Antispambot WordPress shortcode function

antispambot-wordpress-shortcode.php

<?php
/**
 * Hide email from Spam Bots using a shortcode.
 * Anti-Spambot Email Shortcode, v1.1.1
 * https://wordpress.org/plugins/antispambot
 *
 * @param array  $atts    Shortcode attributes. Not used.
 * @param string $content The shortcode content. Should be an email address.
 *
 * @return string The obfuscated email address.
 */
function wpcodex_hide_email_shortcode( $atts , $content = null ) {
	$email = strtok($content,'?'); //allow e.g. ?subject=foo+bar&body=bif in email
	$urlpart = strtok('');
	if (strlen($urlpart) > 0) {
		$urlpart = '?'.$urlpart;
	}
	if ( ! is_email( $email ) ) {
		return $content;
	}
	extract( shortcode_atts( array(
				'hex_encoding' => 0,
				'nolink' => false,
				'linktext' => false,
			), $atts, 'antispambot' ) );
	if ($nolink) {
		return antispambot( $email, $hex_encoding );
	} else {
		$url = esc_url('mailto:' . antispambot( $email, $hex_encoding ) . $urlpart );
		if ($linktext) {
			return '<a href="'. $url . '">' . htmlspecialchars($linktext) . '</a>';
		} else {
			return '<a href="'. $url . '">' . antispambot( $email, $hex_encoding ) . '</a>';
		}
	}
}
add_shortcode( 'email', 'wpcodex_hide_email_shortcode' );