MDL-36985 core_files: added option to remove draft files on save

text areas can now specify $options['removeorphaneddrafts'] when saving
their data using file_postupdate_standard_editor(). If set to true,
this option clears all user drafts which are not referenced in the text

lib/filelib.php

@@ -237,6 +237,9 @@ function file_postupdate_standard_editor($data, $field, array $options, $context
     if (!isset($options['maxbytes'])) {
         $options['maxbytes'] = 0; // unlimited
     }
+    if (!isset($options['removeorphaneddrafts'])) {
+        $options['removeorphaneddrafts'] = false; // Don't remove orphaned draft files by default.
+    }
 
     if ($options['trusttext']) {
         $data->{$field.'trust'} = trusttext_trusted($context);
@@ -249,6 +252,10 @@ function file_postupdate_standard_editor($data, $field, array $options, $context
     if ($options['maxfiles'] == 0 or is_null($filearea) or is_null($itemid) or empty($editor['itemid'])) {
         $data->{$field} = $editor['text'];
     } else {
+        // Clean the user drafts area of any files not referenced in the editor text.
+        if ($options['removeorphaneddrafts']) {
+            file_remove_editor_orphaned_files($editor);
+        }
         $data->{$field} = file_save_draft_area_files($editor['itemid'], $context->id, $component, $filearea, $itemid, $options, $editor['text'], $options['forcehttps']);
     }
     $data->{$field.'format'} = $editor['format'];
@@ -792,6 +799,38 @@ function file_restore_source_field_from_draft_file($storedfile) {
     }
     return $storedfile;
 }
+
+/**
+ * Removes those files from the user drafts filearea which are not referenced in the editor text.
+ *
+ * @param stdClass $editor The online text editor element from the submitted form data.
+ */
+function file_remove_editor_orphaned_files($editor) {
+    global $CFG, $USER;
+
+    // Find those draft files included in the text, and generate their hashes.
+    $context = context_user::instance($USER->id);
+    $baseurl = $CFG->wwwroot . '/draftfile.php/' . $context->id . '/user/draft/' . $editor['itemid'] . '/';
+    $pattern = "/" . preg_quote($baseurl, '/') . "(.+?)[\?\"']/";
+    preg_match_all($pattern, $editor['text'], $matches);
+    $usedfilehashes = [];
+    foreach ($matches[1] as $matchedfilename) {
+        $matchedfilename = urldecode($matchedfilename);
+        $usedfilehashes[] = \file_storage::get_pathname_hash($context->id, 'user', 'draft', $editor['itemid'], '/',
+                                                             $matchedfilename);
+    }
+
+    // Now, compare the hashes of all draft files, and remove those which don't match used files.
+    $fs = get_file_storage();
+    $files = $fs->get_area_files($context->id, 'user', 'draft', $editor['itemid'], 'id', false);
+    foreach ($files as $file) {
+        $tmphash = $file->get_pathnamehash();
+        if (!in_array($tmphash, $usedfilehashes)) {
+            $file->delete();
+        }
+    }
+}
+
 /**
  * Saves files from a draft file area to a real one (merging the list of files).
  * Can rewrite URLs in some content at the same time if desired.

lib/tests/filelib_test.php

@@ -1340,6 +1340,51 @@ EOF;
         $this->assertEquals(0, $fileinfo['foldercount']);   // No subdirectories inside the directory.
         $this->assertEquals($file->get_filesize(), $fileinfo['filesize_without_references']);
     }
+
+    /**
+     * Test confirming that draft files not referenced in the editor text are removed.
+     */
+    public function test_file_remove_editor_orphaned_files() {
+        global $USER, $CFG;
+        $this->resetAfterTest(true);
+        $this->setAdminUser();
+
+        // Create three draft files.
+        $filerecord = ['filename'  => 'file1.png'];
+        $file = self::create_draft_file($filerecord);
+        $draftitemid = $file->get_itemid();
+
+        $filerecord['itemid'] = $draftitemid;
+
+        $filerecord['filename'] = 'file2.png';
+        self::create_draft_file($filerecord);
+
+        $filerecord['filename'] = 'file 3.png';
+        self::create_draft_file($filerecord);
+
+        // Confirm the user drafts area lists 3 files.
+        $fs = get_file_storage();
+        $usercontext = context_user::instance($USER->id);
+        $draftfiles = $fs->get_area_files($usercontext->id, 'user', 'draft', $draftitemid, 'itemid', 0);
+        $this->assertCount(3, $draftfiles);
+
+        // Now, spoof some editor text content, referencing 2 of the files; one requiring name encoding, one not.
+        $editor = [
+            'itemid' => $draftitemid,
+            'text' => '
+                <img src="'.$CFG->wwwroot.'/draftfile.php/'.$usercontext->id.'/user/draft/'.$draftitemid.'/file%203.png" alt="">
+                <img src="'.$CFG->wwwroot.'/draftfile.php/'.$usercontext->id.'/user/draft/'.$draftitemid.'/file1.png" alt="">'
+        ];
+
+        // Run the remove orphaned drafts function and confirm that only the referenced files remain in the user drafts.
+        $expected = ['file1.png', 'file 3.png']; // The drafts we expect will not be removed (are referenced in the online text).
+        file_remove_editor_orphaned_files($editor);
+        $draftfiles = $fs->get_area_files($usercontext->id, 'user', 'draft', $draftitemid, 'itemid', 0);
+        $this->assertCount(2, $draftfiles);
+        foreach ($draftfiles as $file) {
+            $this->assertContains($file->get_filename(), $expected);
+        }
+    }
 }
 
 /**

mod/assign/submission/onlinetext/locallib.php

@@ -174,7 +174,8 @@ class assign_submission_onlinetext extends assign_submission_plugin {
             'maxfiles' => EDITOR_UNLIMITED_FILES,
             'maxbytes' => $this->assignment->get_course()->maxbytes,
             'context' => $this->assignment->get_context(),
-           'return_types' => (FILE_INTERNAL | FILE_EXTERNAL | FILE_CONTROLLED_LINK)
+            'return_types' => (FILE_INTERNAL | FILE_EXTERNAL | FILE_CONTROLLED_LINK),
+            'removeorphaneddrafts' => true // Whether or not to remove any draft files which aren't referenced in the text.
         );
         return $editoroptions;
     }