This page is part of the FHIR Specification ~~(v4.3.0: R4B - STU~~ (v5.0.0-snapshot3: R5 Snapshot #3, to support Connectathon 32 ). The current version which supercedes this version is 5.0.0 . For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B

2.47 2.14 Resource SubscriptionStatus - Content

FHIR Infrastructure icon

Work Group

Maturity Level : 0

~~Draft~~ Trial Use

Security Category : Business

Compartments : Not linked to any defined compartments

The SubscriptionStatus resource describes the state of a Subscription during notifications.

2.47.1 2.14.1 Scope and Usage

This document contains information about the SubscriptionStatus resource and details specific to options in it. ~~It is defined as part of the topic-based model of~~ See Subscriptions ~~(Publish / Subscribe pattern).~~ for general information about using Subscriptions in FHIR.

The SubscriptionStatus resource is used to convey information about the current state of a Subscription ~~and the contents of a notification. Information contained within a SubscriptionStatus falls into three categories: Information to identify the relevant Subscription (e.g., a reference~~ during client notifications. It is not persisted or allowed to a Subscription , SubscriptionTopic ) Information about the current state of the Subscription (e.g., Subscription status, number of events the Subscription has generated) Information about the current notification (e.g., notification type, the events in this notification) be referenced by other resources except as described below.

2.47.2 2.14.2 Boundaries and Relationships

The SubscriptionStatus resource is used in ~~topic-based FHIR Subscriptions. This resource is designed only to be used to convey state information~~ the Subscriptions Framework . Information about ~~a subscription~~ the Boundaries and ~~notification during various operations, for example included with notifications or as~~ Relationships both within the ~~result~~ Subscriptions Framework and to other areas of ~~a status request.~~ the FHIR specification can be found here .

2.47.3 2.14.3 References to this Resource

No ~~resources refer to~~ references for this ~~resource directly. This resource does not implement any patterns.~~ Resource.

Structure

Name	Flags	Card.	Type	Description & Constraints
SubscriptionStatus	D TU		DomainResource	Status information about a Subscription provided during event notification + Rule: events listed in event notifications Elements defined in Ancestors: id , meta , implicitRules , language , text , contained , extension , modifierExtension
status	Σ	0..1	code	requested \| active \| error \| off \| entered-in-error ~~SubscriptionStatusCodes~~ Subscription Status ( Required )
type	?! Σ	1..1	code	handshake \| heartbeat \| event-notification \| query-status \| query-event SubscriptionNotificationType ( Required )
eventsSinceSubscriptionStart	Σ	0..1	~~string~~ integer64	Events since the Subscription was created
notificationEvent		0..*	BackboneElement	Detailed information about any events relevant to this notification
eventNumber		1..1	~~string~~ integer64	Event number
timestamp		0..1	instant	The instant this event occurred
focus		0..1	Reference ( Any )	The focus of this event
additionalContext		0..*	Reference ( Any )	Additional context for this event
subscription	Σ	1..1	Reference ( Subscription )	Reference to the Subscription responsible for this notification
topic	Σ	0..1	canonical ( SubscriptionTopic )	Reference to the SubscriptionTopic this notification relates to
error	Σ	0..*	CodeableConcept	List of errors on the subscription Subscription Error Codes ( Example )
Documentation for this format

See the Extensions for this resource

UML Diagram ( Legend )

XML Template

<SubscriptionStatus xmlns="http://hl7.org/fhir"> 
 <!-- from Resource: id, meta, implicitRules, and language -->
 <!-- from DomainResource: text, contained, extension, and modifierExtension -->
 <status value="[code]"/><!-- 0..1 requested | active | error | off | entered-in-error -->
 <type value="[code]"/><!-- 1..1 handshake | heartbeat | event-notification | query-status | query-event -->
 <

 <eventsSinceSubscriptionStart value="[integer64]"/><!-- 0..1 Events since the Subscription was created -->

 <notificationEvent>  <!-- 0..* Detailed information about any events relevant to this notification -->
  <

