Response from a POST request in Groovy RESTClient is missing data - groovy

Question

I am using groovy RESTClient 0.6 to make a POST request. I expect an XML payload in the response. I have the following code:
def restclient = new RESTClient('<some URL>')
def headers= ["Content-Type": "application/xml"]
def body= getClass().getResource("/new_resource.xml").text
/*
If I omit the closure from the following line of code
RESTClient blows up with an NPE..BUG?
*/
def response = restclient.post(
path:'/myresource', headers:headers, body:body){it}
println response.status //prints correct response code
println response.headers['Content-Length']//prints 225
println response.data //Always null?!
The response.data is always null, even though when I try the same request using Google chrome's postman client, I get back the expected response body. Is this a known issue with RESTClient?

Answer 1

The HTTP Builder documentation says that data is supposed to contain the parsed response content but, as you've discovered, it just doesn't. You can, however, get the parsed response content from the reader object. The easiest, most consistent way I've found of doing this is to set the default success and failure closures on your RESTClient object like so:
def restClient = new RESTClient()
restClient.handler.failure = { resp, reader ->
[response:resp, reader:reader]
}
restClient.handler.success = { resp, reader ->
[response:resp, reader:reader]
}
You'll get the same thing on success and failure: a Map containing the response (which is an instance of HttpResponseDecorator) and the reader (the type of which will be determined by the content of the response body).
You can then access the response and reader thusly:
def map = restClient.get([:]) // or POST, OPTIONS, etc.
def response = map['response']
def reader = map['reader']
assert response.status == 200

Answer 2

I faced a similar issue and I took the cue from Sams solution but used closures to address it (similar solution but coded using closures instead of the returned object).
resp.data is always null when using the RESTClient, however the reader contains the data, so it would look something like this:
def restclient = new RESTClient('<some URL>')
def headers= ["Content-Type": "application/xml"]
def body= getClass().getResource("/new_resource.xml").text
try {
restclient.post(path:'/myresource', headers:headers, body:body) { resp, reader ->
resp.status // Status Integer
resp.contentType // Content type String
resp.headers // Map of headers
resp.data // <-- ALWAYS null (the bug you faced)
reader // <-- Data you're looking for
}
} catch (Exception e) {
e.response.status // Get HTTP error status Integer
}