Internet Printing Protocol (IPP): The 'ippget' Delivery Method for Event Notifications

Abstract

The notification extension document [ipp-ntfy] defines operations that a client can perform in order to create Subscription Objects in a Printer and carry out other operations on them. A Subscription Object represents a Subscription abstraction. The Subscription Object specifies that when one of the specified Events occurs, the Printer sends an asynchronous Event Notification to the specified Notification Recipient via the specified Delivery Method (i.e., protocol). The notification extension document [ipp-ntfy] specifies that each Delivery Method is defined in another document. This document is one such document, and it specifies the 'ippget' delivery method. The 'ippget' Delivery Method is a 'pull and push' Delivery Method. That is, the Printer saves Event Notification for a period of time and expects the Notification Recipient to fetch the Event Notifications (the pull part). The Printer continues to send Event Notifications to the Notification Recipient as Events occur (the push part) if the client has selected the option to wait for additional Event Notifications. When a Printer supports this Delivery Method, it holds each Event Notification for an amount of time, called the Event Notification Lease Time. When a Notification Recipient wants to receive Event Notifications, it performs an IPP operation called 'Get-Notifications', which this document defines. This operation causes the Printer to return all Event Notifications held for the Notification Recipient. If the Notification Recipient has selected the option to wait for additional Event Notifications, the Printer continues sending Event Notifications to the Notification Recipient as additional Events occur. The basic set of IPP documents includes: Design Goals for an Internet Printing Protocol [RFC2567] Rationale for the Structure and Model and Protocol for the Internet Printing Protocol [RFC2568] Internet Printing Protocol/1.1: Model and Semantics [RFC2911] Internet Printing Protocol/1.1: E ...