object_file_system: embed_origin_url(), rewrite_pluginfile_urls()

classes/local/store/object_file_system.php

@@ -47,6 +47,9 @@
 
 abstract class object_file_system extends \file_system_filedir {
 
+    const PLUGINFILE_ORIGIN_SEGMENT_PREFIX = 'objectfs-origin=';
+
+    public $objectfs = true;
     public $externalclient;
     private $preferexternal;
     private $deleteexternally;
@@ -768,13 +771,60 @@ public function redirect_to_presigned_url($contenthash, $headers = array()) {
                 }
                 header('Cache-Control: ' . $cachevisibility . ', max-age=' . ($signedurl->expiresat - time()));
             }
-            redirect($signedurl->url);
+            redirect($this->embed_origin_url(
+                $signedurl->url
+            ));
         } catch (\Exception $e) {
             debugging('Failed to redirect to pre-signed url: ' . $e->getMessage());
             return false;
         }
     }
 
+    /**
+     * Embed origin URL in presigned URL.
+     *
+     * @param string $presignedurl
+     * @return string $presignedurl with embedded origin
+     * @throws moodle_exception
+     */
+    public function embed_origin_url($presignedurl): string {
+        $me = me();
+        if (empty($me)) {
+            throw new moodle_exception('invalidurl');
+        }
+
+        return sprintf(
+            "%s#%s%s",
+            $presignedurl,
+            self::PLUGINFILE_ORIGIN_SEGMENT_PREFIX,
+            urlencode($me)
+        );
+    }
+
+    /**
+     * Convert redirected URLs in $text.
+     *
+     * @param string  $text The content that may contain URLs in need of rewriting.
+     * @return string The processed text.
+     */
+    public function rewrite_pluginfile_urls($text): string {
+        if (!$this->presigned_url_configured()) { // Do nothing.
+            return $text;
+        }
+
+        $re = sprintf(
+            '!https?://\S*?\#%s(\S+\w)!',
+            preg_quote(self::PLUGINFILE_ORIGIN_SEGMENT_PREFIX),
+        );
+        return preg_replace_callback(
+            $re,
+            function ($matches) {
+                global $CFG;
+                return sprintf('%s%s', $CFG->wwwroot, urldecode($matches[1]));
+            },
+            $text
+        );
+    }
 
     /**
      * Return if the file system supports presigned_urls.

classes/local/store/s3/client.php

@@ -45,8 +45,6 @@ class client extends object_client_base {
     const MAX_TEMP_LIMIT = 2097152;
 
     protected $client;
-    protected $bucket;
-    private $signingmethod;
 
     public function __construct($config) {
         global $CFG;
@@ -64,6 +62,14 @@ public function __construct($config) {
             $this->enablepresignedurls = $config->enablepresignedurls;
             $this->signingmethod = $config->signingmethod;
             $this->bucketkeyprefix = $config->key_prefix;
+            $this->cloudfrontresourcedomain = $config->cloudfrontresourcedomain;
+
+            if ('cf' === $this->signingmethod) {
+                if (!$this->cloudfrontresourcedomain) {
+                    throw new \moodle_exception(OBJECTFS_PLUGIN_NAME . ': cloudfrontresourcedomain not configured');
+                }
+            }
+
             $this->set_client($config);
         } else {
             parent::__construct($config);
@@ -536,7 +542,7 @@ private function generate_presigned_url_cloudfront($contenthash, array $headers
         if ($nicefilename) {
             $key .= $this->get_nice_filename($headers);
         }
-        $resource = $this->config->cloudfrontresourcedomain . '/' . $key;
+        $resource = $this->cloudfrontresourcedomain . '/' . $key;
         // This is the id of the Cloudfront key pair you generated.
         $keypairid = $this->config->cloudfrontkeypairid;
 

lib.php

@@ -125,3 +125,20 @@ function tool_objectfs_status_checks() {
 
     return [];
 }
+
+/**
+ * Convert presigned URLs in $text to the origin URL.
+ *
+ * @param   string  $text The content that may contain ULRs in need of rewriting.
+ * @param   int     $contextid This parameter and the next two identify the file area to use.
+ * @return  string  The processed text.
+ */
+function tool_objectfs_file_rewrite_urls($text, $contextid) {
+    $fs = get_file_storage()->get_file_system();
+
+    if (!isset($fs->objectfs)) {
+        return $text;
+    }
+
+    return $fs->rewrite_pluginfile_urls($text);
+}

tests/object_file_system_test.php

@@ -24,7 +24,7 @@
 require_once(__DIR__ . '/classes/test_client.php');
 require_once(__DIR__ . '/tool_objectfs_testcase.php');
 
