Emerging Technologies for the Enterprise 2011

Jon Moore - Chief Engineer, Comcast Interactive Media

REST is the new “black” in web API development RESTful APIs are all the rage due to the great scalability and simplicity of the REST architecture in general. Most folks are familiar with many of the REST constraints, often paraphrased as “everything is a resource” and “use HTTP as your application protocol” (read with GET, update with PUT, add with POST, etc.). However, Roy Fielding’s thesis also mentions a less commonly seen and understood constraint: using “hypermedia as the engine of application state.” In this talk, we’ll explain what this constraint means and show how it can provide an architecture with looser coupling between clients and servers – making it possible to upgrade the server without breaking clients (or, seen another way, making clients more robust to server-side changes). We’ll show an example API that uses XHTML as the media type (rather than the usual JSON or XML suspects) and talk about how this aids with API discoverability. Finally, watch as we do some live coding during the talk to carry out multiple server side upgrades without breaking a pre-compiled client, evolving a very chatty protocol into one that makes fewer, coarser HTTP requests, again, without requiring client-side changes.