Add Admin CSS

Extended Description

/**
 * Add CSS to admin pages.
 *
 * @param string $css String to be added to admin pages.
 * @return string
 */
function my_admin_css( $css ) {
    $css .= "
        #site-heading a span { color:blue !important; }
        #favorite-actions { display:none; }
    ";
    return $css;
}
add_filter( 'c2c_add_admin_css', 'my_admin_css' );

/**
 * Add CSS file(s) to admin pages.
 *
 * @param array $files CSS files to be added to admin pages.
 * @return array
 */
function my_admin_css_files( $files ) {
    $files[] = 'http://yui.yahooapis.com/2.9.0/build/reset/reset-min.css';
    return $files;
}
add_filter( 'c2c_add_admin_css_files', 'my_admin_css_files' );

Installation

Frequently Asked Questions

Q. Can I add CSS I defined via a file, or one that is hosted elsewhere?
A. Yes, via the “Admin CSS Files” input field on the plugin’s settings page.

Q. Can I limit what admin pages the CSS gets output on?
A. No, not presently. At least not directly. By default, the CSS is added for every admin page on the site.
However, you can preface your selectors with admin page specific class(es) on ‘body’ tag to ensure CSS only applies on certain admin pages. (e.g. body.index-php h2, #icon-index { display: none; }).
Or, you can hook the ‘c2c_add_admin_css’ and ‘c2c_add_admin_css_files’ filters and determine the current admin page content to decide whether the respective hook argument should be returned (and thus output) or not.

Q. Can I limit what users the CSS applies to?
A. No, not presently. At least not directly. By default, the CSS is added for any user that can enter the admin section of the site.
You can hook the ‘c2c_add_admin_css’ and ‘c2c_add_admin_css_files’ filters and determine the current user to decide whether the respective hook argument should be returned (and thus output) for the user or not.

Q. How can I edit the plugin’s settings in the event I supplied CSS that prevents the admin pages from properly functioning or being seen?
A. It is certainly possible that you can put yourself in an unfortunate position by supplying CSS that could hide critical parts of admin pages, making it seeminly impossible to fix or revert your changes. Fortunately, there are a number of approaches you can take to correct the problem.
The recommended approach is to visit the URL for the plugin’s settings page, but appended with a special query parameter to disable the output of its JavaScript. The plugin’s settings page would typically be at a URL like https://example.com/wp-admin/themes.php?page=add-admin-css%2Fadd-admin-css.php. Append &c2c-no-css=1 to that, so that the URL is https://example.com/wp-admin/themes.php?page=add-admin-css%2Fadd-admin-css.php&c2c-no-css=1 (obviously change example.com with the domain name for your site).
There are other approaches you can use, though they require direct database or server filesystem access:

• Some browsers (such as Firefox, via View -> Page Style -> No Style) allow you to disable styles for sites loaded in that tab. Other browsers may also support such functionality natively or through an extension. Chrome has an extension called Web Developer that adds the functionality.
• If you’re familiar with doing so and have an idea of what CSS style you added that is causing problems, you can use your browser’s developer tools to inspect the page, find the element in question, and disable the offending style.
• In the site’s wp-config.php file, define a constant to disable output of the plugin-defined JavaScript: define( 'C2C_ADD_ADMIN_CSS_DISABLED', true );. You can then visit the site’s admin. Just remember to remove that line after you’ve fixed the CSS (or at least change “true” to “false”). This is an alternative to the query parameter approach described above, though it persists while the constant remains defined. There will be an admin notice on the plugin’s setting page to alert you to the fact that the constant is defined and effectively disabling the plugin from adding any CSS.
• Presuming you know how to directly access the database: within the site’s database, find the row with the option_name field value of c2c_add_admin_css and delete that row. The settings you saved for the plugin will be deleted and it will be like you’ve installed the plugin for the first time.
• If your server has WP-CLI installed, you can delete the plugin’s setting from the commandline: wp option delete c2c_add_admin_css

The initial reaction by some might be to remove the plugin from the server’s filesystem. This will certainly disable the plugin and prevent the CSS you configured through it from taking effect, restoring the access and functionality to the backend. However, reinstalling the plugin will put you back into the original predicament because the plugin will use the previously-configured settings, which wouldn’t have changed.

