Developers looking to implement scalable REST-based Web APIs often have to decide whether to define an application-specific REST interface, or whether to piggyback REST-style message exchange on some other, higher-level data exchange protocol. The protocol increasingly mentioned in the context of the latter solution is Atom. In a recent blog post, for instance, David Van Couvering listed several reasons to use Atom for publishing REST-based services.

While the jury is still out as to whether Atom, or some other high-level publishing protocol is the route to RESTful API bliss, those using Atom for that purpose will find a new java.net project, ROME Propono useful:

ROME Propono provides client and server libraries for web publishing via the IETF Atom Publishing Protocol (APP) and the XML-RPC based MetaWeblog API. It provides:

• Atom Publishing Protocol (APP) client library, which makes it easy for your Java client and server applications to interact with APP services.
• Atom Publishing Protocol server framework, which makes it possible for you to add APP server capabilties to your Java web applications.
• Atom Publishing Protocol file-server sample: a simple file-based APP implementation that stores Atom entries and associated media files in a directory strcuture within your webapp's context directory.
• Blog Client library, which makes it easy for your Java client and server applications [to] interact with blog servers that support either MetaWeblog API or APP.

The ROME Propono client and server libraries each depend on a common Atom-specific API, which is part of the ROME project.

What are your preferred ways to implement REST-based Web APIs? Do you see value in using Atom for REST-based services?