Session variables $ _SESSION vs class variables in PHP

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Session variables $ _SESSION vs class variables in PHP

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#1 by (1 votes)

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I wanted to know the pros and cons of using session variables in class constructor or even within the methods of a class.

Let's say I have the following class:

class minhaClasse {
    private $arrEnvSettings;

    public function __construct(array $setParam=NULL) {

        $arrIni["userType"] = $_SESSION["userType"];
        //$arrIni["outrasVar"] = "valor padrão de inicialização";


        //Unindo $setParam com $arrIni
        //Permite mudar os valores de inicialização
        if(!is_null($setParam)){
            $this->$arrEnvSettings =  array_merge($arrIni,$setParam);
        }
        else{
            $this->$arrEnvSettings =$arrIni;
        }
    }

    public function homePage() {

        if($this->$arrEnvSettings["userType"]=1){
            //Mostrar home page admin
        }
        else{
            //Mostrar home page para não admin
        }

    }
}

As an example I have a system that was designed to be accessed say by 8 types of users. At the beginning of the process, when we are testing the login and password we will be able to recover the $userType and save it inside the $_SESSION["userType"]=1 session, for example (ADMIN).

Later when I instantiate the object, I could use the following two examples:

//Exemplo - 1
$objSite = new minhaClasse();
echo $objSite->homePage();

//ou

//Exemplo - 2
$arrInicializ ["userType"]= $_SESSION["userType"];
$objSite = new minhaClasse(arrInicializ);
echo $objSite->homePage();

In example 1 it would not be necessary to initialize the variable with the value of the session because it is already done in the constructor (default). This would save many lines of code every time the object was used.

In the second example we would have to initialize the variable every time the object was instantiated. We would have more line of code, but we would not be using the session within the class.

What leads to a question: Is using a session within classes a good practice or not?

If yes , we could even save variables within the class (within methods) because we could access the direct value of $ _SESSION. And with that the code would have fewer rows. But I do not know if it would be good practice.

If not , we would have to start the class variables with the values of the session variables (each instantiation) and then use the variables within the class (as the theory says - good practice) , but would this create "unnecessary" lines? in the code.

What do you think?

php classes instanciar-objeto

asked by anonymous 05.05.2016 / 19:12

1 answer

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score 1 · Answer 1

In this case, I share with the same idea that I learned when I started to learn Python : Explicit is better than Implicit

Why?

When I move from the data I'm going to work with within a class, it's easier to know what's going to be used. When you implicitly use $_SESSION within the class, you may be limiting its use to various factors.

I mean the following: If you need to make any changes to the data used, you would have to "fuck" the source code of your class. And I do not think it's cool, because you may have to change all the points where you are instantiating this class.

As I said, I prefer "explicit than" implicit. "Then I would do it this way:

class MinhaClasse
{
         protected $dadosSessao = [];

         public function __construct(array $dadosSessao, $outro = null)
         {
               $this->setDadosSessao($dadosSessao);
         }

         public function setDadosSessao($dadosSessao)
         {
             $this->dadosSessao = $dadosSessao;
         }


}

The way to use it would look like this:

 $minha_classe = new MinhaClasse($_SESSION, OUTRO_VALOR);

An interesting option you can do in this case is to create a static method, which will be used to create the instance of your class based on $_SESSION . This method will work as a factory.

class Session {

     // Pode receber os dados indepedente do mecanismo do PHP ou não

     public function __construc(array $data)

     {
          $this>data = $data;
     }

     public static function createFromGlobalSession()
     {
          return new static($_SESSION);
     }
}

$session = Session::createFromGlobalSession();