How to use this, exactly?

[Luc45]

Hey, great code, thanks!

I'm having some trouble using it, though. Here's a quick test I'm doing:

add_action( 'wp_async_shutdown', [$this, 'testing_async'], 10, 1 );

I expect this to run public function testing_async() asynchronously when WordPress be shutting down, right?

public function testing_async() {
    error_log('test', 1, 'someemail@gmail.com');
}

But this is never called. OK, this didn't work. Let's try the "extend class" approach.

public function testing_async() {
    $test = new WP_Async_Test();
}

WP_Async_Test.php:

<?php

class WP_Async_Test extends WP_Async_Task {

    //protected $action = 'shutdown';
    protected $action = 'testing_async';

    /**
     * Prepare data for the asynchronous request
     *
     * @throws Exception If for any reason the request should not happen
     *
     * @param array $data An array of data sent to the hook
     *
     * @return array
     */
    protected function prepare_data( $data ) {

    }

    /**
     * Run the async task action
     */
    protected function run_action() {
        error_log('hi', 1, 'someemail@gmail.com');
    }

}

This didn't work either... What am I doing wrong?

[Luc45]

OK, Part 2. I'm trying to do a slow task after a user registers. Everything works, except that it is not Async.

Register.php
do_action('my_app_user_register', $user_id);

MyAppPlugin.php:

public function __construct() {
    add_action( 'my_app_user_register', [$this, 'user_register'], 10, 1 );
    add_action( 'plugins_loaded', [$this, 'listen_async'] );
}

/**
*   Runs when a user registers on WordPress
*/
public function user_register($user_id) {
    error_log('user_register', 1, 'someemail@gmail.com'); // runs
    add_action( 'wp_async_myapp_user_registered', [$this, 'call_async']);
}

/**
*   Listen to Async Calls
*/
public function listen_async() {
    new WP_Async_Setup_Database;
}

/**
*   Bogus function just so WP_Async_Setup_Database can listen for the "myapp_user_registered" action
*/
public function call_async() {
    return;
}

WP_Async_Setup_Database.php

<?php

class WP_Async_Setup_Database extends WP_Async_Task {

    protected $action = 'myapp_user_registered';

    /**
     * Prepare data for the asynchronous request
     *
     * @throws Exception If for any reason the request should not happen
     *
     * @param array $data An array of data sent to the hook
     *
     * @return array
     */
    protected function prepare_data( $data ) {
        error_log('prepare_data '.json_encode($data), 1, 'someemail@gmail.com'); // runs
        return array(
            'user_id' => $data[0]
        );
    }

    /**
     * Run the async task action
     */
    protected function run_action() {
        error_log('run_action '.json_encode($_POST), 1, 'someemail@gmail.com'); // runs
        if (isset($_POST['user_id'])) {
            // Slow action here. It runs, but not async. I will not include MyAppCPanel here as it's just a bunch of code running MySQL on a external server
           $myApp = new MyAppCPanel;
           $myApp->setup_database($user_id);
        }
    }

}

Everything runs, but not Async.