Xpressengine\Document\Models\Document::user PHP Method

    public function user()
    {
        return $this->belongsTo('Xpressengine\\User\\Models\\User', 'userId');
    }

 /**
  * preview
  *
  * @param Request     $request
  * @param PageHandler $pageHandler page handler
  *
  * @return \Xpressengine\Presenter\RendererInterface
  */
 public function preview(Request $request, PageHandler $pageHandler)
 {
     $pageId = $this->pageId;
     $config = $pageHandler->getPageConfig($pageId);
     $user = $request->user();
     /** @var \Illuminate\Http\Request $request */
     $request = app('request');
     $title = $request->get('pageTitle');
     $mode = $request->get('mode');
     $documentInputs = $request->except('_token', 'certifyKey_confirmation', 'anonymity', 'queryString', 'notice', '_codes', '_links', '_hashTags', '_mentions', '_files');
     $previewDoc = new Document($documentInputs);
     $previewDoc->id = 'preview-' . app('xe.keygen')->generate();
     $previewDoc->instanceId = $pageId;
     $previewDoc->user()->associate($user);
     $page = new PageEntity(['pageId' => $pageId, 'uid' => $previewDoc->id, 'content' => $previewDoc]);
     $content = $previewDoc->content;
     return XePresenter::make('show', ['pageId' => $pageId, 'page' => $page, 'title' => $title, 'content' => $content, 'config' => $config]);
 }