Domain Alias - enable by default and document.

[finnlewis]

Discussing in Tech Drop-in:

Christian wanted to have both www.haringeyfeast.com and haringeyfeast.com resolve to the same microsite.

@stephen-cox showed us that domain alias module needs enabling and configuring.

@stephen-cox suggested that perhaps we should enable this by default.

[finnlewis]

Maybe we can then add docs to https://docs.localgovdrupal.org/microsites/how-to/add-URLs.html

[rupertj]

+1 to this. We've set up domain alias to add our Stage and Dev domains to microsites so we can move the DB between environments without having to edit every single microsite entity and set the URL.

[finnlewis]

You doing any work on this @rupertj or shall I dive in a make a pull request?

[rupertj]

Go for it. All I've done so far is enable it on H&Fs set up to fix the environment problem :)

[finnlewis]

Also see hot-to here: https://docs.localgovdrupal.org/microsites/how-to/add-URLs.html#how-to-enable-and-configure-domain-aliases-for-microsites

@Adnan-cds mentioned you might have some code to help automate this?

[Adnan-cds]

mentioned you might have some code to help automate this?

This is what we are using currently:

use Drupal\domain\DomainInterface;
use Drupal\domain\DomainNegotiatorInterface;

/**
 * Implements hook_domain_request_alter().
 *
 * Resolves dynamic domain aliases for local/dev/staging/np/edit URLs. Example:
 * - https://local.example.net/ resolves to https://example.net/ or
 *   https://www.example.net/
 * - https://dev.example.net/ resolves to https://example.net/ or
 *   https://www.example.net/
 * - https://np.example.net/ resolves to https://example.net/ or
 *   https://www.example.net/
 * - https://edit.example.net/ resolves to https://example.net/ or
 *   https://www.example.net/
 * - https://staging.example.net/ resolves to https://example.net/ or
 *   https://www.example.net/
 *
 * Also takes fixed domain aliases into account.  For example, the following
 * applies when example.org is a domain alias for example.net:
 * - https://local.example.org/ resolves to https://example.net/
 * - https://dev.example.org/ resolves to https://example.net/ and so on.
 * This does not work where the domain alias uses regular expression.  For
 * example, this will not work when *.example.org is a domain alias for
 * example.net.
 */
function modulename_domain_request_alter(DomainInterface &$active_domain_record) {

  if ($active_domain_record->getMatchType() !== DomainNegotiatorInterface::DOMAIN_MATCHED_NONE) {
    return;
  }

  $active_url_parts = parse_url($active_domain_record->getUrl());
  if (!$active_url_parts) {
    return;
  }
  $active_hostname = $active_url_parts['host'];
  $active_hostname_w_optional_port = $active_domain_record->getHostname();

  $matches = [];
  // Nonlive hostnames start with "local" or "devN" or "np";
  // e.g. dev5.example.net.
  $is_nonlive_env = preg_match('#^(dev\d*|edit|local|np|staging)\.(?<live_microsites_hostname>.+)#', $active_hostname, $matches);
  $is_live_env = !$is_nonlive_env;
  if ($is_live_env) {
    return;
  }

  $potential_domain = $matches['live_microsites_hostname'];
  $potential_domain_w_www_prefix = 'www.' . $matches['live_microsites_hostname'];
  $live_domain_record = Drupal::service('entity_type.manager')->getStorage('domain')->loadByHostname($potential_domain);
  $live_domain_record = $live_domain_record ?? Drupal::service('entity_type.manager')->getStorage('domain')->loadByHostname($potential_domain_w_www_prefix);
  $live_domain_record = $live_domain_record ?? _modulename_find_domain_record_from_alias($matches['live_microsites_hostname']);
  if (empty($live_domain_record)) {
    return;
  }

  // Finally, swap the active domain with the canonical one.
  $active_domain_record = $live_domain_record;
  $active_domain_record->setMatchType(DomainNegotiatorInterface::DOMAIN_MATCHED_ALIAS);
  $active_domain_record->setCanonical();
  $active_domain_record->setHostname($active_hostname_w_optional_port);
  $active_domain_record->setPath();
  $active_domain_record->setUrl();
}

/**
 * Finds domain record for given domain alias.
 *
 * Ignores domain aliases with port numbers and regular expressions due to
 * performance overhead.
 *
 * @see Drupal\domain_alias\DomainAliasStorage::loadByHostname()
 */
function _modulename_find_domain_record_from_alias(string $domain_alias): ?DomainInterface {

  $is_domain_alias_in_use = Drupal::service('entity_type.manager')->hasDefinition('domain_alias');
  if (!$is_domain_alias_in_use) {
    return NULL;
  }

  $live_domain_alias = Drupal::service('entity_type.manager')->getStorage('domain_alias')->loadByPattern($domain_alias);
  if (empty($live_domain_alias)) {
    return NULL;
  }

  // e.g. group_2.
  $live_domain_id = $live_domain_alias->getDomainId();
  $live_domain_record = Drupal::service('entity_type.manager')->getStorage('domain')->load($live_domain_id);
  return $live_domain_record;
}