Blogging Roller

Check out Tim Bray's Atomic Monday post for a summary of recent developments in the world of AtomPub protocol and Atom format. With the uptick in interest in Atom and especially AtomPub protocol's usage in mainstream APIs from Google and Microsoft, I wonder if if would make sense to update RSS and Atom in Action.

The bulk of the book is up-to-date, for what it covers. RSS and Atom haven't really changed and, though the book came out before the spec was finalized, the AtomPub material is basically sound. The ROME material is still current too.

What's missing are all of the new developments: a dozen or more new AtomPub based APIs from Google (GData and OpenSocial) and Microsoft (Live and Astoria) and new tools like Apache Abdera (incubating). Not to mention Windows RSS Platform 2.0 and ROME 1.0 (which is coming soon). Updating the book to cover all of those topics would be quite an endeavor and I'm not sure it's the right approach to covering AtomPub. What do you think?

For Java developers starting out with RSS and Atom, here are some notes to help you figure out the differences between the Java.net ROME and Apache Abdera (incubating) projects.

ROME is a set of Java tools for parsing, fetching and generating all forms of RSS and Atom feeds. The core ROME library is relatively small and depends only on the somewhat creaky old JDOM XML parser. Available separately are modules to support various feed extensions such as OpenSearch, iTunes, GeoRSS, etc. ROME was originally developed and open sourced by Sun Portal dev team members in 2004.

ROME Propono is a subproject of ROME that supports publishing/editing entries and files to blog servers and AtomPub servers. Propono is made up of three parts: 1) a Blog Client library can publish via either the old lagacy MetaWeblog API or the shiny new AtomPub protocol, 2) an AtomPub client that publishes only via AtomPub and 3) a framework for creating AtomPub servers. Propono was developed by Ramesh Mandava and Dave Johnson, based on code from RSS and Atom in Action and open sourced as part of the Sun Web Developer Pack in 2007.

Abdera is a set of Java tools for working with Atom feeds and AtomPub protocol. This includes a parser, writers, an AtomPub client and a framework for creating AtomPub servers. Abdera's Atom feed parser uses STAX, so it uses less memory and is faster than ROME. Abdera's Atom feed support is more comprehensive than ROME's and it supports signatures, encryption, Atom to JSON, extensions for Threading, Paging, GeoRSS, OpenSearch, GoogleLogin, etc. etc. Abdera was developed by IBM and contribued to Apache in 2006.

Now let's compare frameworks. The pros and cons of ROME are:

• Pro: complete RSS support, all of the dozen various flavors
• Pro: it's generally simple and small, depending only one jar (JDOM)
• Pro: easy to understand and use the AtomPub server framework
• Pro: MetaWeblog API support
• Con: Atom feed support not as comprehensive as Abdera
• Con: parser uses lots of memory, slower, JDOM based
• Con: community not as active, seems to be in maintenance mode (See also Ohloh stats)

The pros and cons of Abdera are:

• Pro: comprehensive Atom feed support, lots more Atom extensions
• Pro: faster more efficient parser
• Pro: In the Apache Incubator with active and growing community (See also Ohloh stats)
• Con: lots of dependencies
• Con: AtomPub server framework poorly documented, overly complex (rewrite coming soon)
• Con: no RSS support (there is something in Abdera contrib, but it's incomplete).

There you have it. ROME and Abdera folks: think that's a fair comparison? Are you a ROME or Abdera user? How would you like to see these frameworks move forward?

There have been some interetsing Atom items recently on James Snell's blog. There was a link to a nice IBM DeveloperWorks article on using Abdera to write Atom feeds to JSON. (I was kinda hoping for an XSL/T, but not matter how you do it, it's a definitely feature that belongs in Abdera.) And there's a good quote from Adrian Sutton's blog post about the Atom features in IBM's Roller and Abdera based Lotus Connections product. And most recently, James linked to the new Google Feed Server project: an Abdera based AtomPub server from Google. All good stuff.

Gotta say, Abdera's looking better and better. It's got the features (IRI support, encrytion, pluggable auth, STAX parsing, etc.) and it's got Dan and appears to have some good momentum going. At this rate, I'm not sure how much more work I'll be putting into ROME Propono. If somebody were to, just for example, contribute an Abdera based AtomPub implementation to Roller, I might have to stop entirely.

