Automattic

Thorsten Ott

<p>This plugins adds more features to the debug-bar and is mainly aimed at developers who like to debug their code or want to measure runtimes to find glitches in their code.<br />
It also allows lookup of variables by adding simple code snippets in your source.</p>
<p>Please note that this plugin should be used solely for debugging or on a development environment and is not intended for use in a production site.</p>
<h3>Requirements</h3>
<p>This plugin requires <a href="https://wordpress.org/extend/plugins/debug-bar" rel="ugc">the debug-bar plugin >0.5</a> and a developers’ brain to work correctly.</p>
<h3>Usage</h3>
<h4>Usage example to debug the loop of a theme</h4>
<p>Add your checkpoints in the index.php or any other template file as shown below.</p>
<pre><code><?php if (have_posts()) : ?>

<?php Debug_Bar_Extender::instance()->checkpoint('loop start'); ?>

<?php while (have_posts()) : the_post(); ?>

<?php Debug_Bar_Extender::instance()->trace_var( $post ); ?>

<?php Debug_Bar_Extender::instance()->checkpoint('loop1'); ?>

<div <?php post_class() ?> id="post-<?php the_ID(); ?>">
<?php //before_post(); ?>
<h2><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php printf(__('Permanent Link to %s', 'kubrick'), the_title_attribute('echo=0')); ?>"><?php the_title(); ?></a></h2>
<small><?php the_time(get_option('date_format')) ?> by <?php the_author() ?></small>
<div class="entry">
<?php the_content(__('Read the rest of this entry &raquo;', 'kubrick')); ?>
</div>
<p class="postmetadata"><?php the_tags(__('Tags:', 'kubrick') . ' ', ', ', '<br />'); ?> <?php printf(__('Posted in %s', 'kubrick'), get_the_category_list(', ')); ?> | <?php edit_post_link(__('Edit', 'kubrick'), '', ' | '); ?> <?php comments_popup_link(__('No Comments »', 'kubrick'), __('1 Comment »', 'kubrick'), __('% Comments »', 'kubrick')); ?></p>
<?php after_post(); ?>
</div>

<?php Debug_Bar_Extender::instance()->checkpoint('loop2'); ?>

<?php endwhile; ?>

<?php Debug_Bar_Extender::instance()->checkpoint('loop end'); ?>

<div class="navigation">
<div class="alignleft"><?php next_posts_link(__('&laquo; Older Entries', 'kubrick')) ?></div>
<div class="alignright"><?php previous_posts_link(__('Newer Entries &raquo;', 'kubrick')) ?></div>
</div>
<?php else : ?>
</code></pre>
<h3>Advanced usage</h3>
<p>Looking at the source of the debug-bar-extender.php you will notice that there are various filters to control the default settings. This is useful when you are working on a multisite install and want to use the debug bar without having to adjust the settings every time. Here’s an example of how settings enforced by a php file in mu-plugins/ could look like</p>
<pre><code>add_filter( 'debugbarextender_default_settings', 'my_debug_bar_extender_settings' );
// enforce debug bar settings
function my_debug_bar_extender_settings( $default_settings ) {
    $default_settings = array(
            'enable_profiler'               => 1,
            'enable_variable_lookup'        => 1,
            'track_default_vars'            => 0,
            'add_default_checkpoints'       => 1,
            'savequeries_debugmode_enable'  => 1,
            'use_error_log'                 => 0,
            'allow_url_settings'            => 1,
            'enable_admin_bar_menu'         => 1,
    );
    return $default_settings;
}

add_filter( 'debugbarextender_default_checkpoint_actions', 'my_debug_bar_extender_checkpoints' );
// initiate some default checkpoints
function my_debug_bar_extender_checkpoints( $default_checkpoints ) {
    $default_checkpoints = array(
                    'muplugins_loaded',
                    'wp_head',
                    'wp_footer',
                    'loop_start',
                    'loop_end',
                    'shutdown',
    );
    return $default_checkpoints;
}
</code></pre>
<h3>Wishlist</h3>
<p>This is a work in progress, so feel free to pass by on <a href="http://hitchhackerguide.com/wordpress-plugins/debug-bar-extender/" rel="nofollow ugc">our plugin page</a> and leave us<br />
your suggestions in the comments.</p>


Debug-Bar-Extender

Extends the debug-bar plugin with additional tabs to measure runtimes between checkpoints and lookup variable content.

