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Laravel – why is my php protected variable being nulled in child class?

I have a Laravel controller with a protected var that I want to use in many other controllers, however when I try to access it in child class I got the error:

Call to a member function add() on null

which means that the previously initiated variable is now null and I don’t know why, the code:

class Controller extends BaseController {
  protected $ipfs_node_root;

  public function __construct() 
  {
    Funcoes::consolelog('Controller::creating ipfs node access point...');
    $ipfs_node_root = new IPFS();

  }

}

in a extended class:

class PostController extends Controller {

 private function handle(){

    Funcoes::consolelog('PostController::handle uploading file content to ipfs node.');
    // for the sake of test, I change the _root to _local ipfs_node and it works
    $ipfs_node_local = new IPFS();
    $arq_hash = $this->ipfs_node_root->add($arq->get());
 }
}

The PostController class has no __construct.

EDIT
I’ve added a __construct method to the child class but the error continues:

public function __construct() 
{
    parent::__construct();
    Funcoes::consolelog('PostController::__construct');
}
Tags:

2

Answers


  1. 0

    When you extend a class containing a constructor, the extension class must also contain a constructor and that constructor must call parent::_construct(), or you get what you’re gettting.

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  2. 0

    $ipfs_node_root = new IPFS(); is setting a separate, locally scoped variable that doesn’t exist outside the constructor.

    You want $this->ipfs_node_root = new IPFS(); instead.

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