Another thing I worked on over the winter break was an all-Dave feed, a single page and feed that combines all of the various things that I post to the web: blog entries, Flickr photos, del.icio.us links and Twitter activity. So far, this is what I've got: http://rollerweblogger.org/roller/page/feeds.

Happy New Year to all the readers of this blog and all the folks who happen to have arrived here via one of the various planets, spam blogs and Google search result pages that include it. I hope you all have a prosperous and pleasant year ahead. I'm hoping for the same. It's nice to start the new year with some good news and I've got some; check this out:

RSS and Atom in Action has been out for over a year now and just as the phenomenal sales are starting to drop off, something wonderful has happened. The book has been nominated for the prestigious Stephen T. Colbert Award for Literary Excellence. As you can see in the photo above, at least one copy of the book is already carrying the Colbert nominee seal. Avoid the rush and buy your copy of RSS and Atom in Action now.

Those who have read Colbert's I Am America (And So Can You!) will understand the significance of this important award and understand the impact on future sales of the book. To learn more about the nomination process and criteria, buy yourself a copy of Colbert's book and then flip to page 214½. Cheers!

• snellspace.com: Sync!
  "Within the course of implementing several Atompub servers, the issue of “feed synchronization” has come up repeatedly"
• Paul Fremantle's Blog: A new kind of (SOA) Registry
  "as we looked at the REST space, we kept noticing how close the [AtomPub] is to our needs"


• OpenSocial - Berlin Web 2.0 Expo
  Google API evangelist Pat Chanezon's OpenSocial presentation
• opensocket - Run OpenSocial Gadgets in Facebook
  An OpenSocial container written as a Facebook application.
• Ruby on Rails: OpenSocial container plugin 0.0.1
  "This is a very early version, but it is under very active development "


• IBM's Carol Jones on Web 2.0 Research and Collaborative Software
  Redmonk video discussion of Lotus Connections, Dogear, internal/private vs. external bookmarking
• Wayne Horkan's weblog eclectic: Weblog language translator
  With Roller specific functionality. Based on JavaScript and Google translation API
• ZDNet.com: Social nets and identity fragmentation
  FaberNovel Consulting has mapped out some trends in social networking and digital identity"
• Postgres at Hi5: June 2007 user group preso
  How unique features of PostgreSQL helped Hi5 scale (PDF presentation)
• Scaling Java and PostgreSQL with Hyperic
  Another perspective on PostgreSQL scalability at Hi5 (PDF presentation)
• Skrentablog: Scaling Facebook, Hi5 with memcached
  "discussion of high volume [sites] using memcached as a critical scaling tool"

• Sound Opinions from Chicago Public Radio and American Public Media
  Best podcast ever


• The Aquarium: GlassFish Interim Governance Board - Now Complete
  "The complete roster is Tony, Greg Luck (Wotif.com) and Pierre Delisle (Google), and Simon and myself (Sun)"
• Bistro!: GlassFish/SJS AS in production - which bundle, which profile, ...?
  Explains differences between developer, cluster and enterprise profiles
• GlassFish Podcast: The GlassFish Podcast
  Finally, a Glassfish podcast! Props to Alexis Moussine-Pouchkine
• Apple - Downloads - UNIX & Open Source - GlassFish
  Download Glassfish V2 directly from Apple
• Red Hat and Sun Collaborate to Advance Open Source Java Technology
  "Red Hat has signed Sun's broad contributor agreement that covers participation in all Sun-led open source projects."


• Megginson: First looks at OpenSocial: part 1 (URLs)
  Lists the URIs for the AtomPub collections available in OpenSocial
• Megginson: First looks at OpenSocial: part 2 (members and friends)
  How OpenSocial members and friends are represented in Atom format
• Megginson: First looks at OpenSocial: part 3 (activities)
  How OpenSocial activities are represented in Atom format and manipulated via AtomPub protocol
• Megginson: First looks at OpenSocial: part 4 (persistence data)
  How OpenSocial persistence is implemented via AtomPub protocol
• Google: OpenSocial Container Sample
  Shows "basic demonstration-level OpenSocial container can be implemented"
• Dare Obasanjo: OpenSocial Tech. Overview and Critique
  "Despite these misgivings, I think this is a step in the right direction. Web widget and social graph APIs need to be standardized across the Web."


