Simple HTTP routing utility

Router.php

<?php

/**
 * Class Router is static class which serves for routing purposes and can be used in 2 modes: full-map and on-the-go modes.
 *
 * Reads request uri path from $_GET['_REQUEST_URI']
 */

class Router
{
  const GET_VAR = '_REQUEST_URI';

	public static function explode($methods, $path)
	{
		self::route($methods, $path);
		return self::validateRoute($path);
	}

	public static function matches($methods, $path)
	{
		self::route($methods, $path);
		//var_dump(self::$map); die();
		return (bool) self::validateRoute($path);
	}

	public static function run()
	{
		foreach(self::$map as $path => $meta)
			if (self::validateRoute($path, 'withCallback') !== null)
				break;
	}

	/**
	 * Tries rule described by $path and returns:
	 * - tokens array, if rule contains @ symbol(s)
	 * - true, if rule is constant string
	 * - null, if rule does not meet
	 *
	 * Call route() for $path before to use this method.
	 *
	 * @param string $path Path of the route, to be key of self::$map
	 * @param bool $runCallback
	 * @throws LogicException
	 * @return mixed|null
	 */
	private static function validateRoute($path, $runCallback = false)
	{
		$path = self::slashTrim($path);
		if (!array_key_exists($path, self::$map))
			throw new LogicException('tryRule call before mapping route path.');

		$meta = self::$map[$path];

		self::init();

		if (!in_array('ALL', $meta['methods']) && !in_array(self::$METHOD, $meta['methods']))
			return null;

		switch ($meta['type'])
		{
			case 'const':
				if (self::$URI !== $path)
					return null;
				$tokens = true;
				break;
			case 'var':
				mb_regex_encoding('UTF-8');
				mb_ereg_search_init(self::$URI, $meta['regex']);
				if (!mb_ereg_search_regs())
					return null;
				$tokens = array_slice(mb_ereg_search_getregs(), 1);
				break;
			default:
				throw new LogicException('Unknown routing rule type');
		}

		if ($runCallback && is_callable($meta['callback']))
			call_user_func_array($meta['callback'], $tokens);

		return $tokens;
	}

	/**
	 * Parses route and adds it to self::$map
	 * @param string $methods Examples: 'ALL' , 'GET' , 'GET|POST'
	 * @param string $path Route path; both left and right slashes will be removed automatically
	 * @param callback $callback Standard PHP callback
	 * @param string $name Optional route name (for reverse-routing)
	 */
	public static function route($methods, $path, $callback = null, $name = null)
	{
		$methods = explode('|', trim(strtoupper($methods)));
		$methods = array_map('trim', $methods);
		$methods = array_filter($methods, 'strlen');

		# Trim both left and right slashes:
		# x-@/ and x-@ are the same route rules and will match x-10 and x-10/
		# Trailing slash at the end in the path specified makes no sense;
		# if in need for empty token after last slash, we expect x-@/@
		$path = self::slashTrim($path);

		$meta = array('name' => $name, 'methods' => $methods, 'callback' => $callback);

		if (mb_strpos($path, '@', null, 'UTF-8') === false)
			$meta['type'] = 'const';
		else
		{
			$r = '^'.str_replace('@', '([^/]*?)', preg_quote($path)).'/?$';
			$meta = array_merge($meta, array('type' => 'var', 'regex' => $r));
		}

		self::$map[$path] = $meta;
	}

	/**
	 * Initializes static fields from request variables.
	 */
	private static function init()
	{
		static $initialized = false;

		if (!$initialized)
		{
			if (array_key_exists(self::GET_VAR, $_GET))
				self::$URI = self::slashTrimL($_GET[self::GET_VAR]);
			else
				self::$URI = ''; // direct access to index.php, no redirect applied; or variable passed in GET

			self::$parts = explode('/', self::$URI); // allowed with UTF-8 strings because it is prefix-free
			self::$METHOD = strtoupper(trim($_SERVER['REQUEST_METHOD']));

			$initialized = true;
		}
	}

	/**
	 * Returns n-th segment of the path or null index is out of range.
	 * Left trailing slash removed from path.
	 * @param $n
	 * @return mixed
	 */
	public static function part($n)
	{
		self::init();
		return array_key_exists($n, self::$parts)? self::$parts[$n] : null;
	}


	public static function slashTrim($path)
	{
		return self::slashTrimL(self::slashTrimR($path));
	}

	public static function slashTrimR($path)
	{
		$l = mb_strlen($path, 'UTF-8');
		if (mb_substr($path, $l-1, 1, 'UTF-8') === '/')
			$path = mb_substr($path, 0, $l-1, 'UTF-8');
		return $path;
	}

	public static function slashTrimL($path)
	{
		if (mb_substr($path, 0, 1, 'UTF-8') === '/')
			$path = mb_substr($path, 1, mb_strlen($path, 'UTF-8')-1, 'UTF-8');
		return $path;
	}

