====== Backup And Restore Modules ======

The backup and restore process for modules is actually pretty well documented:

  * [[http://docs.moodle.org/dev/Backup_2.0_for_developers|Backup]]
  * [[http://docs.moodle.org/dev/Restore_2.0_for_developers|Restore]]

There are a few potential pitfalls however.

===== Backup =====

If you want to backup the files associated with the module instance, you have to use the ''annotate_files'' function. For instance:

<code>
$rainmaker->annotate_files('mod_rainmaker', 'rainmaker_docs', 'id');
</code>

The 3rd argument of the function is documented as 'elementname'. This suggests you can name the resulting xml element whatever you want. But that is not actually the case: you should use the table column that contains the id which is also used in the mdl_files.itemid column for that particular module.

For instance, if your rainmaker module's instance id is stored in the mdl_rainmaker table, and that is used to identify the file, then mdl_rainmaker.id is the column name you need.

===== Restore =====

To restore files associated with your module's instance, use the ''after_execute'' function. There, make a call to ''add_related_files'':

<code>
protected function after_execute() {
    $this->add_related_files($component = 'mod_rainmaker', $filearea = 'rainmaker_docs', $mappingitemname = 'rainmaker');
}
</code>

Here, the ''$mappingitemname'' refers to the xml element containing the ''id'' attribute that you're interested in.

===== Duplicate of an existing module =====

When you duplicate an existing module and replace everything to the new modulename, you have to make sure the definition is uppercase.

<code>
public static function define_decode_rules() {
	$rules = array();

	$rules[] = new restore_decode_rule('FREETRAININGVIEWBYID',
			'/mod/freetraining/view.php?id=$1', 'course_module');
	$rules[] = new restore_decode_rule('FREETRAININGVIEWBYQ',
			'/mod/freetraining/view.php?q=$1', 'freetraining');
	$rules[] = new restore_decode_rule('FREETRAININGINDEX',
			'/mod/freetraining/index.php?id=$1', 'course');

	return $rules;
}
</code>

Take the ''FREETRAININGVIEWBYID'' as example, eveything has to be in UPPERCASE, otherwise the backup/duplicate function will not work.