Improve ETag & Last-Modifed support in WebRequest

This change improves the following use cases with
`WebRequest.checkNotModified(String etag)` and
`WebRequest.checkNotModified(long lastModifiedTimeStamp)`:

1) Allow weak comparisons for ETags

Per rfc7232 section-2.3, ETags can be strong or weak;
this change allows comparing weak forms `W/"etagvalue"` but does
not make a difference between strong and weak comparisons.

2) Allow multiple ETags in client requests

HTTP clients can send multiple ETags values in a single header such as:
`If-None-Match: "firstvalue", "secondvalue"`
This change makes sure each value is compared to the one provided by
the application side.

3) Extended support for ETag values

This change adds padding `"` to the ETag value provided by
the application, if not already done:
`etagvalue` => `"etagvalue"`

It also supports wildcard values `*` that can be sent by HTTP clients.

4) Sending validation headers for 304 responses

As defined in https://tools.ietf.org/html/rfc7232#section-4.1
`304 Not Modified` reponses must generate `Etag` and `Last-Modified`
HTTP headers, as they would have for a `200 OK` response.

5) Providing a new method to validate both Etag & Last-Modified

Also, this change adds a new method
`WebRequest.checkNotModified(String etag, long lastModifiedTimeStamp)`
in order to support validation of both `If-None-Match` and
`Last-Modified` headers sent by HTTP clients, if both values are
supported by the application code.

Even though this approach is recommended by the HTTP rfc (setting both
Etag and Last-Modified headers in the response), this requires more
application logic and may not apply to all resources produced by the
application.

Issue: SPR-11324

spring-web/src/main/java/org/springframework/web/context/request/FacesWebRequest.java

@@ -155,6 +155,17 @@ public class FacesWebRequest extends FacesRequestAttributes implements NativeWeb
 		return false;
 	}
 
+	/**
+	 * Last-modified handling not supported for portlet requests:
+	 * As a consequence, this method always returns {@code false}.
+	 *
+	 * @since 4.2
+	 */
+	@Override
+	public boolean checkNotModified(String etag, long lastModifiedTimestamp) {
+		return false;
+	}
+
 	@Override
 	public String getDescription(boolean includeClientInfo) {
 		ExternalContext externalContext = getExternalContext();

spring-web/src/main/java/org/springframework/web/context/request/ServletWebRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -21,6 +21,7 @@ import java.util.Date;
 import java.util.Iterator;
 import java.util.Locale;
 import java.util.Map;
+
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
@@ -35,6 +36,9 @@ import org.springframework.web.util.WebUtils;
  * {@link WebRequest} adapter for an {@link javax.servlet.http.HttpServletRequest}.
  *
  * @author Juergen Hoeller
+ * @author Brian Clozel
+ * @author Markus Malkusch
+ *
  * @since 2.0
  */
 public class ServletWebRequest extends ServletRequestAttributes implements NativeWebRequest {
@@ -72,7 +76,6 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 		super(request, response);
 	}
 
-
 	@Override
 	public Object getNativeRequest() {
 		return getRequest();
@@ -93,7 +96,6 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 		return WebUtils.getNativeResponse(getResponse(), requiredType);
 	}
 
-
 	/**
 	 * Return the HTTP method of the request.
 	 * @since 4.0.2
@@ -169,11 +171,24 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 	}
 
