PHP Mass Redirection

redirects.php

<?php

	/**
	 * Simple PHP script for mass redirects
	 * 
	 * @author:  Michael Niles <github@blindmikey.com>
	 * @version: 1.0.0
	 */

	/**
	 * To Use, add this line to the top of your wp-config.php:
	 * require_once 'redirects.php';
	 */

	$new_site_domain = 'www.mynewsite.com';

	/**
	 * Array of redirects
	 *
	 * In the format of: {from} => {to}
	 * Where {to} is relative to yoursite.com
	 * And Where {from} is without http:// or https:// and without a trialing "/"
	 *
	 * @var array
	 */
	$redirects = array (
		/**
		 *
		 * REDIRECT BLOCK
		 *
		 */
		'www.somedomain.com' => '/welcome/',
	);


	/**
	 *
	 * Do not tread below - there be dragons
	 *
	 */

	$current_url = rtrim($_SERVER[HTTP_HOST] . $_SERVER[REQUEST_URI], '/');

	// optional:
	// catch sub.domain.ext/page/X and turn into sub.domain.ext
	// else if catch sub.domain.ext/?cat=X and turn into sub.domain.ext
	/*
	$pagePattern = '/\/page\/[0-9]+/i';
	$catPattern = '/\/\?cat\=[0-9]+/i';
	if ( preg_match($pagePattern, $current_url, $match) )
	{
		$current_url = str_replace($match[0], '', $current_url);
	}
	else if ( preg_match($catPattern, $current_url, $match) )
	{
		$current_url = str_replace($match[0], '', $current_url);
	}
	*/

	// look into our redirect array and if we find a match, redirect
	if ( ! empty($redirects[$current_url]) ) {
		$redirect_to = $redirects[$current_url];
		header('Location: http'.(isSecure() ? 's' : '').'://'.$new_site_domain.$redirect_to, true, 301);
		die();
	}

	// make sure we serve https if needed
	function isSecure() {
		return (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off')
		       || $_SERVER['SERVER_PORT'] == 443;
	}