Something weird is happening in my class. Basically I'm trying to manipulate the $wp_admin_bar through AJAX but when I receive the response I get a NULL value. Although debugging the global when my method is initialised, I get the right values.

My class:

class my_class(){

   var $DefaultBar;
   public function __construct(){
      $this->initialise();
   }

   public function initialise(){
      add_action( 'wp_before_admin_bar_render', array( $this , 'admin_bar_load' )); //or admin_bar_menu
      add_action( 'wp_ajax_get_the_page',  array( $this ,'get_the_page') );
   }

   public function admin_bar_load(){
      global $wp_admin_bar;

      //here I assign the value to the class variable declared before
      $GLOBALS['default_bar'] = $wp_admin_bar;
      //if I var_dump here, I get all the values

   }

   public function get_the_page(){

      global $default_bar;

      ob_start();
      include 'inc/forms/my_page.php';
      $response = ob_get_contents();
      ob_end_clean();
      wp_send_json($response);

   }
}

In my page, called with action get_the_page() through AJAX, on $(document).ready I've placed then:

<?php var_dump($default_bar); ?>

EDIT / SOLUTION

I realised there's a timing issue about calls. I just changed the logic of my class.

Something weird is happening in my class. Basically I'm trying to manipulate the $wp_admin_bar through AJAX but when I receive the response I get a NULL value. Although debugging the global when my method is initialised, I get the right values.

My class:

class my_class(){

   var $DefaultBar;
   public function __construct(){
      $this->initialise();
   }

   public function initialise(){
      add_action( 'wp_before_admin_bar_render', array( $this , 'admin_bar_load' )); //or admin_bar_menu
      add_action( 'wp_ajax_get_the_page',  array( $this ,'get_the_page') );
   }

   public function admin_bar_load(){
      global $wp_admin_bar;

      //here I assign the value to the class variable declared before
      $GLOBALS['default_bar'] = $wp_admin_bar;
      //if I var_dump here, I get all the values

   }

   public function get_the_page(){

      global $default_bar;

      ob_start();
      include 'inc/forms/my_page.php';
      $response = ob_get_contents();
      ob_end_clean();
      wp_send_json($response);

   }
}

In my page, called with action get_the_page() through AJAX, on $(document).ready I've placed then:

<?php var_dump($default_bar); ?>

EDIT / SOLUTION

I realised there's a timing issue about calls. I just changed the logic of my class.

• plugins
• plugin-development
• admin-bar

• I suppose the admin bar isn't rendered in AJAX calls, so admin_bar_load() will be loaded when you request the page, but not when making the ajax call – kero Commented Nov 12, 2018 at 16:41
• hey @kero, thank you so much. I suppose that too, but how to achieve it then? Do you have an idea? – middlelady Commented Nov 12, 2018 at 16:43
• The request the admin bar is rendered in is not the same request that handled the AJAX request, you can't set a variable in one request then read it in another like that, that's not how PHP works – Tom J Nowell ♦ Commented Nov 12, 2018 at 16:49
• Alright @TomJNowell but to manipulate the $wp_admin_bar I have 2 ways, as far as I know: wp_before_admin_bar_render and admin_bar_menu hooks. So do you say that I should hook those into the wp_ajax_ function? – middlelady Commented Nov 12, 2018 at 16:58
• 1 Take a step back. Why do you want/need the admin bar in the AJAX call? You might have to test this, I'm not sure if simply setting show_admin_bar to true could solve this – kero Commented Nov 12, 2018 at 18:16

1 Answer 1

That's not how PHP requests work, you cannot set a variable in one request, then read it in another request. It isn't like a Node or Python application where the program runs continuously in the background, every request is a blank slate.

So, to make it work, in the first request you need to put it somewhere that the second request can read from, for which there are several options:

• Cookies
• User meta
• Options/Transients

As it's a logged in user, and persisting across sessions would make sense, user meta seems the most logical choice, via update_user_meta and get_user_meta