IMS common cartridge
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Moodle1.9 Moodle 2.0
What is Common Cartridge?
Common Cartridge is a specification that describes format for creating and sharing primarily educational digital content. The specification is developed by IMS Global Learning Consortium and describes in details the packaging format and infrastructure needed to support format for presenting it to the end-user. (See FAQ for more info especially What is Common Cartridge?)
Why Common Cartridge?
Common Cartridge solves two problems. The first is to provide a standard way to represent digital course materials for use in on-line learning systems so that such content can be developed in one format and used across a wide variety of learning systems (often referred to as course management systems, learning management systems, virtual learning environments, or instructional management systems). The second is to enable new publishing models for on-line course materials and digital books that are modular, web-distributed, interactive, and customizable. (cited from CC FAQ - http://www.imsglobal.org/cc/ccfaqs.html#2) We feel that it is important to support all efforts in on-line educational community and try to standardize content exchange format(s). That way we support openness of Moodle and increase possibility of interoperability with other LMS systems.
Implementation
Since Moodle 2.0 is still not ready for integration of any third-party format we will start development on experimental import extension for Moodle 1.9. In Moodle 1.9 the only supported third-party format (other than native moodle) is Blackboard 5.5&6. Blackboard package support is implemented through use of XSL transformation. That means that if we try to upload directly blacboard package moodle will detect that and transform package manifest using XSL transformation, reorder it's resources thus creating a moodle package and import that transformed package. This is a prefferd way of implementing support for importing any third-party format. The main reason for this is that there is no currently any API for managing restore of course content and that would mean that any third-party format developer would have to develop all that code again from scratch.
As we can see in restorelib.php blackboard conversion is initiated in function restore_precheck. That would be appropriate place for adding precheck for any other third-party format.
<?php
...
function restore_precheck($id,$file,&$errorstr,$noredirect=false) {
...
//Check for Blackboard backups and convert
if ($status){
require_once("$CFG->dirroot/backup/bb/restore_bb.php");
if (!defined('RESTORE_SILENTLY')) {
echo "
".get_string("checkingforbbexport").' ';
}
$status = blackboard_convert($CFG->dataroot."/temp/backup/".$backup_unique_code);
}
...
//Check for IMS Common Cartridge backups and convert
if ($status){
require_once("$CFG->dirroot/backup/cc/restore_cc.php");
if (!defined('RESTORE_SILENTLY')) {
echo "
".get_string("checkingforccexport").' ';
}
$status = ims_cc_convert($CFG->dataroot."/temp/backup/".$backup_unique_code);
}
}
Additional notes regarding package type detection
Current third-party format checking in Moodle 1.9 is far from being adequate. In case of blackboard type detection system only checks for existence of imsmanifest.xml. Almost all IMS based content packages use this file name for their manifest (blackboard, SCORM, Common Cartridge etc.). Therefore a better file type detection is needed, not only for the presence of the manifest file but also regarding it's content.
Every manifest has a specific xml namespaces that define organization of the file. By checking for specific item described in particular standard for a content type in question we can detect what type of package we are working with.
For example Common Cartridge manifest looks like this:
<?xml version="1.0" encoding="UTF-8" ?>
<manifest identifier="M102815" xmlns="http://www.imsglobal.org/xsd/imscc/imscp_v1p1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
...
</manifest>
By checking for existence and value of xmlns attribute we can reliably detect the type in question. As additional check a validation can be performed using XSD files from common cartridge definition.
