Hooks and API

Technical reference for extending Restrict Email Domain for WordPress. All classes use the singleton pattern and are prefixed REDW_.

Constants

REDW_VERSION          // Plugin version
REDW_PLUGIN_DIR       // Plugin directory path
REDW_PLUGIN_URL       // Plugin URL
REDW_PLUGIN_BASENAME  // Plugin basename
REDW_STORE_URL        // EDD store URL
REDW_ITEM_ID          // EDD item ID
REDW_ITEM_NAME        // EDD item name

Core classes

Class	File	Responsibility
REDW_Settings	includes/class-settings.php	Load, save, and sanitize settings and domain lists
REDW_Validator	includes/class-validator.php	Domain matching, front-end AJAX validation, notifications
REDW_Logger	includes/class-logger.php	Log writes, stats, CSV export, cleanup
REDW_Import_Export	includes/class-import-export.php	Import/export of settings and domain lists
REDW_Admin	admin/class-admin.php	Admin screens and admin AJAX handlers

REDW_Settings

$settings = REDW_Settings::get_instance();
$value    = $settings->get( 'key', 'default' );
$settings->set( 'key', 'value' );
$all      = $settings->get_all();
$settings->update_all( array( 'key' => 'value' ) );

$allowed  = $settings->get_allowed_domains();  // array
$banned   = $settings->get_banned_domains();   // array
$emails   = $settings->get_whitelist_emails(); // array

$json     = $settings->export_settings();
$result   = $settings->import_settings( $json_string );

Settings keys (stored in the redw_settings option):

Key	Type	Default
allowed_domains	string	‘’
banned_domains	string	‘’
error_message	string	Registration is restricted for this domain or email.
enable_logging	bool	true
log_retention_days	int	30
enable_real_time_validation	bool	true
whitelist_emails	string	‘’
notification_email	string	admin email
enable_notifications	bool	false
case_sensitive	bool	false
strict_subdomain_matching	bool	false
delete_data_on_uninstall	bool	false

REDW_Validator

$validator  = REDW_Validator::get_instance();
$is_allowed = $validator->is_email_allowed( 'user@example.com' );      // bool
$is_allowed = $validator->validate_and_log( $email, 'my_source' );      // logs + notifies if blocked
$message    = $validator->get_validation_error( 'user@blocked.com' );   // string

Matching order inside is_email_allowed(): email whitelist, then allowed domains (if any), then banned domains (if any), else allow.

REDW_Logger

$logger = REDW_Logger::get_instance();
$logger->log_blocked_attempt( $email, $source );
$logs   = $logger->get_logs( array( 'limit' => 50, 'offset' => 0, 'source' => '', 'domain' => '', 'date_from' => '', 'date_to' => '' ) );
$stats  = $logger->get_stats( 30 ); // total_blocked, by_source, top_domains, daily_blocked
$count  = $logger->get_log_count( $args );
$csv    = $logger->export_logs( $args );
$logger->cleanup_old_logs();

Options

Option	Purpose
redw_settings	All plugin settings (array)
redw_license_key	License key
redw_license_status	License status
redw_license_data	License data from the EDD API
redw_version	Installed version

Log table schema

CREATE TABLE {prefix}redw_logs (
    id mediumint(9) NOT NULL AUTO_INCREMENT,
    email varchar(100) NOT NULL,
    domain varchar(100) NOT NULL,
    source varchar(50) NOT NULL,
    ip_address varchar(45) NOT NULL,
    user_agent text,
    created_at datetime DEFAULT CURRENT_TIMESTAMP,
    PRIMARY KEY (id),
    KEY email (email),
    KEY domain (domain),
    KEY source (source),
    KEY created_at (created_at)
);

Registration hooks used

The plugin hooks WordPress and integration registration flows. Core hooks: registration_errors (priority 20) and wpmu_validate_user_signup (priority 20). See Integrations for the per-plugin hooks and log source values.

Cron

redw_cleanup_logs runs daily and deletes log rows older than log_retention_days.

AJAX actions

Front-end (nonce redw_ajax_nonce):

• redw_validate_email (and nopriv variant) - real-time email validation.

Admin (nonce redw_admin_nonce, capability manage_options):

• redw_save_settings
• redw_test_email
• redw_validate_domains
• redw_check_config
• redw_get_integration_status
• redw_cleanup_logs
• redw_export_settings, redw_import_settings
• redw_export_logs
• redw_export_domains, redw_import_domains
• redw_quick_import_disposable

Front-end validation response shape:

{ "success": true,  "data": { "message": "Email domain is allowed" } }
{ "success": false, "data": { "message": "Registration is restricted for this domain or email." } }

Creating a custom integration

To cover a plugin that bypasses standard WordPress hooks, add a class that runs only when the target plugin is present, validates through REDW_Validator, and exposes get_integration_status().

class REDW_Custom_Plugin {
    private static $instance = null;
    private $validator;

    public static function get_instance() {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    private function __construct() {
        if ( ! class_exists( 'Custom_Plugin_Class' ) ) {
            return;
        }
        $this->validator = REDW_Validator::get_instance();
        add_filter( 'custom_plugin_registration_errors', array( $this, 'validate_registration' ), 10, 2 );
    }

    public function validate_registration( $errors, $email ) {
        if ( ! $this->validator->validate_and_log( $email, 'custom_plugin' ) ) {
            $errors->add( 'email_domain_restricted', $this->validator->get_validation_error( $email ) );
        }
        return $errors;
    }

    public function get_integration_status() {
        return array(
            'name'               => 'Custom Plugin',
            'active'             => class_exists( 'Custom_Plugin_Class' ),
            'version'            => defined( 'CUSTOM_PLUGIN_VERSION' ) ? CUSTOM_PLUGIN_VERSION : null,
            'supported_features' => array( 'Registration Forms' ),
        );
    }
}

Load the class (for example on plugins_loaded) and add its class name to RestrictEmailDomainWP::get_integrations_status() so it appears on the Tools tab.