CIT 383: Administrative Scripting

1. RSS CIT 383: Administrative Scripting CIT 383: Administrative Scripting

2. CIT 383: Administrative Scripting Topics • Web Feeds • Aggregators • RSS • Atom • Feeds in Ruby

3. CIT 383: Administrative Scripting Web Feeds A web feed is a data format used for providing users with frequently updated information, like weather, news, comments. • Content providers syndicate a web feed by providing it via a URL on their web site. • Readers subscribe to a web feed to get updates. • Software like RSS Bandit or Google Reader aggregate multiple web feeds in a single interface so user does not have to visit sites to check for updates manually.

4. CIT 383: Administrative Scripting What data is available via feeds? • Blogs • Blog comments • Tagged blog entries • Music • News • Pictures (from Flickr) • Social networking sites • Transport schedules (Google Transit) • Videos • Weather

5. CIT 383: Administrative Scripting Web Feeds User pulls content from provider. Provider doesn’t know user e-mail. Unsubscribe by configuring client. E-mail Provider pushes content to user. Provider has user e-mail address. Unsubscribe by contacting provider. Feeds vs E-mail

6. CIT 383: Administrative Scripting Aggregators

7. CIT 383: Administrative Scripting Browser Firefox (live bookmarks) Firefox Sage add-on IE 7 Opera Standalone Akregator BottomFeeder Liferea RSS Bandit Online AmphetaDesk Bloglines Fastladder Google Reader Indirect iGoogle MyYahoo sidebars Aggregators

8. CIT 383: Administrative Scripting Web Feed Formats Web feeds include both content and metadata Content: Title, link, full or summarized text Metadata: Author, publication date XML-data formats Atom RSS

9. CIT 383: Administrative Scripting RSS Variants RSS-DEV Working Group RDF Site Summary 0.90 from Netscape RDF Site Summary 1.0 Harvard’s Berkman Center Rich Site Summary 0.91 from Netscape Really Simple Syndication 2.0

10. CIT 383: Administrative Scripting RSS 1.0 Example

11. CIT 383: Administrative Scripting Atom Alternative to RSS, published as RFC 4287. Features: • Requires title, unique ID, and last updated time. • Payload container specifies content type • Plain text • Escaped or well-formed HTML • Base64-encoded binary data • Separate summary and content elements. • Standardizes feed autodiscovery.

12. CIT 383: Administrative Scripting Atom Example

13. CIT 383: Administrative Scripting Ruby Feeds RSS • Part of Ruby core library. • Parses and writes RSS. FeedTools • Available as a gem. • Parses Atom and RSS. • Can convert between Atom and RSS versions. Rails • Can write Atom and RSS feeds.

14. CIT 383: Administrative Scripting FeedTools require ‘feed_tools’ url = ‘http://www.pragprog.com/podcasts/feed.rss’ feed = FeedTools::Feed.open(url) feed.entries.each_with_index do |entry,i| puts “#{i} #{entry.title}” end

15. CIT 383: Administrative Scripting References • Michael Fitzgerald, Learning Ruby, O’Reilly, 2008. • David Flanagan and Yukihiro Matsumoto, The Ruby Programming Language, O’Reilly, 2008. • Hal Fulton, The Ruby Way, 2nd edition, Addison-Wesley, 2007. • Robert C. Martin, Clean Code, Prentice Hall, 2008. • Dave Thomas with Chad Fowler and Andy Hunt, Programming Ruby, 2nd edition, Pragmatic Programmers, 2005.