Feeds

Day of REST approaches for the cloud

It's a style thing

Protecting against web application threats using SSL

Comment The term REST keeps on popping up when vendors and analysts talk about cloud storage. We're told that RESTful interfaces are more advanced than traditional filer interfaces such as NFS or CIFS. What is REST all about? Let's take a fairly simplistic look at REST, cast an eye in the direction of its advantages over the traditional NAS protocols, and try an overview comparison with Microsoft's SOAP protocol.

REST stands for REpresentational State Transfer and the term was introduced in a University of California at Irvine doctoral thesis by computer scientist Roy Fielding in 2000. The document's abstract states: "REST emphasizes scalability of component interactions, generality of interfaces, independent deployment of components, and intermediary components to reduce interaction latency, enforce security, and encapsulate legacy systems."

Fielding has been involved with authoring Internet standards for HTTP and URIs (Uniform resource Indicators) and his work has received a lot of attention.

His paper charts the development of the REST idea from an initial client-server architecture which decouples client systems from servers and enables clients to talk to different servers and evolve separately from them. This interface became stateless in the sense that servers received requests and had no need to be aware of the situation or state behind the request. They just blindly serve it, with no stored context, and leave the responsibility for maintaining state with the client. Servers don't have to store state between requests and can be more efficient with their resources.

Fielding then says we add a visible cache constraint, with data coming from servers being labelled as cacheable or non-cacheable. Cacheable data can be re-used by client systems for subsequent requests by their users or applications, thus avoiding server access latency. Fielding says that this client-cache-stateless-server architecture was that used by the early world-wide web.

He adds a constraint that there must be a uniform interface between components and this becomes a central feature of REST. He states: "Implementations are decoupled from the services they provide, which encourages independent evolvability." This degrades efficiency as information is transferred in a standard form and not in forms suited to individual applications. REST is designed: "to be efficient for large-grain hypermedia data transfer, optimizing for the common case of the Web, but resulting in an interface that is not optimal for other forms of architectural interaction."

He goes on to define REST by four interface constraints: "identification of resources; manipulation of resources through representations; self-descriptive messages; and, hypermedia as the engine of application state." He then adds: "layered system constraints... the layered system style allows an architecture to be composed of hierarchical layers by constraining component behavior such that each component cannot "see" beyond the immediate layer with which they are interacting."

The benefit of this is that: "Within REST, intermediary components can actively transform the content of messages because the messages are self-descriptive and their semantics are visible to intermediaries."

Finally: "REST allows client functionality to be extended by downloading and executing code in the form of applets or scripts." In summary he says: "REST... gains the separation of concerns of the client-server style without the server scalability problem, allows information hiding through a generic interface to enable encapsulation and evolution of services, and provides for a diverse set of functionality through downloadable feature-engines."

Choosing a cloud hosting partner with confidence

Next page: SOAP and REST

More from The Register

next story
Wanna keep your data for 1,000 YEARS? No? Hard luck, HDS wants you to anyway
Combine Blu-ray and M-DISC and you get this monster
Google+ GOING, GOING ... ? Newbie Gmailers no longer forced into mandatory ID slurp
Mountain View distances itself from lame 'network thingy'
US boffins demo 'twisted radio' mux
OAM takes wireless signals to 32 Gbps
Apple flops out 2FA for iCloud in bid to stop future nude selfie leaks
Millions of 4chan users howl with laughter as Cupertino slams stable door
Students playing with impressive racks? Yes, it's cluster comp time
The most comprehensive coverage the world has ever seen. Ever
Run little spreadsheet, run! IBM's Watson is coming to gobble you up
Big Blue's big super's big appetite for big data in big clouds for big analytics
Seagate's triple-headed Cerberus could SAVE the DISK WORLD
... and possibly bring us even more HAMR time. Yay!
prev story

Whitepapers

Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.
WIN a very cool portable ZX Spectrum
Win a one-off portable Spectrum built by legendary hardware hacker Ben Heck
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
The next step in data security
With recent increased privacy concerns and computers becoming more powerful, the chance of hackers being able to crack smaller-sized RSA keys increases.