 	@Override
-	@SuppressWarnings("deprecation")
 	public boolean checkNotModified(long lastModifiedTimestamp) {
 		HttpServletResponse response = getResponse();
-		if (lastModifiedTimestamp >= 0 && !this.notModified &&
+		if (lastModifiedTimestamp >= 0 && !this.notModified) {
-				(response == null || !response.containsHeader(HEADER_LAST_MODIFIED))) {
+			if (response == null || !response.containsHeader(HEADER_LAST_MODIFIED)) {
+				this.notModified = isTimeStampNotModified(lastModifiedTimestamp);
+				if (response != null) {
+					if (this.notModified && supportsNotModifiedStatus()) {
+						response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
+					}
+					response.setDateHeader(HEADER_LAST_MODIFIED, lastModifiedTimestamp);
+				}
+			}
+		}
+		return this.notModified;
+	}
+
+	@SuppressWarnings("deprecation")
+	private boolean isTimeStampNotModified(long lastModifiedTimestamp) {
 		long ifModifiedSince = -1;
 		try {
 			ifModifiedSince = getRequest().getDateHeader(HEADER_IF_MODIFIED_SINCE);
@@ -192,43 +207,77 @@ public class ServletWebRequest extends ServletRequestAttributes implements Nativ
 				}
 			}
 		}
-			this.notModified = (ifModifiedSince >= (lastModifiedTimestamp / 1000 * 1000));
+		return (ifModifiedSince >= (lastModifiedTimestamp / 1000 * 1000));
+	}
+
+	@Override
+	public boolean checkNotModified(String etag) {
+		HttpServletResponse response = getResponse();
+		if (StringUtils.hasLength(etag) && !this.notModified) {
+			if (response == null || !response.containsHeader(HEADER_ETAG)) {
+				etag = addEtagPadding(etag);
+				this.notModified = isETagNotModified(etag);
 				if (response != null) {
 					if (this.notModified && supportsNotModifiedStatus()) {
 						response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
 					}
-				else {
+					response.setHeader(HEADER_ETAG, etag);
-					response.setDateHeader(HEADER_LAST_MODIFIED, lastModifiedTimestamp);
 				}
 			}
 		}
 		return this.notModified;
 	}
 
+	private String addEtagPadding(String etag) {
+		if (!(etag.startsWith("\"") || etag.startsWith("W/\"")) || !etag.endsWith("\"")) {
+			etag = "\"" + etag + "\"";
+		}
+		return etag;
+	}
+
+	private boolean isETagNotModified(String etag) {
+		if (StringUtils.hasLength(etag)) {
+			String ifNoneMatch = getRequest().getHeader(HEADER_IF_NONE_MATCH);
+			if (StringUtils.hasLength(ifNoneMatch)) {
+				String[] clientETags = StringUtils.delimitedListToStringArray(ifNoneMatch, ",", " ");
+				for (String clientETag : clientETags) {
+					// compare weak/strong ETags as per https://tools.ietf.org/html/rfc7232#section-2.3
+					if (StringUtils.hasLength(clientETag) &&
+							(clientETag.replaceFirst("^W/", "").equals(etag.replaceFirst("^W/", ""))
+								|| clientETag.equals("*"))) {
+						return true;
+					}
+				}
+			}
+		}
+		return false;
+	}
+
+	private boolean supportsNotModifiedStatus() {
+		String method = getRequest().getMethod();
+		return (METHOD_GET.equals(method) || METHOD_HEAD.equals(method));
+	}
+
 	@Override
-	public boolean checkNotModified(String etag) {
+	public boolean checkNotModified(String etag, long lastModifiedTimestamp) {
 		HttpServletResponse response = getResponse();
-		if (StringUtils.hasLength(etag) && !this.notModified &&
+		if (StringUtils.hasLength(etag) && !this.notModified) {
-				(response == null || !response.containsHeader(HEADER_ETAG))) {
+			if (response == null ||
-			String ifNoneMatch = getRequest().getHeader(HEADER_IF_NONE_MATCH);
+					(!response.containsHeader(HEADER_ETAG) && !response.containsHeader(HEADER_LAST_MODIFIED))) {
-			this.notModified = etag.equals(ifNoneMatch);
+				etag = addEtagPadding(etag);
+				this.notModified = isETagNotModified(etag) && isTimeStampNotModified(lastModifiedTimestamp);
 				if (response != null) {
 					if (this.notModified && supportsNotModifiedStatus()) {
 						response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
 					}
-				else {
 					response.setHeader(HEADER_ETAG, etag);
+					response.setDateHeader(HEADER_LAST_MODIFIED, lastModifiedTimestamp);
 				}
 			}
 		}
 		return this.notModified;
 	}
 
