From 2596deb834c77df776d38378326ec15bc282bd64 Mon Sep 17 00:00:00 2001
From: Mark Hobson <markhobson@gmail.com>
Date: Sat, 14 Jul 2018 13:04:13 +0100
Subject: [PATCH] Preserve media type parameters when setting charset

Issue: SPR-17040
---
 .../AbstractWireFeedHttpMessageConverter.java |  2 +-
 .../AtomFeedHttpMessageConverterTests.java    | 18 ++++++++++++++++
 .../RssChannelHttpMessageConverterTests.java  | 21 +++++++++++++++++++
 3 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/spring-web/src/main/java/org/springframework/http/converter/feed/AbstractWireFeedHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/feed/AbstractWireFeedHttpMessageConverter.java
index e196db666b2a..424a6d9f5d38 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/feed/AbstractWireFeedHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/feed/AbstractWireFeedHttpMessageConverter.java
@@ -90,7 +90,7 @@ protected void writeInternal(T wireFeed, HttpOutputMessage outputMessage)
 				Charset.forName(wireFeed.getEncoding()) : DEFAULT_CHARSET);
 		MediaType contentType = outputMessage.getHeaders().getContentType();
 		if (contentType != null) {
-			contentType = new MediaType(contentType.getType(), contentType.getSubtype(), charset);
+			contentType = new MediaType(contentType, charset);
 			outputMessage.getHeaders().setContentType(contentType);
 		}
 
diff --git a/spring-web/src/test/java/org/springframework/http/converter/feed/AtomFeedHttpMessageConverterTests.java b/spring-web/src/test/java/org/springframework/http/converter/feed/AtomFeedHttpMessageConverterTests.java
index 1d7af4d85e42..2c82594a02a1 100644
--- a/spring-web/src/test/java/org/springframework/http/converter/feed/AtomFeedHttpMessageConverterTests.java
+++ b/spring-web/src/test/java/org/springframework/http/converter/feed/AtomFeedHttpMessageConverterTests.java
@@ -24,7 +24,9 @@
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import com.rometools.rome.feed.atom.Entry;
 import com.rometools.rome.feed.atom.Feed;
@@ -39,6 +41,8 @@
 import org.springframework.http.MockHttpInputMessage;
 import org.springframework.http.MockHttpOutputMessage;
 
+import static java.util.Collections.singletonMap;
+
 /**
  * @author Arjen Poutsma
  */
@@ -130,4 +134,18 @@ public void writeOtherCharset() throws IOException, SAXException {
 				outputMessage.getHeaders().getContentType());
 	}
 
+	@Test
+	public void writeOtherContentTypeParameters() throws IOException {
+		Feed feed = new Feed("atom_1.0");
+
+		MockHttpOutputMessage outputMessage = new MockHttpOutputMessage();
+		converter.write(feed, new MediaType("application", "atom+xml", singletonMap("type", "feed")), outputMessage);
+
+		Map<String, String> expectedParameters = new HashMap<>();
+		expectedParameters.put("charset", "UTF-8");
+		expectedParameters.put("type", "feed");
+		assertEquals("Invalid content-type", new MediaType("application", "atom+xml", expectedParameters),
+				outputMessage.getHeaders().getContentType());
+	}
+
 }
diff --git a/spring-web/src/test/java/org/springframework/http/converter/feed/RssChannelHttpMessageConverterTests.java b/spring-web/src/test/java/org/springframework/http/converter/feed/RssChannelHttpMessageConverterTests.java
index 80e3a4d21bf3..e8e793b14621 100644
--- a/spring-web/src/test/java/org/springframework/http/converter/feed/RssChannelHttpMessageConverterTests.java
+++ b/spring-web/src/test/java/org/springframework/http/converter/feed/RssChannelHttpMessageConverterTests.java
@@ -23,7 +23,9 @@
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import com.rometools.rome.feed.rss.Channel;
 import com.rometools.rome.feed.rss.Item;
@@ -36,6 +38,8 @@
 import org.springframework.http.MockHttpInputMessage;
 import org.springframework.http.MockHttpOutputMessage;
 
+import static java.util.Collections.singletonMap;
+
 /**
  * @author Arjen Poutsma
  */
@@ -133,6 +137,23 @@ public void writeOtherCharset() throws IOException, SAXException {
 				outputMessage.getHeaders().getContentType());
 	}
 
+	@Test
+	public void writeOtherContentTypeParameters() throws IOException {
+		Channel channel = new Channel("rss_2.0");
+		channel.setTitle("title");
+		channel.setLink("http://example.com");
+		channel.setDescription("description");
+
+		MockHttpOutputMessage outputMessage = new MockHttpOutputMessage();
+		converter.write(channel, new MediaType("application", "rss+xml", singletonMap("x", "y")), outputMessage);
+
+		Map<String, String> expectedParameters = new HashMap<>();
+		expectedParameters.put("charset", "UTF-8");
+		expectedParameters.put("x", "y");
+		assertEquals("Invalid content-type", new MediaType("application", "rss+xml", expectedParameters),
+				outputMessage.getHeaders().getContentType());
+	}
+
 	private static CompareMatcher isSimilarTo(final String content) {
 		return CompareMatcher.isSimilarTo(content)
 				.ignoreWhitespace();