Class Object in PHP session reset during AJAX operation?

Question

I have a simple example of PHP sessions and AJAX, which works when holding an array in session:

Request file:

<?php
    session_start();
    $_SESSION['data'] = array('foo','bar');
    echo count($_SESSION['data']);
?>
<html>
<head>
    <title>Test</title>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.6.1/jquery.min.js"></script>
</head>
<body>
    <button id="but1">Go</button>
    <script type="text/javascript">
        $('#but1').click(function() {
            $.ajax({
                url:'ajaxtest_remote.php',
                success:function(result) {
                    alert(result);
                }
            });
        });
    </script>
</body>
</html>

Remote file:

<?php
    session_start();
    echo 'count=' . count($_SESSION['data']);
?>

The echo on the first file shows 2, and the alert in the success function displays "count=2". Happy days.

Where the problem happens is if I swap my array for a class object:

Request File:

<?php
    session_start();
    include('ajaxtest_class.php');
    $_SESSION['obj'] = new TestClass('foo,bar');
    echo count($_SESSION['obj']->dataList);
?>
<!-- HMTL AS ABOVE -->

Remote File:

<?php
    session_start();
    echo 'count=' . count($_SESSION['obj']->dataList);
?>

Class File:

<?php
    class TestClass {
        var $dataList;
        function TestClass($incoming) {
            $this->dataList = explode(',',$incoming);
        }
    }
?>

This still displays a 2 on the first page, but the ajax success alert comes back "count=0". Can anyone explain why this is?

Update1

If I import the class file into remote it still doesn't work, although I can prove the class is loaded.

<?php
    session_start();
    include('ajaxtest_class.php');
    $c = new TestClass('a,b,c');
    echo 'count=' . count($_SESSION['obj']->dataList) . '-' . count($c->dataList);
?>

The new alert from the ajax success reads count=0-3.

Update2

var_dump($_SESSION['obj']);

object(__PHP_Incomplete_Class)#8 (2) {
    ["__PHP_Incomplete_Class_Name"]=>
    string(9) "TestClass"
    ["dataList"]=>
    array(2) {
        [0]=>
        string(3) "foo"
        [1]=>
        string(3) "bar"
    }
}

try to debug it both times with a var_dump. are you on an old php4 ? or why do you write your classes like this. php5 way would be to have a function __construct($incoming) — Rufinus
– Rufinus, Commented Jun 9, 2011 at 14:07
I don't get to try oop PHP very often, still very much a novice! So I should just replace the name of my constructor with _construct? — shanethehat
– shanethehat, Commented Jun 9, 2011 at 14:19

Fosco · Accepted Answer · 2011-06-10 13:23:06Z

6

You would need to include the Class in the remote_ajax file (before session_start()):

edit: The serialize/unserialize requirement is a limitation of PHP4.

Request file:

<?php
include('ajaxtest_class.php');
session_start();
$_SESSION['obj'] = serialize(new TestClass('foo,bar'));

Remote file:

<?php
    session_start();
    include('ajaxtest_class.php');
    $obj = unserialize($_SESSION['obj']);
    echo 'count=' . count($obj->dataList);
?>

In PHP, the class constructor should be defined differently:

<?php
    class TestClass {
        var $dataList;
        function __construct($incoming) {
            $this->dataList = explode(',',$incoming);
        }
    }
?>

edited Jun 10, 2011 at 13:23

answered Jun 9, 2011 at 14:04

Fosco

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18 Comments

netcoder Over a year ago

+1 Indeed, unless the class is loaded, it will be a __PHP_Incomplete_Class with no dataList property.

shanethehat Over a year ago

I've made the adjustment exactly as above, but still get count=0

Fosco Over a year ago

@shanethehat I posted a quick troubleshooting step.. what does var_dump return?

shanethehat Over a year ago

Thanks, I've updated the question with the output. It is an incomplete class, even after importing the class file.

shanethehat Over a year ago

I've figured it out. You must include the class file before calling session_start(). Makes sense I suppose.

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