For a full list of available versions, see the Directory of published versions

2.4. Business Rules

The Ontario Health Subscription Service follows a set of business rules to ensure reliable, consistent, and standardized behavior across all subscriber interactions. These rules define the expected behavior for notification delivery, acknowledgment handling, and message processing, ensuring seamless integration with diverse healthcare systems. By adhering to these rules, subscribers and publishers can maintain data integrity, interoperability, and compliance with Ontario Health’s standards for event-driven information exchange.

The following sections outline the key business rules governing the subscription lifecycle, notification delivery, and acknowledgment requirements.

2.4.1. Generic Rules

Once Only Delivery

• Once-only delivery ensures that a message or event is processed exactly once by the target system, preventing duplicates while guaranteeing reliable data transfer.
• Subsriber is responsible to configure subscription so it avoid creating two or more subscriptions with the same delivery channel and filters.

Guaranteed Notification Delivery

The Subscription Service is responsible for successful receipt and processing of Notification by the Subscriber, ensuring guaranteed delivery of notifications to Subscribers, rather than operating on a best-effort basis. Any intermediary service (for example SOFA service) shall only guarantee notification delivery to the point of sending the notification to the Subscriber end point.

• For REST-hook notifications: Subscribers must not return a 2xx HTTP status code until the notification is fully processed.
• For WebSocket notifications: Subscribers must not send an acknowledgment (ACK) until they have successfully processed the notification.

Synchronous and Asynchronous Modes of Delivery

Subscription service will have to support sync and async notification delivery mechanisms.

2.4.2. List Management Rules

• The Point-of-Service system shall ensure that business identifiers (Group.Identifier) are unique and maintained internally as a requirement for submission of Patient and Practitioner Lists to Pub Sub Service.

• The Point-of-Service system may have multiple patient or practitioner lists for different cohort to support the subscription management.

• The Point-of-Service system is responsible for the creation and maintenance of these lists.