How to store and receive variables in WP sessions?

6 comments

1. Sessions aren’t enabled in wordpress by default, if you want to activate php sessions add this at the beginning of your functions.php:

   if (!session_id()) {
       session_start();
   }
   

   You now can use $_SESSION['your-var'] = 'your-value'; to set a session variable. Take a look at the PHP documentation on sessions.

   ---

   Update:

   There was a second answer, which, in my mind, had a value too – unfortunately it got deleted, I’m re-adding the information here. The answer was referring to WP Session Manager a plugin written by @eamann as a alternative solution.
   I read some things about the plugin, but never used it because – so far – I’m sticking with PHP sessions – never had the problem that I couldn’t use them. This is a statement/comment by the plugin author himself I found about some possible advantages.

2. add this at in your functions.php

   <?php
   
   function tatwerat_startSession() {
       if(!session_id()) {
           session_start();
       }
   }
   
   add_action('init', 'tatwerat_startSession', 1);
   

3. Maybe there are no usual sessions in WordPress … anyway, WordPress knows the concept of users. You can manage information related to specific users with the the functions add_user_meta, update_user_meta, get_user_meta, and delete_user_meta.

   If you need the information saved in this way in JavaScript, you can write a little PHP script that vomits what you need, and call it with Ajax.

4. I will explain how to set a username session with the Native PHP Sessions for WordPress plugin. You can apply this logic to your problem.

   Add this to your functions.php file

   if (!session_id()) {
       session_start();
   }
   
     if ( isset( $_POST['wp-submit'] ) ){
   
       $_SESSION['username']=$_POST['log'];
   
     }
   

   $_POST[‘log’] is referencing the username input box from the wordpress login form. When a user logs in, the username is stored to $_SESSION[‘username’].
   In your case, you would change ‘log’ to the form variable names you have ‘car_color’.

   Reference the username later in some other php file by

   $username=$_SESSION['username'];
   

5. You must first start a session in WordPress but you can’t start a session in WordPress just like that.

   Before starting sessions, you need to check if some plugin started the session earlier because you may have unexpected problems. So you need a little algorithm for that.

   if (version_compare(PHP_VERSION, '7.0.0', '>=')) {
       if(function_exists('session_status') && session_status() == PHP_SESSION_NONE) {
           session_start(apply_filters( 'cf_geoplugin_php7_session_options', array(
             'cache_limiter' => 'private_no_expire',
             'read_and_close' => false
          )));
       }
   }
   else if (version_compare(PHP_VERSION, '5.4.0', '>=') && version_compare(PHP_VERSION, '7.0.0', '<'))
   {
       if (function_exists('session_status') && session_status() == PHP_SESSION_NONE) {
           session_cache_limiter('private_no_expire');
           session_start();
       }
   }
   else
   {
       if(session_id() == '') {
           if(version_compare(PHP_VERSION, '4.0.0', '>=')){
               session_cache_limiter('private_no_expire');
           }
           session_start();
       }
   }
   

   I’ve also added support for older PHP versions here.

6. On the PHP page that receives the AJAX request, set $_SESSION like this.

   $car_color = <user selected form input data>;
   $_SESSION['car_color'] = $car_color;
   

   Access the $_SESSION variable

   if(isset($_SESSION['car_color'])) {
       $value = $_SESSION['car_color'];
   } else {
       $value = 'Please select a car color.';
   }
   

   This tutorial goes into more detail about proper setup and disposal of sessions.

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