Problem with the magic method __call

Question

I’m trying to use the magic method __call and the function call_user_func_array to recover the method name to be able to upload a file. I am doing it as follows

//Classe que importa os objetos

$obj = 'NovoObjeto';

$metodo = 'importarXML';

$objCriado = new $obj();

$objCriado->$metodo();

Each object of mine extends from a class called FullObject and in that class I have the following statement of the magical method:

//FullObject
function __call($name,$arguments = null) {
    if(method_exists($this, $name)) { 
        $this->method = $name;
        return call_user_func_array(array($this,$name),$arguments);
    } else {
        throw new Exception('erro');
    }
}

//Classo NovoObjeto
class NovoObjeto extends FullObject {
    function importarXML() { ... }
}

The problem that happens is that if there is no method, it launches a Exception, but if there is the method it does not pass the method name to the property $this->method.

And I need to save this name, because I will be using it elsewhere, but I want to avoid having to pass it always as a parameter.

Answer 1

Your problem, if I understand correctly, boils down to not understanding exactly how the magic __call() method works and therefore have created a logic that would never work as expected.

See what the manual says (free translation):

Overload methods are invoked when interacting with properties or methods that have not been declared or are not visible in the current scope

Can you understand why I highlighted that term?

If the method not exist, __call() will be invoked. But your test launches a Exception if it does not exist, then its logic kills the functionality of this overload method.

If the method exists, __call() will not be invoked and with that, your property will not be populated.

What you could do is name the method somewhat different from the real, as an underline, a number or even by simply changing the visibility of the method (although this is wrong from the point of view of the Information Withholding Principle) and then consider this modification made to __call(), before invoking.

Another possible solution, a little more complex, is to use a Design Pattern called Decorator which, roughly speaking, is an object involving another, altering its functionality in Runtime.

Answer 2

I decided to do it this way:

$objCriado->{'_'.$metodo}();

//FullObject
public function __call($name, $arguments = null) 
{
  $realName = substr($name, 1);
  if(method_exists($this, $realName)) { 
    $this->method = $realName;
    return call_user_func_array(array($this, $realName), $arguments); 
  }else{ 
    throw new Exception('erro'); 
  } 
} 

I have now discovered that the magical method __call is called only when there is no method found, hence I forced the past methods not to exist so that I called him and could do what I needed.

I don’t know if it’s the best solution or not, but it’s the one I’ve found now so I can continue.