Thursday, June 6, 2013

Getting Postman to test Restlet

Postman is a wonderful Chrome application for testing REST method calls. However it was a bit hard to get it to work for testing Rest calls with my Restlet server. Here are the gotchas I faced and havent yet figured them out completely. I love to record them so I can come back much later and they are still here ;)

Postman does not add the Content-Type header by itself. If you select an HTTP method which allows a body (e.g POST), it allows you to create the body and select the format (JSON/XML etc) but you must remember to add the Content-Type header.
If your application requires authentication, you can add that too. Postman supports basic, digest as well as OAuth (which I would love to test out next).
The biggest problem I ran into was when I sent XML or JSON body and the Restlet server replied back with 415 - Unsupported Media Type. The request does not even hit my application side! If you write a client application and choose the Media Type of MediaType.APPLICATION_XML and the server side method is annotated by @Post("txt:xml") it works. However, when you set the Content-Type header in Postman to application/xml it does not work. To debug this further, I installed wireshark and dumped the packet contents. I was surprised to find that the client built using Restlet framework was sending a Content-Type header as text/plain. This had to be some issue on my end. Interestingly, if I made the corresponding changes in Postman, the request coming out from that application also started to work. These are the two headers I inserted. Note that a Content-Type of text/plain still does not work. You must indicate the charset as well to make it work.

Content-Type: text/plain; charset=UTF-8

Accept: application/xml

About Tukeys

Tukeys provides consulting and software services to companies in healthcare and communications that are dealing with technical or scaling challenges. Please reach out to me on LinkedIn.

An interesting quote from John Tukey, who was an American mathematician (1915-2000) -

An approximate answer to the right problem is worth a good deal more than an exact answer to an approximate problem.

Today maths and statistics form the basis of how software is developed and used around us.

About Me

Medhavi I have over 20 years of experience in healthcare, communications and AI.

I have a passion for defining innovative applications, creating product/technology strategy and solving challenging problems. My product mindset is helpful to any company to find patterns, reduce costs, and gain efficiencies.

I was the VP of Engineering at Vibrent Health, where I led the web, mobile, API and data products that supported one of the largest NIH programs - All of Us Research Program. Our system enrolled almost a million users and collected data from EHRs, surveys and wearables. Before that, I worked at hCentive, a pioneer in health exchanges.

As the CTO of 3CLogic, I helped create the first PC and web-only contact center solution that implemented PBX and CRM functionality as an affordable SaaS solution. As the Chief Architect of NexTone, I was instrumental in the development of SIP and SIP based products. SIP and associated protocols form the basis of modern WebRTC APIs.

If you are a growth company or invest in growing companies that are facing technical or scaling challenges, I can be a tremendous help. Contact me on LinkedIn.