Create a Shortcode in WordPress to display Gists by ID. (Example: [github-gist id="GIST-ID"])

WordPress Gist Shortcode

add_shortcode('github-gist', 'pu_embed_gist');
function pu_embed_gist($atts, $content = null)
{
  extract(shortcode_atts(array('id' => null), $atts));
	if( $id != null)
	{
		$args = array('sslverify' => false);
		$result = wp_remote_get('https://api.github.com/gists/' . $id, $args);
		$json = json_decode($result['body'], true);
		if(isset($json['description']))
		{
			$description = $json['description'];
			if(isset($json['files']['gistfile1.txt']['content']))
			{
				$content = $json['files']['gistfile1.txt']['content'];
				echo '
<h2>'.$description.'</h2>
';
				echo '
<pre><code>';
				echo $content;
				echo '</code></pre>
';
			}
		}
	}
}