Issue #3036845 by Liam Morland: Display error page when pdftk fails

fillpdf.module

@@ -330,6 +330,12 @@ function fillpdf_parse_uri($uri = NULL) {
   $context = fillpdf_link_to_stub_context($uri);
 
   fillpdf_merge_pdf($context['fid'], $context['nids'], $context['webforms'], $context['sample'], $context['force_download'], FALSE, $context['flatten'], TRUE, $context['uc_order_ids'], $context['uc_order_product_ids'], $context['entity_ids']);
+
+  // Normally, fillpdf_merge_pdf() calls fillpdf_merge_perform_pdf_action()
+  // which send the PDF to the browser and calls drupal_exit(). If there is an
+  // error, it will not exit. Returning empty string ensures that a page is
+  // rendered on which to display error messages.
+  return '';
 }
 
 /**
@@ -763,6 +769,10 @@ function fillpdf_merge_pdf($fid, $nids = NULL, $webform_array = NULL, $sample =
   }
   $data = fillpdf_execute_merge($method, $fields, $fillpdf_info, 'url', $flatten, $image_data);
 
+  if (!$data) {
+    return;
+  }
+
   if (!empty($webform['webform'])) {
     $node = $webform['webform'];
   }
@@ -1092,6 +1102,11 @@ function fillpdf_merge_perform_pdf_action($fillpdf_object, $action = 'download',
     return;
   }
 
+  // If the PDF is empty, return.
+  if (!$pdf_data) {
+    return;
+  }
+
   // Generate the filename of downloaded PDF from title of the PDF set in
   // admin/structure/fillpdf/%fid.
   $output_name = _fillpdf_process_filename($pdf_info->title, $token_objects);
@@ -1554,6 +1569,9 @@ function fillpdf_execute_merge($method, array $fields, $fillpdf, $mode = 'url',
       if ($data === FALSE) {
         $error = t('pdftk not properly installed. No PDF generated.');
       }
+      elseif (!$data) {
+        $error = t('Error with pdftk. No PDF generated.');
+      }
       if ($error) {
         drupal_set_message($error, 'error');
         watchdog('fillpdf', $error, array(), WATCHDOG_ERROR);