• snellspace.com: Notes, Part 2
  "lots and lots of things that can be modeled as collections of web resources"
• netzooid: Building Services with AtomPub
  "While APP is not the one true protocol, I think I?m hooked"

Joe Cheng: I’m starting a (hopefully short) series of blog posts documenting the specifics of how the upcoming AtomPub-enabled release of Windows Live Writer will behave, and what AtomPub-enabled blog* servers can do to ensure the best interop with us. I also hope other blog client implementers can learn from our experience and consider using the same rules and behaviors we do when implementing their own AtomPub support.

Very nice. I'll be watching this one closely, looking for ways to improve Roller's and ROME's AtomPub support.

Google Blog Search turned up this nice article on creating custom modules with ROME by Sujit Pal, and a nice mini-review of my book:

Sujit Pal: "However, Dave Johnson's book provides a lot of background information and a lot of nice examples in Java and C#. I would highly recommend it to anyone who needs to get up to speed quickly with ROME and RSS/Atom."

It's good to see people are still buying and finding the book useful. It's been out for over a year now, but I don't think it's really out of date at all. I've been keeping the examples up-to-date as part of the Blogapps project and even enhancing them: the example Atom protocol client code from the book is now part of the ROME Propono project.

The next releases that I'd like to announce are the Blogapps 2.1 Examples and the Blogapps 2.1 Server.

If you'd like to learn more about the Blogapps examples and server then read The Blogapps Project article at Java.net. Here's a quick summary:

The Blogapps project hosts a collection of useful RSS and Atom utilities and examples from RSS and Atom In Action by Dave Johnson. They're designed to be useful even if you haven't read the book and they're available under the Apache License 2.0 so you can use the code in your applications and you can modify and redistribute them as you wish.

What's changed since 2.0? The examples have been updated to include the latest version of ROME Propono, which means that most of them now support the final Atom protcol spec. The server has been updated to include Roller 4.0 RC5, which also includes Atom protocol support and JSPWiki 2.4. And of course, various bugs have been fixed. Here are the release files, installation instructions and release notes.

• Blogapps server install instructions
• Blogapps Server-2.1.tar.gz
• Blogapps-Server-2.1.zip

• Blopapps example release notes
• Blogapps-Examples-2.1.tar.gz
• Blogapps Examples-2.1.zip

This blog entry was posted via Atom protocol and the MatisseBlogger blog-client, which you can see in the screen-shot below (which was also posted via Atom.

What's next? Not sure at this point, but I will do another Blogapps release once ROME 1.0 is released.

The first release to discuss is ROME Propono, which includes a ROME based Atom protocol client library, Atom protocol server framework and an Blog Client library abstraction that supports both Atom protocol and the MetaWeblog API.

I've been working on Propono 0.6 off-and-on since May, keeping it in sync with the latest version of the Atom protocol, testing it against Tim Bray's APE and adding various improvements needed in my other projects. Over the weekend I finally had enough time to get a release out. You can find the full-details at the link below but basically this release adds support for the final Atom Publishing Protocol specification and better support for relative URIs.

• ROME Propono 0.6 release notes / change list
• API documentation
• Propono 0.6 Binary tar.gz
• Propono 0.6 Binary zip
• Propono 0.6 Source tar.gz
• Propono 0.6 Source zip

What's next? Once ROME 1.0 is released Real Soon Now, I'll get a another release out and I'll probably call it ROME Propono 1.0.

Just learned from Tim's blog that Greg Borenstein just came up with a cute logo for the Atom Protocol Exerciser (Ape), which, in case you don't know, is the closest thing we have to a compatibility test for Atom servers. The logo is featured on the Ape's home page.

Second, Tim mentioned that he's updated his Atom Protocol Exerciser (Ape) to support the new Atom protocol namespace and to add a couple of new tests. That's perfect timing for me because I'm starting to work on Roller's APP implementation and some other APP based things.

I need my own local copy of the Ape, so I decided to download the code an get it up and running. To make things easy, I decided to do this work on my Ubuntu system because it's already setup with gcc, cvs, Apache HTTPD and Ruby. For my future reference and to help other Atom fans to get started, here are my notes from my Ape setup experience.