John Blackbourn

<p>Query Monitor is the developer tools panel for WordPress and WooCommerce. It enables debugging of database queries, PHP errors, hooks and actions, block editor blocks, enqueued scripts and stylesheets, HTTP API calls, and more.</p>
<p>It includes some advanced features such as debugging of Ajax calls, REST API calls, user capability checks, and full support for block themes and full site editing. It includes the ability to narrow down much of its output by plugin or theme, allowing you to quickly determine poorly performing plugins, themes, or functions.</p>
<p>Query Monitor focuses heavily on presenting its information in a useful manner, for example by showing aggregate database queries grouped by the plugins, themes, or functions that are responsible for them. It adds an admin toolbar menu showing an overview of the current page, with complete debugging information shown in panels once you select a menu item.</p>
<p>Query Monitor supports versions of WordPress up to three years old, and PHP version 7.4 or higher.</p>
<p>For complete information, please see <a href="https://querymonitor.com/" rel="nofollow ugc">the Query Monitor website</a>.</p>
<p>Here’s an overview of what’s shown for each page load:</p>
<ul>
<li>Database queries, including notifications for slow, duplicate, or erroneous queries. Allows filtering by query type (<code>SELECT</code>, <code>UPDATE</code>, <code>DELETE</code>, etc), responsible component (plugin, theme, WordPress core), and calling function, and provides separate aggregate views for each.</li>
<li>The template filename, the complete template hierarchy, and names of all template parts that were loaded or not loaded (for block themes and classic themes).</li>
<li>PHP errors presented nicely along with their responsible component and call stack, and a visible warning in the admin toolbar.</li>
<li>Usage of “Doing it Wrong” or “Deprecated” functionality in the code on your site.</li>
<li>Blocks and associated properties within post content and within full site editing (FSE).</li>
<li>Matched rewrite rules, associated query strings, and query vars.</li>
<li>Enqueued scripts and stylesheets, along with their dependencies, dependents, and alerts for broken dependencies.</li>
<li>Language settings and loaded translation files (MO files and JSON files) for each text domain.</li>
<li>HTTP API requests, with response code, responsible component, and time taken, with alerts for failed or erroneous requests.</li>
<li>User capability checks, along with the result and any parameters passed to the capability check.</li>
<li>Environment information, including detailed information about PHP, the database, WordPress, and the web server.</li>
<li>The values of all WordPress conditional functions such as <code>is_single()</code>, <code>is_home()</code>, etc.</li>
<li>Transients that were updated.</li>
<li>Usage of <code>switch_to_blog()</code> and <code>restore_current_blog()</code> on Multisite installations.</li>
</ul>
<p>In addition:</p>
<ul>
<li>Whenever a redirect occurs, Query Monitor adds an HTTP header containing the call stack, so you can use your favourite HTTP inspector or browser developer tools to trace what triggered the redirect.</li>
<li>The response from any jQuery-initiated Ajax request on the page will contain various debugging information in its headers. PHP errors also get output to the browser’s developer console.</li>
<li>The response from an authenticated WordPress REST API request will contain an overview of performance information and PHP errors in its headers, as long as the authenticated user has permission to view Query Monitor’s output. An <a href="https://developer.wordpress.org/rest-api/using-the-rest-api/global-parameters/#_envelope" rel="nofollow ugc">an enveloped REST API request</a> will include even more debugging information in the <code>qm</code> property of the response.</li>
</ul>
<p>By default, Query Monitor’s output is only shown to Administrators on single-site installations, and Super Admins on Multisite installations.</p>
<p>In addition to this, you can set an authentication cookie which allows you to view Query Monitor output when you’re not logged in (or if you’re logged in as a non-Administrator). See the Settings panel for details.</p>
<h3>Other Plugins</h3>
<p>I maintain several other plugins for developers. Check them out:</p>
<ul>
<li><a href="https://wordpress.org/plugins/user-switching/" rel="ugc">User Switching</a> provides instant switching between user accounts in WordPress.</li>
<li><a href="https://wordpress.org/plugins/wp-crontrol/" rel="ugc">WP Crontrol</a> lets you view and control what’s happening in the WP-Cron system</li>
</ul>
<h3>Privacy Statement</h3>
<p>Query Monitor is private by default and always will be. It does not persistently store any of the data that it collects. It does not send data to any third party, nor does it include any third party resources. <a href="https://querymonitor.com/privacy/" rel="nofollow ugc">Query Monitor’s full privacy statement can be found here</a>.</p>
<h3>Accessibility Statement</h3>
<p>Query Monitor aims to be fully accessible to all of its users. <a href="https://querymonitor.com/accessibility/" rel="nofollow ugc">Query Monitor’s full accessibility statement can be found here</a>.</p>


Query Monitor – The developer tools panel for WordPress

If you are a WordPress Developer, this should be the first plugin that you should install.

Must have!


...it would be nice to have an option to deactivate the plugin on mobile devices. I noticed that it slows down the loading and time to be able to interact with the pages significantly. Sure, sometimes it would be useful to have it on mobile as well, and that could be added as an option.Otherwise it's a great, no the best plugin for that use case 😀👍 


Great, just one thing...


One of my must haves for plugin development from the beginning. 


Must have


Thank you for this ingenious plugin. It has already saved me hours of work debugging. It is also extremely helpful when optimising your own plugins. I have never had any problems with Query Monitor. I can only recommend it to every developer to use it as well.


Perfect for Debugging


The best debugging plugin for Wordpress dev. It gives a huge wealth of information about what’s going on under the hood. A must have for debugging queries and finding out simple bits of server information.


A must have for WP developer


Essential for any WP dev and debugging!


The Best WP Debug Plugin and Great Support


I use this plugin almost every day. Saved my time a hundred times.


Absolutely must have for WP development


Amazing tool. Beyond belief this is free.


Wordpress ecosystem at its best


At first impressions it looks like what the browser does.


Good plugin

Excellent plugin!


Query Monitor is an incredibly useful tool for developers and site administrators. It provides detailed insights into database queries, page load times, and resource consumption, making it a must-have for debugging and performance optimization.



I particularly appreciate how it highlights potential errors in the code and plugins during development, saving time and effort in troubleshooting. Its intuitive interface and in-depth reports make identifying issues straightforward.



Overall, it’s a fantastic plugin that I highly recommend to anyone building or maintaining WordPress websites.


Essential for Debugging and Performance Monitoring

best

Useful plugin


Sometimes you feel like your site is a black box and that is something that Query Monitor solves.  It provides insight into what is happening, shows errors, and gives you stats and timings for the page load process.  This helps in tracking down problems, in picking which plugins are the most performant, and when developing, to see what templates are being loaded.  Amazing plugin, for free.  Thank you John Blackbourn! 


An Amazing Tool

Query Monitor is the developer tools panel for WordPress and WooCommerce.

Debug-Bar-Extender vs Query Monitor – The developer tools panel for WordPress