Question

I know it looks like a banal question but please read the whole thing, I am stumped by this.

I have an AJAX call on one of my pages, it’s a dynamic messaging system:

function validateMessage(){

  var recipient = document.getElementById("send_to").value;
  var subject = document.getElementById("popup_subject").value;
  var message = document.getElementById("popup_message").value;

  var parameters="message="+message+"&recipient="+recipient+"&subject="+subject;

   if (window.XMLHttpRequest)
    {// code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp=new XMLHttpRequest();
   }
   else
   {// code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
   }

   xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
        document.getElementById("error_mess").innerHTML = xmlhttp.responseText;
    }
  }

  xmlhttp.open("POST","include/send_message.php",false);
  xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
  xmlhttp.send(parameters);

  }

It’s implemented as synchronous for a reason, that’s not the issue here. I tried switching to asynchronous and the problem remains.

This is the send_message.php file, it just grabs the POST variables and saves them into the database:

<?php
session_start();
include('db.php');
dbConnect();

$message=$_POST['message'];
$subject=$_POST['subject'];
$recipient=$_POST['recipient'];

$result=mysql_query("select * from korisnici where username='$recipient' ") or die(mysql_error());
$row=mysql_fetch_array($result);
$num=mysql_num_rows($result);

if($recipient=="Poruka za..." || $subject=="Naslov..." || $message=="Poruka" || $recipient=="" || $subject=="" || $message=="")
    echo "<p style='color:red;'>Morate popuniti sva polja.</p>";
elseif($num==0)
    echo "<p style='color:red;'>Korisnik ne postoji.</p>";
else{
    $prima=$row['id_user'];
    $salje=$_SESSION['id_user'];
    mysql_query("insert into poruke (salje, prima, naslov, poruka)
        values ('$salje', '$prima', '$subject', '$message') ") or die(mysql_error());
    echo "<p style='color:green;'>Poruka uspješno poslata!</p>";
}

?>

However, when I tried to save the $_SESSION[‘id_user’] variable (as the sender) I found a problem – it turns out the session is being destroyed every time this AJAX call runs! So doing print_r($_SESSION) right after session_start() prints an empty array.

The session is alive on the original page itself, and refreshing that page keeps the session alive. Only when I click the button to make the AJAX call, the session disappears. Can someone spot the issue?

Answer 1

Here’s the solution, as given to me by he technical support team of my hosting provider:

Set suhosin.session.encrypt=Off in /home/username/public_html

Set suPHP_ConfigPath /home/username/public_html in .htaccess.

And that’s it, works now. No time to investigate these settings at this point, but I hope this will help someone in the same situation.