Advanced Customization

For developers who require customization beyond standard shortcode parameters, the plugin provides hooks for styling the output with CSS and altering data with PHP. These advanced techniques offer a deeper level of control over the verification system’s appearance and functionality.

Styling the Search Form with Custom CSS #

Apply custom CSS to target the elements of the verification form and its output. Add the following snippet to your theme’s stylesheet or a custom CSS plugin to alter the appearance of the search form.

/*Certificate Tracker*/
.certificate-tracker {
    text-align: center;
}
.certificate-tracker #search_by_id_th {
    margin-bottom: 20px;
}
input#search_by_id {
    border-radius: 5px;
    border: solid 1px rgba(0,0,0,.2);
    border-style: solid;
    margin: 10px;
    width: 100%;
    max-width: 300px;
    text-align: center;
    color: #313131;
}

This CSS centers the form (.certificate-tracker), adds space below the title (#search_by_id_th), and applies custom styling to the search input field (input#search_by_id).

Obfuscating User Data with a PHP Filter Hook #

In scenarios where user privacy is a concern, you may need to obfuscate personally identifiable information. Use the elc_ctid_verifier_alter_username filter hook to programmatically intercept and modify a user’s first or last name before it is displayed.

This is particularly useful for obscuring full names while still confirming a partial match. Add the following PHP snippet to your theme’s functions.php file or a custom plugin to achieve this.

/**
 * Snippet for 'elc_ctid_verifier_alter_username' filter hook.
 * Plugin: Certificate Verifier for LearnDash
 * Requires version: 2.3 (for now)
 */
add_filter( 'elc_ctid_verifier_alter_username',
    function ( $s ) {
        // First and/or last name can use more than one word.
        // We split the first/last to separate words
        // and then obfuscate the parts.
        // E.g. 'Daan Van den Berg' will return 'D*** V** d** B***'.
        //
        $split_pattern = '/[\n\r\t\v\s]/';
        $parts = preg_split( $split_pattern, $s );

        // Obfuscate the first/last name except the first letter.
        // Editor's Note: The source documentation contains a truncated regular
        // expression. The pattern below reflects the presumed correct and
        // functional version.
        $replace_pattern = '/(?!^)./u';
        $tmp = '';
        foreach ( $parts as $val ) {
            $tmp .= preg_replace( $replace_pattern, '*', trim( $val ) ) . ' ';
        }
        $s = trim( $tmp );
        // Always return $s.
        return $s;
    }
);

This code splits a name into its component parts (e.g., ‘Daan Van den Berg’) and replaces all but the first letter of each part with an asterisk, resulting in an obfuscated output like ‘D*** V** d** B***’.

By combining a flexible shortcode system with powerful developer hooks, the LearnDash Certificate Verifier provides a comprehensive toolkit for building a verification system that precisely meets your project’s needs.