function checkwriteable($pdphandler, $user, $item)
{
$subject = new Subject(Subject::SUBJECT_CATEGORY_DEFAULT);
$subject->getAttributes()->add(new Attribute(new Uri(SubjectIdentifier::SUBJECT_ID), new Uri(DataTypes::STRING), StringAttribute::getInstance($user)));
$resource = new Resource();
$resource->getAttributes()->add(new Attribute(new Uri(ResourceIdentifier::RESOURCE_ID), new Uri(DataTypes::STRING), StringAttribute::getInstance($item)));
$writeaction = new Action();
$writeaction->getAttributes()->add(new Attribute(new Uri(ActionIdentifier::ACTION_ID), new Uri(DataTypes::STRING), StringAttribute::getInstance('info:escidoc/names:aa:1.0:action:update-item')));
$writerequest = new Request($resource, $writeaction);
$writerequest->add($subject);
$requestarray = array($writerequest);
$requests = new Requests();
$requests->addAll($requestarray);
$pdpresults = $pdphandler->evaluate($requests);
if (!$pdpresults->get(0)->getDecision() === Decision::PERMIT) {
throw new Exception("You are not allowed to update the dataset");
}
}
$_SESSION["pdphandler"] = new PDPHandler(new Net_URL($escidoccoreservice));
$_SESSION["pdphandler"]->setHandle($_SESSION["eSciDocUserHandle"]);
$user = $_SESSION["userhandler"]->retrieveCurrentUser();
$escidocitemid = $_REQUEST["item"];
$targeturl = $_REQUEST["dataciteurl"];
$registermode = $_REQUEST["dataciteregistry"];
$subject = new Subject(Subject::SUBJECT_CATEGORY_DEFAULT);
$subject->getAttributes()->add(new Attribute(new Uri(SubjectIdentifier::SUBJECT_ID), new Uri(DataTypes::STRING), StringAttribute::getInstance($user->getObjid())));
$resource = new Resource();
$resource->getAttributes()->add(new Attribute(new Uri(ResourceIdentifier::RESOURCE_ID), new Uri(DataTypes::STRING), StringAttribute::getInstance($escidocitemid)));
$writeaction = new Action();
$writeaction->getAttributes()->add(new Attribute(new Uri(ActionIdentifier::ACTION_ID), new Uri(DataTypes::STRING), StringAttribute::getInstance('info:escidoc/names:aa:1.0:action:update-item')));
$writerequest = new Request($resource, $writeaction);
$writerequest->add($subject);
$requestarray[0] = $writerequest;
$requests = new Requests();
$requests->addAll($requestarray);
// echo DOMMapper::marshal($requests);
$pdpresults = $_SESSION["pdphandler"]->evaluate($requests);
if ($pdpresults->get(0)->getDecision() !== Decision::PERMIT) {
throw new Exception("To register a DOI you need write access to the dataset.");
}
if (!($registermode === 'register' || $registermode === 'metadata' || $registermode === 'deactivate')) {
throw new Exception("Please choose as registration mode one of: <br>register DOI, <br>update DOI metadata, or <br>deactivate DOI.");
}
$item = $_SESSION["itemhandler"]->retrieve($escidocitemid);
uniquedoi($dbo, $item, $pmdinstance);
$successmessage = registerDOIFromItem($item, $targeturl, $publication, $doidbrestserver, $registermode);
echo json_encode(array("success" => true, "message" => $successmessage));
} catch (Exception $e) {
echo json_encode(array("success" => false, "message" => $e->getMessage()));