where-did-they-go-from-here Referer filter

gistfile1.txt

/**
 * Enqueues the scripts needed by WDTGFH.
 *
 * @since 1.7
 * @return void
 */
function wherego_enqueue_scripts() {
	global $post;

	if ( is_singular() ) {

		wp_enqueue_script( 'wherego_tracker', plugins_url( 'includes/js/wherego_tracker.js', WHEREGO_PLUGIN_FILE ), array( 'jquery' ) );

		wp_localize_script( 'wherego_tracker', 'ajax_wherego_tracker', array(
				'ajax_url' => admin_url( 'admin-ajax.php' ),
				'wherego_nonce' => wp_create_nonce( 'wherego-tracker-nonce' ),
				'wherego_id' => $post->ID,
				'wherego_sitevar' => wherego_get_referer(),
				'wherego_rnd' => wp_rand( 1, time() ),
			)
		);
	}

}
add_action( 'wp_enqueue_scripts', 'wherego_enqueue_scripts' );

/**
 * Referer filter
 * This allows us to manipulate and trick the plugin for custom tracking
 *
 * @return string
 */
function wherego_get_referer() {
	$referer = isset( $_SERVER['HTTP_REFERER'] ) ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_REFERER'] ) ) : '';
	return apply_filters( 'wherego_get_referer', $referer );
}