Provides a plugin to test whether a server will allow background job processing or not for WooComm import / export plugins.

sv-background-test.php

<?php
/**
 * Plugin Name: Background Processing Test for Import / Export
 * Plugin URI: http://skyverge.com/
 * Description: Tests whether or not the server can connect to itself to process jobs asynchronously.
 * Author: SkyVerge
 * Author URI: http://www.skyverge.com/
 * Version: 1.0.0
 * Text Domain: sv-background
 *
 * Copyright: (c) 2017 SkyVerge, Inc. (info@skyverge.com)
 *
 * License: GNU General Public License v3.0
 * License URI: http://www.gnu.org/licenses/gpl-3.0.html
 *
 * @package   Background-Processing-Test
 * @author    SkyVerge
 * @category  Admin
 * @copyright Copyright (c) 2017, SkyVerge, Inc.
 * @license   http://www.gnu.org/licenses/gpl-3.0.html GNU General Public License v3.0
 */

defined( 'ABSPATH' ) or exit;

// fire it up!
add_action( 'plugins_loaded', 'sv_background_processing_test' );

/**
 * Main plugin class
 *
 * @since 1.0.0
 */
class SV_Background_Processing_Test {


	/** @var SV_Background_Processing_Test single instance of this plugin */
	protected static $instance;

	/** @var string $message the message based on the result of the tool */
	protected $message;

	/**
	 * Initialize the class.
	 *
	 * @since 1.0.0
	 */ 
	public function __construct() {

		// add test content for the request
		add_action( 'init', array( $this, 'init' ), 25 );

		if ( is_admin() ) {

			// add plugin links
			add_filter( 'plugin_action_links_' . plugin_basename( __FILE__ ), array( $this, 'add_plugin_links' ) );

			// add zeh tool!
			add_filter( 'woocommerce_debug_tools', array( $this, 'add_debug_tool' ) );

			// translate the success message
			add_filter( 'gettext', array( $this, 'translate_success_message' ), 10, 3 );
		}
	}


	/** Plugin methods ***************************************/


	/**
	 * Initialize the test
	 *
	 * @since 1.0.0
	 */
	public function init() {

		// super-simplistic test response for checking whether loopback connections are enabled on server
		if ( ! empty( $_REQUEST['sv_wc_test_loopback_connections'] ) ) {
			echo '[TEST_LOOPBACK]';
			exit;
		}
	}


	/**
	 * Adds loopback connection testing tool to WC system status -> tools page.
	 *
	 * @since 1.0.0
	 *
	 * @param array $tools system status tools
	 * @return array
	 */
	public function add_debug_tool( $tools ) {

		$tools['sv_wc_test_loopback_request'] = array(
			'name'     => __( 'Background Processing Test', 'sv-background' ),
			'button'   => __( 'Run Test', 'sv-background' ),
			'desc'     => __( 'This tool will test whether your server is capable of processing background jobs for WooCommerce imports or exports.', 'sv-background' ),
			'callback' => array( $this, 'test_loopback_connection' ),
		);

		return $tools;
	}


	/**
	 * Tests whether loopback connections work by firing a GET request to the server itself
	 *
	 * @since 1.0.0
	 *
	 * @return bool whether the request was successful or not
	 */
	function test_loopback_connection() {

		$url     = add_query_arg( 'sv_wc_test_loopback_connections', 1, home_url( '/' ) );
		$result  = wp_remote_get( $url );
		$success = is_array( $result ) && ! empty( $result['body'] ) && '[TEST_LOOPBACK]' === $result['body'];

		if ( ! $success && is_admin() ) {
			$this->message = esc_html__( 'Could not connect. Please ask your hosting company to ensure your server has loopback connections enabled.', 'sv-background' );
		} elseif ( $success && is_admin() ) {
			$this->message = esc_html__( 'Success! You should be able to process background jobs.', 'sv-background' );
		}

		return $success;
	}


	/**
	 * Translate the tool success message.
	 *
	 * This could possibly be removed in favor of returning the message string in `test_loopback_connection()`
	 *  when WC 3.1 is common.
	 *
	 * @since 1.0.0
	 *
	 * @param string $translated the text to output
	 * @param string $original the original text
	 * @param string $domain the textdomain
	 * @return string updated text
	 */
	public function translate_success_message( $translated, $original, $domain ) {

		if ( 'woocommerce' === $domain && ( 'Tool ran.' === $original || 'There was an error calling %s' === $original ) ) {
			$translated = $this->message;
		}

		return $translated;
	}


	/** Helper methods ***************************************/


	/**
	 * Main SV_Background_Processing_Test Instance, ensures only one instance is/can be loaded
	 *
	 * @since 1.0.0
	 * @see sv_background_processing_test()
	 * @return SV_Background_Processing_Test
 	*/
	public static function instance() {
		if ( is_null( self::$instance ) ) {
			self::$instance = new self();
		}
		return self::$instance;
	}


	/**
	 * Adds plugin page links
	 *
	 * @since 1.0.0
	 * @param array $links all plugin links
	 * @return array $links all plugin links + our custom links (i.e., "Settings")
	 */
	public function add_plugin_links( $links ) {

		$plugin_links = array(
			'<a href="' . admin_url( 'admin.php?page=wc-status&tab=tools' ) . '">' . __( 'View Tools', 'sv-background' ) . '</a>',
		);

		return array_merge( $plugin_links, $links );
	}


}


/**
 * Returns the One True Instance of SV_Background_Processing_Test
 *
 * @since 1.0.0
 * @return SV_Background_Processing_Test
 */
function sv_background_processing_test() {
    return SV_Background_Processing_Test::instance();
}