Custom eZ Platform actions, before and after

1_before.php

<?php
class DemoController
{
  public function showBlogPostAction(Location $location, $viewType, $layout = false, array $params = array())
  {
    // We need the author, whatever the view type is.
    $author = $this->userService->loadUser($location->getContentInfo()->ownerId);
    // TODO once the keyword service is available, load the number of keyword for each keyword
    // Delegate view rendering to the original ViewController
    // (makes it possible to continue using defined template rules)
    // We just add "author" to the list of variables exposed to the final template
    return $this->get('ez_content')->viewLocation(
        $location->id,
        $viewType,
        $layout,
        array('author' => $author) + $params
    );
  }
}

2_after.php

<?php
class DemoController
{
  public function showBlogPostAction(ContentView $view)
    {
        $author = $this->userService()->loadUser($view->getContent()->contentInfo->ownerId);
        $view->addParameters(['author' => $author]);
        
        return $view;
    }
}

Updated usage of the UserService. It is pseudo code, let's say it is injected ;-)

Did you forget the after file?