Used a helper to get the default site slug.

application/config/module.config.php

@@ -400,6 +400,7 @@
  'blockLayout' => Service\ViewHelper\BlockLayoutFactory::class,
  'blockThumbnailTypeSelect' => Service\ViewHelper\BlockThumbnailTypeSelectFactory::class,
  'dataType' => Service\ViewHelper\DataTypeFactory::class,
+ 'defaultSiteSlug' => Service\ViewHelper\DefaultSiteSlugFactory::class,
  'i18n' => Service\ViewHelper\I18nFactory::class,
  'media' => Service\ViewHelper\MediaFactory::class,
  'navigationLink' => Service\ViewHelper\NavigationLinkFactory::class,

application/src/Service/ViewHelper/DefaultSiteSlugFactory.php

@@ -0,0 +1,33 @@
+<?php
+namespace Omeka\Service\ViewHelper;
+
+use Interop\Container\ContainerInterface;
+use Omeka\View\Helper\DefaultSiteSlug;
+use Zend\ServiceManager\Factory\FactoryInterface;
+
+/**
+ * Service factory to get the default site slug, or the first site slug.
+ *
+ * @todo Store the default site as slug instead of id?
+ * @todo Set a setting for the default site of the user?
+ */
+class DefaultSiteSlugFactory implements FactoryInterface
+{
+ /**
+ * Create and return the DefaultSiteSlug view helper.
+ *
+ * @return DefaultSiteSlug
+ */
+ public function __invoke(ContainerInterface $services, $requestedName, array $options = null)
+ {
+ $defaultSiteId = $services->get('Omeka\Settings')->get('default_site');
+ $api = $services->get('Omeka\ApiManager');
+ if ($defaultSiteId) {
+ $slugs = $api->search('sites', ['id' => $defaultSiteId], ['returnScalar' => 'slug'])->getContent();
+ } else {
+ $slugs = $api->search('sites', ['limit' => 1], ['returnScalar' => 'slug'])->getContent();
+ }
+ $defaultSiteSlug = (string) reset($slugs);
+ return new DefaultSiteSlug($defaultSiteSlug);
+ }
+}

application/src/Service/ViewHelper/PublicResourceUrlFactory.php

@@ -13,21 +13,13 @@
 class PublicResourceUrlFactory implements FactoryInterface
 {
  /**
- * Create and return the PublicResourceUrlFactory view helper
+ * Create and return the PublicResourceUrl view helper
  *
- * @return PublicResourceUrlFactory
+ * @return PublicResourceUrl
  */
  public function __invoke(ContainerInterface $services, $requestedName, array $options = null)
  {
- // Get the slug for the default site, else the first one.
- $defaultSiteId = $services->get('Omeka\Settings')->get('default_site');
- $api = $services->get('Omeka\ApiManager');
- if ($defaultSiteId) {
- $slugs = $api->search('sites', ['id' => $defaultSiteId], ['returnScalar' => 'slug'])->getContent();
- } else {
- $slugs = $api->search('sites', ['limit' => 1], ['returnScalar' => 'slug'])->getContent();
- }
- $defaultSiteSlug = reset($slugs);
- return new PublicResourceUrl($defaultSiteSlug);
+ $defaultSiteSlug = $services->get('ViewHelperManager')->get('defaultSiteSlug');
+ return new PublicResourceUrl($defaultSiteSlug());
  }
 }

application/src/View/Helper/DefaultSiteSlug.php

@@ -0,0 +1,35 @@
+<?php
+namespace Omeka\View\Helper;
+
+use Zend\View\Helper\AbstractHelper;
+
+/**
+ * View helper to get the default site slug, or the first one.
+ */
+class DefaultSiteSlug extends AbstractHelper
+{
+ /**
+ * @var string
+ */
+ protected $defaultSiteSlug;
+
+ /**
+ * Construct the helper.
+ *
+ * @param string|null $defaultSiteSlug
+ */
+ public function __construct($defaultSiteSlug)
+ {
+ $this->defaultSiteSlug = $defaultSiteSlug;
+ }
+
+ /**
+ * Return the default site slug, or the first one.
+ *
+ * @return string|null
+ */
+ public function __invoke()
+ {
+ return $this->defaultSiteSlug;
+ }
+}