WordPress debugging: disable heartbeats

TivneT — Tue, 07 Feb 2023 13:07:18 +0000

Takeaways:

WordPress heartbeats disturb debugging by issuing regular AJAX requests.
Heartbeats can be disabled with a PHP code or by using a special WordPress plugin.
Heartbeats are required for normal WordPress and WooCommerce operation, so disable them only temporarily, for debugging.

Background:

What are heartbeats in WordPress?

Heartbeats is an essential feature of the WordPress administration.

To provide auto-saving, post locking, login expiration warnings, etc. WordPress sends regular AJAX calls, "heartbeats" from the browser to the server.

How to debug PHP code in WordPress?

As a PhpStorm user, to debug a WordPress website, I first install and activate Xdebug.

Then I configure PhpStorm to listen for Xdebug connections, set breakpoints in the WordPress code, and start a debugging session by visiting the website with a special cookie set.

The official instructions for debugging WordPress with PhpStorm can be found on the JetBrains website:

Debugging WordPress with PHPStorm

It provides a comprehensive guide on how to set up and use PhpStorm for debugging WordPress, including the installation and activation of Xdebug, configuring PhpStorm, and starting a debugging session.

What is the problem with heartbeats?

Once PHPStorm and Xdebug set up, I can inspect variables and step through the code during the paused execution at the breakpoints.
However, every so and so seconds, my debugging screen opens a new tab showing a heartbeat request:

This is annoying, consumes memory and slows down the website and PHPStorm IDE.

What can be done?

To stop heartbeats, place this to your WordPress theme's functions.php:

add_action(
    'init',
    function () {
        wp_deregister_script( 'heartbeat' );
    }
);

There are a couple of issues with this simple method:

The post autosave will fail, causing PHP notices and JavaScript errors.
When you push the code to production, you might forget to remove that code snippet and break the website operation.

A solution would be to place the code to a custom plugin and never push that plugin to the live site.

A better way would be using a 3rd party plugin that has that code in place and also takes care of the side effects.

Here is a popular plugin that you can try:

Heartbeat Control

If your site is running WooCommerce, you might consider this premium extension, which provides multiple administration tools, including stopping heartbeats:

Admin Tools for WooCommerce