Adapt to changes in HttpClient 5.6

As of 5.6, HttpClient no longer removes the gzip encoding response
header albeit providing an InputStream that's already decoded. This
makes it a odd situation where the response headers advertizes that the
content is gzipped, while the content itself is not.

Talking to one of the maintainers, querying the HttpEntity is a more
idiomatic way of detecting this with HttpClient. This commit does
exactly that, which needs isGzipResponse to be made protected.

See https://issues.apache.org/jira/browse/HTTPCLIENT-2409 for more
details.

Closes gh-1754

See gh-1754

Author: snicoll

spring-ws-core/src/main/java/org/springframework/ws/transport/http/AbstractHttpSenderConnection.java

@@ -109,8 +109,10 @@ protected final InputStream getResponseInputStream() throws IOException {
 		return (isGzipResponse()) ? new GZIPInputStream(inputStream) : inputStream;
 	}
 
-	/** Determine whether the response is a GZIP response. */
-	private boolean isGzipResponse() throws IOException {
+	/**
+	 * Determine whether the response is a GZIP response.
+	 */
+	protected boolean isGzipResponse() throws IOException {
 		Iterator<String> iterator = getResponseHeaders(HttpTransportConstants.HEADER_CONTENT_ENCODING);
 		if (iterator.hasNext()) {
 			String encodingHeader = iterator.next();

spring-ws-core/src/main/java/org/springframework/ws/transport/http/HttpComponents5Connection.java

@@ -143,6 +143,15 @@ protected void onSendAfterWrite(WebServiceMessage message) throws IOException {
 	 * Receiving response
 	 */
 
+	@Override
+	protected boolean isGzipResponse() throws IOException {
+		HttpEntity entity = getHttpEntity();
+		if (entity != null) {
+			return HttpTransportConstants.CONTENT_ENCODING_GZIP.equals(entity.getContentEncoding());
+		}
+		return super.isGzipResponse();
+	}
+
 	@Override
 	protected int getResponseCode() throws IOException {
 		return this.httpResponse.getCode();
@@ -155,28 +164,19 @@ protected String getResponseMessage() throws IOException {
 
 	@Override
 	protected long getResponseContentLength() throws IOException {
-
-		if (this.httpResponse instanceof ClassicHttpResponse response) {
-
-			HttpEntity entity = response.getEntity();
-			if (entity != null) {
-				return entity.getContentLength();
-			}
+		HttpEntity entity = getHttpEntity();
+		if (entity != null) {
+			return entity.getContentLength();
 		}
 		return 0;
 	}
 
 	@Override
 	protected InputStream getRawResponseInputStream() throws IOException {
-
-		if (this.httpResponse instanceof ClassicHttpResponse response) {
-
-			HttpEntity entity = response.getEntity();
-			if (entity != null) {
-				return entity.getContent();
-			}
+		HttpEntity entity = getHttpEntity();
+		if (entity != null) {
+			return entity.getContent();
 		}
-
 		throw new IllegalStateException("Response has no enclosing response entity, cannot create input stream");
 	}
 
@@ -192,4 +192,11 @@ public Iterator<String> getResponseHeaders(String name) throws IOException {
 		return Arrays.stream(this.httpResponse.getHeaders(name)).map(NameValuePair::getValue).iterator();
 	}
 
+	private HttpEntity getHttpEntity() {
+		if (this.httpResponse instanceof ClassicHttpResponse response) {
+			return response.getEntity();
+		}
+		return null;
+	}
+
 }