}
}
+
+/**
+ * Try to restore aliases and references to external files.
+ *
+ * The queue of these files was prepared for us in {@link restore_dbops::send_files_to_pool()}.
+ * We expect that all regular (non-alias) files have already been restored. Make sure
+ * there is no restore step executed after this one that would call send_files_to_pool() again.
+ *
+ * You may notice we have hardcoded support for Server files, Legacy course files
+ * and user Private files here at the moment. This could be eventually replaced with a set of
+ * callbacks in the future if needed.
+ *
+ * @copyright 2012 David Mudrak <david@moodle.com>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class restore_process_file_aliases_queue extends restore_execution_step {
+
+ /**
+ * What to do when this step is executed.
+ */
+ protected function define_execution() {
+ global $DB;
+
+ $this->log('processing file aliases queue', backup::LOG_INFO);
+
+ $fs = get_file_storage();
+
+ // Load the queue.
+ $rs = $DB->get_recordset('backup_ids_temp',
+ array('backupid' => $this->get_restoreid(), 'itemname' => 'file_aliases_queue'),
+ '', 'info');
+
+ // Iterate over aliases in the queue.
+ foreach ($rs as $record) {
+ $info = unserialize(base64_decode($record->info));
+
+ // Try to pick a repository instance that should serve the alias.
+ $repository = $this->choose_repository($info);
+
+ if (is_null($repository)) {
+ $this->notify_failure($info, 'unable to find a matching repository instance');
+ continue;
+ }
+
+ if ($info->oldfile->repositorytype === 'local' or $info->oldfile->repositorytype === 'coursefiles') {
+ // Aliases to Server files and Legacy course files may refer to a file
+ // contained in the backup file or to some existing file (if we are on the
+ // same site).
+ try {
+ $reference = file_storage::unpack_reference($info->oldfile->reference);
+ } catch (Exception $e) {
+ $this->notify_failure($info, 'invalid reference field format');
+ continue;
+ }
+
+ // Let's see if the referred source file was also included in the backup.
+ $candidates = $DB->get_recordset('backup_files_temp', array(
+ 'backupid' => $this->get_restoreid(),
+ 'contextid' => $reference['contextid'],
+ 'component' => $reference['component'],
+ 'filearea' => $reference['filearea'],
+ 'itemid' => $reference['itemid'],
+ ), '', 'info, newcontextid, newitemid');
+
+ $source = null;
+
+ foreach ($candidates as $candidate) {
+ $candidateinfo = unserialize(base64_decode($candidate->info));
+ if ($candidateinfo->filename === $reference['filename']
+ and $candidateinfo->filepath === $reference['filepath']
+ and !is_null($candidate->newcontextid)
+ and !is_null($candidate->newitemid) ) {
+ $source = $candidateinfo;
+ $source->contextid = $candidate->newcontextid;
+ $source->itemid = $candidate->newitemid;
+ break;
+ }
+ }
+ $candidates->close();
+
+ if ($source) {
+ // We have an alias that refers to another file also included in
+ // the backup. Let us change the reference field so that it refers
+ // to the restored copy of the original file.
+ $reference = file_storage::pack_reference($source);
+
+ // Send the new alias to the filepool.
+ $fs->create_file_from_reference($info->newfile, $repository->id, $reference);
+ $this->notify_success($info);
+ continue;
+
+ } else {
+ // This is a reference to some moodle file that was not contained in the backup
+ // file. If we are restoring to the same site, keep the reference untouched
+ // and restore the alias as is if the referenced file exists.
+ if ($this->task->is_samesite()) {
+ if ($fs->file_exists($reference['contextid'], $reference['component'], $reference['filearea'],
+ $reference['itemid'], $reference['filepath'], $reference['filename'])) {
+ $reference = file_storage::pack_reference($reference);
+ $fs->create_file_from_reference($info->newfile, $repository->id, $reference);
+ $this->notify_success($info);
+ continue;
+ } else {
+ $this->notify_failure($info, 'referenced file not found');
+ continue;
+ }
+
+ // If we are at other site, we can't restore this alias.
+ } else {
+ $this->notify_failure($info, 'referenced file not included');
+ continue;
+ }
+ }
+
+ } else if ($info->oldfile->repositorytype === 'user') {
+ if ($this->task->is_samesite()) {
+ // For aliases to user Private files at the same site, we have a chance to check
+ // if the referenced file still exists.
+ try {
+ $reference = file_storage::unpack_reference($info->oldfile->reference);
+ } catch (Exception $e) {
+ $this->notify_failure($info, 'invalid reference field format');
+ continue;
+ }
+ if ($fs->file_exists($reference['contextid'], $reference['component'], $reference['filearea'],
+ $reference['itemid'], $reference['filepath'], $reference['filename'])) {
+ $reference = file_storage::pack_reference($reference);
+ $fs->create_file_from_reference($info->newfile, $repository->id, $reference);
+ $this->notify_success($info);
+ continue;
+ } else {
+ $this->notify_failure($info, 'referenced file not found');
+ continue;
+ }
+
+ // If we are at other site, we can't restore this alias.
