Considering a RESTful Approach to Net-Centricity in DoD
Tieu Luu makes a case for the REST architectural style in a recent article, using a Department of Defense’s project, called Net-Centric Data Strategy (NCDS), as an example. He argues that some of the core objectives of NCDS can be more naturally supported by the four basic principles of REST, viz., Uniform Interface, Self-Descriptive Messages, Addressable Resources and Hypermedia as the Engine of Application State.
In 2003 DoD established an enterprise level data strategy, called Net-Centric Data Strategy, which has a set of fairly well defined basic goals. Four of these goals share some common characteristics with the World Wide Web for sharing and utilizing the data within the enterprise. The authors have chosen these four goals of this initiative to illustrate their point:
- Make the Data Visible. This means that all the consumers of the data can discover the existence of that data.
- Make the Data Accessible. This means that the consumers have appropriate authority to access the data.
- Make the Data Understandable. This basically means — make it self-descriptive.
- Support the Unanticipated User. This essentially means no limit on the number of the users, in a style similar to the World Wide Web.
The author goes into detail explaining the existing natural synergy between the REST principles and the NCDS goals. For example, he explains how the REST principle of Uniform Interfaces can naturally support the data accessibility and unanticipated user features of NCDS. He summarizes the coverage of these four goals of NCDS by the above four basic REST principles in a table as shown below:
Alignment with Net-Centric Data Strategy
· All resources exposing the same uniform interface enables ubiquitous access to data
· Supports the unanticipated user since all users anticipated or not access resources through the same uniform interface
· Use of standard representation formats and descriptive metadata enables data to be understandable by a broad audience
· Every resource or piece of data has an addressable URI making it discoverable and thus increases its visibility
· The URI not only allows the resource to be discovered, but also allows it to be accessed
· These URIs also allow information to be linked to provide context to increase understandability
Hypermedia as the Engine of Application State
· This principle of “connectedness” requires resources to contain links to other relevant resources, enabling related resources to be discoverable through each other’s representations
· This connectedness of resources results in a network of information that provides the context to increase understandability
The author also acknowledges those scenarios of DoD in which SOAP and WS-* would be more effective, for instance in an application-to-application integration scenario. He continues to defend his position that he is not positioning REST as a better approach, but simply an alternative that could offer benefits under certain scenarios. In the end he expresses his hope, that is, his article will convince DoD to use REST as well.
InfoQ has published a series of articles, news and presentations covering the REST architectural style as well as the ongoing debate around REST.
Re: Miscredited Author
A Possible Area for REST to play in....
There are roughly 6-8 core capabilities of the Net-Centric infrastructure, from machine-to-machine messaging, to web services, to collaboration, to file sharing.
Most of the current direction has been to build these capabilities with WS-* technologies including strong SAML support. There is a discovery aspect to these set of services, where you register XML metadata for services and
data that you register.
One of the capabilities is called File Based Exposure, this allows users to download files using their browser via normal HTTP URL links. This is a form of REST right?
All the other services are based tightly on WS-* and utilize SAML. Getting the DoD to change from this model to a REST model will happen when the federal budget is balanced or when REST becomes WS-* :^))