Issue #3333776: Fatal error when trying to display inline a SVG image that does not exist and with stage_file_proxy module enabled

src/Plugin/Field/FieldFormatter/SvgImageFieldFormatter.php

@@ -2,6 +2,7 @@
 
 namespace Drupal\svg_image_field\Plugin\Field\FieldFormatter;
 
+use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\Core\Field\FieldItemListInterface;
@@ -46,6 +47,13 @@ class SvgImageFieldFormatter extends FormatterBase implements ContainerFactoryPl
    */
   protected $fileUrlGenerator;
 
+  /**
+   * The config factory.
+   *
+   * @var \Drupal\Core\Config\ConfigFactoryInterface
+   */
+  protected $configFactory;
+
   /**
    * {@inheritdoc}
    */
@@ -232,9 +240,8 @@ class SvgImageFieldFormatter extends FormatterBase implements ContainerFactoryPl
         continue;
       }
       $uri = $item->entity->getFileUri();
-      $stageFileProxy = $this->moduleHandler->moduleExists('stage_file_proxy');
-      if (file_exists($uri) === FALSE && !$stageFileProxy) {
-        $this->logger->error('The specified file %file could not be displayed by image formatter due file not exists.', ['%file' => $uri]);
+      if (!is_file($uri) && !$this->isStageFileProxyConfigured()) {
+        $this->logger->error('File %file could not be displayed by image formatter because it does not exist on server.', ['%file' => $uri]);
         continue;
       }
       if ($this->getSetting('enable_alt')) {
@@ -247,36 +254,6 @@ class SvgImageFieldFormatter extends FormatterBase implements ContainerFactoryPl
       if ($this->getSetting('enable_title') && !empty($item->title)) {
         $attributes['title'] = $item->title;
       }
-      $svg_data = NULL;
-
-      if ($this->getSetting('inline')) {
-        $svg_file = file_get_contents($uri);
-        $dom = new \DOMDocument();
-        libxml_use_internal_errors(TRUE);
-        if (!empty($svg_file)) {
-          $dom->loadXML($svg_file);
-        }
-        if ($this->getSetting('force_fill')) {
-          $dom->documentElement->setAttribute('fill', 'currentColor');
-        }
-        if (isset($dom->documentElement)) {
-          if ($this->getSetting('apply_dimensions')) {
-            $dom->documentElement->setAttribute('height', $attributes['height']);
-            $dom->documentElement->setAttribute('width', $attributes['width']);
-          }
-          $svg_data = $dom->saveXML($dom->documentElement);
-        }
-        else {
-          $svg_data = $dom->saveXML();
-        }
-        if ($this->getSetting('sanitize')) {
-          $svgSanitizer = new Sanitizer();
-          if ($this->getSetting('sanitize_remote')) {
-            $svgSanitizer->removeRemoteReferences(TRUE);
-          }
-          $svg_data = $svgSanitizer->sanitize($svg_data);
-        }
-      }
 
       $cache_contexts = [];
       if ($image_link_setting == 'file') {
@@ -289,23 +266,96 @@ class SvgImageFieldFormatter extends FormatterBase implements ContainerFactoryPl
         $cache_contexts[] = 'url.site';
       }
 
-      $elements[$delta] = [
+      $element = [
         '#theme' => 'svg_image_field_formatter',
-        '#inline' => $this->getSetting('inline') ? TRUE : FALSE,
         '#attributes' => $attributes,
-        '#uri' => $this->getSetting('inline') ? NULL : $uri,
-        '#svg_data' => $svg_data,
         '#link_url' => $url,
         '#cache' => [
           'tags' => $item->entity->getCacheTags(),
           'contexts' => $cache_contexts,
         ],
       ];
+
+      // Set properties based on if the SVG is displayed inline or not.
+      if ($this->getSetting('inline') && $svg_data = $this->loadInlineSvgData($uri, $attributes)) {
+        $element['#inline'] = TRUE;
+        $element['#svg_data'] = $svg_data;
+      }
+      else {
+        $element['#inline'] = FALSE;
+        $element['#uri'] = $uri;
+      }
+
+      $elements[$delta] = $element;
     }
 
