How to use external function in php route

I am building simple php route But I I have the following, which is working

Route::add('/', function(){
    echo 'Hello world message';
});

My challange is that… I want to be able to load the function directly from a controller which I am calling

use ControllersLoginController;

Route::add('/', LoginController::login());

the login() is a function i created inside LoginController class I get this error

<b>Warning</b>:  call_user_func_array() expects parameter 1 to be a valid callback, no array or string given in <b>C:xampphtdocsConfigRoute.php</b> on line <b>75</b><br />

My Route.php

<?php

namespace Config;

class Route{   private static $routes = Array();   private static $pathNotFound = null;   private static $methodNotAllowed = null;

  public static function add($expression, $function, $method = 'get')  {
    array_push(self::$routes,Array(
      'expression' => $expression,
      'function' => $function,
      'method' => $method
    ));   }

  public static function pathNotFound($function){
    self::$pathNotFound = $function;   }

  public static function methodNotAllowed($function){
    self::$methodNotAllowed = $function;   }

  public static function run($basepath = '/')

  {

    // Parse current url
    $parsed_url = parse_url($_SERVER['REQUEST_URI']);//Parse Uri

    if(isset($parsed_url['path'])){
      $path = $parsed_url['path'];
    }else{
      $path = '/';
    }

    // Get current request method
    $method = $_SERVER['REQUEST_METHOD'];

    $path_match_found = false;

    $route_match_found = false;

    foreach(self::$routes as $route){

      // If the method matches check the path

      // Add basepath to matching string
      if($basepath!=''&&$basepath!='/'){
        $route['expression'] = '('.$basepath.')'.$route['expression'];
      }

      // Add 'find string start' automatically
       //$route['expression'] = '^'.$route['expression'];
 
      //  Add 'find string end' automatically
       $route['expression'] = $route['expression'].'$';

      //echo $path.'<br/>';

      // Check path match 
      if(preg_match('#'.$route['expression'].'#',$path,$matches)){

        $path_match_found = true;

        // Check method match
        if(strtolower($method) == strtolower($route['method'])){

          array_shift($matches);// Always remove first element. This contains the whole string

          if($basepath!=''&&$basepath!='/'){
            array_shift($matches);// Remove basepath
          }
          call_user_func_array($route['function'], $matches);

          $route_match_found = true;

          // Do not check other routes
          break;
        }
      }
    }

    // No matching route was found
    if(!$route_match_found){

      // But a matching path exists
      if($path_match_found){
        header("HTTP/1.0 405 Method Not Allowed");
        if(self::$methodNotAllowed){
          call_user_func_array(self::$methodNotAllowed, Array($path,$method));
        }
      }else{
        header("HTTP/1.0 404 Not Found");
        if(self::$pathNotFound){
          call_user_func_array(self::$pathNotFound, Array($path));
        }
      }

    }

  }

}

Is there anyway i can make use of external function inside the route?

Answer

It wants a callback, so you need to pass a function itself. In your case using the parenthesis () invokes (calls) the function and returns the result of it instead of passing the function itself.

So here is a simple example of how you could do it:

Route::add('/', LoginController::login);

---

Wrapping it into a another function enables you to even pass arguments.

// shorthand function syntax since 7.4
Route::add('/', fn() => LoginController::login());

// example arguments (just a prototype)
Route::add('/', fn() => LoginController::login($username, $password));

or

Route::add('/', function() { LoginController::login() });

// example arguments (just a prototype)
Route::add('/', function() { LoginController::login($username, $password) });