轻量级router[类似laravel router]

github地址：https://github.com/NoahBuscher/Macaw/blob/master/Macaw.php

代码加上一些注释，方便以后再看。

<?php namespace NoahBuscher\Macaw;

/**
 * method static Macaw get(string $route, Callable $callback)
 * method static Macaw post(string $route, Callable $callback)
 * method static Macaw put(string $route, Callable $callback)
 * method static Macaw delete(string $route, Callable $callback)
 * method static Macaw options(string $route, Callable $callback)
 * method static Macaw head(string $route, Callable $callback)
 */
class Macaw {
 public static $halts = false;
 public static $routes = array();
 public static $methods = array();
 public static $callbacks = array();
 public static $patterns = array(
  ':any' => '[^/]+',
  ':num' => '[0-9]+',
  ':all' => '.*',
 );
 public static $error_callback;
 /**
  * Defines a route w/ callback and method
  * 注册路由，把注册的方法(GET,POST..)，uri，closure分别push到对应的数组中
  */
 public static function __callstatic( $method, $params ) {
  $uri = $params[0];
  $callback = $params[1];
  array_push( self::$routes, $uri );
  array_push( self::$methods, strtoupper( $method ) );
  array_push( self::$callbacks, $callback );
 }
 /**
  * Defines callback if route is not found
  * 可以自定义没找到路由时执行的方法
  */
 public static function error( $callback ) {
  self::$error_callback = $callback;
 }

 /**
  * 自定义是否匹配到一次就停止，true停止，false不停止即可以定义多个同名路由，通过foreach全部执行
  * @param  boolean $flag true / false
  * @return none
  */
 public static function haltOnMatch( $flag = true ) {
  self::$halts = $flag;
 }
 /**
  * Runs the callback for the given request
  * 根据当前的uri匹配对应的路由并执行
  */
 public static function dispatch() {
  $uri = parse_url( $_SERVER['REQUEST_URI'], PHP_URL_PATH ); //路径部分(包括前边的/)，不包括参数
  $method = $_SERVER['REQUEST_METHOD'];   //方法 GET / POST / PUT / DELETE
  $searchs = array_keys( static::$patterns );
  $replaces = array_values( static::$patterns );
  $found_route = false;

  //check if route is defined without regex,检查是否定义了路由(非:any,:all形式的)
  if ( in_array( $uri, self::$routes ) ) {
   $route_pos = array_keys( self::$routes, $uri ); //返回匹配路由的键值，可能多个(同名路由)
   foreach ( $route_pos as $route ) {
    if ( self::$methods[$route] == $method ) {  //寻找路由对应的方法名(GET,POST...),确定是否注册。
     $found_route = true;
     //if route is not an object,检测对应闭包函数是function还是controller route
     if ( !is_object( self::$callbacks[$route] ) ) {
      //grab all parts based on a / separator 控制器路由
      $parts = explode( '/', self::$callbacks[$route] );
      //collect the last index of the array
      $last = end( $parts );
      //grab the controller name and method call
      $segments = explode( '@', $last );
      //instanitate controller
      $controller = new $segments[0]();
      //call method
      $controller->$segments[1]();
      if ( self::$halts )return;   //匹配一次就停止?

     }else {
      //call closure
      call_user_func( self::$callbacks[$route] );
      if ( self::$halts )return;
     }

    }

   }
  }else {
   //check if defined with regex 是否注册了正则路由(:any,:num..)
   $pos = 0;
   foreach ( self::$routes as $route ) {
    if ( strpos( $route, ':' ) !== false ) {
     $route = str_replace( $searchs, $replaces, $route );
    }
    if ( preg_match( '#^'.$route.'$#', $uri, $matched ) ) {
     if ( self::$methods[$pos] == $method ) {
      $found_route = true;
      array_shift( $matched );
      if ( !is_object( self::$callbacks[$pos] ) ) {
       //grab all parts based on a / separator
       $parts = explode( '/', self::$callbacks[$pos] );
       //collect the last index of the array
       $last = end( $parts );
       //grab the controller name and method call
       $segments = explode( '@', $last );
       //instanitate controller
       $controller = new $segments[0]();
       //call method and pass any extra parameters to the method
       $controller->$segments[1]( implode( ",", $matched ) );
       if ( self::$halts ) {
        return;
       }else {
        call_user_func_array( self::$callbacks[$pos], $matched );
        if ( self::$halts ) return;
       }

      }
     }
    }
    $pos++;
   }
  }

  //return the error callback if the route was not found
  if ( $found_route == false ) {
   if ( !self::$error_callback ) {
    self::$error_callback = function() {
     header( $_SERVER['SERVER_PROTOCOL']." 404 Not Found" ); //请求页面时通信协议的名称和版本。例如，“HTTP/1.0”。
     echo '404';
    }
   }
   call_user_func( self::$error_callback );

  }
 }
}