Issue 69: Error handling in case the key is empty or not configured.

src/Controller/ViewerController.php

@@ -95,7 +95,20 @@ public function editor(MediaInterface $media, Request $request, $edit = FALSE) {
       );
     }
 
-    $render_array = $this->getViewerRender($media, $wopi_client_url, $edit, $options);
+    try {
+      $render_array = $this->getViewerRender($media, $wopi_client_url, $edit, $options);
+    }
+    catch (CollaboraNotAvailableException $e) {
+      $this->getLogger('cool')->warning(
+        "Cannot show the viewer/editor.<br>\n" . Error::DEFAULT_ERROR_MESSAGE,
+        Error::decodeException($e) + [],
+      );
+      return new Response(
+        (string) $this->t('The Collabora Online editor/viewer is not available.'),
+        Response::HTTP_BAD_REQUEST,
+        ['content-type' => 'text/plain'],
+      );
+    }
 
     $render_array['#theme'] = 'collabora_online_full';
     $render_array['#attached']['library'][] = 'collabora_online/cool.frame';
@@ -122,6 +135,9 @@ public function editor(MediaInterface $media, Request $request, $edit = FALSE) {
    *
    * @return array|array{error: string}
    *   A stub render element array, or an array with an error on failure.
+   *
+   * @throws \Drupal\collabora_online\Exception\CollaboraNotAvailableException
+   *   The key to use by Collabora is empty or not configured.
    */
   protected function getViewerRender(MediaInterface $media, string $wopi_client, bool $can_write, $options = NULL) {
     $cool_settings = $this->config('collabora_online.settings')->get('cool');

src/Controller/WopiController.php

@@ -12,6 +12,7 @@
 
 namespace Drupal\collabora_online\Controller;
 
+use Drupal\collabora_online\Exception\CollaboraNotAvailableException;
 use Drupal\collabora_online\MediaHelper;
 use Drupal\collabora_online\WopiTokenManager;
 use Drupal\Component\Datetime\TimeInterface;
@@ -327,7 +328,13 @@ protected function verifyTokenForMediaId(
     string $token,
     int|string $expected_media_id,
   ): array|null {
-    $values = $this->tokenManager->decodeAndVerify($token);
+    try {
+      $values = $this->tokenManager->decodeAndVerify($token);
+    }
+    catch (CollaboraNotAvailableException $e) {
+      $this->getLogger('cool')->warning('A token cannot be decoded: @message', ['@mesage' => $e->getMessage()]);
+      return NULL;
+    }
     if ($values === NULL) {
       return NULL;
     }

src/WopiTokenManager.php

@@ -14,6 +14,7 @@
 
 namespace Drupal\collabora_online;
 
+use Drupal\collabora_online\Exception\CollaboraNotAvailableException;
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\key\KeyRepositoryInterface;
@@ -61,6 +62,9 @@ public function __construct(
    * @return array|null
    *   Data decoded from the token, or NULL on failure or if the token has
    *   expired.
+   *
+   * @throws \Drupal\collabora_online\Exception\CollaboraNotAvailableException
+   *   The key to use by Collabora is empty or not configured.
    */
   public function decodeAndVerify(
     #[\SensitiveParameter]
@@ -106,6 +110,9 @@ public function decodeAndVerify(
    *   The access token.
    *
    * @param-out int|float $expire_timestamp_reference
+   *
+   * @throws \Drupal\collabora_online\Exception\CollaboraNotAvailableException
+   *   The key to use by Collabora is empty or not configured.
    */
   public function encode(array $payload, int|float|null &$expire_timestamp_reference = NULL): string {
     $expire_timestamp_reference = $this->getExpireTimestamp();
@@ -136,12 +143,20 @@ protected function getExpireTimestamp(): float {
    *
    * @return string
    *   The key value.
+   *
+   * @throws \Drupal\collabora_online\Exception\CollaboraNotAvailableException
+   *   The key to use by Collabora is empty or not configured.
    */
   protected function getKey(): string {
     $default_config = $this->configFactory->get('collabora_online.settings');
-    $key_id = $default_config->get('cool')['key_id'];
-
-    $key = $this->keyRepository->getKey($key_id)->getKeyValue();
+    $key_id = $default_config->get('cool')['key_id'] ?? '';
+    if (!$key_id) {
+      throw new CollaboraNotAvailableException('No key was chosen for use in Collabora.');
+    }
+    $key = $this->keyRepository->getKey($key_id)?->getKeyValue();
+    if (!$key) {
+      throw new CollaboraNotAvailableException(sprintf("The key with id '%s' is empty or does not exist.", $key_id));
+    }
     return $key;
   }