SPR-7706 - 304 responses should not have non-0 Content-Length

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java

@@ -5,7 +5,7 @@
  * 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
+ * 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,
@@ -121,11 +121,11 @@ public class ResourceHttpRequestHandler extends WebContentGenerator implements H
 		}
 
 		// header phase
-		setHeaders(response, resource, mediaType);
 		if (new ServletWebRequest(request, response).checkNotModified(resource.lastModified())) {
 			logger.debug("Resource not modified - returning 304");
 			return;
 		}
+		setHeaders(response, resource, mediaType);
 
 		// content phase
 		if (METHOD_HEAD.equals(request.getMethod())) {

org.springframework.web/src/main/java/org/springframework/web/filter/ShallowEtagHeaderFilter.java

@@ -5,7 +5,7 @@
  * 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
+ * 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,
@@ -69,7 +69,6 @@ public class ShallowEtagHeaderFilter extends OncePerRequestFilter {
 				if (logger.isTraceEnabled()) {
 					logger.trace("ETag [" + responseETag + "] equal to If-None-Match, sending 304");
 				}
-				response.setContentLength(0);
 				response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
 			}
 			else {
@@ -89,8 +88,8 @@ public class ShallowEtagHeaderFilter extends OncePerRequestFilter {
 	}
 
 	private void copyBodyToResponse(byte[] body, HttpServletResponse response) throws IOException {
-		response.setContentLength(body.length);
 		if (body.length > 0) {
+			response.setContentLength(body.length);
 			FileCopyUtils.copy(body, response.getOutputStream());
 		}
 	}
@@ -113,7 +112,7 @@ public class ShallowEtagHeaderFilter extends OncePerRequestFilter {
 	/**
 	 * Generate the ETag header value from the given response body byte array.
 	 * <p>The default implementation generates an MD5 hash.
-	 * @param bytes the response bdoy as byte array
+	 * @param bytes the response body as byte array
 	 * @return the ETag header value
 	 * @see org.springframework.util.DigestUtils
 	 */
@@ -168,6 +167,10 @@ public class ShallowEtagHeaderFilter extends OncePerRequestFilter {
 			this.statusCode = sc;
 		}
 
+		@Override
+		public void setContentLength(int len) {
+		}
+
 		@Override
 		public ServletOutputStream getOutputStream() {
 			return this.outputStream;

org.springframework.web/src/test/java/org/springframework/web/filter/ShallowEtagHeaderFilterTests.java

@@ -1,11 +1,11 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2010 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
+ * 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,
@@ -23,7 +23,6 @@ import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletResponse;
 
-import static org.junit.Assert.*;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -31,6 +30,8 @@ import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.util.FileCopyUtils;
 
+import static org.junit.Assert.*;
+
 public class ShallowEtagHeaderFilterTests {
 
 	private ShallowEtagHeaderFilter filter;
@@ -87,6 +88,7 @@ public class ShallowEtagHeaderFilterTests {
 				assertEquals("Invalid request passed", request, filterRequest);
 				byte[] responseBody = "Hello World".getBytes("UTF-8");
 				FileCopyUtils.copy(responseBody, filterResponse.getOutputStream());
+				filterResponse.setContentLength(responseBody.length);
 			}
 		};
 
@@ -94,7 +96,7 @@ public class ShallowEtagHeaderFilterTests {
 
 		assertEquals("Invalid status", 304, response.getStatus());
 		assertEquals("Invalid ETag header", "\"0b10a8db164e0754105b7a99be72e3fe5\"", response.getHeader("ETag"));
-		assertEquals("Invalid Content-Length header", 0, response.getContentLength());
+		assertFalse("Response has Content-Length header", response.containsHeader("Content-Length"));
 		assertArrayEquals("Invalid content", new byte[0], response.getContentAsByteArray());
 	}
 
@@ -120,7 +122,7 @@ public class ShallowEtagHeaderFilterTests {
 
 		assertEquals("Invalid status", 304, response.getStatus());
 		assertEquals("Invalid ETag header", "\"0b10a8db164e0754105b7a99be72e3fe5\"", response.getHeader("ETag"));
-		assertEquals("Invalid Content-Length header", 0, response.getContentLength());
+		assertFalse("Response has Content-Length header", response.containsHeader("Content-Length"));
 		assertArrayEquals("Invalid content", new byte[0], response.getContentAsByteArray());
 	}