Expose value annotations via the API (search and read only)

application/Module.php

@@ -290,6 +290,8 @@ public function addTermDefinitionsToContext(LaminasEvent $event)
         }
         $context['o-cnt'] = 'http://www.w3.org/2011/content#';
         $context['o-time'] = 'http://www.w3.org/2006/time#';
+        $context['oa'] = 'http://www.w3.org/ns/oa#';
+        $context['rdf'] = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#';
         $event->setParam('context', $context);
     }
 

application/src/Api/Adapter/ValueAnnotationAdapter.php

@@ -1,12 +1,21 @@
 <?php
 namespace Omeka\Api\Adapter;
 
+use Doctrine\ORM\QueryBuilder;
+use Omeka\Api\Exception;
 use Omeka\Api\Representation\ValueAnnotationRepresentation;
 use Omeka\Api\Request;
 use Omeka\Entity\ValueAnnotation;
 
 class ValueAnnotationAdapter extends AbstractResourceEntityAdapter
 {
+    protected $sortFields = [
+        'id' => 'id',
+        'is_public' => 'isPublic',
+        'created' => 'created',
+        'modified' => 'modified',
+    ];
+
     public function getResourceName()
     {
         return 'value_annotations';
@@ -22,14 +31,70 @@ public function getEntityClass()
         return ValueAnnotation::class;
     }
 
-    public function search(Request $request)
+    public function buildQuery(QueryBuilder $qb, array $query)
     {
-        return AbstractAdapter::search($request);
+        parent::buildQuery($qb, $query);
+
+        // The visibility filter only checks the annotation's own public flag, not
+        // the parent resource's. Join through Value to check both.
+        $services = $this->getServiceLocator();
+        $acl = $services->get('Omeka\Acl');
+        if ($acl->userIsAllowed('Omeka\Entity\Resource', 'view-all')) {
+            return;
+        }
+
+        $identity = $services->get('Omeka\AuthenticationService')->getIdentity();
+        $valueAlias = $qb->createAlias();
+        $parentResourceAlias = $qb->createAlias();
+
+        $qb->join(
+            'Omeka\Entity\Value',
+            $valueAlias,
+            'WITH',
+            $qb->expr()->eq("$valueAlias.valueAnnotation", 'omeka_root')
+        );
+        $qb->join("$valueAlias.resource", $parentResourceAlias);
+
+        $parentVisibilityExpr = $qb->expr()->eq(
+            "$parentResourceAlias.isPublic",
+            $qb->createNamedParameter(true)
+        );
+        if ($identity) {
+            $parentVisibilityExpr = $qb->expr()->orX(
+                $parentVisibilityExpr,
+                $qb->expr()->eq(
+                    "$parentResourceAlias.owner",
+                    $qb->createNamedParameter($identity)
+                )
+            );
+        }
+        $qb->andWhere($parentVisibilityExpr);
     }
 
     public function read(Request $request)
     {
-        return AbstractAdapter::read($request);
+        // The visibility filter doesn't catch a public annotation on a private
+        // resource, so verify the parent explicitly. Return 404 rather than 403
+        // to avoid revealing that the resource exists.
+        $response = parent::read($request);
+
+        $acl = $this->getServiceLocator()->get('Omeka\Acl');
+        if ($acl->userIsAllowed('Omeka\Entity\Resource', 'view-all')) {
+            return $response;
+        }
+
+        // The ResourceVisibilityFilter applies to lazy-loaded associations, so
+        // if the parent resource is not visible to this user, getResource() returns null.
+        $entity = $response->getContent();
+        if (!$entity->getValue()->getResource()) {
+            throw new Exception\NotFoundException(sprintf(
+                $this->getTranslator()->translate('%1$s entity with criteria %2$s not found'),
+                $this->getEntityClass(),
+                json_encode(['id' => $entity->getId()])
+            ));
+        }
+
+        return $response;
     }
 
     public function create(Request $request)

application/src/Api/Representation/ValueAnnotationRepresentation.php

@@ -5,12 +5,33 @@ class ValueAnnotationRepresentation extends AbstractResourceEntityRepresentation
 {
     public function getResourceJsonLdType()
     {
-        return 'o:ValueAnnotation';
+        return ['o:ValueAnnotation', 'oa:Annotation'];
     }
 
     public function getResourceJsonLd()
     {
-        return [];
+        $value = $this->annotatedValue();
+        $valueJson = $value->jsonSerialize();
+        // Unset @annotation to avoid a circular reference back to this object.
+        unset($valueJson['@annotation']);
+        return [
+            'oa:hasTarget' => [
+                '@type' => 'rdf:Statement',
+                'rdf:subject' => $this->resource()->getReference(),
+                'rdf:predicate' => ['@id' => $value->property()->uri()],
+                'rdf:object' => $valueJson,
+            ],
+        ];
+    }
+
+    public function annotatedValue()
+    {
+        return new ValueRepresentation($this->resource->getValue(), $this->getServiceLocator());
+    }
+
+    public function resource()
+    {
+        return $this->getAdapter('resources')->getRepresentation($this->resource->getValue()->getResource());
     }
 
     public function displayValues(array $options = [])

application/src/Entity/ValueAnnotation.php

@@ -12,6 +12,11 @@ class ValueAnnotation extends Resource
      */
     protected $id;
 
+    /**
+     * @OneToOne(targetEntity="Value", mappedBy="valueAnnotation")
+     */
+    protected $value;
+
     public function getResourceName()
     {
         return 'value_annotations';
@@ -21,4 +26,9 @@ public function getId()
     {
         return $this->id;
     }
+
+    public function getValue()
+    {
+        return $this->value;
+    }
 }

application/src/Service/AclFactory.php

@@ -282,6 +282,7 @@ protected function addRulesForAllRoles(Acl $acl)
                 'Omeka\Api\Adapter\AssetAdapter',
                 'Omeka\Api\Adapter\ApiResourceAdapter',
                 'Omeka\Api\Adapter\DataTypeAdapter',
+                'Omeka\Api\Adapter\ValueAnnotationAdapter',
             ],
             [
                 'search',
@@ -299,6 +300,7 @@ protected function addRulesForAllRoles(Acl $acl)
                 'Omeka\Entity\Property',
                 'Omeka\Entity\ResourceTemplate',
                 'Omeka\Entity\Asset',
+                'Omeka\Entity\ValueAnnotation',
             ],
             [
                 'read',