Check if loading from .dev tld (ie is local environment) adapted from http://stackoverflow.com/a/3211416/1469799

check_dev.php

<?php
function slug_check_dev() {

  $urlParts = parse_url( htmlspecialchars("//$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]", ENT_QUOTES, 'UTF-8' ) );
  $hostParts = explode('.', $urlParts[ 'host'] );
  $hostParts = array_reverse( $hostParts );
  if ( $hostParts[ 0 ] === 'dev' ) {
  	return true;
  }

}