wp-maintenance-webhook.php

<?php
/**
 * This script will allow you to enable or disable WORDPRESS maintenance mode via webhooks.
 * 
 * This is not an official Wordpress script file, so use it at your own risk.
 * Copy and paste this file at the root of Wordpress (file name "wp-maintenance-webhook.php").
 * 
 * Access to this webhook will required basic HTML authentication. The credentials are defined as
 * global constants in this file.
 * 
 * @author 10 Quality <info@10quality.com>
 * @license MIT
 * @package wp-maintenance-webhook
 * @version 1.0.0
 */

/**
 * File authentication credentials.
 * @since 1.0.0
 */
define( 'HTTP_USER', 'YOUR USER NAME HERE' );
define( 'HTTP_PASSWORD', 'YOUR PASSWORD HERE' );
define( 'ABSPATH', __DIR__ );
define( 'FS_CHMOD_FILE', 0755 );

/**
 * Webhook class listener / handler.
 * @since 1.0.0
 */
class WebhookHandler
{
    /**
     * Flag that indicates if webhook endpoint has been authenticated.
     * @since 1.0.0
     * 
     * @var bool
     */
    protected $has_auth = false;
    /**
     * Init handler.
     * @since 1.0.0
     */
    public function __construct()
    {
        $this->authenticate();
        if ( $this->has_auth )
            $this->listener();
    }
    /**
     * Webhook "enable_maintenance" handler.
     * @since 1.0.0
     */
    protected function webhook_enable_maintenance()
    {
        $file = ABSPATH . '/.maintenance';
        $time = time();
        $maintenance_string = '<?php $upgrading = ' . $time . '; ?>';
        if ( file_exists( $file ) )
            unlink( $file );
        file_put_contents( $file, $maintenance_string );
        chmod( $file, FS_CHMOD_FILE );
        // Output
        $this->output( [
            'error'             => false,
            'time'              => $time,
            'message'           => 'Maintenance mode enabled!',
            'maintenance'       => true,
        ] );
    }
    /**
     * Webhook "disable_maintenance" hadler.
     * @since 1.0.0
     */
    protected function webhook_disable_maintenance()
    {
        $file = ABSPATH . '/.maintenance';
        if ( file_exists( $file ) )
            unlink( $file );
        // Output
        $this->output( [
            'error'             => false,
            'message'           => 'Maintenance mode disabled!',
            'maintenance'       => false,
        ] );
    }
    /**
     * Listens to webhook requests.
     * @since 1.0.0
     */
    private function listener()
    {
        $webhook = $this->input( 'webhook' );
        $webhooks = ['enable_maintenance', 'disable_maintenance'];
        if ( ! in_array( $webhook, $webhooks ) ) {
            header( 'HTTP/1.0 401 Unauthorized' );
            // Output
            $this->error( [
                'error'     => true,
                'message'   => 'Unauthorized',
            ] );
            exit;
        }
        $this->{'webhook_' . $webhook}();
    }
    /**
     * Checks HTTP authentication
     * @since 1.0.0
     */
    private function authenticate()
    {
        $auth = $this->input( 'auth', ':' );
        list( $user, $password ) = explode( ':', strpos( $auth, ':' ) !== false ? $auth : ( $auth . ':' ) );
        if ( ! isset( $user )
            || ! isset( $password )
            || empty( $user )
            || empty( $password )
            || $user !== HTTP_USER
            || $password !== HTTP_PASSWORD
        ) {
            header( 'HTTP/1.0 401 Unauthorized' );
            // Output
            $this->error( [
                'error'     => true,
                'message'   => 'Unauthorized',
            ] );
            exit;
        } else {
            $this->has_auth = true;
        }
    }
    /**
     * Retrieves a value form query string.
     * @since 1.0.0
     * 
     * @param string $key
     * @param string $default
     * 
     * @return string
     */
    private function input( $key, $default = null )
    {
        if ( array_key_exists( $key, $_GET ) ) {
            return preg_replace( '/[\<\?\>\.\\\[\]\{\}\'\"]/', '', strip_tags( trim( $_GET[$key] ) ) );
        }
        return $default;
    }
    /**
     * Prints output.
     * @since 1.0.0
     * 
     * @param array $args
     */
    private function output( $args )
    {
        $format = $this->input( 'output', 'json' );
        switch ( $format ) {
            case 'json':
                $this->echo_json( $args );
                die;
                break;
            case 'html':
            default:
                $this->echo_html( $args );
                break;
        }
    }
    /**
     * Prints error output.
     * @since 1.0.0
     * 
     * @param array $args
     */
    private function error( $args )
    {
        $format = $this->input( 'output', 'json' );
        switch ( $format ) {
            case 'json':
                $this->echo_json( $args );
                break;
            case 'html':
            default:
                $this->echo_html( $args );
                break;
        }
    }
    /**
     * Echos / prints arguments in JSON format.
     * @since 1.0.0
     * 
     * @param array $args
     */
    private function echo_json( $args )
    {
        header( 'Content-Type: application/json' );
        echo json_encode( $args );
    }
    /**
     * Echos / prints arguments in HTML format.
     * @since 1.0.0
     * 
     * @param array $args
     */
    private function echo_html( $args )
    {
        ob_start();
        ?>
        <!DOCTYPE html>
        <html>
            <head>
                <title>Maintenance Webhook</title>
            </head>
            <body>
                <table>
                    <tbody>
                        <?php foreach ( $args as $key => $value ) : ?>
                            <tr>
                                <th><?php echo ucfirst( $key ) ?></th>
                                <td><?php echo ! is_bool( $value ) ? $value : ( $value ? 'true' : 'false' ) ?></td>
                            </tr>
                        <?php endforeach ?>
                    </tbody>
                </table>
            </body>
        </html>
        <?php
        echo ob_get_clean();
    }
}

new WebhookHandler();