Going from SOAP to REST Web Services

I received a questions in my email today from blog reader, Rob Rawlins:

A client of mine wants me to change the SOAP web service I publish into a REST service, and I dont even know where to begin.

After googling around for a while you're one of the only people I could find mentioning ColdFusion and REST in the same sentence :-D

Any ideas on where I should be beginning with this?

It's a good question, and I'm not surprised that there isn't a whole lot on the internet about ColdFusion and REST, since it is so easy to create SOAP web services in CFML. So I thought this would make a good blog entry...

To start it is essential to understand what the differences between the REST architecture and the SOAP architecture are. I've written a blog entry called REST vs SOAP Web Services which should give you a primer. For more details I would check out Roger Costello's Building Web Services the REST Way.

My next step would be to take a look at some actual REST web services that are popular, and well designed. If you are a visual learner like me this is an easy way to understand how they work.

• Flickr API - Flickr has API's using REST, SOAP, and XML-RPC so it's a good one to see the differences.
• Yahoo API's - Many of the Yahoo API's use REST.
• 37Signals API's - Basecamp, Backpack, Highrise all use the REST approach.

Once you have translated all the SOAP method requests into an REST request requests implementing the service should not be that difficult. Just invoke your SOAP component methods locally, and format the response in XML.

Before I had a chance to post this entry Rob has already implemented his REST service, and said:

Coincidentally I've already worked on my own solution which seems to be working nicely. I simply created a 'wrapper' for my current SOAP webservice, that uses <cfinvoke> to invoke the webservice with the POST data sent by the REST call, and then reformat the XML data ready to be parsed, I hadn't realized how simple it was, its actualy of benefit too me as it allows a more OO development approach to the service, and also makes for a much lower overhead and bandwidth.

The new service is super snappy, I'm very pleased.