Verify that the stream is more than ZERO bytes before un-gzipping

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/post/SendResponseFilter.java

@@ -125,6 +125,10 @@ public class SendResponseFilter extends ZuulFilter {
 					// before sending to client
 					// else, stream gzip directly to client
 					if (context.getResponseGZipped() && !isGzipRequested) {
+						// If origin tell it's GZipped but the content is ZERO bytes,
+						// don't try to uncompress
+						final Long len = context.getOriginContentLength();
+						if (len == null || len > 0) {
 							try {
 								inputStream = new GZIPInputStream(is);
 							}
@@ -138,6 +142,10 @@ public class SendResponseFilter extends ZuulFilter {
 								inputStream = is;
 							}
 						}
+						else {
+							// Already done : inputStream = is;
+						}
+					}
 					else if (context.getResponseGZipped() && isGzipRequested) {
 						servletResponse.setHeader(ZuulHeaders.CONTENT_ENCODING, "gzip");
 					}