  <eventNumber value="[integer64]"/><!-- 1..1 Event number -->

  <timestamp value="[instant]"/><!-- 0..1 The instant this event occurred -->
  <focus><!-- 0..1 Reference(Any) The focus of this event --></focus>
  <additionalContext><!-- 0..* Reference(Any) Additional context for this event --></additionalContext>
 </notificationEvent>
 <subscription><!-- 1..1 Reference(Subscription) Reference to the Subscription responsible for this notification --></subscription>
 <topic><!-- 0..1 canonical(SubscriptionTopic) Reference to the SubscriptionTopic this notification relates to --></topic>
 <error><!-- 0..* CodeableConcept List of errors on the subscription --></error>
</SubscriptionStatus>

JSON Template

{
  "resourceType" : "SubscriptionStatus",
  // from Resource: id, meta, implicitRules, and language
  // from DomainResource: text, contained, extension, and modifierExtension
  "status" : "<code>", // requested | active | error | off | entered-in-error
  "type" : "<code>", // R!  handshake | heartbeat | event-notification | query-status | query-event
  "

  "eventsSinceSubscriptionStart" : "<integer64>", // Events since the Subscription was created

  "notificationEvent" : [{ // Detailed information about any events relevant to this notification
    "

    "eventNumber" : "<integer64>", // R!  Event number

    "timestamp" : "<instant>", // The instant this event occurred
    "focus" : { Reference(Any) }, // The focus of this event
    "additionalContext" : [{ Reference(Any) }] // Additional context for this event
  }],
  "subscription" : { Reference(Subscription) }, // R!  Reference to the Subscription responsible for this notification
  "

  "topic" : "<canonical(SubscriptionTopic)>", // Reference to the SubscriptionTopic this notification relates to

  "error" : [{ CodeableConcept }] // List of errors on the subscription
}

Turtle Template

@prefix fhir: <http://hl7.org/fhir/> .


[ a fhir:SubscriptionStatus;
  fhir:nodeRole fhir:treeRoot; # if this is the parser root

  # from Resource: .id, .meta, .implicitRules, and .language
  # from DomainResource: .text, .contained, .extension, and .modifierExtension
  fhir:SubscriptionStatus.status [ code ]; # 0..1 requested | active | error | off | entered-in-error
  fhir:SubscriptionStatus.type [ code ]; # 1..1 handshake | heartbeat | event-notification | query-status | query-event
  fhir:

  fhir:SubscriptionStatus.eventsSinceSubscriptionStart [ integer64 ]; # 0..1 Events since the Subscription was created

  fhir:SubscriptionStatus.notificationEvent [ # 0..* Detailed information about any events relevant to this notification
    fhir:

    fhir:SubscriptionStatus.notificationEvent.eventNumber [ integer64 ]; # 1..1 Event number

    fhir:SubscriptionStatus.notificationEvent.timestamp [ instant ]; # 0..1 The instant this event occurred
    fhir:SubscriptionStatus.notificationEvent.focus [ Reference(Any) ]; # 0..1 The focus of this event
    fhir:SubscriptionStatus.notificationEvent.additionalContext [ Reference(Any) ], ... ; # 0..* Additional context for this event
  ], ...;
  fhir:SubscriptionStatus.subscription [ Reference(Subscription) ]; # 1..1 Reference to the Subscription responsible for this notification
  fhir:SubscriptionStatus.topic [ canonical(SubscriptionTopic) ]; # 0..1 Reference to the SubscriptionTopic this notification relates to
  fhir:SubscriptionStatus.error [ CodeableConcept ], ... ; # 0..* List of errors on the subscription
]

Changes since R4

This resource did not exist in Release 3

This analysis is available as XML or JSON .

~~Conversions between R3 and R4~~

Structure

Name	Flags	Card.	Type	Description & Constraints
SubscriptionStatus	D TU		DomainResource	Status information about a Subscription provided during event notification + Rule: events listed in event notifications Elements defined in Ancestors: id , meta , implicitRules , language , text , contained , extension , modifierExtension
status	Σ	0..1	code	requested \| active \| error \| off \| entered-in-error ~~SubscriptionStatusCodes~~ Subscription Status ( Required )
type	?! Σ	1..1	code	handshake \| heartbeat \| event-notification \| query-status \| query-event SubscriptionNotificationType ( Required )
eventsSinceSubscriptionStart	Σ	0..1	~~string~~ integer64	Events since the Subscription was created
notificationEvent		0..*	BackboneElement	Detailed information about any events relevant to this notification
eventNumber		1..1	~~string~~ integer64	Event number
timestamp		0..1	instant	The instant this event occurred
focus		0..1	Reference ( Any )	The focus of this event
additionalContext		0..*	Reference ( Any )	Additional context for this event
subscription	Σ	1..1	Reference ( Subscription )	Reference to the Subscription responsible for this notification
topic	Σ	0..1	canonical ( SubscriptionTopic )	Reference to the SubscriptionTopic this notification relates to
error	Σ	0..*	CodeableConcept	List of errors on the subscription Subscription Error Codes ( Example )
Documentation for this format

