PHP Sessions will not carry over to other pages

Question

After years of developing websites and in this case, the same website I'm having a problem with, I'm at a complete loss with what's happening. I have a standard php login that consists of three pages:

login.php to input login information, checklogin.php to check the input credentials then home.php as the landing page

All of which have worked perfectly fine for years as they've barely been changed within that time. Now, recently I've moved hosting company and with that obviously meant the daunting task of re-installing all of my preferred web hosting software and configuring it to my websites needs. So anyway since the website coding hasn't changed, I've figured it must be a server problem, either the server configuration or a setting I must have missed out.

The configuration set up I have now worked for all of three days then 'poof' it just doesn't want to set sessions any more. I can set one and display it but if I try to carry it over to another page, it won't work.

Can anyone explain what may have just magically happened within three days that decided to just ruin everything?

A few notes:

• Yes, I am using session_start(); on my landing page and any I intend to take the sessions to.
• I've used the tags to give you an idea of what software my server is running for web pages (Since I'm still unsure what's causing it)
• The php session path is /var/lib/php/sessions/ which has the correct permissions for Apache/nginx
• MySQL is collecting the data and php is setting the sessions on page 2 but then page 3 seems to have lost the sessions.

Here's an example of a quick throw-together I did to test it:

Page 1: Setting the sessions:

<?php
session_start();
require_once'../connect.php'; // Database connection
$user_info = mysql_fetch_array(mysql_query("SELECT * FROM users WHERE id = '1'"));

$_SESSION['myid'] = $user_info['id'];
$_SESSION['myuser'] = $user_info['username'];

// Echo the set sessions just to make sure they set

echo 'ID: ' . $_SESSION['myid'] . ' - Username: ' . $_SESSION['myuser'] . '';
echo '<br /><a href="/page2.php">Click here to take your sessions to the next page</a>';
?>

Page 2: Moving on with the sessions:

<?php
session_start();
echo 'ID: ' . $_SESSION['myid'] . ' - Username: ' . $_SESSION['myuser'] . '';
?>

As you can see from the basic example above, page 2 should display my sessions but it just won't. Any help with this is much appreciated, it's driving me mad, mainly for the fact of not knowing what's causing it. Let me know if any further details are needed and I'll try to be as specific as possible.

Answer 1

First thing todo in such a situation is to turn on error reporting with this:

<?php
    error_reporting(E_ALL);
    ini_set("display_errors", 1);
?>

After that i would guess you don't have write permission on your tmp folder or the tmp folder is full!

So check your permissions on the folder and if it has space left.

Answer 2

Well I finally worked out where I was going wrong so I'll explain for anyone who runs into the same problem.

Having the PHP sessions stored in /var/lib/php/session was my main problem, not because of read/write permissions but because the partition of the / directory was absolutely tiny and filled with logs.

A quick fix would be to just delete the logs and anything else cluttering the directory but I personally went with moving the session storing directory to a bigger partition: /home

You can do this in your php.ini file which will probably be set to either /tmp or /var/lib/php/session

; session.save_path = "/home"

You will need to restart any php service and/or web server you have running to reload php.ini, in my case was nginx and php-fpm

$ service nginx restart
$ service php-fpm restart

(Depending on your OS) You can check how big your partitions are on your server with:

$ df -h

Which should give you something like this:

> df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
                       50G  6.1G   41G  13% /
tmpfs                  12G     0   12G   0% /dev/shm
/dev/sdb1             477M   60M  392M  14% /boot
/dev/mapper/VolGroup-lv_home
                      409G   71M  388G   1% /home

So just choose your preferred partition and make it your session path in php.ini

Thanks to everyone who commented trying to help solve my problem :)

Answer 3

What version of PHP are your servers running? I recently lost login authentication because of the upgrade to PHP v5.4(?not sure).

Basically, session_is_registered is depricated and gone. I switched to validating a session identity:

if(isset($_SESSION['valid_user']))

This may not be the most secure adaptation, but it worked for my low security website.