+ } else {
+ $this->notify_failure($info, 'restoring at another site');
+ continue;
+ }
+
+ } else {
+ // This is a reference to some external file such as in boxnet or dropbox.
+ // If we are restoring to the same site, keep the reference untouched and
+ // restore the alias as is.
+ if ($this->task->is_samesite()) {
+ $fs->create_file_from_reference($info->newfile, $repository->id, $info->oldfile->reference);
+ $this->notify_success($info);
+ continue;
+
+ // If we are at other site, we can't restore this alias.
+ } else {
+ $this->notify_failure($info, 'restoring at another site');
+ continue;
+ }
+ }
+ }
+ $rs->close();
+ }
+
+ /**
+ * Choose the repository instance that should handle the alias.
+ *
+ * At the same site, we can rely on repository instance id and we just
+ * check it still exists. On other site, try to find matching Server files or
+ * Legacy course files repository instance. Return null if no matching
+ * repository instance can be found.
+ *
+ * @param stdClass $info
+ * @return repository|null
+ */
+ private function choose_repository(stdClass $info) {
+ global $DB, $CFG;
+ require_once($CFG->dirroot.'/repository/lib.php');
+
+ if ($this->task->is_samesite()) {
+ // We can rely on repository instance id.
+ try {
+ return repository::get_repository_by_id($info->oldfile->repositoryid, SYSCONTEXTID);
+ } catch (Exception $e) {
+ return null;
+ }
+
+ } else {
+ // We can rely on repository type only.
+ if (empty($info->oldfile->repositorytype)) {
+ return null;
+ }
+
+ // Both Server files and Legacy course files repositories have a single
+ // instance at the system context to use. Let us try to find it.
+ if ($info->oldfile->repositorytype === 'local' or $info->oldfile->repositorytype === 'coursefiles') {
+ $sql = "SELECT ri.id
+ FROM {repository} r
+ JOIN {repository_instances} ri ON ri.typeid = r.id
+ WHERE r.type = ? AND ri.contextid = ?";
+ $ris = $DB->get_records_sql($sql, array($info->oldfile->repositorytype, SYSCONTEXTID));
+ if (empty($ris)) {
+ return null;
+ }
+ $repoid = reset(array_keys($ris));
+ try {
+ return repository::get_repository_by_id($repoid, SYSCONTEXTID);
+ } catch (Exception $e) {
+ return null;
+ }
+ }
+
+ return null;
+ }
+ }
+
+ /**
+ * Let the user know that the given alias was successfully restored
+ *
+ * @param stdClass $info
+ */
+ private function notify_success(stdClass $info) {
+ $filedesc = $this->describe_alias($info);
+ $this->log('successfully restored alias', backup::LOG_DEBUG, $filedesc, 1);
+ }
+
+ /**
+ * Let the user know that the given alias can't be restored
+ *
+ * @param stdClass $info
+ * @param string $reason detailed reason to be logged
+ */
+ private function notify_failure(stdClass $info, $reason = '') {
+ $filedesc = $this->describe_alias($info);
+ if ($reason) {
+ $reason = ' ('.$reason.')';
+ }
+ $this->log('unable to restore alias'.$reason, backup::LOG_WARNING, $filedesc, 1);
+ }
+
+ /**
+ * Return a human readable description of the alias file
+ *
+ * @param stdClass $info
+ * @return string
+ */
+ private function describe_alias(stdClass $info) {
+
+ $filedesc = $this->expected_alias_location($info->newfile);
+
+ if (!is_null($info->oldfile->source)) {
+ $filedesc .= ' ('.$info->oldfile->source.')';
+ }
+
+ return $filedesc;
+ }
+
+ /**
+ * Return the expected location of a file
+ *
+ * Please note this may and may not work as a part of URL to pluginfile.php
+ * (depends on how the given component/filearea deals with the itemid).
+ *
+ * @param stdClass $filerecord
+ * @return string
+ */
+ private function expected_alias_location($filerecord) {
+
+ $filedesc = '/'.$filerecord->contextid.'/'.$filerecord->component.'/'.$filerecord->filearea;
+ if (!is_null($filerecord->itemid)) {
+ $filedesc .= '/'.$filerecord->itemid;
+ }
+ $filedesc .= $filerecord->filepath.$filerecord->filename;
+
+ return $filedesc;
+ }
+}
+
+
/**
* Abstract structure step, to be used by all the activities using core questions stuff
* (like the quiz module), to support qtype plugins, states and sessions
