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   1  <?php
   2  /**
   3   * Handle Trackbacks and Pingbacks Sent to WordPress
   4   *
   5   * @since 0.71
   6   *
   7   * @package WordPress
   8   * @subpackage Trackbacks
   9   */
  10  
  11  if (empty($wp)) {
  12      require_once( dirname( __FILE__ ) . '/wp-load.php' );
  13      wp( array( 'tb' => '1' ) );
  14  }
  15  
  16  /**
  17   * Response to a trackback.
  18   *
  19   * Responds with an error or success XML message.
  20   *
  21   * @since 0.71
  22   *
  23   * @param int|bool $error         Whether there was an error.
  24   *                                Default '0'. Accepts '0' or '1'.
  25   * @param string   $error_message Error message if an error occurred.
  26   */
  27  function trackback_response($error = 0, $error_message = '') {
  28      header('Content-Type: text/xml; charset=' . get_option('blog_charset') );
  29      if ($error) {
  30          echo '<?xml version="1.0" encoding="utf-8"?'.">\n";
  31          echo "<response>\n";
  32          echo "<error>1</error>\n";
  33          echo "<message>$error_message</message>\n";
  34          echo "</response>";
  35          die();
  36      } else {
  37          echo '<?xml version="1.0" encoding="utf-8"?'.">\n";
  38          echo "<response>\n";
  39          echo "<error>0</error>\n";
  40          echo "</response>";
  41      }
  42  }
  43  
  44  // Trackback is done by a POST.
  45  $request_array = 'HTTP_POST_VARS';
  46  
  47  if ( !isset($_GET['tb_id']) || !$_GET['tb_id'] ) {
  48      $tb_id = explode('/', $_SERVER['REQUEST_URI']);
  49      $tb_id = intval( $tb_id[ count($tb_id) - 1 ] );
  50  }
  51  
  52  $tb_url  = isset($_POST['url'])     ? $_POST['url']     : '';
  53  $charset = isset($_POST['charset']) ? $_POST['charset'] : '';
  54  
  55  // These three are stripslashed here so they can be properly escaped after mb_convert_encoding().
  56  $title     = isset($_POST['title'])     ? wp_unslash($_POST['title'])      : '';
  57  $excerpt   = isset($_POST['excerpt'])   ? wp_unslash($_POST['excerpt'])    : '';
  58  $blog_name = isset($_POST['blog_name']) ? wp_unslash($_POST['blog_name'])  : '';
  59  
  60  if ($charset)
  61      $charset = str_replace( array(',', ' '), '', strtoupper( trim($charset) ) );
  62  else
  63      $charset = 'ASCII, UTF-8, ISO-8859-1, JIS, EUC-JP, SJIS';
  64  
  65  // No valid uses for UTF-7.
  66  if ( false !== strpos($charset, 'UTF-7') )
  67      die;
  68  
  69  // For international trackbacks.
  70  if ( function_exists('mb_convert_encoding') ) {
  71      $title     = mb_convert_encoding($title, get_option('blog_charset'), $charset);
  72      $excerpt   = mb_convert_encoding($excerpt, get_option('blog_charset'), $charset);
  73      $blog_name = mb_convert_encoding($blog_name, get_option('blog_charset'), $charset);
  74  }
  75  
  76  // Now that mb_convert_encoding() has been given a swing, we need to escape these three.
  77  $title     = wp_slash($title);
  78  $excerpt   = wp_slash($excerpt);
  79  $blog_name = wp_slash($blog_name);
  80  
  81  if ( is_single() || is_page() )
  82      $tb_id = $posts[0]->ID;
  83  
  84  if ( !isset($tb_id) || !intval( $tb_id ) )
  85      trackback_response(1, 'I really need an ID for this to work.');
  86  
  87  if (empty($title) && empty($tb_url) && empty($blog_name)) {
  88      // If it doesn't look like a trackback at all.
  89      wp_redirect(get_permalink($tb_id));
  90      exit;
  91  }
  92  
  93  if ( !empty($tb_url) && !empty($title) ) {
  94      header('Content-Type: text/xml; charset=' . get_option('blog_charset') );
  95  
  96      if ( !pings_open($tb_id) )
  97          trackback_response(1, 'Sorry, trackbacks are closed for this item.');
  98  
  99      $title =  wp_html_excerpt( $title, 250, '&#8230;' );
 100      $excerpt = wp_html_excerpt( $excerpt, 252, '&#8230;' );
 101  
 102      $comment_post_ID = (int) $tb_id;
 103      $comment_author = $blog_name;
 104      $comment_author_email = '';
 105      $comment_author_url = $tb_url;
 106      $comment_content = "<strong>$title</strong>\n\n$excerpt";
 107      $comment_type = 'trackback';
 108  
 109      $dupe = $wpdb->get_results( $wpdb->prepare("SELECT * FROM $wpdb->comments WHERE comment_post_ID = %d AND comment_author_url = %s", $comment_post_ID, $comment_author_url) );
 110      if ( $dupe )
 111          trackback_response(1, 'We already have a ping from that URL for this post.');
 112  
 113      $commentdata = compact('comment_post_ID', 'comment_author', 'comment_author_email', 'comment_author_url', 'comment_content', 'comment_type');
 114  
 115      wp_new_comment($commentdata);
 116      $trackback_id = $wpdb->insert_id;
 117  
 118      /**
 119       * Fires after a trackback is added to a post.
 120       *
 121       * @since 1.2.0
 122       *
 123       * @param int $trackback_id Trackback ID.
 124       */
 125      do_action( 'trackback_post', $trackback_id );
 126      trackback_response( 0 );
 127  }