	/**
	 * Comes from $_SERVER['REQUEST_METHOD'], trimmed and uppercased.
	 * @var string
	 */
	private static $METHOD;

	/**
	 * Comes from $_GET[self::GET_VAR], left trailing slash delimiter removed.
	 * @var string
	 */
	private static $URI;

	/**
	 * self::$URI exploded by "/"
	 * @var array
	 */
	private static $parts;


	/**
	 * Routing map, an array of items with following structure:
	 * ['type' => 'const|var', 'path' => '...', 'methods' => '', 'callback' => ..., 'name' => '...', 'regex' => '...']
	 *
	 * type = const -> path is a string without @ tokens, simple comparison is possible;
	 * type = var -> path contains @ tokens, regex required
	 *
	 * name - route name; null by default
	 *
	 * regex - only applicable for type=var
	 *
	 * @var array
	 */
	private static $map = array();



	public static function _test()
	{
		echo "slashTrimL(''): ".print_r(self::slashTrimL(''), true).'</br>';
		echo "slashTrimL('/'): ".print_r(self::slashTrimL('/'), true).'</br>';
		echo "slashTrimL('//'): ".print_r(self::slashTrimL('//'), true).'</br>';
		echo "slashTrimL('/x'): ".print_r(self::slashTrimL('/x'), true).'</br>';
		echo "slashTrimL('/x/'): ".print_r(self::slashTrimL('/x/'), true).'</br>';

		echo "slashTrimR('x/y'): ".print_r(self::slashTrimR('x/y'), true).'</br>';
		echo "slashTrimR('/x/y/'): ".print_r(self::slashTrimR('/x/y/'), true).'</br>';

		echo "slashTrim('/'): ".print_r(self::slashTrim('/'), true).'</br>';
		echo "slashTrim('/x/y/'): ".print_r(self::slashTrim('/x/y/'), true).'</br>';

		self::_testMethod('GET', 'dashboard', array(
			array('methodName' => 'matches', 'methods' => 'GET', 'path' => '/dashboard', 'expected' => true),
			array('methodName' => 'matches', 'methods' => 'GET', 'path' => 'dashboard', 'expected' => true),
			array('methodName' => 'matches', 'methods' => 'GET', 'path' => 'dashboard/', 'expected' => true),
			array('methodName' => 'matches', 'methods' => 'GET|POST', 'path' => '/dashboard/', 'expected' => true),
			array('methodName' => 'matches', 'methods' => 'ALL', 'path' => 'dashboard', 'expected' => true),
			array('methodName' => 'matches', 'methods' => 'ALL', 'path' => '/dashboard/@', 'expected' => false),
			array('methodName' => 'matches', 'methods' => 'GET', 'path' => 'dashboard-@', 'expected' => false)
		));

		self::_testMethod('GET', 'a/b', array(
			array('methodName' => 'matches', 'methods' => 'GET', 'path' => '/a/b/', 'expected' => true),
			array('methodName' => 'matches', 'methods' => 'ALL', 'path' => 'a/b', 'expected' => true),
			array('methodName' => 'matches', 'methods' => 'POST|GET|DELETE', 'path' => '/a/b/@', 'expected' => false),
			array('methodName' => 'matches', 'methods' => 'GET|POST', 'path' => '/dashboard/', 'expected' => false),
			array('methodName' => 'matches', 'methods' => 'GET', 'path' => '/a/b//', 'expected' => false)
		));

		self::_testMethod('POST', 'category-money/post-10', array(
			array('methodName' => 'explode', 'methods' => 'POST', 'path' => '/category-@/post-@', 'expected' => array('money', '10')),
			array('methodName' => 'explode', 'methods' => 'ALL', 'path' => 'category-@/post-@/', 'expected' => array('money', '10')),
			array('methodName' => 'explode', 'methods' => 'POST|GET|DELETE', 'path' => '/@/post-@', 'expected' => array('category-money', '10')),
			array('methodName' => 'explode', 'methods' => 'POST', 'path' => 'category-@', 'expected' => null),
			array('methodName' => 'explode', 'methods' => 'ALL', 'path' => 'category-/post-@', 'expected' => null)
		));
	}

	private static function _testMethod($method, $uri, $calls)
	{
		self::init();
		self::$METHOD = $method;
		self::$URI = $uri;
		echo "<h3>REQUEST: ".$method." /".$uri."</h3>";

		foreach($calls as $call)
		{
			$res = call_user_func(array('Router', $call['methodName']), $call['methods'], $call['path']);
			$ok = $res === $call['expected'];
			echo $call['methodName']."('".$call['methods']."', '".$call['path']."') = ".var_export($res, true);
			if ($ok)
				echo ' <span style="color: green">OK</span>';
			else
				echo ' <span style="color: red">ERROR</span>';
			echo "<br/>";
		}
	}
}