Call a function stored outside the class

American_horizo

Hi, i've this code saved into messagesManager.php
<?php

function isLogged()
{return $_SESSION['utente'];}


class gestioneMessaggi {

  private  $db;

  function connettiAlDatabase()
  { 	
     //...some code

//now i need to call the isLogged function
  }
}

?>

How i can call isLogged function from inside the method of the class?

Weedpacket

isLogged();

American_horizo

thanks works
Now for design decision i need to place the

function isLogged()
{return $_SESSION['utente'];}

in a separate file called checkSession.php
So, in need to include it into the messagesManager.php file
I tryed to use both include and require, but it throws this error:
Warning: Cannot modify header information - headers already sent by (output started at /home/u781508829/public_html/checkSession.php:5) in /home/u781508829/public_html/messagesManager.php on line 172

at line 172 i try to redirect to another page throught header location

The problem seems to be the open and close php tags placed in checkSession.php
<?php and ?>
removing the last one all works fine!

But the strange thing is that i've other files imported that use final ?> tag, why the error only appens for checkSession.php?

NogDog

Because you have some kind of white-space after one of the ?> tags (which is why I never use them at the end of a script 🙂 ).

PS: Depending on a user-defined function closely couples your class to the application code, which is less than desirable, but that's a whole 'nother discussion. 😉

American_horizo

NogDog;11039573 wrote:
Because you have some kind of white-space after one of the ?> tags (which is why I never use them at the end of a script 🙂 ).

No there are not white spaces

PS: Depending on a user-defined function closely couples your class to the application code, which is less than desirable, but that's a whole 'nother discussion. 😉

So, do you mean that is better to include the isLogged dunction inside the class?

NogDog

American horizo;11039597 wrote:
...
So, do you mean that is better to include the isLogged dunction inside the class?

Probably better is to include that function in some class, though it does not have to be the class in question here. It should be in a class that is related to what that function does. If the main class you're working on here needs that function -- or "method" now -- there are a few ways to handle it. My first choice is to pass an instance of the support class into the new class via its constructor, as this makes the dependency about as obvious as possible, and if you use type-hinting it will throw a fatal error the first time you test it if you fail to pass in an object of the appropriate type.

class Login
{
    function isLogged()
    {
        return $_SESSION['utente'];
    }
    // any other related functions...
}

///////////////////////////

class gestioneMessaggi {

  private  $db;
  private $login;

  public function __construct(Login $login)
  {
    $this->login = $login;
  }

  function connettiAlDatabase()
  {     

     //...some code

//now i need to call the isLogged function
if($this->login->isLogged() {
  // do something...
}
  }
}

///////////////////////////

//usage:

$test = new gestioneMessaggi(new Login());
$test->connettiAlDatabase();

This is by no means the only way, nor necessarily the best solution in all circumstances, but it's a good starting point for discussion/consideration, I think.

American_horizo

Uhm, i find much intuitive to write that

class gestioneMessaggi {

  private  $db;
  private $login;

  public function __construct()
  {
     $this->login=new Login();
  }

//...
}

it is equally feasible?

Weedpacket

Only if your [font=monospace]gestioneMessaggi[/font] objects will only have to use one precise class of login object, and will never have to deal with logins that aren't instances of the [font=monospace]Login[/font] class. (In NogDog's code [font=monospace]Login[/font] probably isn't a class, only an interface; an object of any class that implements that interface could be used.)

American_horizo

LoginClass.php assemble all methods for manage users login, so: check username, password, initialize sessions and check if session exists (isLogged method)
In gestioneMessaggi class, i only need to check if users that attempting to send a message is logged or not calling the isLogged method

Actually this is the idea.. In future probably i will need to use other methods of the LoginClass inside gestioneMessaggi, in this case which will be the right approach?

NogDog

It sounds like you are starting to think along the correct lines: put related attributes and functions into classes, and have other classes that deal with other "things" use instances of those other classes as needed, so that the "using" class's code remains dedicated to its specific are of interest.

If it helps, I found Matt Zandstra's book PHP 5 Objects, Patterns, and Pratice very helpful in making a lot of this take shape in my head. (I'm not sure how much it was the book versus how much I had simply reached the point where I was ready to start understanding it. 🙂 )

American_horizo

uhm i don't uderstand 😃

definetivly when use

 public function __construct(Login $login)
  {
    $this->login = $login;
  }

and when

 public function __construct()
  {
     $this->login=new Login();
  }

PHP 5 Objects, Patterns, and Pratice

thanks i wil lsearch for it

NogDog

Either of those approaches can work, and each can potentially be a better choice. Mainly it comes down to whether it makes sense for a class to create its own, discreet instance of a class separate from any other instance (which is what you get with your second example), or if you expect the class to use an already existing instance that is supplied to it (per your first example). For instance, you probably don't want each class that needs to access the database have to open up its own database connection, so it may be a good choice to make that a required parameter that must be passed into the containing class. I tend to find this approach (as per your first example) easier to maintain and less prone to errors, plus it affords me the ability to pass child classes derived from the parent class into the containing class without having to touch the containing class's code.

<?php

/**
 * Customized implementation of PDO
 */
class DB extends PDO
{
	// various code here to deal with DB queries and such
}

/**
 * Special use variation on the DB class
 */
class DB2 extends DB
{
	// various code here to deal with DB queries and such,
	// in a slightly different way
}

// ====================================================

/**
 * A class that needs access to the DB
 */
class Foo {
	private $pdo;
	public function __construct(PDO $pdo)
	{
		$this->pdo = $pdo;
	}
}

// =====================================================

// any of these would be valid:

$test1 = new Foo(new PDO($dsn));

$dbh = new DB($dsn);
$test2 = new Foo($dbh);

$test3 = new Foo(new DB2($dsn));