ISLANDORA-1748 -- add hook_islandora_datastream_filename_alter(). (#706)

* ISLANDORA-1748 -- add hook_datastream_filename_alter().

Co-authored-by: Diego Pino Navarro <DiegoPino@users.noreply.github.com>

includes/datastream.inc

@@ -63,6 +63,10 @@ function islandora_view_datastream(AbstractDatastream $datastream, $download = F
     if ($duplicate_extension_position === FALSE) {
       $filename .= $extension;
     }
+
+    // Allow other modules to modify or replace the filename.
+    drupal_alter('islandora_datastream_filename', $filename, $datastream);
+
     header("Content-Disposition: attachment; filename=\"$filename\"");
   }
 

islandora.api.php

@@ -945,3 +945,24 @@ function callback_islandora_breadcrumbs_backends(AbstractObject $object) {
   // Do something to get an array of breadcrumb links for $object, root first.
   return array($root_link, $collection_link, $object_link);
 }
+
+/**
+ * Permit modules to alter the filename of a downloaded datastream.
+ *
+ * @param string $filename
+ *   The filename being created.
+ *
+ * @param AbstractDatastream $datastream
+ *   The datastream object being downloaded.
+ */
+function hook_islandora_datastream_filename_alter(&$filename, AbstractDatastream $datastream) {
+
+  // Example taken from islandora_datastream_filenamer.
+  $pattern = variable_get('islandora_ds_download_filename_pattern', FALSE);
+  if ($pattern) {
+    $filename = token_replace($pattern,
+      array('datastream' => $datastream),
+      array('clear' => TRUE)
+    );
+  }
+}