I would like to raise this post also. What is the status of LabVIEW REST API?
I'm not sure if you've found what you're looking for or if this helps but there's a toolkit developed by JKI SW, I played around with it and it has all the HTTP commands packed in a nice way.
I'm building an application using it, so far I only used the GET command and it works flawlessly!
Package link: http://jki.net.s3-website-us-east-1.amazonaws.com/tools#easyxml/
JKI's HTTP REST Client is also available directly on NI's Tools Network: HTTP REST Client by JKI
Of course one could also implement a REST client manually using LabVIEW's HTTP Client VIs palette as discussed as second option here: How to Connect to the Tinymesh Cloud Service API?