Pass a value via URL to a node edit form and use it to redirect after saving the node

Question

I have a node that includes a series of embedded views. When displaying, I have to pass a value via URL arguments (http://example.org/node/x?id=y), so that the views can get the appropriate information. The user needs to be able to edit this node, but when they save and return to the node it has lost the id=y part and the display is incomplete.

I know I can use hook_form_alter() to redirect, but I can't figure out how can I redirect after the node is saved using that URL argument?

Answer 1

Using hook_form_alter(), you can add a submission handler that sets the redirection. The code for the submission handler would be similar to the following one.

function mymodule_node_edit_submit(array &$form, FormStateInterface $form_state) {
  $node = $form_state->getFormObject()->getEntity();
  $id = \Drupal::request()->query->get('id');
  $form_state->setRedirect('entity.node.canonical', ['node' => $node->id()], [query => ['id' => $id]]);
}

The code for hook_form_BASE_FORM_ID_alter() would simply be the following one.

function mymodule_form_node_form_alter(&$form, FormStateInterface $form_state) {
  $node = $form_state->getFormObject()->getEntity();

  // Since this hook is invoked for every node, check its content type.
  if ($node->getType() == 'the content type you are interested in') {
    $form['actions']['submit']['#submit'][] = 'mymodule_node_edit_submit';
  }
}

The hook_form_FORM_ID_alter() implementation should be named mymodule_form_node_<content_type_machine_name>_alter(). (Replace mymodule with the module machine name, <content_type_machine_name> with the content type machine name.) In this case, since the hook is invoked only for a content type, it doesn't need to check the node content type before adding the submission handler.