feat: disallow search engine indexing for vanity domains

src/Configuration/EventManagementConfiguration.php

@@ -44,6 +44,7 @@ public function modify(Container $container)
         $container['subscribers'] = $container->service(function (Container $container) {
             $subscribers = [
                 new Subscriber\AssetsSubscriber($container['site_url'], $container['assets_url'], $container['ymir_project_type']),
+                new Subscriber\DisallowIndexingSubscriber($container['site_url']),
                 new Subscriber\ImageEditorSubscriber($container['console_client'], $container['file_manager']),
                 new Subscriber\PluploadSubscriber($container['plugin_relative_path'], $container['rest_namespace'], $container['assets_url'], $container['plupload_error_messages']),
                 new Subscriber\RedirectSubscriber($container['ymir_primary_domain_name'], $container['is_multisite']),

src/Subscriber/DisallowIndexingSubscriber.php

@@ -0,0 +1,80 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of Ymir WordPress plugin.
+ *
+ * (c) Carl Alexander <support@ymirapp.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Ymir\Plugin\Subscriber;
+
+use Ymir\Plugin\EventManagement\SubscriberInterface;
+
+/**
+ * Subscriber for managing whether we allow indexing or not.
+ */
+class DisallowIndexingSubscriber implements SubscriberInterface
+{
+    /**
+     * WordPress site URL.
+     *
+     * @var string
+     */
+    private $siteUrl;
+
+    /**
+     * Constructor.
+     */
+    public function __construct(string $siteUrl)
+    {
+        $this->siteUrl = rtrim($siteUrl, '/');
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getSubscribedEvents(): array
+    {
+        return [
+            'admin_notices' => 'displayAdminNotice',
+            'pre_option_blog_public' => 'filterBlogPublic',
+        ];
+    }
+
+    /**
+     * Display admin notice about search indexing being disabled.
+     */
+    public function displayAdminNotice()
+    {
+        if ($this->isIndexingAllowed()) {
+            return;
+        }
+
+        echo '<div class="notice notice-warning"><p><strong>Ymir:</strong> Search engine indexing is disallowed when using a vanity domain. To learn how to map a domain to your environment, check out <a href="https://docs.ymirapp.com/guides/domain-mapping.html">this guide</a>.</p></div>';
+    }
+
+    /**
+     * Filter the "blog_public" option value.
+     */
+    public function filterBlogPublic($value)
+    {
+        if (!$this->isIndexingAllowed()) {
+            $value = 0;
+        }
+
+        return $value;
+    }
+
+    /**
+     * Determine whether if search engine indexing should be allowed or not.
+     */
+    private function isIndexingAllowed(): bool
+    {
+        return false === stripos($this->siteUrl, '.ymirsites.com');
+    }
+}

tests/Unit/Subscriber/DisallowIndexingSubscriberTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of Ymir WordPress plugin.
+ *
+ * (c) Carl Alexander <support@ymirapp.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Ymir\Plugin\Tests\Unit\Subscriber;
+
+use Ymir\Plugin\Subscriber\DisallowIndexingSubscriber;
+use Ymir\Plugin\Tests\Unit\TestCase;
+
+/**
+ * @covers \Ymir\Plugin\Subscriber\DisallowIndexingSubscriber
+ */
+class DisallowIndexingSubscriberTest extends TestCase
+{
+    public function testFilterBlogPublicReturnsSameValueIfIndexingAllowed()
+    {
+        $this->assertSame('value', (new DisallowIndexingSubscriber('https://foo.com'))->filterBlogPublic('value'));
+    }
+
+    public function testFilterBlogPublicReturnsZeroValueIfSiteUrlUsesVanityDomain()
+    {
+        $this->assertSame(0, (new DisallowIndexingSubscriber('https://subdomain.ymirsites.com'))->filterBlogPublic('value'));
+    }
+}