How to connect wp functions to your php file?

Question

WordPress

I created a WP plugin, in the plugin folder I created a second php file that executes a post cURL request and direct access is allowed to it .

require($_SERVER['DOCUMENT_ROOT'].'/wp-load.php');

$body = array(
    'id' => '1',
    'user_id' => '100'
);

$args = array(
    'body' => $body
);

$response = wp_remote_post( 'https://site.ru/test.php', $args );
$body = wp_remote_retrieve_body( $response );
echo $body;

How to do without connecting the string require($_SERVER['DOCUMENT_ROOT'].'/wp-load.php');?
Wrote in WP, I was sent to a page with recommendations:

If you need to have 'pages' directly accessible by an external service, then you must use query_vars and/or rewrite the rules to create a virtual page that calls the function.
Please see the plugins API reference for more information: codex.wordpress.org/Plugin_API
if you are trying to use AJAX please read this: codex.wordpress.org/AJAX_in_Plugins
For other possibilities, or better understand why we don't allow it, read this: ottopress.com/2010/dont-include-wp-load-please

I read it, I feel that there is a solution to my problem, but I did not understand how to implement it. In the example, we are talking about connecting css and js, I couldn’t find out anything useful there, I realized that it require($_SERVER['DOCUMENT_ROOT'].'/wp-load.php');’s impossible to connect, because. this loads the entire wp system and the file path may be different for different wp users.
Help to understand, please. How can I change the script so that it doesn't load the wp core all the time?
If the second php file is connected to the main plugin file, a cURL post request is immediately executed and the result of cURL execution is displayed instead of the entire site.
Thank you!

Answer 1

Use CURL?

$curl = curl_init();
 
$url = "https://site.ru/test.php";
 
$args = array(
  'id' => '1',
  'user_id' => '100'
);
 
curl_setopt_array($curl,
    array(
  CURLOPT_URL => $url,
  CURLOPT_POST       => true,
        CURLOPT_POSTFIELDS => $args,
        CURLOPT_RETURNTRANSFER     => true,
    )
);
$data = curl_exec($curl);
curl_close($curl);
echo $data;