// SHORTCODE - Include File
// http://www.amberpanther.com/knowledge-base/using-the-wordpress-shortcode-api-to-include-an-external-file-in-the-post-content/

function include_file($atts) {
  //check the input and override the default filepath NULL
  //if filepath was specified
  extract(shortcode_atts(array('filepath' => 'NULL'), $atts));
  //check if the filepath was specified and if the file exists
  if ($filepath!='NULL' && file_exists(CHILD_SS_DIR.$filepath)){
  //turno on output buffering to capture script output
  ob_start();
  //include the specified file
  include(CHILD_SS_DIR.$filepath);
  //assign the file output to $content variable and clean buffer
  $content = ob_get_clean();
  //return the $content
  //return is important for the output to appear at the correct position
  //in the content
  return $content;
  }
}
//register the Shortcode handler
add_shortcode('include', 'include_file');