CODEWITHSUNDEEP
phpmysqlsession
Michael.Lumley
Michael.Lumley

Reputation: 2385

Updating PHP Session Variables When Database Changes

Bottom Line Up Front: Is there a way to update session variables from a script on the server running outside the session?

Detail: I am using MySQL to store large amounts of user information. When a user logs in, I store some of that information in $_SESSION, as a way of caching the data in order to cut down on the number of SELECT queries. The user works with the data, and any changes made are saved to the database.

The problem is that the data on the database could change while the user is working with the $_SESSION representation of the data. In that case, one set of changes could overwrite the other. It's not feasible to 'lock' the data in the database while it is being used in $_SESSION.

It would be fairly straightforward to flag the database with a $_SESSION id when the data is 'checked out' and then update the $_SESSION representation of the data, if a script makes changes to the checked out data. I just don't know what (if anything) can be called from a script on the server called outside the session to change the variables within that session.

Upvotes: 0

Views: 3235

Answers (3)

Samiul Amin Shanto
Samiul Amin Shanto

Reputation: 1397

After getting your comment, I think this solution will work for you:

when you start session, keep session id in you database: i.e

<?php
session_start();
$sid = session_id(); // suppose o4lb6s392r2mj1vv6nhlrjfmp1
$_SESSION['user_solr'] = 'admin';

you will get a string. when you want alter session data, without refresh user page load, do following to change user's session data:

<?php
session_id('o4lb6s392r2mj1vv6nhlrjfmp1'); // previous session id
session_start();
$_SESSION['user_solr'] = 'editor';

Updated: This will also work:

<?php
session_start('o4lb6s392r2mj1vv6nhlrjfmp1'); // previous session id
$_SESSION['user_solr'] = 'editor';

Upvotes: 3

Alexandru Guzinschi
Alexandru Guzinschi

Reputation: 5726

Store your session in database and use SQL trigger to update the session table. That way when the user table is changed, the sql trigger will update the session table also.

You can read more and see some examples in MySQL documentation

Upvotes: 1

Max Langerak
Max Langerak

Reputation: 1207

What you could do is make an Ajax request to the server every so often, which checks whether the session variables have been updated:

place the $_SESSION variables inside of a hidden input, and send it towards the server.

your php/html

<form id='formid'>
<input type='hidden' name='name' value='<?php echo $_SESSION['name']; ?>'>
</form>

the JS 

window.setInterval($("#formid").submit());

$("#formid").submit(function(){
   $.ajax({
      type: "POST",
      url: "someFileToUpdateTheSession.php",
      data: $(this).serialize(),
      success: function(){
          // Do what you want to do when the session has been updated
      }
   });

   return false;
});

Other php file

<?php
   session_start();
   $_SESSION["name"] = $_POST["name"];
   // etc.
?>

Then you just check if the $_SESSION variables have changed, and if so, you update the $_SESSION variables.

Upvotes: 0

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