See the Extensions for this resource

UML Diagram ( Legend )

XML Template

<SubscriptionStatus xmlns="http://hl7.org/fhir"> 
 <!-- from Resource: id, meta, implicitRules, and language -->
 <!-- from DomainResource: text, contained, extension, and modifierExtension -->
 <status value="[code]"/><!-- 0..1 requested | active | error | off | entered-in-error -->
 <type value="[code]"/><!-- 1..1 handshake | heartbeat | event-notification | query-status | query-event -->
 <

 <eventsSinceSubscriptionStart value="[integer64]"/><!-- 0..1 Events since the Subscription was created -->

 <notificationEvent>  <!-- 0..* Detailed information about any events relevant to this notification -->
  <

  <eventNumber value="[integer64]"/><!-- 1..1 Event number -->

  <timestamp value="[instant]"/><!-- 0..1 The instant this event occurred -->
  <focus><!-- 0..1 Reference(Any) The focus of this event --></focus>
  <additionalContext><!-- 0..* Reference(Any) Additional context for this event --></additionalContext>
 </notificationEvent>
 <subscription><!-- 1..1 Reference(Subscription) Reference to the Subscription responsible for this notification --></subscription>
 <topic><!-- 0..1 canonical(SubscriptionTopic) Reference to the SubscriptionTopic this notification relates to --></topic>
 <error><!-- 0..* CodeableConcept List of errors on the subscription --></error>
</SubscriptionStatus>

JSON Template

{
  "resourceType" : "SubscriptionStatus",
  // from Resource: id, meta, implicitRules, and language
  // from DomainResource: text, contained, extension, and modifierExtension
  "status" : "<code>", // requested | active | error | off | entered-in-error
  "type" : "<code>", // R!  handshake | heartbeat | event-notification | query-status | query-event
  "

  "eventsSinceSubscriptionStart" : "<integer64>", // Events since the Subscription was created

  "notificationEvent" : [{ // Detailed information about any events relevant to this notification
    "

    "eventNumber" : "<integer64>", // R!  Event number

    "timestamp" : "<instant>", // The instant this event occurred
    "focus" : { Reference(Any) }, // The focus of this event
    "additionalContext" : [{ Reference(Any) }] // Additional context for this event
  }],
  "subscription" : { Reference(Subscription) }, // R!  Reference to the Subscription responsible for this notification
  "

  "topic" : "<canonical(SubscriptionTopic)>", // Reference to the SubscriptionTopic this notification relates to

  "error" : [{ CodeableConcept }] // List of errors on the subscription
}

Turtle Template

@prefix fhir: <http://hl7.org/fhir/> .


[ a fhir:SubscriptionStatus;
  fhir:nodeRole fhir:treeRoot; # if this is the parser root

  # from Resource: .id, .meta, .implicitRules, and .language
  # from DomainResource: .text, .contained, .extension, and .modifierExtension
  fhir:SubscriptionStatus.status [ code ]; # 0..1 requested | active | error | off | entered-in-error
  fhir:SubscriptionStatus.type [ code ]; # 1..1 handshake | heartbeat | event-notification | query-status | query-event
  fhir:

  fhir:SubscriptionStatus.eventsSinceSubscriptionStart [ integer64 ]; # 0..1 Events since the Subscription was created

  fhir:SubscriptionStatus.notificationEvent [ # 0..* Detailed information about any events relevant to this notification
    fhir:

    fhir:SubscriptionStatus.notificationEvent.eventNumber [ integer64 ]; # 1..1 Event number

