Link to create a node, save it, and then go to the edit page

Question

I want to enable users to click a link to create a node of a specific content type. However, instead of going to /node/add/contenttype, which is the standard Drupal flow, I want the node of the relevant content type to automatically be created and saved, and then redirect the user to the newly created node's edit page.

In other words, when a user clicks "add a node," I want to create the node for the user and send the user to the edit page.

I want to do this because I have a very long, complicated form and I want to use the Autosave Form module to automatically save the form; however, this module can only save a node/entity that has already been saved once (entities with an entity ID).

What's the simplest way to implement this?

I'm thinking that I will need to define a custom route that checks permission, runs code to create the node, and then redirects to the node.

EDIT: Overriding the NodeController

As suggested by 4k4, I overrode the NodeController as follows. However, the problem is that when I go to /node/add/contenttype, the node is created and the form is shown, but it's an old form; when I try to save it, I get this error: "The content has either been modified by another user, or you have already submitted modifications. As a result, your changes cannot be saved."

class MymoduleNodeController extends NodeController {
  public function add(NodeTypeInterface $node_type) {
    $content_type = $node_type->id();
    if ($content_type == 'MYTYPE') {
      $node = $this->entityManager()->getStorage('node')->create([
        'type' => $node_type->id(),
      ]);
      $node->save();
      $form = $this->entityFormBuilder()->getForm($node);

      return $form;
    }
    else { // Default node creation behavior

Answer 1

I think the simplest way is to save the node right after you've created it in a custom version of NodeController::add():

  public function add(NodeTypeInterface $node_type) {
    $node = $this->entityManager()->getStorage('node')->create([
      'type' => $node_type->id(),
    ]);

    $form = $this->entityFormBuilder()->getForm($node);

    return $form;
  }

Edit:

Because building the form directly with the saved node doesn't work, return a redirect response for the node edit form:

    $node->save();
    return $this->redirect('entity.node.edit_form', ['node' => $node->id()]);