Shortcode for Embedding GitHub Gist's - Used in DobsonDev Shortcodes Plugin for WordPress

embedGist-shortcode.php

<?php

/* Adds a shortcode for displaying GitHub Gists */
function dobson_create_github_gist($atts) {
  extract(shortcode_atts(array(
    'source' => "Invalid Source",
  ), $atts));
  $source_headers = @get_headers($source);
  if (strpos($source_headers[0], '404 Not Found')) {
    return '<p> Invalid GitHub Gist source. Please check your source. </p>';
  } else {
    return '<script src="' . $source . '.js"></script>';
  }
}
add_shortcode('embedGist', 'dobson_create_github_gist');

?>