    fhir:SubscriptionStatus.notificationEvent.timestamp [ instant ]; # 0..1 The instant this event occurred
    fhir:SubscriptionStatus.notificationEvent.focus [ Reference(Any) ]; # 0..1 The focus of this event
    fhir:SubscriptionStatus.notificationEvent.additionalContext [ Reference(Any) ], ... ; # 0..* Additional context for this event
  ], ...;
  fhir:SubscriptionStatus.subscription [ Reference(Subscription) ]; # 1..1 Reference to the Subscription responsible for this notification
  fhir:SubscriptionStatus.topic [ canonical(SubscriptionTopic) ]; # 0..1 Reference to the SubscriptionTopic this notification relates to
  fhir:SubscriptionStatus.error [ CodeableConcept ], ... ; # 0..* List of errors on the subscription
]

Changes since Release 4

This resource did not exist in Release 3

This analysis is available as XML or JSON .

~~Conversions between R3 and R4~~

~~See the Profiles & Extensions and the alternate~~ Additional definitions: Master Definition XML + JSON , XML Schema / Schematron + JSON Schema , ShEx (for Turtle ) + see the extensions , the spreadsheet version & the dependency analysis

2.47.4.1 2.14.4.1 Terminology Bindings

Path	Definition	Type	Reference
SubscriptionStatus.status	State values for FHIR Subscriptions.	Required	SubscriptionStatusCodes (a valid code from SubscriptionStatus )
SubscriptionStatus.type	The type of notification represented by the status message.	Required	SubscriptionNotificationType
SubscriptionStatus.error	Codes to represent subscription error details	Example	SubscriptionErrorCodes

Path

Definition

Type

Reference

SubscriptionStatus.status

State values for FHIR Subscriptions.

Required

SubscriptionStatusCodes (a valid code from SubscriptionStatus )

SubscriptionStatus.type

The type of notification represented by the status message.

Required

SubscriptionNotificationType

SubscriptionStatus.error

Codes to represent subscription error details

Example

SubscriptionErrorCodes

2.47.4.2 2.14.4.2 Constraints

id UniqueKey

Level

Location

Description

Expression

~~sst-1~~ sst-1

Rule

(base)

events listed in event notifications

type = 'event-notification' implies (notificationEvent.exists() and notificationEvent.first().exists())

2.47.5 2.14.5 Timing and Currency

This resource is used to communicate information about a Subscription and the events represented by a notification bundle. The process of sending a notification (e.g., a notification this status is included with) can change the status of that subscription. Servers SHALL populate elements with the most recent information at the time of generation (e.g., when a notification is created) and receivers SHOULD be aware that this information might not be current at the time a notification is processed (e.g., a subscription was active but has subsequently moved to an error state).

2.47.6 2.14.6 Content and PHI

Subscription notifications MAY contain PHI. Applications are responsible for following FHIR security guidance and compliance with relevant security requirements (e.g., corporate policy, government regulation, etc.). Hinting for the allowed amount of PHI is available in the relevant Subscription resource, via the channel and payload information.

Since Subscription Topic definitions contain human-readable descriptions and definitions, the purpose of a topic may be understood by viewing the resource. Given that canonical links to topics are intended to be resolvable and/or searchable (e.g., indexed in a registry), it is assumed that anyone with a link to a topic also knows what that topic is about. Thus, topics MAY be considered PHI and SHOULD be reviewed before inclusion in a notification.

Hinting about when a canonical topic URL may be included with a notification can be derived from a subscription's payload level. E.g.:

empty: SHOULD NOT be present
id-only: MAY be present
full-resource: SHOULD be present

2.47.7 2.14.7 Notification Types

This specification describes five distinct outbound notification types: Event , Handshake , Heartbeat , Query Status , and Query Event . For each, the notification body is a subscription-notification Bundle with a SubscriptionStatus resource used to convey Subscription and notification details.

2.47.7.1 2.14.7.1 Event Notification

The primary notification bundle type is a notification about an event.

Element Optionality Notes

SubscriptionStatus.status Recommended Current status of the relevant subscription (e.g., active ).

SubscriptionStatus.type Required SHALL be event-notification

SubscriptionStatus.eventsSinceSubscriptionStart Required Servers SHALL include this value when sending event notifications in order to allow clients to detect missing events.
This value is inclusive of this notification (e.g., the first event notification sent would include one (1) in this element).

