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Explore and Make use of Nationally Defined Messaging APIs


Subscriptions Overview

Types of Subscription and how they are used

To receive event messages a consumer will need to subscribe to events they want to receive. The flow of event messages from publishers to subscribers is described on the Messaging Architecture Overview page.

Types of Subscription

Explicit Subscriptions

An explicit subscription relates to where a subscriber wishes to receive event messages for a specific patient, for example, a Pharmacist wishing to receive hospital admission and discharge events for a specific Patient.

Explicit event message subscriptions for patients can be created using the Subscription API, using the Create Subscription interaction. The organizations MESH mailbox must be configured to receive the required event message types as per the requirements on the Event Receiver Requirements page.

Explicit subscriptions SHOULD only be active for patients under the subscribing organisations direct care. Explicit subscriptions for a patient should be stopped when the patient leaves the subscribing organisations direct care. This can be done either by removing the explicit subscription using the Delete Subscription API interaction or by including the end element as part of the subscription resource.

Rule-Based (Generic) Subscriptions

A rule-based subscription relates to where a subscriber wishes to receive all published events that meet a particular rule set. There are two specific types of rule-based subscription currently:

  • Geographical: Subscriptions that relate to individuals who reside within the geographic boundaries of a specific organisation (For example, a Health Visiting Service wishing to view events for all children within a specific local authority area).

    A geographical rule based subscription will result in a subscriber receiving events for any patients within the specified geographical area, therefore a subscriber wishing to use this form of subscription must demonstrate that they have a legitimate relationship with all patients in the area. If a provider is only responsible for a subset of patients within a geographical area, then geographical subscriptions are not appropriate as the provider will receive information for patients with which they do not have a legitimate relationship. In this scenario the provider should use explicit subscriptions to receive events for the patients with which they have a legitimate relationship.

  • Registered Org: Subscriptions that relate to individuals who are registered with a specific organisation (currently only applicable for GP organisations).

Currently the Subscription API does not support the configuration of generic subscriptions. Details of how to setup generic subscriptions is outlined on the Event Receiver Requirements page.

Subscription matching and message delivery

Multiple matched subscriptions

A subscriber may create a number of different subscriptions, some explicit and some generic. If an event message published to the National Events Management Service (NEMS) matches the criteria of multiple subscriptions for a single receiving MESH mailbox, the NEMS will only send one copy of the event message to the receiving mailbox.

Tags: fhir

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