Re-add old blog posts from Astro

source/_posts/queuing-private-messages-drupal-8.md

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+---
+title: Queuing Private Messages in Drupal 8
+date: 2018-02-27
+excerpt: Introducing the Private Message Queue module for Drupal 8.
+tags:
+    - drupal
+    - drupal-8
+    - drupal-modules
+    - drupal-planet
+    - open-source
+---
+
+My current project at [Microserve][0] is a Drupal 8 website that uses the
+[Private Message][1] module for users to send messages to each other.
+
+In some cases though, the threads could contain hundreds of recipients so I
+decided that it would be good to queue the message requests so that they can be
+processed as part of a background process for better performance. The Private
+Message module does not include this, so I've written and released a separate
+[Private Message Queue][2] module.
+
+## Queuing a Message
+
+The module provices a `PrivateMessageQueuer` service
+(`private_message_queue.queuer`) which queues the items via the `queue()`
+method.
+
+The method accepts an array of `User` objects as the messsage recipients, the
+message body text and another user as the message owner. (I’m currently
+considering [whether to make the owner optional][4], and default to the current
+user if one is not specified)
+
+Here is an example:
+
+```php
+$recipients = $this->getRecipients(); // An array of User objects.
+$message = 'Some message text';
+$owner = \Drupal::currentUser();
+
+$queuer = \Drupal::service('private_message_queue.queuer');
+$queuer->queue($recipients, $message, $owner);
+```
+
+These three pieces of data are then saved as part of the queued item. You can
+see these by checking the "queue" table in the database or by running
+`drush queue-list`.
+
+![](/images/blog/private-message-queue.png)
+
+```
+$ drush queue-list
+Queue                  Items  Class
+private_message_queue  19     Drupal\Core\Queue\DatabaseQueue
+```
+
+## Processing the Queue
+
+The module also provides a `PrivateMessageQueue` queue worker, which processes
+the queued items. For each item, it creates a new private message setting the
+owner and the message body.
+
+It uses the `PrivateMessageThread` class from the Private Message module to find
+for an existing thread for the specified recipients, or creates a new thread if
+one isn't found. The new message is then added to the thread.
+
+The queue is processed on each cron run, so I recommend adding a module like
+[Ultimate Cron][3] so that you can process the queued items frequently (e.g.
+every 15 minutes) and run the heavier tasks like checking for updates etc less
+frequently (e.g. once a day).
+
+You can also process the queue manually with Drush using the
+`drush queue-run <queue-name>` command - e.g.
+`drush queue-run private_message_queue`.
+
+```
+$ drush queue-run private_message_queue
+Processed 19 items from the private_message_queue queue in 3.34 sec.
+```
+
+[0]: {{site.companies.microserve.url}}
+[1]: https://www.drupal.org/project/private_message
+[2]: https://www.drupal.org/project/private_message_queue
+[3]: https://www.drupal.org/project/ultimate_cron
+[4]: https://www.drupal.org/project/private_message_queue/issues/2948233