SubscriptionStatus.notificationEvent Required For notifications that include events, this element SHALL be present. Details about specific elements within this structure are included in this table.

SubscriptionStatus.notificationEvent.eventNumber Required This element is mandatory if a notificationEvent is present.

SubscriptionStatus.notificationEvent.timestamp Recommended So that clients can discover when an event actually occurred, timestamp is recommended.

SubscriptionStatus.notificationEvent.focus

Special

Element	Optionality	Notes
SubscriptionStatus.status	Recommended	Current status of the relevant subscription (e.g., `active` ).
SubscriptionStatus.type	Required	SHALL be `event-notification`
SubscriptionStatus.eventsSinceSubscriptionStart	Required	Servers SHALL include this value when sending event notifications in order to allow clients to detect missing events. This value is inclusive of this notification (e.g., the first event notification sent would include one (1) in this element).
SubscriptionStatus.notificationEvent	Required	For notifications that include events, this element SHALL be present. Details about specific elements within this structure are included in this table.
SubscriptionStatus.notificationEvent.eventNumber	Required	This element is mandatory if a `notificationEvent` is present.
SubscriptionStatus.notificationEvent.timestamp	Recommended	So that clients can discover when an event actually occurred, `timestamp` is recommended.
SubscriptionStatus.notificationEvent.focus	Special	Links contained in the `focus` element contain resource IDs, so will or will not be present based on the payload level relevant to the notification: `empty`: SHALL NOT be present `id-only`: SHALL be present `full-resource`: SHALL be present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.notificationEvent.additionalContext	Special	Links contained in the `additionalContext` element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available: `empty`: SHALL NOT be present `id-only`: SHOULD be present `full-resource`: SHOULD be present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.topic	Optional	See Content and PHI .

Links contained in the


focus

element contain resource IDs, so will or will not be present based on the payload level relevant to the notification:

empty: SHALL NOT be present
id-only: SHALL be present
full-resource: SHALL be present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.notificationEvent.additionalContext

Special

Links contained in the


additionalContext

element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available:

empty: SHALL NOT be present
id-only: SHOULD be present
full-resource: SHOULD be present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.topic Optional See Content and PHI .

Example event notification

2.47.7.2 2.14.7.2 Handshake Notification

When a connection to an Endpoint is established or re-established, a server MAY send a Handshake notification to the endpoint.

The client expectations upon receipt of a Handshake notification differ for each channel type (e.g., for the rest-hook channel type, a client endpoint responds to event notifications with standard HTTP response codes).

Element Optionality Notes

SubscriptionStatus.status Recommended Current status of the relevant subscription (e.g., active ).

SubscriptionStatus.type Required SHALL be handshake

SubscriptionStatus.eventsSinceSubscriptionStart Optional For a new Subscription, if this value is present it SHALL be zero (0).
A sender MAY send a handshake with a non-zero number of events, for example as process for re-establishing communication after an error state.
Note: this value SHALL NOT be incremented by sending a handshake notification.

SubscriptionStatus.notificationEvent Special A server MAY include historical events for a client with a handshake, if any exist. For example, during a reconnection process, a server MAY opt to include all events since the last successful transmission to the client. Details about specific elements within this structure are included in this table.

SubscriptionStatus.notificationEvent.eventNumber Special This element is mandatory if a notificationEvent is present.

SubscriptionStatus.notificationEvent.timestamp Special If a server is including prior events, timestamp is recommended, so that clients can process historical events with proper context.