There was quite a flurry of blogging about the Atom Publishing Protocol (APP) over the weekend, all kicked off by Dare Obasanjo's criticisms of the protocol. Some of the posts were critical of Dare and his motives, but I'm thankful he started the conversation. Here's the dump from my del.icio.us account:

• Dare Obasanjo: Why GData/APP Fails as a General Purpose Editing Protocol for the Web - Good only for microcontent, no support for partial updates, poor support for hierarchy and "we [Microsoft] will likely standardize on a different RESTful protocol"

• Bill de hÓra: APP on the Web has failed: miserably, utterly, and completely - APP editor Bill de hÓra responds to Dare's APP critique
  
  
• snellspace.com: Silly: James Snell responds to Dare's APP critique. Cites usage of APP in Lotus Connections.
  
  
• Joe Gregorio: In which we narrowly save Dare from inventing his own publishing protocol: APP editor Joe Gregorio's point-by-point response to Dare's APP criticisms
  
  
• David Megginson: REST, the lost update and the sneakernet test: - "Without exclusive locks, there’s no way to avoid this problem, but it is possible to detect it."
  
  
• Tim Bray: I’ve Seen This Movie: Tim Bray responds to Dare's post: "Microsoft has tried to swim against the current of the Internet a few times before"
  
  
• snellspace.com: Beyond APP - Partial updates: Dare's post inspires James to post a strawman proposal for using HTTP PATCH to implement partial updates w/Atom.
  
  
• Keith Fahlgren: Partial Updates, a simpler strawman: "The basic inspiration is thinking about each operation as an XSLT template"
  
  
• snellspace.com: Partial Updates in APP, Part 2: James responds to Keith's simpler strawman.
  
  
• Dare Obasanjo: GData isn't a Best Practice Implementation of the Atom Publishing Protocol: Dare responds to the flurry of APP posts he kicked off

Atom and LDAP sitting in a tree. Trey Drake has released his OpenDS based Atom store as an open source project on Java.net at http://atom.dev.java.net. It's a directory server distributed as a Java web application that supports both Atom Publishing Protocol (APP) and Lightweight Directory Access Protocol (LDAP).

Signing, encrypting and decrypting Atom. On IBM developerWorks, Nicolas Chase explains how "digital signatures and encryption can easily mesh with Atom data using the Apache Abdera API."

Google GData: A Uniform Web API for All Google Services. Dare Obasanjo praises Google for creating a single uniform and RESTful web services API for eight of its key services, the APP based GData API. He writes "not only is it now possible to create a single library that knows how to talk to all of Google's existing and future Web services since they all use GData. It is also a lot easier to provide 'tooling' for these services than it would be for Yahoo's family of Web services given that they use a simple and uniform interface."

RESTful web services support in Netbeans. Geertjan links to blog entries and a screen-cast that explain Netbeans 6.0 support for RESTful web services, including the early access JSR-311 REST API.

Generate code from your WADL REST API. Eduardo at The Aquarium links to Thomas Steiner who is making progress on a WADL editor and a generator, bringing WSDL-like code generation to RESTful web services.

Is it this http://cyber.law.harvard.edu/rss/rss.html, promoted by Dave Winer?

This http://www.rssboard.org/rss-specification, from the RSS advisory board?

Or one of the other dozen or so incompatible formats.

It doesn't really matter. There's only one Atom: RFC-4287.

Hat tip to Sam Ruby.

German Viscuso: Generally spoken GData provides a general interface to make information available even beyond a browser context by providing a single API that could be used to query, update, and index structured data anywhere on the web. Could GData become a simple and open replacement for all the proprietary communications protocols currently in use by database vendors?

As usual, I'm enjoying JavaOne and meeting lots of new people and putting faces to names. I've also been practicing my talk daily so I can give you my best performance, so eat lunch a little early or a little late and come see how it goes. Here are the details:

• TS-6029 - Beyond Blogging: Feeds in Action
• Friday 05/11/2007  12:10 PM -1:10 PM
• Moscone Center Esplanade 307 / 310

Trey Drake: How do you demo a directory server? Build cool apps around it. To that end, we've built an Atom/APP server, a lightweight OpenID server, a blogging and "twitter" like app - all powered by OpenDS. Drop by our booth (Glassfish alley at CommunityONE and .org section of the pavilion during JavaONE). Ludo and I will introduce OpenDS and show off the demos in two talks; today at CommunityONE at 5PM and Wednesday at 1:30 in the CommunityCorner.

Very cool. I'm not going to be the only one talking about Atom protocol at JavaOne. I'll have to stop by the CommunityCorner, that sounds too good to miss.