Content Hub Pull Syndication provides organizations with greater flexibility and enhanced security for content syndication across multiple Drupal sites. Designed for strict compliance environments, Pull Syndication enables subscriber sites to actively fetch content updates from the Content Hub Service Queue. This approach removes the need for public webhooks and supports environments behind firewalls or private networks.

Key benefits¶

• Secure and private environments

  Pull Syndication eliminates the requirement for inbound webhooks or public site access, which makes it ideal for sites behind firewalls.

• Configurable delivery mode

  Switch easily between traditional Push Syndication, which is webhook-based, and the new Pull Syndication for each subscriber site.

• No webhook requests

  This mode avoids webhook landing requests on the site. This decreases site traffic and does not introduce site visits.

How Pull Syndication works¶

1. Publisher updates content

   A publisher site exports content. Content Hub matches it against subscriber filters and the interest list, similar to webhook-based syndication.

2. Service-side queue

   Matching content items are added to a dedicated syndication queue in the Content Hub Service.

3. Subscriber pulls updates

   Subscriber sites request new items from their queue when ready and import the content into their Drupal site.

4. Scheduled or manual sync

   Imports are processed on a schedule, for example through cron, or manually through Drupal’s admin UI or Drush commands.

Configuration and use¶

Switching syndication modes¶

To switch syndication modes:

1. Go to Administration > Configuration > Web services > Acquia Content Hub at /admin/config/services/acquia-contenthub.

2. In the Syndication Strategy section, toggle between Push and Pull modes for each subscriber.

   • Push uses the existing webhook model.
   • Pull enables the new pull model.
   

Queue controls¶

Pull mode displays service queue counts. The import limit and visibility timeout are set by default to 50 items and 24 hours, respectively.

• Import limit: This is the number of items fetched and processed per batch. This limit is not equal to the number of items imported and does not include dependencies.
• Visibility timeout: This is the timeframe an item is in the processing state after it is claimed by the client.

Manual and automated processing¶

Use the Import Items button in the admin UI or run Drush commands, for example drush ach-import, to process both local and Content Hub service queue items.

Drush queue operations¶

Drush commands are available to delete queue items and post-purge operations. Visit the Using Drush with Content Hub page for details.

Considerations¶

• No hybrid support

  A site must use either Push or Pull, not both simultaneously.

• Webhook not strictly required

  In Pull Syndication, a user needs to register a webhook URL, but it does not need to be a valid webhook. The site does not receive webhook requests from the service. Certain other features, such as interest list updates, still require configured webhooks.

• Queue-based

  Pull mode relies on scheduled or manual imports rather than immediate updates. Because webhook delivery is disabled in Pull Syndication mode, delete operations are not immediate. Deletions are processed in the next scheduled import or cron run, similar to how create and update actions are handled.

• Post purge, publisher discovery, and secret regeneration

  Automatic operations, such as post-purge operations, automatic publisher discovery, or shared secret regeneration through a webhook, are not supported in Pull mode. These actions require manual Drush commands.

• Queue processing updates

  Cron jobs that use the old drush queue-run <import queue name> command must switch to the drush ach-import command for compatibility with Pull mode.

• No self-healing

  The self-healing mechanisms available in push-based syndication through webhooks are not operational in Pull mode. Manual monitoring and intervention are required for stuck or failed queue items.

• Tracking table status updates

  On the publisher, transitions from EXPORTED to CONFIRMED status do not occur through webhooks.

• Filter creation

  In Pull syndication mode, if webhooks are not configured properly, the user cannot assign the sites to a filter in the Content Hub dashboard. Filters can be created from the Content Hub dashboard; however, a Drush command must be used to assign sites to the filter.

• Manual UI queueing

  In Pull Syndication mode, adding items manually to the import queue from the Content Hub dashboard is not supported. A future Drush command is planned to support adding items to the Content Hub import queue manually.

Continuous improvement¶

The Pull Syndication feature in Content Hub is under continuous development to address limitations and enhance functionality for compliance and workflow needs.