SubscriptionStatus.notificationEvent.focus

Special

Element	Optionality	Notes
SubscriptionStatus.status	Recommended	Current status of the relevant subscription (e.g., `active` ).
SubscriptionStatus.type	Required	SHALL be `handshake`
SubscriptionStatus.eventsSinceSubscriptionStart	Optional	For a new Subscription, if this value is present it SHALL be zero (0). A sender MAY send a handshake with a non-zero number of events, for example as process for re-establishing communication after an error state. Note: this value SHALL NOT be incremented by sending a `handshake` notification.
SubscriptionStatus.notificationEvent	Special	A server MAY include historical events for a client with a `handshake`, if any exist. For example, during a reconnection process, a server MAY opt to include all events since the last successful transmission to the client. Details about specific elements within this structure are included in this table.
SubscriptionStatus.notificationEvent.eventNumber	Special	This element is mandatory if a `notificationEvent` is present.
SubscriptionStatus.notificationEvent.timestamp	Special	If a server is including prior events, `timestamp` is recommended, so that clients can process historical events with proper context.
SubscriptionStatus.notificationEvent.focus	Special	Links contained in the `focus` element contain resource IDs, so will or will not be present based on the payload level relevant to the notification: `empty`: SHALL NOT be present `id-only`: SHALL be present if a `notificationEvent` is included `full-resource`: SHALL be present if a `notificationEvent` is present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.notificationEvent.additionalContext	Special	Links contained in the `additionalContext` element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available: `empty`: SHALL NOT be present `id-only`: SHOULD be present if a `notificationEvent` is present `full-resource`: SHOULD be present if a `notificationEvent` is present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.topic	Optional	See Content and PHI .

Links contained in the


focus

element contain resource IDs, so will or will not be present based on the payload level relevant to the notification:

empty: SHALL NOT be present
id-only: SHALL be present if a notificationEvent is included
full-resource: SHALL be present if a notificationEvent is present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.notificationEvent.additionalContext

Special

Links contained in the


additionalContext

element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available:

empty: SHALL NOT be present
id-only: SHOULD be present if a notificationEvent is present
full-resource: SHOULD be present if a notificationEvent is present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.topic Optional See Content and PHI .

Example handshake notification

The client is not expected to take any special action in receipt of a Handshake notification beyond the channel-specific requirement for receiving an event notification.

2.47.7.3 2.14.7.3 Heartbeat Notification

A heartbeat notification is a subscription-notification Bundle of type heartbeat sent without incrementing the subscription event count, though servers MAY include the most recent event in the notification. For servers, heartbeat notifications allow systems to ensure that the connection is still alive and valid. For clients, heartbeat notifications serve as a method to detect errors in communication. Note that a client is not required to take any action in receipt of a heartbeat beyond the channel-specific requirement for receiving an event notification (e.g., accepting the notification bundle with an HTTP 200).

Heartbeat intervals are negotiated while creating a Subscription. If accepted, servers SHOULD send one heartbeat per interval on the accepted subscription.

Element Optionality Notes

SubscriptionStatus.status Recommended Current status of the relevant subscription (e.g., active ).

SubscriptionStatus.type Required SHALL be heartbeat

SubscriptionStatus.eventsSinceSubscriptionStart Recommended The presence of this value allows clients to detect missing notifications.
Note: this value SHALL NOT be incremented by sending a heartbeat notification.

SubscriptionStatus.notificationEvent Special A server MAY include historical events for a client with a heartbeat, if any exist. For example, a server MAY opt to include the most recent event since the last successful transmission to the client. Details about specific elements within this structure are included in this table.

SubscriptionStatus.notificationEvent.eventNumber Special This element is mandatory if a notificationEvent is present.

SubscriptionStatus.notificationEvent.timestamp Special If a server is including any prior events, timestamp is recommended, so that clients can process historical events with proper context.

SubscriptionStatus.notificationEvent.focus

Special

Element	Optionality	Notes
SubscriptionStatus.status	Recommended	Current status of the relevant subscription (e.g., `active` ).
SubscriptionStatus.type	Required	SHALL be `heartbeat`
SubscriptionStatus.eventsSinceSubscriptionStart	Recommended	The presence of this value allows clients to detect missing notifications. Note: this value SHALL NOT be incremented by sending a `heartbeat` notification.
SubscriptionStatus.notificationEvent	Special	A server MAY include historical events for a client with a `heartbeat`, if any exist. For example, a server MAY opt to include the most recent event since the last successful transmission to the client. Details about specific elements within this structure are included in this table.
SubscriptionStatus.notificationEvent.eventNumber	Special	This element is mandatory if a `notificationEvent` is present.
SubscriptionStatus.notificationEvent.timestamp	Special	If a server is including any prior events, `timestamp` is recommended, so that clients can process historical events with proper context.
SubscriptionStatus.notificationEvent.focus	Special	Links contained in the `focus` element contain resource IDs, so will or will not be present based on the payload level relevant to the notification: `empty`: SHALL NOT be present `id-only`: SHALL be present if a `notificationEvent` is included `full-resource`: SHALL be present if a `notificationEvent` is present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.notificationEvent.additionalContext	Special	Links contained in the `additionalContext` element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available: `empty`: SHALL NOT be present `id-only`: SHOULD be present if a `notificationEvent` is present `full-resource`: SHOULD be present if a `notificationEvent` is present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.topic	Optional	See Content and PHI .

