react-websocket/doc/ConnectionGroups.md

# ConnectionGroups

Often websocket connections share a context. This could be a room for a chat, an URI for pushing updates, or anything else where one client need to be able to send messages directly or indirectly to other clients. This is the problem that *ConnectionGroups* solve.

A `WebSocketConnection` can, but doesn't have to, be part of a group. The group is set using `WebSocketConnection::setGroup(string $name)` with groups being created and destroyed on the fly. Once part of a group, the other members of the group can be addressed:

```php
$websocket->setGroup("somename");

// Note: use getGroupName() to get the group name
foreach ($websocket->getGroup() as $other) {
  $other->write("Hello");
}
```

To remove a group from a connection, pass `null` to `WebSocketConnection::setGroup()`.

The group will emit a `join` event (`WebSocketConnection::EVENT_JOIN`) when another member joins the group, and a `leave` event (`WebSocketConnection::EVENT_LEAVE`) when a member leaves. The events will be sent to the leaving member as well, so consider this in your logic.