SilverStripe convertDataObjectSet is stripping additional properties - silverstripe

Question

I am attempting to add the 'AbsoluteLink' property to each DataObject in a DataList and then convert the list to JSON with JSONDataFormatter::convertDataObjectSet().
I have the following function:
public function json() {
$data = ResourceCentreArticlePage::get()->filter('ShowInMenus', '1')->filter('ShowInSearch', '1')->sort('Created', 'DESC');
$pageArray = new ArrayList();
foreach ($data as $page) {
$page->AbsoluteLink = $page->AbsoluteLink();
$pageArray->push($page);
}
// If I dump out the content of $pageArray here the object has the AbsoluteLink property
$jsonFormatter = new JSONDataFormatter();
$jsonData = $jsonFormatter->convertDataObjectSet($pageArray);
// If I dump out the content of $jsonData here there is no AbsoluteLink property
$this->response->addHeader("Content-type", "application/json");
return $jsonData;
}
The problem:
The AbsoluteLink property is removed after running the $pageArray through the convertDataObjectSet method.
What am I missing?

Answer 1

Using $jsonFormatter->setCustomAddFields(); will help here.
Add the following to the Page class:
public function getMyAbsoluteLink() {
return $this->AbsoluteLink();
}
For example to the Page.php:
class Page extends SiteTree {
public function getMyAbsoluteLink() {
return $this->AbsoluteLink();
}
}
And use that "magic field" like this:
public function json() {
$pages = Page::get()
->filter('ShowInMenus', '1')
->filter('ShowInSearch', '1')
->sort('Created', 'DESC');
$jsonFormatter = new JSONDataFormatter();
// add your custom field
$jsonFormatter->setCustomAddFields(["MyAbsoluteLink"]);
$jsonData = $jsonFormatter->convertDataObjectSet(
$pages
);
return $jsonData;
}
Note the $jsonFormatter->setCustomAddFields(["MyAbsoluteLink"]); and I removed the array manipulation.
Also I removed your array manipulation. How the convertDataobjectSet function works it seems you can't amend the objects before it runs.