Links contained in the


focus

element contain resource IDs, so will or will not be present based on the payload level relevant to the notification:

empty: SHALL NOT be present
id-only: SHALL be present if a notificationEvent is included
full-resource: SHALL be present if a notificationEvent is present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.notificationEvent.additionalContext

Special

Links contained in the


additionalContext

element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available:

empty: SHALL NOT be present
id-only: SHOULD be present if a notificationEvent is present
full-resource: SHOULD be present if a notificationEvent is present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.topic Optional See Content and PHI .

Example heartbeat notification

2.47.7.4 2.14.7.4 Query Status

Clients can ask a server at any time for the current status of a Subscription via the $status operation .

Since the $status operation is part of the FHIR REST API, the guidance below assumes that a user has been authenticated and is allowed access to all relevant resources.

Element Optionality Notes

SubscriptionStatus.status Required Current status of the relevant subscription (e.g., active ).

SubscriptionStatus.type Required SHALL be query-status

SubscriptionStatus.eventsSinceSubscriptionStart Required This value is required for clients to know if there are missing notifications.
Note: this value SHALL NOT be incremented by sending a query-status notification.

SubscriptionStatus.notificationEvent Prohibited A query-status notification SHALL NOT contain any event information.

SubscriptionStatus.topic Recommended See Content and PHI , but note that guidance will vary since there is an active user session.

Element	Optionality	Notes
SubscriptionStatus.status	Required	Current status of the relevant subscription (e.g., `active` ).
SubscriptionStatus.type	Required	SHALL be `query-status`
SubscriptionStatus.eventsSinceSubscriptionStart	Required	This value is required for clients to know if there are missing notifications. Note: this value SHALL NOT be incremented by sending a `query-status` notification.
SubscriptionStatus.notificationEvent	Prohibited	A `query-status` notification SHALL NOT contain any event information.
SubscriptionStatus.topic	Recommended	See Content and PHI , but note that guidance will vary since there is an active user session.

Example query-status notification

2.47.7.5 2.14.7.5 Query Event

Some servers may allow clients to ask for events which have already occurred. Notification bundles returned by such operations or queries should use the query-event type.

Element Optionality Notes

SubscriptionStatus.status Recommended Current status of the relevant subscription (e.g., active ).

SubscriptionStatus.type Required SHALL be query-event.

SubscriptionStatus.eventsSinceSubscriptionStart Recommended This value is allows clients to know if they are missing notifications.
Note: this value SHALL NOT be incremented by sending a query-event bundle.

SubscriptionStatus.notificationEvent Required For notifications that include events, this element SHALL be present. Details about specific elements within this structure are included in this table.

SubscriptionStatus.notificationEvent.eventNumber Required This element is mandatory if a notificationEvent is present.

SubscriptionStatus.notificationEvent.timestamp Recommended So that clients can discover when an event actually occurred, timestamp is recommended.

SubscriptionStatus.notificationEvent.focus

Special

Element	Optionality	Notes
SubscriptionStatus.status	Recommended	Current status of the relevant subscription (e.g., `active` ).
SubscriptionStatus.type	Required	SHALL be `query-event`.
SubscriptionStatus.eventsSinceSubscriptionStart	Recommended	This value is allows clients to know if they are missing notifications. Note: this value SHALL NOT be incremented by sending a `query-event` bundle.
SubscriptionStatus.notificationEvent	Required	For notifications that include events, this element SHALL be present. Details about specific elements within this structure are included in this table.
SubscriptionStatus.notificationEvent.eventNumber	Required	This element is mandatory if a `notificationEvent` is present.
SubscriptionStatus.notificationEvent.timestamp	Recommended	So that clients can discover when an event actually occurred, `timestamp` is recommended.
SubscriptionStatus.notificationEvent.focus	Special	Links contained in the `focus` element contain resource IDs, so will or will not be present based on the payload level relevant to the notification: `empty`: SHALL NOT be present `id-only`: SHALL be present `full-resource`: SHALL be present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.notificationEvent.additionalContext	Special	Links contained in the `additionalContext` element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available: `empty`: SHALL NOT be present `id-only`: SHOULD be present `full-resource`: SHOULD be present Note that servers SHOULD include the `Reference.type` element if if the type is not specified in `Reference.reference`
SubscriptionStatus.topic	Recommended	See Content and PHI , but note that guidance will vary since there is an active user session.

