How to fix this error about the Node class not found?

Question

I've installed Drupal 8, I've created a PHP file to read a XML file and insert some items, but I'm getting this error.

Fatal error: Uncaught Error: Class 'Drupal\node\Entity\Node' not found in C:\xampp\htdocs\drupal8\migracion.php:12 Stack trace: #0 {main} thrown in C:\xampp\htdocs\drupal8\migracion.php on line 12

This is the code I am using.

define('DRUPAL_DIR', __DIR__);
use \Drupal\Core\DrupalKernel;
use \Symfony\Component\HttpFoundation\Request;
use \Drupal\node\Entity\Node;
use \Drupal\file\Entity\File;
use \Drupal\pathauto\PathautoState;

$fileContentXML = file_get_contents(DRUPAL_DIR . "/sites/default/files/migration/data.xml");
$xml_file = simplexml_load_string($fileContentXML);
foreach ($xml_file->channel->item as $item) {
  $node = Node::create(['type' => 'article']);
  $nid = trim($item->nid);
  $node->set('nid', $nid);
  $node->set('uid', 1);
  $node->enforceIsNew();
  $node->save();
}

How can I fix this error?

Answer 1

The code shown in the question doesn't bootstrap Drupal, nor does it load the Node module. An external script needs to do that, differently from a module.

I usually use the authenticate.php file as guideline for writing code for an external script file that needs to bootstrap Drupal.

use Drupal\Core\DrupalKernel;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\node\NodeInterface;
use Symfony\Cmf\Component\Routing\RouteObjectInterface;
use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Route;

// Change the directory to the Drupal root.
// Edit the following line to make it point to the directory containing the autoload.php file.
chdir('.');
$autoloader = (require_once 'autoload.php');

try {
  $request = Request::createFromGlobals();
  $kernel = DrupalKernel::createFromRequest($request, $autoloader, 'prod');
  $kernel->boot();

  // A route is required for route matching.
  $request->attributes->set(RouteObjectInterface::ROUTE_OBJECT, new Route('<none>'));
  $request->attributes->set(RouteObjectInterface::ROUTE_NAME, '<none>');
  $kernel->preHandle($request);

  // Ensure our request includes the session if appropriate.
  if (PHP_SAPI !== 'cli') {
    $request->setSession($kernel->getContainer()->get('session'));
  }
} catch (HttpExceptionInterface $e) {
  $response = new Response('', $e->getStatusCode());
  $response->prepare($request)->send();
  exit;
}

\Drupal::moduleHandler()->addModule('system', 'core/modules/system');
\Drupal::moduleHandler()->addModule('node', 'core/modules/node');
\Drupal::moduleHandler()->load('system');
\Drupal::moduleHandler()->load('node');

$xml = simplexml_load_string(file_get_contents('./sites/default/files/migration/data.xml'));
foreach ($xml->channel->item as $item) {
  $node = \Drupal::entityManager()->getStorage('node')->create(
    'type' => 'article',
    'nid' => (int)$item->nid,
    'uid' => 1,
    'status' => NodeInterface::PUBLISHED
  ]);
  if ($node) {
    // The following line isn't necessary, as create() already calls enforceIsNew(). 
    // $node->enforceIsNew();
    $node->save();
  }
}

As side note, Drupal 8 has a migration system. Instead of using an external script that bootstraps Drupal, it would be better to use that. Depending on the migration, that may require to write a custom module. Even in that case, this route is preferable, as most of the migration code has been already written.