As ComputerWorld reported in April, RIA vendor Curl has taken on Adobe AIR with an extension to its RIA environment called Nitro. Curl calls Nitro a "Fit Client"; I'm not exactly sure what that's supposed to mean, but this is how they describe it:
Nitro provides the essential capabilities of the Fit Client such as support for rich user interfaces, complex application logic, and agile development. Curl has enhanced its desktop capabilities with the following new features:
- Applet installer and desktop controls - Curl applets can be installed on the desktop for online and offline operation in a secure sandbox. The installer creates shortcuts on the desktop and start menu with customizable icons and a skinnable user interface.
- Client-side database - Nitro enables developers to build applications with local databases using the popular open source SQLite database engine combined with standard Curl techniques for data presentation and manipulation.
- Demo applets - These Web-enabled applications run standalone on the desktop, update when connected and provide real business value to enterprises.
- Desktop security model - With Nitro, desktop applications use the same security model as Curl applets. They run in a secure sandbox with local data access but limited system privileges. Curl applications can also be fully privileged applications, which require a standard digital signature provided by an established certification authority -- self-signing is not allowed.
Source code is available for both applications. Before trying to run either sample, download and install the Nitro runtime and/or the Nitro IDE.
Nitro isn't restricted to Curl: it "embraces and extends" Ajax, Flash, and Flex: