How to go through all the posts in the plugin?

Question

WordPress

I'm making a plugin that will check if the post has an image or not, I need to pass $post_id to the function, but I don't know where to get it

/*
Plugin Name: WPM Image Holder
Plugin URI: https://wp-masters.com
Description: Set Thumbnail to All Posts where Image is not set
Author: WP Masters
Version: 1.0
*/

class ImageHolders {

  /**
     * Initialise functions
     */
    public function __construct()
    {
        // Put hooks here and look at the example how set function to hooks
        add_action('init', [$this, 'check_post_is_has_thumbnail']);
    }

  /**
     * Check Posts is has Image before Loop in FrontEnd
     */
    public function check_post_is_has_thumbnail($post_id)
    {
        // Your function is going here
    }
}

new ImageHolders();

Can someone help?

Answer 1

Any request get_posts()or wp_query(), in a loop, check what you need.
But this is a rather expensive action, you should not perform it every time init is loaded. You should run it either on a button click or a cron, or replace it with checking for the presence of only the current image