Incomprehensible value when routing, how to find out where the error comes from?

Question

Yii

here is the url

http://film.lc/serial/category/oneserial?id=serial-Bekstrom

do this
frontend/config/main

'urlManager' => [
                'enablePrettyUrl' => true,
                'showScriptName' => false,
                'rules' => [
                            [
                                 'class' => 'frontend\components\FilmUrlRule',
                            ],
                ],

frontend\components\FilmUrlRule

class FilmUrlRule extends Object implements UrlRuleInterface
    {
     public function createUrl($manager, $route, $params)
        {
            var_dump($route);
            var_dump($params);
    }
     public function parseRequest($manager, $request)
        {        return false;
        }
    }

I get the following value of var_dump why and how to understand where the routing error is?
string(19) "serial/category/all" array(0) { }

Answer 1

1. Your parseRequest returns false, which is what you expect from this code.
2. Why did the class appear in the rules
3. Why did it become necessary to create a class and override the standard one, why not do what you want with standard methods?

'urlManager' => [
            'enablePrettyUrl' => true,
            'showScriptName' => false,
            'rules' => [
'serial/category/oneserial' => 'mySomeController/myaction' 
            ],
],

Inside mySomeController:

public function actionMyaction($id){
echo $id;
}

or if serial and category are variables

'rules' => [
'<serial>/<category>/oneserial' => 'mySomeController/myaction' 
            ],

Inside mySomeController:

public function actionMyaction($id,$serial,$category){
echo $id;
echo $serial;
echo $category;
}