REST api’s are being developed for more and more business function. For certain business function once and once only delivery of a message over a REST call is required. Enter Certified Http, an effort led by second life with participation by IBM. It is simple to understand, has a reference implementation in python and they have this to say about their main competition.
These tend to be thoroughly engineered protocol specifications which regrettably repeat the mistakes of the nearly defunct XMLRPC and the soon to join it SOAP — namely, treating services as a function call. This is a reasonable approach, and is probably the most obvious to the engineers working on the problem. The most obvious path, which is followed in both of the examples, is to package a traditional message queue body into an HTTP body sent via POST. Treating web services as function calls severely limits the expressive nature of HTTP and should be avoided.