblog.getPost and wp.getPage fire xmlrpc_call action *after* get_post() is called. 
   * So, we have to detect those methods and prime the post cache early. 
   * @return null 
   */ 
  protected function check_for_early_methods() { 
      global $HTTP_RAW_POST_DATA; 
      if ( false === strpos( $HTTP_RAW_POST_DATA, 'metaWeblog.getPost' ) 
          && false === strpos( $HTTP_RAW_POST_DATA, 'wp.getPage' ) ) { 
          return; 
      } 
      include_once( ABSPATH . WPINC . '/class-IXR.php' ); 
      $message = new IXR_Message( $HTTP_RAW_POST_DATA ); 
      $message->parse(); 
      $post_id_position = 'metaWeblog.getPost' === $message->methodName ?  0 : 1; 
      $this->prime_post_cache( $message->params[ $post_id_position ] ); 
  } 
 
  /** 
   * Prime the post cache with swapped post_content. This is a sneaky way of getting around 
   * the fact that there are no good hooks to call on the *.getPost xmlrpc methods. 
   * 
   * @return null 
   */ 
  private function prime_post_cache( $post_id = false ) { 
      global $wp_xmlrpc_server; 
      if ( ! $post_id ) { 
          $post_id = $wp_xmlrpc_server->message->params[3]; 
      } 
 
      // prime the post cache 
      if ( $this->is_markdown( $post_id ) ) { 
          $post = get_post( $post_id ); 
          if ( ! empty( $post->post_content_filtered ) ) { 
              wp_cache_delete( $post->ID, 'posts' ); 
              $post = $this->swap_for_editing( $post ); 
              wp_cache_add( $post->ID, $post, 'posts' ); 
              $this->posts_to_uncache[] = $post_id; 
          } 
      } 
      // uncache munged posts if using a persistent object cache 
      if ( wp_using_ext_object_cache() ) { 
          add_action( 'shutdown', array( $this, 'uncache_munged_posts' ) ); 
      } 
  } 
 
  /** 
   * Swaps `post_content_filtered` back to `post_content` for editing purposes. 
   * @param  object $post WP_Post object 
   * @return object       WP_Post object with swapped `post_content_filtered` and `post_content` 
   */ 
  protected function swap_for_editing( $post ) { 
      $markdown = $post->post_content_filtered; 
      // unencode encoded code blocks 
      $markdown = $this->get_parser()->codeblock_restore( $markdown ); 
      // restore beginning of line blockquotes 
      $markdown = preg_replace( '/^> /m', '> ', $markdown ); 
      $post->post_content_filtered = $post->post_content; 
      $post->post_content = $markdown; 
      return $post; 
  } 
 
 
  /** 
   * We munge the post cache to serve proper markdown content to XML-RPC clients. 
   * Uncache these after the XML-RPC session ends. 
   * @return null 
   */ 
  public function uncache_munged_posts() { 
      // $this context gets lost in testing sometimes. Weird. 
      foreach( WPCom_Markdown::get_instance()->posts_to_uncache as $post_id ) { 
          wp_cache_delete( $post_id, 'posts' ); 
      } 
  } 
 
  /** 
   * Since *.(get)?[Rr]ecentPosts calls get_posts with suppress filters on, we need to 
   * turn them back on so that we can swap things for editing. 
   * @param  object $wp_query WP_Query object 
   * @return null 
   */ 
  public function make_filterable( $wp_query ) { 
      $wp_query->set( 'suppress_filters', false ); 
      add_action( 'the_posts', array( $this, 'the_posts' ), 10, 2 ); 
  } 
 
  /** 
   * Swaps post_content and post_content_filtered for editing. 
   * @param  array  $posts     Posts returned by the just-completed query 
   * @param  object $wp_query  Current WP_Query object 
   * @return array             Modified $posts 
   */ 
  public function the_posts( $posts, $wp_query ) { 
      foreach ( $posts as $key => $post ) { 
          if ( $this->is_markdown( $post->ID ) && ! empty( $posts[ $key ]->post_content_filtered ) ) { 
              $markdown = $posts[ $key ]->post_content_filtered; 
              $posts[ $key ]->post_content_filtered = $posts[ $key ]->post_content; 
              $posts[ $key ]->post_content = $markdown; 
          } 
      } 
      return $posts; 
  } 
 
  /** 
   * Singleton silence is golden 
   */ 
  private function __construct() {} 
} 
 
add_action( 'init', array( WPCom_Markdown::get_instance(), 'load' ) );