     return $elements;
   }
 
+  /**
+   * Determine if the Stage File Proxy module is enabled and configured.
+   *
+   * @return bool
+   *   True if Stage File Proxy module is enabled and configured.
+   */
+  protected function isStageFileProxyConfigured() {
+    return (
+      $this->moduleHandler->moduleExists('stage_file_proxy') &&
+      $this->configFactory->get('stage_file_proxy.settings')->get('origin')
+    );
+  }
+
+  /**
+   * Load SVG file data for inline display.
+   *
+   * @param string $uri
+   *   The uri to the SVG file.
+   * @param array $attributes
+   *   Attributes to set for the SVG html tag.
+   *
+   * @return string|null
+   *   The loaded SVG XML, or null if the file is missing or empty.
+   */
+  protected function loadInlineSvgData(string $uri, array $attributes): ?string {
+    // If the file is missing or has empty contents, temporarily disable
+    // inline SVG and instead render an <img> tag containing the URL to the
+    // SVG in the src attribute. This approach allows Stage File Proxy to
+    // intercept the request and obtain the original SVG file from the origin
+    // server. And as long as the Stage File Proxy 'hotlink' option is not
+    // enabled, subsequent page loads will render the SVG inline again.
+    if (!is_file($uri) || !$svg_file = @file_get_contents($uri)) {
+      $this->logger->warning('Inline file %file is missing or empty. Inline display will be disabled and an image tag used instead.', ['%file' => $uri]);
+      return NULL;
+    }
+
+    $dom = new \DOMDocument();
+    libxml_use_internal_errors(TRUE);
+    $dom->loadXML($svg_file);
+    if ($this->getSetting('force_fill')) {
+      $dom->documentElement->setAttribute('fill', 'currentColor');
+    }
+    if (isset($dom->documentElement)) {
+      if ($this->getSetting('apply_dimensions')) {
+        $dom->documentElement->setAttribute('height', $attributes['height']);
+        $dom->documentElement->setAttribute('width', $attributes['width']);
+      }
+      $svg_data = $dom->saveXML($dom->documentElement);
+    }
+    else {
+      $svg_data = $dom->saveXML();
+    }
+
+    if ($this->getSetting('sanitize')) {
+      $svgSanitizer = new Sanitizer();
+      if ($this->getSetting('sanitize_remote')) {
+        $svgSanitizer->removeRemoteReferences(TRUE);
+      }
+      $svg_data = $svgSanitizer->sanitize($svg_data);
+    }
+
+    return $svg_data;
+  }
+
   /**
    * Constructs a SvgImageFieldFormatter object.
    *
@@ -329,6 +379,8 @@ class SvgImageFieldFormatter extends FormatterBase implements ContainerFactoryPl
    *   The module handler service.
    * @param \Drupal\Core\File\FileUrlGeneratorInterface $file_url_generator
    *   The file URL generator.
+   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
+   *   The config factory.
    */
   public function __construct(
     $plugin_id,
@@ -340,11 +392,13 @@ class SvgImageFieldFormatter extends FormatterBase implements ContainerFactoryPl
     array $third_party_settings,
     LoggerChannelFactoryInterface $logger,
     ModuleHandlerInterface $module_handler,
-    FileUrlGeneratorInterface $file_url_generator
+    FileUrlGeneratorInterface $file_url_generator,
+    ConfigFactoryInterface $config_factory,
   ) {
     $this->logger = $logger->get('svg_image_field');
     $this->moduleHandler = $module_handler;
     $this->fileUrlGenerator = $file_url_generator;
+    $this->configFactory = $config_factory;
     parent::__construct($plugin_id, $plugin_definition, $field_definition,
       $settings, $label, $view_mode, $third_party_settings);
   }
@@ -368,7 +422,8 @@ class SvgImageFieldFormatter extends FormatterBase implements ContainerFactoryPl
       $configuration['third_party_settings'],
       $container->get('logger.factory'),
       $container->get('module_handler'),
-      $container->get('file_url_generator')
+      $container->get('file_url_generator'),
+      $container->get('config.factory'),
     );
   }