Links contained in the


focus

element contain resource IDs, so will or will not be present based on the payload level relevant to the notification:

empty: SHALL NOT be present
id-only: SHALL be present
full-resource: SHALL be present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.notificationEvent.additionalContext

Special

Links contained in the


additionalContext

element contain resource IDs and MAY or MAY not exist. Presence is determined based on the payload level relevant to the notification, if they are available:

empty: SHALL NOT be present
id-only: SHOULD be present
full-resource: SHOULD be present

Note that servers SHOULD include the


Reference.type

element if if the type is not specified in


Reference.reference

SubscriptionStatus.topic Recommended See Content and PHI , but note that guidance will vary since there is an active user session.

Example query-event notification

2.47.8 2.14.8 Notifications and Errors

If a server encounters errors while sending a notification, the server may retry the notification a fixed number of times and/or refer errors to its own alert logs. If the notification fails, the server SHOULD set the status of the subscription to error . If the error would be useful to a client (e.g., notification failed because the destination SSL certificate expired), servers SHOULD track errors and provide details to the client. If a notification retry attempt succeeds, the server SHOULD update the status to active and MAY remove any error codes. If a subscription fails consistently a server may choose set the subscription status to off and stop trying to send notifications. Errors a server wishes to make accessible to clients are stored in Subscription.error . Servers should provide a mechanism for clearing errors (e.g., when resetting a Subscription.status back to requested after an error). Since Subscription.error represents server errors, a server SHOULD NOT allow clients to add errors. 2.47.8.1 Detecting Delivery Errors There are several mechanisms available to subscribers in order to understand the current state of notification delivery. Below are some example error scenarios with details about how a subscriber can detect the problem state. 2.47.8.1.1 Missing Event The ~~diagram below shows how a subscriber can use the~~ SubscriptionStatus.eventsSinceSubscriptionStart parameter on received notifications to determine that an event has been missed. Diagram showing a missed-event detection and recovery workflow In the above sequence, the subscriber tracks the eventsSinceSubscriptionStart SubscriptionStatus of each received notification (per Subscription). When the subscriber received event 23, the subscriber was aware that the last notification it received was a single notification for event 21. The subscriber then waited an amount of time to ensure that event 22 was indeed missing (and not, for example, still being processed) and started a recovery process. The recovery process itself will vary by subscriber, but should be a well-understood method for recovering resource is key in ~~the event of errors. 2.47.8.1.2 Broken Communication The diagram below show how a subscriber can use a subscription heartbeat period to determine~~ detecting various errors ~~which prevent notifications from reaching the endpoint. Diagram showing broken~~ in communication ~~detection~~ and recovery workflow In the above sequence, the subscriber is aware that the heartbeatPeriod has elapsed for a subscription without receiving any notifications. . 2.47.8.1.3 Recovering from Errors Clients are responsible for devising an appropriate method for recovering from errors. Often, this process will include a series or batch of requests that allow a client to know the current state or a request to an $events operation when available. processing. For example, an application may need to query all relevant resources for a patient in order to ensure nothing has been missed. Once an application has returned to a functional state, it should request the subscription is reactivated by updating the status to either requested or active as appropriate. 2.47.8.1.4 Using the $events operation more information, see Managing Subscriptions and Errors ~~Servers MAY choose to support the $events operation defined on the Subscription resource. The $events operation allows clients to request events which have occurred~~ in the past. Servers which implement the operation MAY use implementation-specific criteria to restrict availability of events (e.g., most recent 10 events, events within the past 30 days, etc.). During a recovery process, clients MAY try to retrieve missing events via the $events operation, which should allow processing to continue as normal. Subscriptions Framework page.