-	private boolean supportsNotModifiedStatus() {
-		String method = getRequest().getMethod();
-		return (METHOD_GET.equals(method) || METHOD_HEAD.equals(method));
-	}
-
 	public boolean isNotModified() {
 		return this.notModified;
 	}

spring-web/src/main/java/org/springframework/web/context/request/WebRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -141,9 +141,12 @@ public interface WebRequest extends RequestAttributes {
 	 *   model.addAttribute(...);
 	 *   return "myViewName";
 	 * }</pre>
-	 * <p><strong>Note:</strong> that you typically want to use either
+	 * <p><strong>Note:</strong> you can use either
 	 * this {@code #checkNotModified(long)} method; or
-	 * {@link #checkNotModified(String)}, but not both.
+	 * {@link #checkNotModified(String)}. If you want enforce both
+	 * a strong entity tag and a Last-Modified value,
+	 * as recommended by the HTTP specification,
+	 * then you should use {@link #checkNotModified(String, long)}.
 	 * <p>If the "If-Modified-Since" header is set but cannot be parsed
 	 * to a date value, this method will ignore the header and proceed
 	 * with setting the last-modified timestamp on the response.
@@ -172,9 +175,12 @@ public interface WebRequest extends RequestAttributes {
 	 *   model.addAttribute(...);
 	 *   return "myViewName";
 	 * }</pre>
-	 * <p><strong>Note:</strong> that you typically want to use either
+	 * <p><strong>Note:</strong> you can use either
 	 * this {@code #checkNotModified(String)} method; or
-	 * {@link #checkNotModified(long)}, but not both.
+	 * {@link #checkNotModified(long)}. If you want enforce both
+	 * a strong entity tag and a Last-Modified value,
+	 * as recommended by the HTTP specification,
+	 * then you should use {@link #checkNotModified(String, long)}.
 	 * @param etag the entity tag that the application determined
 	 * for the underlying resource. This parameter will be padded
 	 * with quotes (") if necessary.
@@ -184,6 +190,42 @@ public interface WebRequest extends RequestAttributes {
 	 */
 	boolean checkNotModified(String etag);
 
+	/**
+	 * Check whether the request qualifies as not modified given the
+	 * supplied {@code ETag} (entity tag) and last-modified timestamp,
+	 * as determined by the application.
+	 * <p>This will also transparently set the appropriate response headers,
+	 * for both the modified case and the not-modified case.
+	 * <p>Typical usage:
+	 * <pre class="code">
+	 * public String myHandleMethod(WebRequest webRequest, Model model) {
+	 *   String eTag = // application-specific calculation
+	 *   long lastModified = // application-specific calculation
+	 *   if (request.checkNotModified(eTag, lastModified)) {
+	 *     // shortcut exit - no further processing necessary
+	 *     return null;
+	 *   }
+	 *   // further request processing, actually building content
+	 *   model.addAttribute(...);
+	 *   return "myViewName";
+	 * }</pre>
+	 * <p><strong>Note:</strong> The HTTP specification recommends
+	 * setting both ETag and Last-Modified values, but you can also
+	 * use {@code #checkNotModified(String)} or
+	 * {@link #checkNotModified(long)}.
+	 * @param etag the entity tag that the application determined
+	 * for the underlying resource. This parameter will be padded
+	 * with quotes (") if necessary.
+	 * @param lastModifiedTimestamp the last-modified timestamp that
+	 * the application determined for the underlying resource
+	 * @return whether the request qualifies as not modified,
+	 * allowing to abort request processing and relying on the response
+	 * telling the client that the content has not been modified
+	 *
+	 * @since 4.2
+	 */
+	boolean checkNotModified(String etag, long lastModifiedTimestamp);
+
 	/**
 	 * Get a short description of this request,
 	 * typically containing request URI and session id.

spring-web/src/test/java/org/springframework/web/context/request/ServletWebRequestHttpMethodsTests.java

