WP Chill

Silkalns

Brian Fegter

Chris Dillon

Razvan Aldea

For admins, developers, and support staff, Debug This provides a ton of information about your WordPress installation, all from the front-end admin bar.
<ul>
<li>The current WP_Query object</li>
<li>Blog info and options</li>
<li>Embed providers</li>
<li>Files in rendered HTML (CSS, images, JavaScript)</li>
<li>Filters and actions</li>
<li>Images sizes</li>
<li>Globals and constants</li>
<li>Menus</li>
<li>Object cache stats</li>
<li>Plugins, must-use plugins, and dropins</li>
<li>Rewrite rules</li>
<li>Queries</li>
<li>PHP and server information</li>
<li>Post attachments</li>
<li>Post types</li>
<li>Scripts and styles enqueued</li>
<li>Shortcodes</li>
<li>Sidebars and widgets</li>
<li>Taxonomies and terms</li>
<li>Themes</li>
<li>Users</li>
<li>WP cron schedules and jobs</li>
<li>WP debug log</li>
</ul>
Debug This helps you save time and effort when trying to figure out what’s going on. Instead of hardcoding debug snippets or writing complex unit 
tests for small functionality, you can simply bring to the surface what you need right from the admin bar.
For example, when viewing a single post, you can see:
<ul>
<li>a list of post attachments,</li>
<li>which menus and sidebars are being displayed,</li>
<li>the post type, post fields, and meta data,</li>
<li>the current query variables and query string,</li>
<li>the rewrite rules applied,</li>
<li>the author,</li>
<li>the terms,</li>
<li>and much more.</li>
</ul>
<h3>Extend</h3>
<h4>Debug This Functions</h4>
New debug modes can be created easily:
<pre><code>add_debug_extension(
 $mode,
 $menu_label,
 $description,
 $callback,
 $group = 'General'
);
</code></pre>
Example
<pre><code>add_debug_extension(
 'actions',
 __('Actions', 'debug-this'),
 __('$wp_actions contains all active registered actions', 'debug-this'),
 'foo_callback',
 'Filters And Actions'
);
function foo_callback($buffer, $template){
 global $wp_actions;
 $debug = print_r($wp_actions, true);
 return $debug;
}
</code></pre>
You can add links to the header of a debug mode page. Place this code within your debug callback function.
<pre><code>add_debug_header_link('http://urltolink', 'Link Label');
</code></pre>
Extensions can be removed as well using <code>remove_debug_extension($mode);</code>
No PRE Tags
If you don’t want your debug output to be enclosed in PRE tags, simply set the following in your extension:
<pre><code>Debug_This::$no_pre = true;
</code></pre>
Saved Queries and Execution Time
Retrieve saved queries and execution time by using the following static properties:
<ul>
<li><code>Debug_This::$execution_time</code></li>
<li><code>Debug_This::$queries</code> – SAVEQUERIES must defined as true</li>
</ul>
URL Helpers
<ul>
<li><code>Debug_This::get_current_debug_url()</code> – current URL with the debug query</li>
<li><code>Debug_This::get_escape_url()</code> – used for the debug escape link that links to original page URL</li>
</ul>
<h4>WP Actions</h4>
<ul>
<li><code>debug_this</code> – receives the $mode arg – outputs the debug code sent from the extension modes. The default action is set to priority 5. This allows you to prepend or append any output without conflict using less or greater priorities.</li>
</ul>
<h4>WP Filters</h4>
There are a few filters you can use to customize Debug This to your needs:
<ul>
<li><code>debug_this_template</code> – receives $template arg – Use your own template</li>
<li><code>debug_this_default_mode</code> – receives $mode arg – Alters the mode for the parent DT admin bar button link.</li>
<li><code>debug_this_output</code> – receives $output, $mode args – Filter debug content before it’s rendered</li>
</ul>
<h4>JavaScript</h4>
To access the built-in Debug This JS functionality, enqueue your custom script with the dependency set to <code>debug-this</code>. Your script will inherit a jQuery dependency.
Object: debugThis
<ul>
<li><code>debugThis.mode</code> – current mode</li>
<li><code>debugThis.defaultMode</code></li>
<li><code>debugThis.template</code> – current included template</li>
<li><code>debugThis.queryVar</code> – the defined query string variable</li>
</ul>
Functions:
<ul>
<li><code>isDebug()</code></li>
<li><code>getDebugMode()</code> – uses <code>isDebug()</code></li>
</ul>
Events:
A jQuery <code>debug-this</code> event is fired from the footer. You can hook into this event with the following;
<pre><code>jQuery(document).bind('debug-this', function(event, debugThis){
 console.log(debugThis);
});
</code></pre>
<h4>Helper Functions</h4>
There are three included functions to help you work with files.
<ul>
<li><code>debug_this_get_file_ownership($file)</code> – returns <code>array('name' => $name, 'group' => $group)</code></li>
<li><code>debug_this_get_file_perms($file)</code> – returns string – Example: 0775</li>
<li><code>debug_this_convert_perms_to_rwx($perms)</code> – returns string – converts permission number to RWX format – Example: 0755 folder becomes drwxr-xr-x</li>
</ul>

Debug This

Very nice, even the phpinfo() colors are displayed correctly.

Great plugin

Peek under the hood with sixty debugging reports just one click away.

Eugen Bobrowski

This is tool that help developers and administrators easier getting information.
The debug bar is available on front side for everyone if WP_DEBUG is true. If you are admin you can open bar on any page. Hover the mouse cursor to bottom right corner and click on
<h4>Features:</h4>
<ul>
<li>Implementation time counter</li>
<li>Queries counter</li>
<li>Queries list (sortable)</li>
<li>Memory counter</li>
<li>Segment checker</li>
<li>Cron jobs information</li>
<li>WP_Cache counter</li>
<li>phpinfo() window</li>
<li>References menu</li>
<li>Image Puller that provide pull missed images from production to develop site</li>
</ul>
Implementation time counter
It count the time from plugin loaded action to debug bar. 
It does not consider processes that implement before and during the plugins are loading.
Queries counter
It count all what is queried via $wpdb object.
Queries list
It show all what is queried via $wpdb object.
The <code>SAVEQUERIES</code> constant must be defined as <code>true</code>.
Memory counter
Returns the amount of memory, in bytes, that’s currently being allocated to your PHP script.
Segment checker
Also you can check any segment of your code.
<pre><code>do_action('check_segment', 'segment_1');

//do somethisng

do_action('check_segment', 'segment_1');
</code></pre>
The code below returns in debug bar new item like this:
<blockquote>
segment_1: 14.14/3/1
</blockquote>
The digits there ara time, queries and how many times this code was implemented.
References menu
The default one item of this menu is Errors. It shows notices and warnings including case when <code>WP_DEBUG</code> is false.
And also you can easy add your item to this menu and print there any var_dump or anything else.
<pre><code>add_filter('wp_debug_refs', 'my_debug_tool_ref');

function my_debug_tool_ref ($refs) {

 global $post;

 $refs['my_ref_id'] = array(
 'title' => 'My ref',
 'content' => 'My ref' . var_export($post, true),
 );
 return $refs;
}
</code></pre>

Debug Tool

Show helpful debug bar at front and admin side. Tool for developers.

Debug This vs Debug Tool