why does add_action or add_shortcode not create an instance of a class

There’s not enough context on where this code resides to say, but there’s likely a dependency or sequencing issue. I tried your code in my test plugin. I had to revise the salcodes_year() function to return a simple year string since I don’t have the referenced file or class, nor the ‘my_url’ option. The shortcode thus modified works for me. I didn’t test Ajax, but if you get the shortcode working, perhaps Ajax will as well.

The shortcode callback shouldn’t echo out any content. It will not cause a failure, but it’s still Doing It Wrong?

Where did you place the Test class declaration? I placed it in my main plugin file and it works from there.

@bcworkz
1. I found $this->val can’t work in the function of add_action or add_shortcode in the same class.
Therefore, $my_crawler = new Test_one($infos); should change to $my_crawler = new Test_one(get_option('my_val'));

2. I get error Fatal error: Uncaught Error: Class ‘Test_one’ not found when I run my code.
The following is my_test1.php:

<?php
class Test_one{
    function a(){
        $this->a1='aaa';
    }
    function b(){
        echo 'a1:'.$this->a1;
    }
    function c(){
        $this->a();
        $this->b();
    }
}

3. my file directory:
The class of Test is in my_plugin_name.php

my_plugin_name—assets
| |
| —js
| |
| –app.js
|
—src
| |
| –my_test1.php
|
|
—my_plugin_name.php

• This reply was modified 2 years, 6 months ago by nobody123.

I think you have a race condition. PHP cannot read the file and parse test1.php fast enough before the main processing thread hits the new Test_one() statement. You’ll need to require the file outside of the salcodes_year() callback. Just in time coding is cool, but that’s simply too close to the need.

So….how do I fix this question?
Thank you

You need to require the file well before you need to instantiate the class. Perhaps within a constructor function of Test? Or within js2php_register() since you essentially are using that as a constructor.

I got this error after moving the code within a constructor function of Test

Fatal error: Uncaught Error: Class 'Test_one' not found in D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-content\plugins\crawler\crawler.php:131 Stack trace: #0 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-content\plugins\crawler\crawler.php(185): Test->__construct() #1 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-settings.php(409): include_once('D:\\Appserv\\Apac...') #2 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-config.php(96): require_once('D:\\Appserv\\Apac...') #3 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-load.php(50): require_once('D:\\Appserv\\Apac...') #4 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-admin\admin.php(34): require_once('D:\\Appserv\\Apac...') #5 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-admin\index.php(10): require_once('D:\\Appserv\\Apac...') #6 {main}

The following is my code:

class Test{
    private $infos;
    
    function __construct()
    {
        add_action( 'wp_ajax_crawler_info', array($this, 'get_info') );
        add_action( 'wp_ajax_nopriv_crawler_info', array($this, 'get_info') );        
        require_once plugin_dir_url(__FILE__) . 'src/ming_crawler.php';
        $this->my_crawler = new Test_one(get_option('my_val'));
    }
  
    function get_info() {
        if ( isset($_REQUEST['my_info']) ) {
    
            $infos = $_REQUEST['my_info'];
            if (get_option('my_url')){
                update_option('my_url', $infos);
            }else{
                add_option('my_url', $infos);
            }
        }
        die();
    }
    
    function salcodes_year() {
        return get_option('my_url');        
    }

    function js2php_register(){
        add_shortcode( 'current_year', array($this, 'salcodes_year') );
    }
    
}
$test = new Test;
$test->js2php_register();

I got this error after moving the code withinjs2php_register()
Fatal error: Uncaught Error: Class 'Test_one' not found in D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-content\plugins\crawler\crawler.php:176 Stack trace: #0 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-content\plugins\crawler\crawler.php(183): Test->js2php_register() #1 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-settings.php(409): include_once('D:\\Appserv\\Apac...') #2 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-config.php(96): require_once('D:\\Appserv\\Apac...') #3 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-load.php(50): require_once('D:\\Appserv\\Apac...') #4 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-admin\admin.php(34): require_once('D:\\Appserv\\Apac...') #5 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-admin\index.php(10): require_once('D:\\Appserv\\Apac...') #6 {main}

The following is my code:

class Test{
    private $infos;
    
    function get_info() {
        if ( isset($_REQUEST['my_info']) ) {
    
            $infos = $_REQUEST['my_info'];
            if (get_option('my_url')){
                update_option('my_url', $infos);
            }else{
                add_option('my_url', $infos);
            }
        }
        die();
    }
    
    function salcodes_year() {
        return get_option('my_url');        
    }

    function js2php_register(){
        add_action( 'wp_ajax_crawler_info', array($this, 'get_info') );
        add_action( 'wp_ajax_nopriv_crawler_info', array($this, 'get_info') );        
        require_once plugin_dir_url(__FILE__) . 'src/ming_crawler.php';
        $this->my_crawler = new Test_one(get_option('my_val'));
        add_shortcode( 'current_year', array($this, 'salcodes_year') );
    }
    
}
$test = new Test;
$test->js2php_register();

You’ve misunderstood. I probably wasn’t clear enough. Move only the require file statement to constructor or js2php_register(), NOT the new Test_one() statement! Moving them together doesn’t accomplish anything, the point is to separate them in time of execution. The new Test_one() statement should remain where it was, in the shortcode callback salcodes_year().

Thank for your advise, but I got error after I move my code.
The error:
Fatal error: Uncaught Error: Class 'Test_one' not found in D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-content\plugins\crawler\crawler.php:160 Stack trace: #0 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-includes\shortcodes.php(356): Test->shortcode_value('', '', 'current_year') #1 [internal function]: do_shortcode_tag(Array) #2 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-includes\shortcodes.php(228): preg_replace_callback('/\\[(\\[?)(curren...', 'do_shortcode_ta...', '\n<p>123456789</...') #3 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-includes\class-wp-hook.php(303): do_shortcode('\n<p>123456789</...') #4 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-includes\plugin.php(189): WP_Hook->apply_filters('\n<p>123456789</...', Array) #5 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-includes\post-template.php(253): apply_filters('the_content', '<!-- wp:paragra...') #6 D:\Appserv\Apache24\htdocs\php7.4\wordpress\wp-content\themes\twentytwentyone_test\template-parts\content\content-single.php(23): the_content()

The code1 (moving tojs2php_register()):

function js2php_register(){
        require_once plugin_dir_url(__FILE__) . 'src/ming_crawler.php';
        add_action( 'wp_ajax_crawler_info', array($this, 'get_info') );
        add_action( 'wp_ajax_nopriv_crawler_info', array($this, 'get_info') );
        add_shortcode( 'current_year', array($this, 'salcodes_year') );
        
    }

OR

The code2 (moving to__construct()):

function __construct()
    {
       require_once plugin_dir_url(__FILE__) . 'src/ming_crawler.php';
    }

No matter which I move to code1 or code2, I got same error.
Could you help me, thanks

• This reply was modified 2 years, 6 months ago by nobody123.

Ah! I see another issue, you use plugin_dir_url(), which returns a HTTPS URL path, which is invalid for any sort of require statement. You want to use plugin_dir_path() instead, which returns the full server path to __FILE__ or whatever was passed to it. Sever path as in /home/user1234/wp/wp-content/plugins/my-plugin/, not httр?://example.com/wp-content/plugins/my-plugin/

Cool!!!
It work!!!
Thank you very very very much!