@@ -0,0 +1,258 @@
+/*
+ * Copyright 2002-2015 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.web.context.request;
+
+import static org.junit.Assert.*;
+
+import java.text.SimpleDateFormat;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.Locale;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+
+import org.springframework.mock.web.test.MockHttpServletRequest;
+import org.springframework.mock.web.test.MockHttpServletResponse;
+
+/**
+ * Parameterized tests for ServletWebRequest
+ * @author Juergen Hoeller
+ * @author Brian Clozel
+ * @author Markus Malkusch
+ */
+@RunWith(Parameterized.class)
+public class ServletWebRequestHttpMethodsTests {
+
+	private SimpleDateFormat dateFormat;
+
+	private MockHttpServletRequest servletRequest;
+
+	private MockHttpServletResponse servletResponse;
+
+	private ServletWebRequest request;
+
+	private String method;
+
+	@Parameters
+	static public Iterable<Object[]> safeMethods() {
+		return Arrays.asList(new Object[][] {
+				{"GET"},
+				{"HEAD"}
+		});
+	}
+
+	public ServletWebRequestHttpMethodsTests(String method) {
+		this.method = method;
+	}
+
+	@Before
+	public void setUp() {
+		dateFormat = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z", Locale.US);
+		servletRequest = new MockHttpServletRequest(method, "http://example.org");
+		servletResponse = new MockHttpServletResponse();
+		request = new ServletWebRequest(servletRequest, servletResponse);
+	}
+
+	@Test
+	public void checkNotModifiedTimestamp() {
+		long currentTime = new Date().getTime();
+		servletRequest.addHeader("If-Modified-Since", currentTime);
+
+		assertTrue(request.checkNotModified(currentTime));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
+	}
+
+	@Test
+	public void checkModifiedTimestamp() {
+		long currentTime = new Date().getTime();
+		long oneMinuteAgo = currentTime - (1000 * 60);
+		servletRequest.addHeader("If-Modified-Since", oneMinuteAgo);
+
+		assertFalse(request.checkNotModified(currentTime));
+
+		assertEquals(200, servletResponse.getStatus());
+		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
+	}
+
+	@Test
+	public void checkNotModifiedETag() {
+		String eTag = "\"Foo\"";
+		servletRequest.addHeader("If-None-Match", eTag);
+
+		assertTrue(request.checkNotModified(eTag));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals(eTag, servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkModifiedETag() {
+		String currentETag = "\"Foo\"";
+		String oldEtag = "Bar";
+		servletRequest.addHeader("If-None-Match", oldEtag);
+
+		assertFalse(request.checkNotModified(currentETag));
+
+		assertEquals(200, servletResponse.getStatus());
+		assertEquals(currentETag, servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkNotModifiedUnpaddedETag() {
+		String eTag = "Foo";
+		String paddedEtag = String.format("\"%s\"", eTag);
+		servletRequest.addHeader("If-None-Match", paddedEtag);
+
+		assertTrue(request.checkNotModified(eTag));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals(paddedEtag, servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkModifiedUnpaddedETag() {
+		String currentETag = "Foo";
+		String oldEtag = "Bar";
+		servletRequest.addHeader("If-None-Match", oldEtag);
+
+		assertFalse(request.checkNotModified(currentETag));
+
+		assertEquals(200, servletResponse.getStatus());
+		assertEquals(String.format("\"%s\"", currentETag), servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkNotModifiedWildcardETag() {
+		String eTag = "\"Foo\"";
+		servletRequest.addHeader("If-None-Match", "*");
+
+		assertTrue(request.checkNotModified(eTag));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals(eTag, servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkNotModifiedETagAndTimestamp() {
+		String eTag = "\"Foo\"";
+		servletRequest.addHeader("If-None-Match", eTag);
+		long currentTime = new Date().getTime();
+		servletRequest.addHeader("If-Modified-Since", currentTime);
+