-class object_file_system_testcase extends tool_objectfs_testcase {
+class object_file_system_test extends tool_objectfs_testcase {
 
     public function set_externalclient_config($key, $value) {
         // Get a reflection of externalclient object as a property.
@@ -899,4 +899,87 @@ public function test_is_configured_alternative_file_system_class_is_not_set() {
         unset($CFG->alternative_file_system_class);
         $this->assertFalse($this->filesystem->is_configured());
     }
+
+    /**
+     * @return array
+     */
+    public function rewrite_pluginfile_urls_s3_provider() {
+        return [
+            ['/pluginfile.php', '/3854/tool_objectfs/content/1/test.pdf'],
+        ];
+    }
+
+    /**
+     * Test rewrite_pluginfile_urls() S3
+     *
+     * @dataProvider rewrite_pluginfile_urls_s3_provider
+     *
+     * @param string $script
+     * @param int    $pluginfile
+     */
+    public function test_rewrite_pluginfile_urls_s3_proper($script, $pluginfile) {
+        global $CFG, $ME;
+
+        if (!$CFG->phpunit_objectfs_s3_integration_test_credentials) {
+            $this->markTestSkipped('No S3 test credentials in config file');
+        }
+
+        $ME = "$script$pluginfile";
+        $bucket = $CFG->phpunit_objectfs_s3_integration_test_credentials['s3_bucket'];
+        $s3_region = $CFG->phpunit_objectfs_s3_integration_test_credentials['s3_region'];
+        $bucketkeyprefix = 'test/';
+        $presignedurl = "https://$bucket.s3.$s3_region.amazonaws.com/$bucketkeyprefix?param1=val1&param2=val2";
+
+        $this->filesystem = new test_file_system();
+        $externalclient = $this->filesystem->get_external_client();
+        $this->set_externalclient_config('enablepresignedurls', '1');
+        $this->set_externalclient_config('signingmethod', 's3');
+        $this->set_externalclient_config('bucketkeyprefix', $bucketkeyprefix);
+        $this->assertTrue($this->filesystem->presigned_url_configured());
+
+        $embedded = $this->filesystem->embed_origin_url($presignedurl);
+        $textformat = 'Fake test with pdf %s';
+        $originaltext = sprintf($textformat, $embedded);
+
+        $this->assertEquals(
+            sprintf($textformat, $CFG->wwwroot.$ME),
+            $this->filesystem->rewrite_pluginfile_urls($originaltext)
+        );
+    }
+
+    /**
+     * Test rewrite_pluginfile_urls() CloudFront
+     *
+     * @dataProvider rewrite_pluginfile_urls_s3_provider
+     *
+     * @param string $script
+     * @param int    $pluginfile
+     */
+    public function test_rewrite_pluginfile_urls_s3_cf($script, $pluginfile) {
+        global $CFG, $ME;
+
+        if (!$CFG->phpunit_objectfs_s3_integration_test_credentials) {
+            $this->markTestSkipped('No S3 test credentials in config file');
+        }
+
+        $ME = "$script$pluginfile";
+        $cloudfrontresourcedomain = 'https://presigned.url';
+        $presignedurl = "$cloudfrontresourcedomain/x?param1=val1&param2=val2";
+
+        $this->filesystem = new test_file_system();
+        $externalclient = $this->filesystem->get_external_client();
+        $this->set_externalclient_config('enablepresignedurls', '1');
+        $this->set_externalclient_config('signingmethod', 'cf');
+        $this->set_externalclient_config('cloudfrontresourcedomain', $cloudfrontresourcedomain);
+        $this->assertTrue($this->filesystem->presigned_url_configured());
+
+        $embedded = $this->filesystem->embed_origin_url($presignedurl);
+        $textformat = 'Fake test with pdf %s';
+        $originaltext = sprintf($textformat, $embedded);
+
+        $this->assertEquals(
+            sprintf($textformat, $CFG->wwwroot.$ME),
+            $this->filesystem->rewrite_pluginfile_urls($originaltext)
+        );
+    }
 }