How to programmatically create a node on user registration with the user as author?

Question

I want to create a single node of content type XYZ for each user upon registration.

I tried to use hook_user_insert() (hook_entity_insert()), but this doesn't work because when I set the nid to the uid, the uid is still 0 (anonymous user), and the node needs to be assigned to the newly created account. (NOTE: This was my misunderstanding, see below.)

I want to create the nodes upon account creation because each user should have only one node of this content type.

In Drupal 7, I managed to do this in Rules using a rule set in which I saved the user account and then created the new node. Since Rules isn't in beta for Drupal 8 yet, I am trying to do this programmatically.

Here is the code I am using:

function MYMODULE_user_insert(Drupal\Core\Entity\EntityInterface $entity) {
  $user = \Drupal::currentUser();
  $profile = Node::create(['type' => 'userprofilenode']);
  $profile->set('uid', $user->id());
  $profile->enforceIsNew();
  $profile->save();

As noted in 4k4's answer, $entity already has a UID. The problem is that I mistakenly introduced the current user, which is 0 (anonymous).

Answer 1

In an insert hook the user is already saved and should have an user id. So creating a node and assigning it to the new user as author should be no problem:

/**
 * Implements hook_ENTITY_TYPE_insert() for user entities.
 *
 * Adds a first node for a new user
 */
function mymodule_user_insert(\Drupal\user\UserInterface $user) {
  \Drupal\node\Entity\Node::create([
    'type' => 'XYZ',
    'title' => 'First node for user #' . $user->id(),
    'uid' => $user->id(),
  ])->save();
}

Answer 2

This is very easy to do in D8 Rules. The advantage you get from using Rules is that you don't have to write code and it doesn't take a custom module or developer to change the action if your needs change in the future. In this way Rules is like Views - you can either program this functionality or you can make it available to the UI for easy building and maintaining.

Here is an export of a Rule which does what you asked - when a new user is created, it creates a new node (of type article, as an example). It then sets the node author to be the new user. It then sets a field of the new node (the body field, in this case) to a value take from the user (the user's email address, in this case). As you can see, Rules are stored in YAML files, and are imported/exported like any other configuration in D8. So you can just import this and you will immediately have a working example which you can then modify to use the specific fields you've defined on your user entity and node type. This Rule additionally displays a system message, which is a very useful way to debug Rules.

langcode: en
status: true
dependencies: {  }
id: create_a_node_for_each_new_user
label: 'Create a node for each new user'
events:
  -
    event_name: 'rules_entity_insert:user'
description: 'Node fields will be populated from values entered on the user form.'
tags: {  }
config_version: '3'
expression:
  id: rules_rule
  uuid: c9428f2d-c0b9-47bf-a7e5-3f2cc8af9f54
  conditions:
    id: rules_and
    uuid: 47b8d622-ed38-4977-8e58-4cca6d89260a
    conditions: {  }
  actions:
    id: rules_action_set
    uuid: d96fd6b5-1638-4b15-adde-5f5d7673fb8f
    actions:
      -
        id: rules_action
        uuid: e09cd52d-76fe-4682-91de-bfed58a651ab
        context_values:
          message: 'Node created using information entered by <em>{{ user.name }}</em> when registering'
          type: status
          repeat: false
        context_mapping: {  }
        context_processors:
          message:
            rules_tokens: {  }
          type:
            rules_tokens: {  }
          repeat:
            rules_tokens: {  }
        provides_mapping: {  }
        action_id: rules_system_message
      -
        id: rules_action
        uuid: fe2acb55-9234-4754-9d2b-3d1889d1775c
        context_values:
          type: article
          title: 'Article created by Rules for {{ user.name }}'
        context_mapping: {  }
        context_processors:
          type:
            rules_tokens: {  }
          title:
            rules_tokens: {  }
        provides_mapping: {  }
        action_id: 'rules_entity_create:node'
      -
        id: rules_action
        uuid: 743be03f-d1b7-4251-a1ac-80b17aa5c86e
        context_values:
          value: '{{ user.mail.value }}'
        context_mapping:
          data: entity.body
        context_processors:
          value:
            rules_tokens: {  }
        provides_mapping: {  }
        action_id: rules_data_set
      -
        id: rules_action
        uuid: 91f3c8f2-eb47-46e6-a9dd-2affc90e15d2
        context_values: {  }
        context_mapping:
          data: entity.uid.target_id
          value: user.uid.value
        context_processors: {  }
        provides_mapping: {  }
        action_id: rules_data_set