PHP 5.4 Router

class.rewrite.php

<?php

	/**
	 * @package toolkit
	 */

	/**
	 * URL rewriter for use in conjunction with the PHP 5.4 internal HTTP server and `rounter.php`.
	 */
	namespace Rewrite;

	class Storage {
		static $matches = array();
	}

	/**
	 * Initialize the rewrite environment.
	 */
	function initialize() {
		set_environment($_SERVER['REQUEST_URI']);
	}

	/**
	 * Set important environment variables and re-parse the query string.
	 * @return boolean
	 */
	function finalize() {
		if (defined('REWRITER_FINALIZED')) return false;

		define('REWRITER_FINALIZED', true);

		if (\is_file($_SERVER['DOCUMENT_ROOT'] . $_SERVER['SCRIPT_NAME'])) {
			$_SERVER['SCRIPT_FILENAME'] = $_SERVER['DOCUMENT_ROOT'] . $_SERVER['SCRIPT_NAME'];
		}

		if (isset($_SERVER['QUERY_STRING'])) {
			$_GET = [];

			parse_str($_SERVER['QUERY_STRING'], $_GET);
		}

		$_SERVER['PHP_SELF'] = $_SERVER['SCRIPT_NAME'];

		return true;
	}

	/**
	 * Adjust the server environment variables to match a given URL.
	 * @param string $url
	 */
	function set_environment($url) {
		$url = rtrim($url, '&?');
		$request_uri = $script_name = $url;
		$query_string = null;

		if (strpos($url, '?') > 0) {
			$script_name = substr($url, 0, strpos($url, '?'));
			$query_string = substr($url, 1 + strpos($url, '?'));
		}

		$_SERVER['REQUEST_URI'] = $request_uri;
		$_SERVER['SCRIPT_NAME'] = $script_name;
		$_SERVER['QUERY_STRING'] = $query_string;
	}

	/**
	 * Parse regular expression matches. eg. $0 or $1
	 * @param string $url
	 * @return string
	 */
	function parse_matches($url) {
		$replace = function($bit) {
			return isset(Storage::$matches[$bit[1]])
				? Storage::$matches[$bit[1]]
				: null;
		};

		return preg_replace_callback('/\$([0-9]+)/', $replace, $url);
	}

	/**
	 * Parse Apache style rewrite parameters. eg. %{QUERY_STRING}
	 * @param string $url
	 * @return string
	 */
	function parse_parameters($url) {
		$replace = function($bit) {
			return isset($_SERVER[$bit[1]])
				? $_SERVER[$bit[1]]
				: null;
		};

		return preg_replace_callback('/%\{([A-Z_+]+)\}/', $replace, $url);
	}

	/**
	 * Change the internal url to a different url.
	 * @param string $from Regular expression to match current url, or optional when used in conjunction with `test`.
	 * @param string $to URL to redirect to.
	 * @return boolean
	 */
	function rewrite($from, $to = null) {
		if (defined('REWRITER_FINALIZED')) return false;

		$url = $_SERVER['SCRIPT_NAME'];

		// From and To given:
		if (isset($to)) {
			$url = preg_replace($from, $to, $url);
		}

		// Use results from last test:
		else {
			$url = parse_matches($from);
		}

		set_environment(
			parse_parameters($url)
		);

		return true;
	}

	/**
	 * Redirect the client to a different url.
	 * @param string $from Regular expression to match current url, or optional when used in conjunction with `test`.
	 * @param string $to URL to redirect to.
	 */
	function redirect($from, $to = null) {
		if (defined('REWRITER_FINALIZED')) return false;

		$url = $_SERVER['SCRIPT_NAME'];

		// From and To given:
		if (isset($to)) {
			$url = preg_replace($from, $to, $url);
		}

		// Use results from last test:
		else {
			$url = parse_matches($from);
		}

		$url = parse_parameters($url);

		header('Location: ' . $url); exit;
	}

	/**
	 * Compare a regular expression against the current request, store the matches for later use.
	 * @return boolean
	 */
	function test($expression) {
		if (defined('REWRITER_FINALIZED')) return false;

		return 0 < (integer)preg_match($expression, $_SERVER['SCRIPT_NAME'], Storage::$matches);
	}

	/**
	 * Does the current request point to a directory?
	 * @return boolean
	 */
	function is_dir() {
		if (defined('REWRITER_FINALIZED')) return false;

		return \is_dir($_SERVER['DOCUMENT_ROOT'] . $_SERVER['REQUEST_URI']);
	}

	/**
	 * Does the current request point to a file?
	 * @return boolean
	 */
	function is_file() {
		if (defined('REWRITER_FINALIZED')) return false;
		
		return \is_file($_SERVER['DOCUMENT_ROOT'] . $_SERVER['REQUEST_URI']);
	}

router.php

<?php

	/**
	 * Router for the testing HTTP server built into PHP 5.4.
	 * Use with the following command from the root directory
	 * of your Symphony installation:
	 *
	 *	php -S localhost:8080 router.php
	 *
	 * If you need to add your own rules, copy this file and
	 * use it as your own custom router.
	 */

	namespace Rewrite;

	require_once 'symphony/lib/toolkit/class.rewrite.php';

	// Prepare environment:
	initialize();

	// SECURITY - Protect crucial files
	test('%^/manifest/(.*)%')
		| test('%.+\.(sql|xsl)$%')
		| test('%^/\.%')
		&& die('<h1>Access Denied</h1>');

	// Do not apply rules when requesting actual files:
	if (is_file()) return false;

	// Make sure the URL ends in a trailing slash:
	test('%(?=/$)%')
		|| redirect('%^.+%', '$0/');

	// Remove references to index.php:
	test('%/(symphony/)?index.php(/.*/?)%')
		&& redirect('$1$2');

	// Admin area rewrite:
	test('%^/symphony/?$%')
		&& rewrite('/index.php?mode=administration&%{QUERY_STRING}')
		&& finalize();

	test('%/symphony(\/(.*\/?))?$%')
		&& rewrite('/index.php?symphony-page=$1&mode=administration&%{QUERY_STRING}')
		&& finalize();

	// Frontend page rewrite:
	rewrite('%^/(.*\/?)$%', '/index.php?symphony-page=$1&%{QUERY_STRING}')
		&& finalize();

	if (isset($_SERVER['SCRIPT_FILENAME'])) {
		include_once $_SERVER['SCRIPT_FILENAME'];
	}

	else {
		include_once 'index.php';
	}