[Resolved] Classes and Sessions

[ethought]

I am learning how to use classes in PHP and storing them and retrieving values of the classes from a Session. But I am getting an error and not sure why.

user.php

<?php

class User
{
	var $username;
	var $firstname;
	var $lastname;

	function setFirstname($data)
	{
		$this->firstname = $data;
	}

	function getFirstname()
	{
		return $this->firstname;
	}

}


?>

Filling Class

session_start();
include('user.php');
$user = new User;
$user->setFirstname('Gregg');		
$_SESSION['user'] = $user;

Accessing Class

session_start();
echo "Welcome " . $_SESSION['user']->getFirstname();

Error I recieve

Fatal error: Unknown(): The script tried
 to execute a method or access a 
property of an incomplete object. 
Please ensure that the class definition 
[b]user[/b] of the object you are trying 
to operate on was loaded _before_ the
 session was started

Not too sure what is going on here. Can someone help?

Thanks.

[kellog]

Your not executing the class properly. Your trying to make a session variable = an object.

$user->setFirstname('Gregg');		
$_SESSION['user'] = $user;

What you want to do is this:

$result = $user->setFirstname('Gregg');		
$_SESSION['user'] = $user->firstname;

Note, you can also have the object return data, such as:

class User
	{
		var $username;
		var $firstname;
		var $lastname;

	function setFirstname($data)
	{
		return $data;
	}

}


$result = $user->setFirstname('Gregg');	
$_SESSION['user'] = $result

[ethought]

I see your point. But I am wanting to put the Class object into the Session so I can access that class object whenever I need the user information. Rather than adding a Session variable for every parameter.

[kellog]

Originally posted by ethought
I see your point. But I am wanting to put the Class object into the Session so I can access that class object whenever I need the user information. Rather than adding a Session variable for every parameter.

As far as I know, that's not possible. What you can do is something like this:

class User
{
	function GetUserData()
	{
		//Code to grab user info from database or wherever you have it.

	//After you retrieve it, parse it into an array and return the array.
	$UserInfo = array ("FirstName" => $FirstName, "LastName" => $LastName, "Whatever" => $Whatever);

	return $UserInfo;
}
}

Then to use the function:

session_start();
include('user.php');
$UserObj = new User;
$Result = $UserObj->GetUserData();		
$_SESSION['info'] = $Result;

//User info can easily be retrieved from a single session variable
echo $_SESSION['info']['FirstName'];
echo $_SESSION['info']['LastName']; //And so on...

[ethought]

Then what's the point of a Class? I could just as easily created a function without the class to perform this.

I think this is possible. I have seen a lot of discussions on this, I just can't get it to work.

[goldbug]

You need to serialize and unserialize the class/session variable in order to pass it.

http://www.php.net/manual/en/function.serialize.php
and
http://www.php.net/manual/en/function.unserialize.php

See also: http://www.php.net/manual/en/language.oop.serialization.php

[ethought]

Originally posted by goldbug
You need to serialize and unserialize the class/session variable in order to pass it.

http://www.php.net/manual/en/function.serialize.php
and
http://www.php.net/manual/en/function.unserialize.php

See also: http://www.php.net/manual/en/language.oop.serialization.php

Those links helped out a great deal. Specifically the last link. I have anoter quesiton. the documentation states:

If you are using sessions and use session_register() to register objects, these objects are serialized automatically at the end of each PHP page, and are unserialized automatically on each of the following pages

Since session_register is depricated and now I should be using $_SESSION['bla'] = $whatever I am assuming I need to serialize and unserialize my class objects manually. Is this correct?

Thanks.

[swr]

You certainly can use $_SESSION['object'] =& $object. The only complication (and the one you encountered) is that you need the class definition available when you go to access it. You need to put the "class User { ..." code into a include file, then include it before calling session_start(). Otherwise it doesn't have the class definition, and can't restore the object.

Serialize and unserialize are still useful though. Placing objects into session variables can cause problems if there are references (they will be de-referenced). Serialize and unserialize will preserve references within the serialized data.

[ethought]

Ok, thanks everyone for all the help. It's all working great now!