Do not decompress HTTP responses when compression disabled

This commit refines changes made in spring-projectsgh-35225 so as to not decompress
HTTP responses if decompression support is not enabled.

Closes spring-projectsgh-35225

Author: bclozel

spring-web/src/main/java/org/springframework/http/client/JdkClientHttpRequest.java

@@ -112,7 +112,7 @@ protected ClientHttpResponse executeInternal(HttpHeaders headers, @Nullable Body
 		TimeoutHandler timeoutHandler = null;
 		try {
 			HttpRequest request = buildRequest(headers, body);
-			responseFuture = this.httpClient.sendAsync(request, new DecompressingBodyHandler());
+			responseFuture = this.httpClient.sendAsync(request, this.compression ? new DecompressingBodyHandler() : HttpResponse.BodyHandlers.ofInputStream());
 
 			if (this.timeout != null) {
 				timeoutHandler = new TimeoutHandler(responseFuture, this.timeout);

spring-web/src/test/java/org/springframework/http/client/AbstractMockWebServerTests.java

@@ -116,29 +116,26 @@ else if(request.getTarget().startsWith("/compress/") && request.getBody() != nul
 					String encoding = request.getTarget().replace("/compress/","");
 					String requestBody = request.getBody().utf8();
 					ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
-					if (encoding.equals("gzip")) {
-						try(GZIPOutputStream gzipOutputStream = new GZIPOutputStream(outputStream)) {
-							gzipOutputStream.write(requestBody.getBytes());
-							gzipOutputStream.flush();
-						}
-					}
-					else if(encoding.equals("deflate")) {
+					if(encoding.equals("deflate")) {
 							try(DeflaterOutputStream deflaterOutputStream = new DeflaterOutputStream(outputStream)) {
 							deflaterOutputStream.write(requestBody.getBytes());
 							deflaterOutputStream.flush();
 						}
 					}
+					// compress anyway with gzip
 					else {
-						outputStream.write(requestBody.getBytes());
+						encoding = "gzip";
+						try(GZIPOutputStream gzipOutputStream = new GZIPOutputStream(outputStream)) {
+							gzipOutputStream.write(requestBody.getBytes());
+							gzipOutputStream.flush();
+						}
 					}
 					Buffer buffer = new Buffer();
 					buffer.write(outputStream.toByteArray());
 					MockResponse.Builder builder = new MockResponse.Builder()
 							.body(buffer)
 							.code(200);
-					if (!encoding.isEmpty()) {
-						builder.setHeader(HttpHeaders.CONTENT_ENCODING, encoding);
-					}
+					builder.setHeader(HttpHeaders.CONTENT_ENCODING, encoding);
 					return builder.build();
 				}
 				return new MockResponse.Builder().code(404).build();

spring-web/src/test/java/org/springframework/http/client/JdkClientHttpRequestFactoryTests.java

@@ -110,12 +110,18 @@ void deleteRequestWithBody() throws Exception {
 	@Test
 	void compressionDisabled() throws IOException {
 		URI uri = URI.create(baseUrl + "/compress/");
+		if (this.factory instanceof JdkClientHttpRequestFactory jdkClientHttpRequestFactory) {
+			jdkClientHttpRequestFactory.enableCompression(false);
+		}
 		ClientHttpRequest request = this.factory.createRequest(uri, HttpMethod.POST);
 		StreamUtils.copy("Payload to compress", StandardCharsets.UTF_8, request.getBody());
 		try (ClientHttpResponse response = request.execute()) {
+		assertThat(request.getHeaders().containsHeader("Accept-Encoding")).isFalse();
 			assertThat(response.getStatusCode()).as("Invalid response status").isEqualTo(HttpStatus.OK);
-			assertThat(response.getHeaders().containsHeader("Content-Encoding")).isFalse();
-			assertThat(response.getBody()).as("Invalid request body").hasContent("Payload to compress");
+			assertThat(response.getHeaders().containsHeader("Content-Encoding")).isTrue();
+			assertThat(StreamUtils.copyToString(response.getBody(), StandardCharsets.UTF_8))
+					.as("Body should not be decompressed")
+					.doesNotContain("Payload to compress");
 		}
 	}