Agile Ajax

Ext JS 2.1 Now GPL (was LGPL)

One thing I overlooked with the release of Ext JS 2.1 is that it is now GPL rather than LGPL. That means that if you build Ext JS 2.1 into your app, it would have to be GPL's if you planned to distribute it. (See this flame thread on the extjs forum).

Not a problem if you are providing a service, but if you are distributing the application, then you are GPL infected.

If we look at part of the GPL v2:

These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.

Now IANAL, but if you distribute a stub application with at least 2 UI implementations that can be downloaded and installed separately, you might be OK. Another argument for designing your applications as service providers that can be accessed by multiple different clients. That way you can change UI frameworks as necessary, such as when your current framework changes open source licenses.

Recent Ajax Framework Releases/Developments

Some noteworthy Ajax Framework releases have come out in the last few weeks, along with some other news of interest:

• Ext JS 2.1 and Ext GWT 1.0 Beta - Better performance, new Slider, StatusBar components. REST support (support for other HTTP methods beyond POST and GET). The Ext GWT 1.0 Beta consummates the love affair between GWT (Google Web Toolkit) and Ext that was started by gwt-ext and MyGWT, but provides the comfort of knowing that it is supported by the Ext JS folks. Note: Ext GWT is pure GWT, not an Ext JS wrapper.
• Dojo 1.1 - First off, API compatibility between 1.0 and 1.1. Unified timing loop (ala Scriptaculous) for animation effects, with increased performance. Syntactic improvements to dojo.query. Unification of XHR functionality into dojo.xhr() function.
• Backbase Enterprise Ajax 4.2 - Backbase has been in the commercial framework game longer than almost anyone. Among the new features: hierarchical data bindings and improved performance. If you've wanted data binding for tree widgets, have a look.
• Google Search, Feed and Translation API - I opined a while back that Google discontinued their SOAP search API because they didn't want people reordering or otherwise manipulating their search results. Looking at the terms of use of the new REST service, you can see that this continues to be a concern:  You agree that you will not, and you will not permit your users or other third parties to: (a) modify or replace the text, images, or other content of the Google Search Results, including by (i) changing the order in which the Google Search Results appear...
• Google App Engine - it only runs Python apps right now, and it's a preview release available to a select few, but you can already see that this is Google's challenge to Amazon's EC2 compute cloud. In at most a year, unless you are security sensitive -- health care, financial services -- or running on Windows, you won't be building and maintaining data centers. The capital requirements for launching sophisticated and scalable online services is about to change.
• Echo3 (beta) - it's getting close. Superior performance to Echo2. Easier development of new components. Automatic serialization of objects between client and server. All HTML rendering now done on client. Overall the JavaScript client code is now of a design quality on par with the server code.

Lots of exciting developments for Ajax developers and Web 2.0 entrepreneurs. I, for one, can't wait to see how the Google App Engine compares to EC2 for deploying and scaling Facebook applications.

Technorati Tags: ajax, dojo, google app engine, gwt, ext js, backbase, echo3, google search

Release of GWT Ext 2.0

Yep, two of my favorite things just got better. The new GWT Ext 2.0 was released with support for Ext 2.0 (is that what the "2.0" means?). You can find the release notes here and a demo here. For those of you who have been stuck under a rock for the last year, GWT is the toolkit from Google that lets you write your Ajax apps as Java which is then compiled into JavaScript. And Ext JS is the super slick, good looking Ajax framework that is sweeping the nation.

Technorati Tags: ajax, gwt, ext

All guns blazing on Ext JS 2.0

The day has finally arrived: Ext JS 2.0 received its final public release today. Judging by the timeouts I've been getting all morning when trying to connect to the Ext site and blog, I'm not the only one who's been waiting anxiously. Originally tied to the YUI framework but now a standalone library, Ext provides the best example I've yet seen of a completely client-side framework for desktop-style RIAs.

As Ajax libraries multiply, they need to differentiate themselves to get my attention. Ext does just that, providing a top-to-tails solution for GUI components: tabs, trees, grids, you name it. Prototype, jQuery, Mootools and Dojo provide powerful general-purpose tools for Ajax development. Ext, on the other hand, uses a component model whose baseline configuration gets you 90% of the way there and whose extensibility gets you the rest of the way. It's a huge achievement that Ext does so while embracing Web standards and user experience design. You don't use Ext to sprinkle a little Ajax on your Web 1.0 application; you use it to build powerful, data-centric applications from the ground up without relying on GWT or .Net to write your JavaScript for you.

For the example application I'm building to show off Really Simple History, I'm constructing parallel versions with Prototype, jQuery and Ext. Frankly, it's the Ext version that I'm most excited to show off. I've been waiting patiently for a couple of months to find a hole in the schedule of busy Ext creator Jack Slocum. Now that Ext 2.0 is out there, I hope to publish an interview with him in this space soon.

With the Ext servers struggling to meet demand, you may have trouble trying to download the library, read the announcement or peruse the completely overhauled documentation. In the meantime, you can read this exhaustive Ajaxian post about all of the changes and new capabilities.

Technorati Tags

• Ext
• JavaScript
• Ajax

New Ajax for Old Iron

In the rush to develop entirely new Web 2.0 systems based on Ajax, it is often easy to lose sight of how it can be used to improve the so-called "legacy" enterprise systems. Over at the Ext JS blog, there's a post about German developer who put together a reporting/BI application to front-end RPG code running on an AS400.


The backend serves up JSON data (together with this old article about reskinning a Spring MVC application with Tibco GI, it makes for a solid approach for refactoring existing webapps) to the Ext JS/Flash front-end. Slick. You can view a demo (unfortunately in German for you non-German speakers) here.



Technorati Tags: ajax, ext js, as400, flash, json