UpdateManagerInstall::submitForm

public UpdateManagerInstall::submitForm(array &$form, FormStateInterface $form_state)

public function submitForm(array &$form, FormStateInterface $form_state) {
  $local_cache = NULL;
  if ($form_state->getValue('project_url')) {
    $local_cache = update_manager_file_get($form_state->getValue('project_url'));
    if (!$local_cache) {
      drupal_set_message($this->t('Unable to retrieve Drupal project from %url.', array('%url' => $form_state->getValue('project_url'))), 'error');
      return;
    }
  }
  elseif ($_FILES['files']['name']['project_upload']) {
    $validators = array('file_validate_extensions' => array(archiver_get_extensions()));
    if (!($finfo = file_save_upload('project_upload', $validators, NULL, 0, FILE_EXISTS_REPLACE))) {
      // Failed to upload the file. file_save_upload() calls
      // drupal_set_message() on failure.
      return;
    }
    $local_cache = $finfo->getFileUri();
  }

  $directory = _update_manager_extract_directory();
  try {
    $archive = update_manager_archive_extract($local_cache, $directory);
  }
  catch (\Exception $e) {
    drupal_set_message($e->getMessage(), 'error');
    return;
  }

  $files = $archive->listContents();
  if (!$files) {
    drupal_set_message($this->t('Provided archive contains no files.'), 'error');
    return;
  }

  // Unfortunately, we can only use the directory name to determine the
  // project name. Some archivers list the first file as the directory (i.e.,
  // MODULE/) and others list an actual file (i.e., MODULE/README.TXT).
  $project = strtok($files[0], '/\\');

  $archive_errors = $this->moduleHandler->invokeAll('verify_update_archive', array($project, $local_cache, $directory));
  if (!empty($archive_errors)) {
    drupal_set_message(array_shift($archive_errors), 'error');
    // @todo: Fix me in D8: We need a way to set multiple errors on the same
    // form element and have all of them appear!
    if (!empty($archive_errors)) {
      foreach ($archive_errors as $error) {
        drupal_set_message($error, 'error');
      }
    }
    return;
  }

  // Make sure the Updater registry is loaded.
  drupal_get_updaters();

  $project_location = $directory . '/' . $project;
  try {
    $updater = Updater::factory($project_location, $this->root);
  }
  catch (\Exception $e) {
    drupal_set_message($e->getMessage(), 'error');
    return;
  }

  try {
    $project_title = Updater::getProjectTitle($project_location);
  }
  catch (\Exception $e) {
    drupal_set_message($e->getMessage(), 'error');
    return;
  }

  if (!$project_title) {
    drupal_set_message($this->t('Unable to determine %project name.', array('%project' => $project)), 'error');
  }

  if ($updater->isInstalled()) {
    drupal_set_message($this->t('%project is already installed.', array('%project' => $project_title)), 'error');
    return;
  }

  $project_real_location = drupal_realpath($project_location);
  $arguments = array(
    'project' => $project,
    'updater_name' => get_class($updater),
    'local_url' => $project_real_location,
  );

  // This process is inherently difficult to test therefore use a state flag.
  $test_authorize = FALSE;
  if (drupal_valid_test_ua()) {
    $test_authorize = \Drupal::state()->get('test_uploaders_via_prompt', FALSE);
  }
  // If the owner of the directory we extracted is the same as the owner of
  // our configuration directory (e.g. sites/default) where we're trying to
  // install the code, there's no need to prompt for FTP/SSH credentials.
  // Instead, we instantiate a Drupal\Core\FileTransfer\Local and invoke
  // update_authorize_run_install() directly.
  if (fileowner($project_real_location) == fileowner($this->sitePath) && !$test_authorize) {
    $this->moduleHandler->loadInclude('update', 'inc', 'update.authorize');
    $filetransfer = new Local($this->root);
    $response = call_user_func_array('update_authorize_run_install', array_merge(array($filetransfer), $arguments));
    if ($response instanceof Response) {
      $form_state->setResponse($response);
    }
  }

  // Otherwise, go through the regular workflow to prompt for FTP/SSH
  // credentials and invoke update_authorize_run_install() indirectly with
  // whatever FileTransfer object authorize.php creates for us.
  else {
    // The page title must be passed here to ensure it is initially used when
    // authorize.php loads for the first time with the FTP/SSH credentials
    // form.
    system_authorized_init('update_authorize_run_install', __DIR__ . '/../../update.authorize.inc', $arguments, $this->t('Update manager'));
    $form_state->setRedirectUrl(system_authorized_get_url());
  }
}