Use case: how to send a message to all users?

[OnkelTem]

Hey guys. I've discovered message stack 40 minutes ago, installed all the modules and now I'm trying to figure out how to use it. First things first, I need it to notify users about different events.
How to create a message - I already know. But how to send it to all the users?

[jhedstrom]

If you are using the message_subscribe_ui module, the subscribers are gathered for you when you call

 $subscribers = \Drupal::service('message_subscribe.subscribers');
  $subscribers->sendMessage($node, $message);

They are defined by flags on the content (eg, subscriptions to nodes are one flag, subscriptions to terms another.)

The message_subscribe_email module can be used either as an example (it builds on the message_subscribe_ui module.), or used as-is to achieve subscriptions.

[jhedstrom]

In your case of wanting to notify all users, you could skip both the message_subscribe_ui and the message_subscribe_email modules and implement your own hook_message_subscribe_get_subscribers to return all users on the site.