Preserve upstream character encoding. Only default to UTF-8 if not set.

fixes gh-530

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

@@ -92,13 +92,15 @@ public class SendResponseFilter extends ZuulFilter {
 			return;
 		}
 		HttpServletResponse servletResponse = context.getResponse();
-		servletResponse.setCharacterEncoding("UTF-8");
+		if (servletResponse.getCharacterEncoding() == null) { // only set if not set
+			servletResponse.setCharacterEncoding("UTF-8");
+		}
 		OutputStream outStream = servletResponse.getOutputStream();
 		InputStream is = null;
 		try {
 			if (RequestContext.getCurrentContext().getResponseBody() != null) {
 				String body = RequestContext.getCurrentContext().getResponseBody();
-				writeResponse(new ByteArrayInputStream(body.getBytes()), outStream);
+				writeResponse(new ByteArrayInputStream(body.getBytes(servletResponse.getCharacterEncoding())), outStream);
 				return;
 			}
 			boolean isGzipRequested = false;

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/post/SendResponseFilterTests.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2013-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.netflix.zuul.filters.post;
+
+import java.io.ByteArrayInputStream;
+import javax.servlet.http.HttpServletRequest;
+
+import com.netflix.zuul.context.RequestContext;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.web.util.WebUtils;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * @author Spencer Gibb
+ */
+public class SendResponseFilterTests {
+
+	@Before
+	public void setTestRequestcontext() {
+		RequestContext context = new RequestContext();
+		RequestContext.testSetCurrentContext(context);
+	}
+
+	@After
+	public void reset() {
+		RequestContext.getCurrentContext().clear();
+	}
+
+	@Test
+	public void runsNormally() throws Exception {
+		String characterEncoding = null;
+		String content = "hello";
+		runFilter(characterEncoding, content, false);
+	}
+
+	@Test
+	public void characterEncodingNotOverridden() throws Exception {
+		String characterEncoding = "UTF-16";
+		String content = "\u00a5";
+		runFilter(characterEncoding, content, true);
+	}
+
+	private void runFilter(String characterEncoding, String content, boolean streamContent) throws Exception {
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		SendResponseFilter filter = createFilter(content, characterEncoding, response, streamContent);
+		assertTrue("shouldFilter returned false", filter.shouldFilter());
+		filter.run();
+		String encoding = RequestContext.getCurrentContext().getResponse().getCharacterEncoding();
+		String expectedEncoding = characterEncoding != null ? characterEncoding : WebUtils.DEFAULT_CHARACTER_ENCODING;
+		assertThat("wrong character encoding", encoding, equalTo(expectedEncoding));
+		assertThat("wrong content", response.getContentAsString(), equalTo(content));
+	}
+
+	private SendResponseFilter createFilter(String content, String characterEncoding, MockHttpServletResponse response, boolean streamContent) throws Exception {
+		HttpServletRequest request = new MockHttpServletRequest();
+		RequestContext context = new RequestContext();
+		context.setRequest(request);
+		context.setResponse(response);
+
+		if (characterEncoding != null) {
+			response.setCharacterEncoding(characterEncoding);
+		}
+
+		if (streamContent) {
+			context.setResponseDataStream(new ByteArrayInputStream(content.getBytes(characterEncoding)));
+		} else {
+			context.setResponseBody(content);
+		}
+
+		context.addZuulResponseHeader(HttpHeaders.CONTENT_LENGTH, String.valueOf(content.length()));
+
+		context.set("error.status_code", HttpStatus.NOT_FOUND.value());
+		RequestContext.testSetCurrentContext(context);
+		SendResponseFilter filter = new SendResponseFilter();
+		return filter;
+	}
+
+}