Handler Loader Class

HandlerLoader.php

<?php

/**
 * class to load the handlers as callbacks for the given events/tags
 * @author  musaid <musaid@alliedmaldives.net>
 * @version  v0.1
 *
 * usage:
 * 		$handle = new HandlerLoader();
 * 		var_dump($handle->getHandlers('/var/www/crawler/folder/'));
 * 		var_dump($handle->getHandlers('/var/www/crawler/folder/', array('handler', 'denormalizer'))); 		
 */

class HandlerLoader {

	/**
	 * get handlers from the files in the given path
	 * @param  string $path directory/path name
	 * @param  array  $tags tags to distinguish relevant files
	 * @return array  $handlers     relevant handlers
	 */
	public function getHandlers($path, $tags = array()) {
		$files = $this->getFiles($path);

		$closures = array();
		$methods = array();

		$handlers = array();

		foreach ($files as $file) {
			$tokens = $this->tokenize($file);
			$handlers = $this->getClosures($handlers, $file, $tokens, $tags);
			$handlers = $this->getMethods($handlers, $tokens, $tags);
		}
		return $handlers;
	}

	/**
	 * get the files in the given path
	 * @param  string $path directory/path name
	 * @param  string $ext  extension of the files needed
	 * @return array $files list of files in the directory/path
	 */
	protected function getFiles($path, $ext = '.php') {

		// handle the extension if a . is provided
		if (preg_match('/^\.\w+/', $ext))
			$ext = str_replace('.', '', $ext);

		$iterator = new FilesystemIterator($path);
		while($iterator->valid()) {
			if (preg_match('/'.$ext.'/i', $iterator->getExtension())) {
				$file_name = $iterator->getPathname();
				$files[] = $file_name;
			}				
			$iterator->next();
		}
		return $files;
	}

	/**
	 * tokenize the files into an array
	 * @param  string $file file name including the path
	 * @return array       files content as tokens
	 */
	protected function tokenize($file) {
		return token_get_all(file_get_contents($file));
	}

	/**
	 * count the matching tags present in the docblock of the method/closure
	 * @param  string $str       docblock comment as a string
	 * @param  array  $tag_array tags to be compared
	 * @return int $matched_tag_count  number of matched tags
	 */
	protected function tagCount($str, $tag_array = array()) {
		preg_match('/@tags ([a-zA-Z0-9_\x7f-\xff, \n*\t]*)/ms', $str, $tags);
		$tags = explode(',', isset($tags[1]) ? $tags[1] : null);
		$tags = array_map(function($item) { return trim($item, "* \t\r\n"); }, $tags);

		$matched_tag_count = 0;

		foreach ($tag_array as $tag_name) {
			foreach ($tags as $tags_name) {
				if ($tag_name == $tags_name) {
					$matched_tag_count++;
				}
			}
		}
		return $matched_tag_count;
	}

	/**
	 * get the events related to each method/closure
	 * @param  string $str docblock comment as a string
	 * @return string      event associated with the method/closure
	 */
	protected function getEvent($str) {
		preg_match('/@event ([a-zA-Z0-9_\x7f-\xff, \t\x5C]*)/ms', $str, $event);
		return !empty($event) ? $event[1] : null;
	}

	/**
	 * get the closures with the given tags and it's associated event
	 * throws an array if the closure misses the event annotation
	 * @param  array  $handlers previous handlers (if any)
	 * @param  string $file     file name where the relevant handlers belong to
	 * @param  array $tokens   tokens to search for handlers
	 * @param  array $tags     tags associated to the handlers (if any)
	 * @return array           matched handlers as callbacks
	 */
	protected function getClosures($handlers = array(), $file, $tokens, $tags) {
		// require the file
		require_once($file);

		foreach ($tokens as $token) {
			if (!is_array($token) || $token[0] != T_VARIABLE) continue;

			$var_name = str_replace('$', '', $token[1]);

			if (!is_callable($$var_name)) continue;

			$rf_func = new ReflectionFunction($$var_name);
			$event = $this->getEvent($rf_func->getDocComment());
			if (empty($event)) {
				throw new Exception("No Event Provided in handler $$var_name in {$file} on line ".$rf_func->getStartLine(), 1);
			}

			if (!empty($tags) && $this->tagCount($rf_func->getDocComment(), $tags) == 0) continue;

			if (!isset($handlers[$event])) {
				$handlers[$event] = array();
			}
			$handlers[$event][] = $$var_name;

		}

		return $handlers;
	}

	/**
	 * get the methods with the given tags and it's associated event
	 * throws an array if the closure misses the event annotation
	 * @param  array  $handlers previous handlers (if any)
	 * @param  array $tokens   tokens to search for handlers
	 * @param  array $tags     tags associated to the handlers (if any)
	 * @return array           matched handlers as a callback (class name and method name)
	 */
	protected function getMethods($handlers = array(), $tokens, $tags) {

		$callback = false;
		$class_token = false;

		$i=0;

		foreach ($tokens as $token) {
			if (!is_array($token)) continue;


			if ($token[0] == T_CLASS) {
				$class_token = true;
			} else if ($class_token && $token[0] == T_STRING) {

				$reflection = new ReflectionClass($token[1]);
				foreach($reflection->getMethods(ReflectionMethod::IS_PUBLIC) as $prop) {
						$method = $prop->getName();
						$rf_method = new ReflectionMethod($token[1], $method);
						$callback = array($token[1], $method);

						if (!is_callable($callback)) continue;

						$event = $this->getEvent($rf_method->getDocComment());
						if (empty($event)) {
							throw new Exception("No Event Provided in handler '$method' in ".$rf_method->getFileName()." on line ".$rf_method->getStartLine(), 1);
						}
						
						if (!empty($tags) && $this->tagCount($rf_method->getDocComment(), $tags) == 0) continue;

						if (!isset($handlers[$event])) {
							$handlers[$event] = array();
						}
						$handlers[$event][] = $callback;
				}
				$class_token = false;
			}

			$i++;

		}
		return $handlers;
	}
}