Array Session Variable

rvr1 · Aug 26, 2004

I hope this will be a basic question for some of you – it’s my first major PHP project and I am picking it up as I go along.

Please can someone explain to me how to store a dynamic number of variables so that they can recalled on future pages. i.e. I wish to mimic the functionality of a shopping cart on a very basic level.

I am familiar with PHP sessions and static session variables, however, don’t really understand how to tackle the problem where the number of variables required is unknown. Some kind of array session variable perhaps?

Any help would be greatly appreciated.

sleipnir214 · Aug 26, 2004

An array will do it. Particularly a multidimensional associative array.

You can also store objects in session variables, too. The "gotcha" is that the class which the object instantiates must be included in your code before your invokation of session_start().

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kenrbnsn · Aug 26, 2004

You can store anything you want in a session variable, including arrays. For example:

Code:

<?
//in first program

start_session();

$test_array = array('1','12','abvd');

$_SESSION['ta'] = serialize($test_array);

?>

<?
//in the second program
start_session();

$test_array = unserialize($_SESSION['ta']);

?>

Read the PHP manual on serialize and unserialize.

Ken

sleipnir214 · Aug 26, 2004

You don't have to serialize and unserialize arrays or objects yourself. PHP does that task automatically.

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kenrbnsn · Aug 26, 2004

Really? I just did a quick test..
Here's the source:

Code:

<?
session_start();
$t = array('1','123','abc');
$_SESSION['t'] = $t;
$_SESSION['s'] = serialize($t);
echo '<pre>';print_r($_SESSION);echo '</pre>';
?>

Here's the result with PHP Version 4.3.8

Code:

Array
(
    [t] => Array
        (
            [0] => 1
            [1] => 123
            [2] => abc
        )

    [s] => a:3:{i:0;s:1:"1";i:1;s:3:"123";i:2;s:3:"abc";}
)

Maybe that's an option that can be turned on in the INI file. BTW, I got the same results on two different machines.

Ken

sleipnir214 · Aug 26, 2004

I don't understand your test. If you serialize an array, you get a string. If you store that string in a session, the next script will correctly retrieve a sting.

Here's my test scripts:

[tt]test_session_class.php[/tt]:

Code:

<?php

class fubar
{
	var $barfu;
	
	function fubar()
	{
		$this->barfu = 3;
	}
}
?>

[tt]test_complex_session1.php[/tt]:

Code:

<?php
include ('test_session_class.php');

session_start();

$_SESSION['bar'] = array
(
	'a' => array
	(
		'b' => array
		(
			'c' => array
			(
				'd',
				'e',
				'f'
			)
		)
	)
);

$_SESSION['baz'] = new fubar();
$_SESSION['baz']->barfu = 1;

print '<html><body><a href="test_complex_session2.php">here</a></body></html>';
?>

[tt]test_complex_session2.php[/tt]:

Code:

<?php
include ('test_session_class.php');
session_start();
print '<pre>';

print_r ($_SESSION['bar']);
print_r ($_SESSION['baz']);

?>

When I point my browser to test_complex_session1.php, it returns a simple link to test_complex_session2.php.

When I click on that link, test_complex_session2.php returns:

[tt]Array
(
[a] => Array
(
=> Array
(
[c] => Array
(
[0] => d
[1] => e
[2] => f
)

)

)

)
fubar Object
(
[barfu] => 1
)[/tt]

The arrays and objects are handed back and forth from one script to anther with no need for invocation of serialize() or unserialize(). This works with every version of PHP 4.3.x I've ever run (includuing 4.3.8) and with PHP 5.0.1.

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kenrbnsn · Aug 26, 2004

Ok.

I got it. I looked at the session temp file after running your example and it contained the serialized strings.

Code:

bar|a:1:{s:1:"a";a:1:{s:1:"b";a:1:{s:1:"c";a:3:{i:0;s:1:"d";i:1;s:1:"e";i:2;s:1:"f";}}}}baz|O:5:"fubar":1:{s:5:"barfu";i:1;}

I was getting confused with the output of the print_r. I was expecting it to show the raw contents of the session variable, not what PHP thinks I want to see. [sad]

Now I can go through my code and remove my serialize/unserialize pairs on session variables.

Ken

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Array Session Variable

rvr1

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sleipnir214

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kenrbnsn

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sleipnir214

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kenrbnsn

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sleipnir214

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kenrbnsn

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