WordPress Comments Recaptcha

CW_Comments_Recaptcha.php

<?php

/**
 * Class CWP_Comments_Recaptcha
 * Allows you to add recaptcha to WordPress Comments
 */
class CW_Comments_Recaptcha {

    const js_url = 'https://www.google.com/recaptcha/api.js';


    public static function init() {
        add_action( 'admin_init', [ __CLASS__, 'register_settings' ] );
        self::maybe_enable_recaptcha();
    }


    /**
     * Checks if reCAPTCHA settings are present
     * then performs the necessary operations to implement the recapture field into forms
     */
    private static function maybe_enable_recaptcha() {

        $recaptcha_for_comments_toggle = get_option( 'recaptcha_for_comments_toggle' );
        $recaptcha_for_comments_site_key = get_option( 'recaptcha_for_comments_site_key' );
        $recaptcha_for_comments_site_secret = get_option( 'recaptcha_for_comments_site_secret' );

        if ( $recaptcha_for_comments_toggle != true || empty( $recaptcha_for_comments_site_key ) || empty( $recaptcha_for_comments_site_secret ) ) {
            return;
        }

        add_action( 'wp_enqueue_scripts', function () {
            wp_register_script( 'recaptcha_external', self::js_url );
            wp_enqueue_script( 'recaptcha_external' );
        } );

        add_action( 'comment_form_after_fields', function () {

            $template = locate_template( 'templates/comments/field-recaptcha.php' );

            if ( $template != '' ) {
                get_template_part( 'templates/comments/comment-field', 'recaptcha' );
            } else {

                $recaptcha_for_comments_site_key = get_option( 'recaptcha_for_comments_site_key' );
                $recaptcha_css_class = '';
                if ( isset( $_GET['submission'] ) && 'security_recaptcha' === $_GET['submission'] ) {
                    $recaptcha_css_class = 'security_fail';
                    echo '<div style="color:red">' . __( 'Security check fail - you appear to be a bot' ) . '</div>';
                }
                echo '<div class="g-recaptcha ' . $recaptcha_css_class . '" data-sitekey="' . $recaptcha_for_comments_site_key . '" ></div>';
            }

        } );

        //only add the reCaptcha validation for logged out users
        if ( function_exists( 'is_user_logged_in' ) && !is_user_logged_in() ) {
            add_filter( 'preprocess_comment', [ __CLASS__, 'validate_recaptcha' ] );
        }

    }


    static function display_recaptcha_toggle_setting( $args ) {
        $option_name = 'recaptcha_for_comments_toggle';
        $data = esc_attr( get_option( $option_name, '' ) );
        $checked = $data == true ? 'checked=checked' : '';
        printf(
            '<input type="checkbox" name="%1$s" id="%2$s" %3$s/>',
            $option_name,
            $args['label_for'],
            $checked
        );
    }


    static function display_recaptcha_site_key_setting( $args ) {
        $option_name = 'recaptcha_for_comments_site_key';
        $data = esc_attr( get_option( $option_name, '' ) );
        printf(
            '<input class="widefat" type="text" name="%1$s" id="%2$s" value="%3$s"/>',
            $option_name,
            $args['label_for'],
            $data
        );
    }


    static function display_recaptcha_site_secret_setting( $args ) {
        $option_name = 'recaptcha_for_comments_site_secret';
        $data = esc_attr( get_option( $option_name, '' ) );
        printf(
            '<input class="widefat" type="text" name="%1$s" id="%2$s" value="%3$s"/>',
            $option_name,
            $args['label_for'],
            $data
        );
    }


    static function recaptcha_for_comments_description() {
        ?>
        <p class="description">Integrate reCAPTCHA into WordPress comments. For more info, visit <a
                    href="https://www.google.com/recaptcha" target="_blank">reCAPTCHA's website</a>.<br/><span
                    style="color:red"><strong>Note:</strong></span> that reCaptcha will not appear for logged in users.
        </p>
        <?php
    }


    /**
     * Server side validation for reCAPTCHA
     *
     * @param $comment_data
     *
     * @return mixed
     */
    static function validate_recaptcha( $comment_data ) {
        $secret = get_option( 'recaptcha_for_comments_site_secret' );
        $response = array_key_exists( 'g-recaptcha-response', $_POST ) ? $_POST['g-recaptcha-response'] : '';
        $verify = file_get_contents( 'https://www.google.com/recaptcha/api/siteverify?secret=' . $secret . '&response=' . $response );
        $captcha_success = json_decode( $verify );

        if ( !$captcha_success->success ) {
            wp_die( __( 'Error: reCAPTCHA failed... Go Back and try again...' ) );
            exit();
        }

        return $comment_data;
    }


    /**
     * Based on the example used here
     *
     * @link http://wordpress.stackexchange.com/questions/97212/add-settings-fields-on-options-discussion-admin-page
     */
    static function register_settings() {
        add_settings_section(
            'recaptcha_for_comments_id',
            'reCAPTCHA',
            [ __CLASS__, 'recaptcha_for_comments_description' ],
            'discussion'
        );

        // Register a callback
        register_setting(
            'discussion',
            'recaptcha_for_comments_toggle',
            'trim'
        );

        register_setting(
            'discussion',
            'recaptcha_for_comments_site_key',
            'trim'
        );

        register_setting(
            'discussion',
            'recaptcha_for_comments_site_secret',
            'trim'
        );

        // Register the field for the "avatars" section.
        add_settings_field(
            'recaptcha_for_comments_toggle',
            'Turn On / Off',
            [ __CLASS__, 'display_recaptcha_toggle_setting' ],
            'discussion',
            'recaptcha_for_comments_id',
            [ 'label_for' => 'recaptcha_for_comments_id' ]
        );

        add_settings_field(
            'recaptcha_for_comments_site_key',
            'Site Key',
            [ __CLASS__, 'display_recaptcha_site_key_setting' ],
            'discussion',
            'recaptcha_for_comments_id',
            [ 'label_for' => 'recaptcha_for_comments_id' ]
        );

        add_settings_field(
            'recaptcha_for_comments_site_secret',
            'Site Secret',
            [ __CLASS__, 'display_recaptcha_site_secret_setting' ],
            'discussion',
            'recaptcha_for_comments_id',
            [ 'label_for' => 'recaptcha_for_comments_id' ]
        );
    }

}

CW_Comments_Recaptcha::init();