WIP on #2.

README.md

@@ -2,7 +2,7 @@
 
 ## Introduction
 
-A Drupal 8 module that serializes PREMIS metadata generated by various Islandora modules and microsrevices. This module produces PREMIS v3 in Turtle RDF for a node by appending `/premis` to the end of the node's URL, e.g., `https://localhost/node/250/premis`.
+A Drupal 8/9 module that serializes PREMIS metadata generated by various Islandora modules and microsrevices. This module produces PREMIS v3 in Turtle RDF for a node by appending `/premis` to the end of the node's URL, e.g., `https://localhost/node/250/premis`.
 
 This module is not ready for prodcution use. But could be soon with your feedback and testing!
 

islandora_premis.info.yml

@@ -3,5 +3,6 @@ description: "Serializes PREMIS data."
 type: module
 package: Islandora
 core: 8.x
+core_version_requirement: ^8 || ^9
 dependencies:
   - islandora

islandora_premis.module

@@ -1,5 +1,8 @@
 <?php
 
+use EasyRdf\Graph;
+use EasyRdf\RdfNamespace;
+
 /**
  * Implements hook_islandora_premis_turtle_alter().
 */
@@ -8,7 +11,7 @@ function islandora_premis_islandora_premis_turtle_alter($nid, &$turtle) {
   $node = \Drupal::entityTypeManager()->getStorage('node')->load($nid);
   $utils = \Drupal::service('islandora.utils');
   $media_source = \Drupal::service('islandora.media_source_service');
-  $gemini = \Drupal::service('islandora.gemini.lookup');
+  $file_uri_lookup = \Drupal::service('islandora_premis.utils');
   $current_path = \Drupal::service('path.current')->getPath();
   if (\Drupal::moduleHandler()->moduleExists('islandora_riprap')) {
     $islandora_riprap_utils = \Drupal::service('islandora_riprap.utils');
@@ -26,29 +29,21 @@ function islandora_premis_islandora_premis_turtle_alter($nid, &$turtle) {
   $base_url = \Drupal::request()->getSchemeAndHttpHost();
   $resource = $base_url . '/node/' . $nid; 
   $url = $base_url . '/node/' . $nid . "?_format=jsonld";
-  $graph = EasyRdf_Graph::newAndLoad($url);
+  $graph = Graph::newAndLoad($url);
   $graph->addType($resource, "http://www.loc.gov/premis/rdf/v3/IntellectualEntity");
 
   $media = $utils->getMedia($node);
 
   if (count($media) > 0) {
     foreach ($media as $medium) {
       $file = $media_source->getSourceFile($medium);
-      $file_url = $gemini->lookup($file);
-      if (is_null($file_url)) {
+      $binary_resource_url = $file_uri_lookup->getUrl($medium->id());
+      if (is_null($binary_resource_url)) {
         return;
       }
 
-      $binary_resource_url = $file_url;
-      if (\Drupal::moduleHandler()->moduleExists('islandora_riprap')) {
-        $riprap_config = \Drupal::config('islandora_riprap.settings');
-        if ($riprap_config->get('use_drupal_urls')) {
-          $binary_resource_url = $islandora_riprap_utils->getLocalUrl($medium->id());
-        }
-      }
-
       // Register some namespaces.
-      $ns = new EasyRdf_Namespace();
+      $ns = new RdfNamespace();
       $ns->set('premisObject', 'http://www.loc.gov/premis/rdf/v3/Object');
       $ns->set('premis', 'http://id.loc.gov/vocabulary/preservation/eventOutcome');
       $ns->set('crypHashFunc', 'http://id.loc.gov/vocabulary/preservation/cryptographicHashFunctions/');

islandora_premis.services.yml

@@ -0,0 +1,3 @@
+services:
+  islandora_premis.utils:
+    class: Drupal\islandora_premis\Utils

src/Controller/IslandoraPremisPremisController.php

@@ -1,5 +1,7 @@
 <?php
 
+use EasyRdf\Graph;
+
 namespace Drupal\islandora_premis\Controller;
 
 use Drupal\Core\Controller\ControllerBase;
@@ -24,7 +26,7 @@ public function main() {
      \Drupal::moduleHandler()->invokeAll('islandora_premis_turtle_alter', [$nid, &$turtle]);
 
      // Create and serialize the graph, then send it to the client.
-     $graph = new \EasyRdf_Graph();
+     $graph = new \EasyRdf\Graph();
      $graph->parse($turtle);
      $output = $graph->serialise('turtle');
 

src/Utils.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace Drupal\islandora_premis;
+
+use Drupal\Core\Site\Settings;
+use Drupal\media\Entity\Media;
+
+/**
+ * Islandora-PREMIS specific utilities.
+ */
+class Utils {
+
+  /**
+   * Get a Fedora URL for a File entity from Gemini.
+   *
+   * @param string $mid
+   *   The Meida entity's ID.
+   *
+   * @return string
+   *   The Fedora URL to the file corresponding to the Media's ID, or False.
+   */
+  public function getUrl($mid) {
+    $media = Media::load($mid);
+    $media_source_service = \Drupal::service('islandora.media_source_service');
+    $source_file = $media_source_service->getSourceFile($media);
+
+    $uri = $source_file->getFileUri();
+    $scheme = \Drupal::service('stream_wrapper_manager')->getScheme($uri);
+
+    if ($scheme == 'fedora') {
+      $flysystem_config = Settings::get('flysystem');
+      if (isset($flysystem_config[$scheme]) && $flysystem_config[$scheme]['driver'] == 'fedora') {
+        $fedora_root = $flysystem_config['fedora']['config']['root'];
+        $fedora_root = rtrim($fedora_root, '/');
+        $parts = parse_url($uri);
+        $path = $parts['host'] . $parts['path'];
+      }
+      else {
+        return false;
+      }
+      $path = ltrim($path, '/');
+      $fedora_uri = "$fedora_root/$path";
+      return($fedora_uri);
+    }
+    else {
+      // 'public' or 'private' filesystem scheme.
+      return(file_create_url($uri));
+    }
+  }
+
+}