Q. How do I disable syntax highlighting?
A. The plugin’s syntax highlighting of CSS (available on WP 4.9+) honors the built-in setting for whether syntax highlighting should be enabled or not.
To disable syntax highlighting, go to your profile page. Next to “Syntax Highlighting”, click the checkbox labeled “Disable syntax highlighting when editing code”. Note that this checkbox disables syntax highlighting throughout the admin interface and not just specifically for the plugin’s settings page.

Q. Does this plugin include unit tests?
A. Yes.

Release Log

1.9.1 (2020-09-25)

• Change: Update plugin framework to 051
  • Allow setting integer input value to include commas
  • Use number_format_i18n() to format integer value within input field
  • Update link to coffee2code.com to be HTTPS
  • Update readme_url() to refer to plugin’s readme.txt on plugins.svn.wordpress.org
  • Remove defunct line of code
• Change: Note compatibility through WP 5.5+
• Change: Restructure unit test file structure
  • New: Create new subdirectory phpunit/ to house all files related to unit testing
  • Change: Move bin/ to phpunit/bin/
  • Change: Move tests/bootstrap.php to phpunit/
  • Change: Move tests/ to phpunit/tests/
  • Change: Rename phpunit.xml to phpunit.xml.dist per best practices

1.9 (2020-06-26)

• This minor release updates its plugin framework, adds a TODO.md file, updates a few URLs to be HTTPS, expands unit testing, updates compatibility to be WP 4.9 through 5.4+, and minor behind-the-scenes tweaks.

Details:

• Change: Allow class to always be instantiated, but add check to only register hooks when in the admin
• Change: Change class names used for admin notice to match current WP convention
• Change: Update plugin framework to 050
  • Allow a hash entry to literally have ‘0’ as a value without being entirely omitted when saved
  • Output donation markup using printf() rather than using string concatenation
  • Update copyright date (2020)
  • Note compatibility through WP 5.4+
  • Drop compatibility with version of WP older than 4.9
• New: Add TODO.md and move existing TODO list from top of main plugin file into it (and add to it)
• Change: Tweak help text for ‘files’ setting for better phrasing and to remove extra sentence spaces
• Change: Note compatibility through WP 5.4+
• Change: Drop compatibility for version of WP older than 4.9
• Change: Update links to coffee2code.com to be HTTPS
• Change: Add translator comment for string with multiple placeholders
• CHange: Minor code reformatting
• Unit tests:
  • New: Add test for options_page_description()
  • New: Add tests for default hooks
  • New: Add tests for setting and query param names
  • New: Label groupings of tests
  • Fix: Adjust tests to properly account for theme support or non-support of html5 when checking expected markup output
  • Fix: Ensure admin-related tests call test_turn_on_admin() so admin init actions are called
  • Fix: Invoke parent class’s setUp() during setUp()
  • Change: Remove unnecessary unregistering of hooks in tearDown()
  • Change: Move test_turn_on_admin() until just before first needed now that other tests can run before it
  • Change: Store plugin instance in class variable to simplify referencing it
  • Change: Use HTTPS for link to WP SVN repository in bin script for configuring unit tests (and delete commented-out code)

1.8 (2019-12-04)

• This minor release adds HTML5 compliance when supported by the theme, modernizes and fixes unit tests, and notes compatibility through WP 5.3+.

Details:

• New: Add HTML5 compliance by omitting type attribute when the theme supports ‘html5’
• Unit tests:
  • New: Add unit test to ensure plugin is hooked to initialize on plugins_loaded
  • Fix: Don’t pass argument to plugin object’s add_css()
  • Fix: Don’t expect type attribute in link tags since they’re not HTML5-compliant
  • Fix: Prevent WP from attempting to print the emoji detection script (which isn’t built in the develop.svn repo)
  • Change: Update unit test install script and bootstrap to use latest WP unit test repo
• Change: Note compatibility through WP 5.3+
• Change: Update copyright date (2020)

Copyright & Disclaimer

Discussion / Support

Have any questions, comments, or suggestions? Please provide them via the plugin’s WordPress.org support forum. I’ll do my best to reply in a timely fashion and help as best I can.

Unfortunately, I cannot provide guaranteed support, nor do I provide support via any other means.

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