Important: This document does not represent best practices for current development. Links to downloads and other resources may no longer be valid.
Introduced in OS X v10.5, Publication Subscription is a technology that offers developers a way to subscribe to web feeds from their applications. Web feeds are documents that contains frequently updated information. You can use Publication Subscription to allow your applications to subscribe to podcasts, photocasts, and any other feed-based document. Plus, Publication Subscription handles all the feed downloads and updates automatically. This document explains how feeds work and how to use them in your application.
Before reading this document, you should have some experience with Objective-C and be familiar with XML.
Organization of This Document
This book contains the following chapters:
Understanding Feeds describes what feeds are and how they work.
Publication Subscription Overview explains the architecture of Publication Subscription.
Subscribing to a Feed explains how to use Publication Subscription to subscribe to a feed.
Viewing and Retrieving Content describes how to read the data in a feed.
For an in-depth description of the Publication Subscription framework, read:
Publication Subscription Framework Reference
For more information about some of the technology areas used by Publication Subscription, refer to:
Core Foundation Design Concepts to learn more about the Cocoa design patterns
Tree-Based XML Programming Guide to learn more about XML and how to use it in Cocoa
There are also a number of good websites about the different feed standards supported by Publication Subscription:
For more information about the RSS 0.9, RSS 1.0 and RSS 2.0 formats, read http://en.wikipedia.org/wiki/Really_Simple_Syndication.
For more information about the Atom Syndication Format, read http://en.wikipedia.org/wiki/Atom_%28standard%29.