Decompressing REST response with GZIPInputStream - grails

Question

I'm trying to decompress a gzip:ed response i receive from a REST service:
Content-Encoding=[gzip], Content-Type=[application/json], Content-Length=[710] ...
I'm using the Grails REST Client Builder Plugin:
def response = new RestBuilder().get(HOST + "/api/..."){
contentType "application/json"
accept "application/json"
}
The returned response is a Spring ResponseEntity. I'm trying to decompress the data using GZIPInputStream:
String body = response.getBody()
new GZIPInputStream(new ByteArrayInputStream(body.getBytes())).text
This fails to Caused by ZipException: Not in GZIP format
Obviously there is something I'm doing wrong, but I can't figure out what. All advice is appriciated.

Answer 1

If you really need to keep using the Rest Client Builder you only need to modify your client code slightly:
def response = new RestBuilder().get(HOST + "/api/..."){
contentType "application/json"
accept byte[].class, "application/json" }
Note the extra parameter in the accept call - byte[].class - which signifies that RestTemplate should refrain from any parsing of the response.
To decompress you can now do:
new GZIPInputStream(new ByteArrayInputStream(response.body))
Yeah, I know, already answered with accept but some might still find it helpful in case switching Rest components is not an option.

Answer 2

I never managed to get it to work with grails / groovy libraries, so i switched to spring and httpcomponents:
HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(HttpClientBuilder.create().build());
RestTemplate restTemplate = new RestTemplate(clientHttpRequestFactory);
ResponseEntity<String> response = restTemplate.exchange(
"some/url/", HttpMethod.GET, new HttpEntity<Object>(requestHeaders),
String.class);
Which decoded gzip automatically and thus there are no longer any need for manual decoding.