DGIR-130 : Error handling for islandora_citations Cite this block

src/Form/SelectCslForm.php

@@ -7,6 +7,7 @@
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\islandora_citations\IslandoraCitationsHelper;
+use Psr\Log\LoggerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -20,32 +21,46 @@ class SelectCslForm extends FormBase {
    * @var Drupal\islandora_citations\IslandoraCitationsHelper
    */
   protected $citationHelper;
+
   /**
    * CSL type value from block.
    *
    * @var string
    */
   private $blockCSLType;
+
   /**
    * The route match.
    *
    * @var \Drupal\Core\Routing\RouteMatchInterface
    */
   protected $routeMatch;
+
   /**
    * The entity type manager.
    *
    * @var \Drupal\Core\Entity\EntityTypeManagerInterface
    */
   protected $entityTypeManager;
 
+  /**
+   * The logger service.
+   *
+   * @var \Psr\Log\LoggerInterface
+   */
+  protected $logger;
+
   /**
    * {@inheritdoc}
    */
-  public function __construct(IslandoraCitationsHelper $citationHelper, RouteMatchInterface $route_match, EntityTypeManagerInterface $entity_type_manager) {
+  public function __construct(IslandoraCitationsHelper $citationHelper,
+                              RouteMatchInterface $route_match,
+                              EntityTypeManagerInterface $entity_type_manager,
+                              LoggerInterface $logger) {
     $this->citationHelper = $citationHelper;
     $this->routeMatch = $route_match;
     $this->entityTypeManager = $entity_type_manager;
+    $this->logger = $logger;
   }
 
   /**
@@ -55,7 +70,8 @@ public static function create(ContainerInterface $container) {
     return new static(
       $container->get('islandora_citations.helper'),
       $container->get('current_route_match'),
-      $container->get('entity_type.manager')
+      $container->get('entity_type.manager'),
+      $container->get('logger.factory')->get('islandora_citations')
     );
   }
 
@@ -90,6 +106,28 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       $default_csl = array_values($cslItems)[0];
     }
     $csl = !empty($default_csl) ? $this->getDefaultCitation($default_csl) : '';
+
+    // We receive error message as a string, and then we display same string
+    // as output.
+    // We expect output in a specific format when there is no error as below
+    // <div class="csl-bib-body">
+    // <div class="csl-entry">“Text_Output”</div>
+    // </div>.
+    // Based on `csl` text output, we will do the error handling.
+    // When HTML output is not as expected, add a form element which indicates
+    // we received error.
+    if (!str_starts_with($csl, '<div class="csl-bib-body">')) {
+      // Add a custom markup element to the form.
+      $form['error_handling_element'] = [
+        '#markup' => 'Form with error',
+      ];
+
+      // Log error message.
+      $this->logger->error($csl);
+
+      return $form;
+    }
+
     $form['csl_list'] = [
       '#type' => 'select',
       '#options' => $cslItems,
@@ -140,13 +178,19 @@ public function renderAjaxCitation(array $form, FormStateInterface $form_state)
         '#children' => '',
       ];
     }
-    // Method call to render citation.
-    $rendered = $this->renderCitation($csl_name);
-    $response = [
-      '#children' => $rendered['data'],
-    ];
 
-    return $form['data'] = $response;
+    try {
+      // Method call to render citation.
+      $rendered = $this->renderCitation($csl_name);
+      $response = [
+        '#children' => $rendered['data'],
+      ];
+
+      return $response;
+    }
+    catch (\Throwable $e) {
+      return $e->getMessage();
+    }
   }
 
   /**

src/IslandoraCitationsHelper.php

@@ -147,8 +147,13 @@ public function renderWithCiteproc(array $data, string $style, string $mode = 'b
    * @throws \Exception
    */
   public function encodeEntityForCiteproc(EntityInterface $entity): object {
-    $cslEncodedData = $this->serializer->normalize($entity, 'csl-json');
-    return (object) $cslEncodedData;
+    try {
+      $cslEncodedData = $this->serializer->normalize($entity, 'csl-json');
+      return (object) $cslEncodedData;
+    }
+    catch (\Exception $e) {
+      $this->logger->error($e->getMessage());
+    }
   }
 
 }

src/Plugin/Block/DisplayCitationsBlock.php

@@ -35,6 +35,7 @@ class DisplayCitationsBlock extends BlockBase implements ContainerFactoryPluginI
    * @var \Drupal\Core\Form\FormBuilderInterface
    */
   protected $formBuilder;
+
   /**
    * Citation helper service.
    *
@@ -83,10 +84,16 @@ public static function create(ContainerInterface $container, array $configuratio
    * {@inheritdoc}
    */
   public function build() {
-    if (!empty($this->citationHelper->getCitationEntityList())) :
-      $build['form'] = $this->formBuilder->getForm('Drupal\islandora_citations\Form\SelectCslForm');
+    $cite_this_form = $this->formBuilder->getForm('Drupal\islandora_citations\Form\SelectCslForm');
+    if (!empty($cite_this_form['error_handling_element'])) {
+      // Hide the entire block.
+      return NULL;
+    }
+
+    if (!empty($this->citationHelper->getCitationEntityList())) {
+      $build['form'] = $cite_this_form;
       return $build;
-    endif;
+    }
   }
 
   /**