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<?php
namespace Studip\LTI13a;
use OAT\Library\Lti1p3Ags\Model\LineItem\LineItemCollection;
use OAT\Library\Lti1p3Ags\Model\LineItem\LineItemCollectionInterface;
use OAT\Library\Lti1p3Ags\Model\LineItem\LineItemInterface;
use OAT\Library\Lti1p3Ags\Repository\LineItemRepositoryInterface;
use Studip\LTIException;
use Grading\Definition;
class LineItemRepository implements LineItemRepositoryInterface
{
/**
* Converts the tool-ID and deployment-ID in the tool name used in the
* Stud.IP grading context.
*
* @param string $tool_id The Stud.IP LTI tool ID.
* @param string $deployment_id The Stud.IP LTI deployment ID.
* @return string The corresponding tool name used in the Stud.IP grading context.
*/
public static function getGradingToolName(string $tool_id, string $deployment_id) : string
{
return sprintf('lti-%s-%s', $tool_id, $deployment_id);
}
/**
* Converts the LTI line item identifier to search parameters to retrieve
* Stud.IP grading definitions.
*
* @param string $line_item_identifier The LTI line item identifier.
*
* @return array The search parameters for searching in the Stud.IP grading context.
* This is an associative array with two keys:
* 'tool' => The identifier of the tool in the Stud.IP grading context.
* 'course_id' => The Stud.IP course-ID.
* In case the search parameters cannot be generated, an empty array is returned.
*/
public static function getSearchParametersFromLineItemIdentifier(string $line_item_identifier) : array
{
//$lineItemIdentifier contains the full URL to the line item.
//We must extract the course-ID, tool-ID and deployment-ID
//from the URL parameters first, before searching a grading definition.
$url_parts = parse_url($line_item_identifier);
$parameters = [];
if (empty($url_parts['query'])) {
//Nothing we can convert.
return [];
}
parse_str($url_parts['query'], $parameters);
if (empty($parameters)) {
//Same as above.
return [];
}
$search_parameters = [
'course_id' => $parameters['cid'],
'tool' => self::getGradingToolName($parameters['tool_id'], $parameters['deployment_id'])
];
if (!empty($parameters['definition_id'])) {
$search_parameters['definition_id'] = $parameters['definition_id'];
}
return $search_parameters;
}
/**
* @inheritDoc
*/
public function find(string $lineItemIdentifier): ?LineItemInterface
{
$search_parameters = self::getSearchParametersFromLineItemIdentifier($lineItemIdentifier);
if (!$search_parameters) {
//Nothing we can search for.
return null;
}
$definition = null;
if (!empty($search_parameters['definition_id'])) {
$definition = Definition::find($search_parameters['definition_id']);
} else {
$definition = Definition::findOneBySQL(
"`course_id` = :course_id AND `tool` = :tool",
[
'course_id' => $search_parameters['course_id'],
'tool' => $search_parameters['tool']
]
);
}
if ($definition) {
return $definition->toLineItem();
}
return null;
}
/**
* @inheritDoc
*/
public function findCollection(
?string $resourceIdentifier = null,
?string $resourceLinkIdentifier = null,
?string $tag = null,
?int $limit = null,
?int $offset = null
): LineItemCollectionInterface
{
$result = new LineItemCollection();
if (!$resourceLinkIdentifier) {
//Nothing we can search for.
return $result;
}
//$resourceLinkIdentifier contains the Stud.IP tool-ID, the deployment-ID and the course-ID,
//separated by underscores.
$id_parts = explode('_', $resourceLinkIdentifier);
if (count($id_parts) !== 3) {
throw new LTIException('Invalid resource link identifier.');
}
$tool_id = $id_parts[0];
$deployment_id = $id_parts[1];
$course_id = $id_parts[2];
$sql = '';
$sql_params = [];
if ($tool_id && $course_id) {
$sql .= "`tool` = :tool AND `course_id` = :course_id";
$sql_params['tool'] = self::getGradingToolName($tool_id, $deployment_id);
$sql_params['course_id'] = $course_id;
} else {
//No tool-ID means no line item collection can be found.
return $result;
}
if ($limit) {
if (empty($sql)) {
$sql .= "TRUE ";
}
$sql .= "LIMIT :limit ";
$sql_params['limit'] = $limit;
}
if ($offset) {
$sql .= "OFFSET :offset";
$sql_params['offset'] = $offset;
}
$definitions = Definition::findBySql($sql, $sql_params);
foreach ($definitions as $definition) {
$result->add($definition->toLineItem());
}
return $result;
}
/**
* @inheritDoc
*/
public function save(LineItemInterface $lineItem): LineItemInterface
{
//The resource link identifier contains the Stud.IP tool-ID, deployment-ID and course-ID
//separated by underscores.
$studip_ids = explode('_', $lineItem->getResourceLinkIdentifier() ?? '');
$tool_id = $studip_ids[0];
$deployment_id = $studip_ids[1];
$course_id = $studip_ids[2];
$definition = new Definition();
$definition->id = $lineItem->getIdentifier();
$definition->name = $lineItem->getLabel();
$definition->course_id = $course_id;
$definition->tool = sprintf('lti-%s-%s', $tool_id, $deployment_id);
$definition->weight = '1.0';
if ($definition->store()) {
return $definition->toLineItem();
} else {
throw new LTIException('Could not save line item.');
}
}
/**
* @inheritDoc
*/
public function delete(string $lineItemIdentifier): void
{
$search_parameters = self::getSearchParametersFromLineItemIdentifier($lineItemIdentifier);
$definition = Definition::findOneBySQL(
'`course_id` = :course_id AND `tool` = :tool',
$search_parameters
);
if ($definition) {
$definition->delete();
}
}
}
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