May 08, 2024

Black Bar Plugin

Black Bar is an unobtrusive Debug Bar for WordPress developers that attaches itself to the bottom of the browser window.

Black Bar is an unobtrusive Debug Bar for WordPress developers. It collects and displays errors, executed SQL queries, slow actions and hooks, theme templates, global variables, and provides a profiler.

How it helps you with development:

Debug your code with the Console
Inspect global variables (COOKIE, GET, POST, SERVER, SESSION, WP_Screen)
Measure performance of your code with the Profiler
View any PHP errors that occur when loading a page in the Console
View executed MySQL queries along with execution time and backtrace
View template files of the active theme in loaded order
View the 50 slowest action and filter hooks along with callbacks ordered by priority

Installation

If you have never installed a WordPress plugin before, you can read instructions on how to do this here.

FAQ

How do I add entries to the Console?

To add entries to the console, insert the following line of PHP anywhere in your code:

apply_filters('console', 'Enter something to debug here');

You can also add an optional log level like this:

apply_filters('console', 'Enter something to debug here', 'error');

The available log levels are: debug, info, notice, warning, error, critical, alert, and emergency.

How do I use the Profiler?

To use the profiler, insert the following lines of PHP before and after the code you are profiling:

Before:

apply_filters('trace:start', 'Enter a description of what you are profiling here');

After:

apply_filters('trace:stop');

How do I enable the plugin for non-administrators?

By default, Black Bar is only visible to administrator users. To enable it for all logged-in users, use this code snippet:

add_filter('blackbar/enabled', 'is_user_logged_in');

How do I change the number of slowest hooks displayed?

By default, Black Bar displays the 50 slowest action/filter hooks. To display all hooks, use this code snippet:

add_filter('blackbar/hooks/all', '__return_true');

Changelog

4.1.4 (2024-05-08)

Added “blackbar/hooks/all” filter hook
Added highlighting of major WordPress hooks
Added support for static callables used for hook callbacks in Site Reviews
Change minimum PHP version to 7.4
Change minimum WordPress version to 6.1

4.0.3 (2023-10-11)

Fixed debugging of non-scalar values
Fixed display of console values with an Unknown log level

4.0.2 (2023-09-18)

Fixed PHP 7 support
Fixed console values which include HTML

4.0.1 (2023-03-04)

Added cache busting to enqueued assets
Added console level filter counts
Added HTTP_COOKIE value to INPUT_SERVER globals

4.0.0 (2023-02-13)

Added console level filters
Added sorting to Action/Filter Hooks
Added syntax highlighting to console entries
Added trace information to SQL queries
Beautified SQL formating
Changed Profiler usage (use the “trace:start” and “trace:stop” hooks)
Improved Profiler, it is now also more accurate
Refreshed UI
Requires PHP >= 7.3

See changelog for all versions.