Push Notification Service - PNS

PNS is an HTTP service accepting (a) WS-connection requests from an application's HTTP-clients and (b) 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

• 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 send request to PNS to see the data of the new notifications (or can wait until some more new notifications are available) using the

  unseenNotificationDataRequest
  

  message. The response is sent to devices via the

  { "newNotificationData": [{ notification_data: string, create_date: string }] }
  

  message

• User devices can request (a range of) already seen notification data using the

  { seenNotificationsRequest: { receivedAfter: string } }
  

  message. The response is sent via the

  { "seenNotificationData": [{ notification_data: string, create_date: string, seen_date: string }] }
  

  message.

---

NOTE

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

---

---

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.

---

Application-facing functions

• PNS delegates requests to authenticate a connection request to the application. For successful authentications, the application returns in its response the user_id of the authenticated user to whom the connecting device belongs.
• The application requests PNS to send notifications to a user's connected devices.

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