rbac authorization check in Yii doesn't work (Getting unknown property: app\models\Post::createdBy) - yii

Question

I looked at the documentation for rbac in Yii and thought I understood how it worked until I actually tried it.
This is the rule for checking whether the author of the post is trying to get the authorization for an action:
class AuthorRule extends Rule
{
public $name = 'isAuthor';
/**
* #param string|integer $user the user ID.
* #param Item $item the role or permission that this rule is associated with
* #param array $params parameters passed to ManagerInterface::checkAccess().
* #return boolean a value indicating whether the rule permits the role or permission it is associated with.
*/
public function execute($user, $item, $params)
{
return isset($params['model']) ? $params['model']->createdBy == $user : false;
}
}
This is how I am trying to use the rule and Yii's rbac:
public function actionUpdate($id)
{
$model = $this->findModel($id);
if (\Yii::$app->user->can('update', ['model' => $model])) {
if ($model->load(Yii::$app->request->post()) && $model->save()) {
return $this->redirect(['view', 'id' => $model->id]);
} else {
return $this->render('update', [
'model' => $model,
]);
}
}
}
However, I get this when I try to edit a Post:
Getting unknown property: app\models\Post::createdBy
So I thought I had to replace createdBy with userId which is a column in the table Post and I am getting a blank page meaning it doesn't work. So I am trying to guess what $user is.
I also tried:
return isset($params['model']) ? $params['model']->userId == $user->id : false;
and I am getting: Trying to get property of non-object.
What should I do to make it work? The doc seemed to suggest you just had to plug the conditional inside the controller action to make it work, but it doesn't seem to be the case at all.
var dump:
object(app\models\Post)[75]
private '_attributes' (yii\db\BaseActiveRecord) =>
array (size=6)
'id' => int 1
'userId' => int 1
'title' => string 'test' (length=4)
'content' => string 'lol' (length=3)
'dateCreated' => null
'dateUpdated' => null
private '_oldAttributes' (yii\db\BaseActiveRecord) =>
array (size=6)
'id' => int 1
'userId' => int 1
'title' => string 'test' (length=4)
'content' => string 'lol' (length=3)
'dateCreated' => null
'dateUpdated' => null
private '_related' (yii\db\BaseActiveRecord) =>
array (size=0)
empty
private '_errors' (yii\base\Model) => null
private '_validators' (yii\base\Model) => null
private '_scenario' (yii\base\Model) => string 'default' (length=7)
private '_events' (yii\base\Component) =>
array (size=0)
empty
private '_behaviors' (yii\base\Component) =>
array (size=0)
empty
null

Answer 1

The first error says, that you don't have a createdBy property in your Post model. Do you?
The second error is about trying to get a property of non-object variable. Could you show var_dump($params['model']); var_dump($user); before the return?