Push Notification Service - PNS

PNS is an HTTP service accepting

• WS-connection requests from an application's HTTP-clients and
• notifications to be instantantly delivered (pushed) from the application to the application's users.

User/client-facing functions

• User devices can connect at the POST /subscribe endpoint and remain connected to PNS with one device or multiple devices

  • the POST request carries a token (session-cookie by default) associated with the credentials of the user which is checked by the application;
  • in case the token refers to valid credentials of a user who is allowed to use the notification service, the endpoint returns the user_id

• Each connected device of each user is notified (by PNS) of the availability of new notifications from the application via the

  { "newNotificationCountChanged": number }
  

  message. (The content (data) of the new notifications is not sent at this point.)

• User devices can request the notification data using the

  { notificationDataRequest: { receivedAfter: string } }
  

  message. If the receivedAfter property is empty, the response will include only data for notications not yet seen. The response is sent via the

  { "notificationData": [{ notification_data: string, created_date: string, seen_date: string }] }
  

  message.

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NOTE

"device" in this context translates in practice into distinct "cookied" sessions, i.e. each distinct client session counts as a distinct device.

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NOTE

Notifications must be kept available until the user requests to see them (i.e. potentially for an infinite period of time) and even for some configurable period thereafter.

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Application-facing functions

• The application can request PNS to send notifications to a user's connected devices using the

  { user_id: string, notifications: [{ data: string, created_date: string }] }
  

message.

The service can be deployed either as a service separate from the application or embedded in the application as library.