+		assertTrue(request.checkNotModified(eTag, currentTime));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals(eTag, servletResponse.getHeader("ETag"));
+		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
+	}
+
+	@Test
+	public void checkNotModifiedETagAndModifiedTimestamp() {
+		String eTag = "\"Foo\"";
+		servletRequest.addHeader("If-None-Match", eTag);
+		long currentTime = new Date().getTime();
+		long oneMinuteAgo = currentTime - (1000 * 60);
+		servletRequest.addHeader("If-Modified-Since", oneMinuteAgo);
+
+		assertFalse(request.checkNotModified(eTag, currentTime));
+
+		assertEquals(200, servletResponse.getStatus());
+		assertEquals(eTag, servletResponse.getHeader("ETag"));
+		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
+	}
+
+	@Test
+	public void checkModifiedETagAndNotModifiedTimestamp() {
+		String currentETag = "\"Foo\"";
+		String oldEtag = "\"Bar\"";
+		servletRequest.addHeader("If-None-Match", oldEtag);
+		long currentTime = new Date().getTime();
+		servletRequest.addHeader("If-Modified-Since", currentTime);
+
+		assertFalse(request.checkNotModified(currentETag, currentTime));
+
+		assertEquals(200, servletResponse.getStatus());
+		assertEquals(currentETag, servletResponse.getHeader("ETag"));
+		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
+	}
+
+	@Test
+	public void checkNotModifiedETagWeakStrong() {
+		String eTag = "\"Foo\"";
+		String weakEtag = String.format("W/%s", eTag);
+		servletRequest.addHeader("If-None-Match", eTag);
+
+		assertTrue(request.checkNotModified(weakEtag));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals(weakEtag, servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkNotModifiedETagStrongWeak() {
+		String eTag = "\"Foo\"";
+		servletRequest.addHeader("If-None-Match", String.format("W/%s", eTag));
+
+		assertTrue(request.checkNotModified(eTag));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals(eTag, servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkNotModifiedMultipleETags() {
+		String eTag = "\"Bar\"";
+		String multipleETags = String.format("\"Foo\", %s", eTag);
+		servletRequest.addHeader("If-None-Match", multipleETags);
+
+		assertTrue(request.checkNotModified(eTag));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals(eTag, servletResponse.getHeader("ETag"));
+	}
+
+	@Test
+	public void checkNotModifiedTimestampWithLengthPart() throws Exception {
+		long currentTime = dateFormat.parse("Wed, 09 Apr 2014 09:57:42 GMT").getTime();
+		servletRequest.setMethod("GET");
+		servletRequest.addHeader("If-Modified-Since", "Wed, 09 Apr 2014 09:57:42 GMT; length=13774");
+
+		assertTrue(request.checkNotModified(currentTime));
+
+		assertEquals(304, servletResponse.getStatus());
+		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
+	}
+
+	@Test
+	public void checkModifiedTimestampWithLengthPart() throws Exception {
+		long currentTime = dateFormat.parse("Wed, 09 Apr 2014 09:57:42 GMT").getTime();
+		servletRequest.setMethod("GET");
+		servletRequest.addHeader("If-Modified-Since", "Wed, 08 Apr 2014 09:57:42 GMT; length=13774");
+
+		assertFalse(request.checkNotModified(currentTime));
+
+		assertEquals(200, servletResponse.getStatus());
+		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
+	}
+
+}

spring-web/src/test/java/org/springframework/web/context/request/ServletWebRequestTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -16,9 +16,11 @@
 
 package org.springframework.web.context.request;
 
-import java.util.Date;
+import static org.junit.Assert.*;
+
 import java.util.Locale;
 import java.util.Map;
+
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletRequest;
@@ -33,12 +35,8 @@ import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.mock.web.test.MockHttpServletResponse;
 import org.springframework.web.multipart.MultipartRequest;
 
-import static org.junit.Assert.*;
-
 /**
  * @author Juergen Hoeller
- * @author Markus Malkusch
- * @since 26.07.2006
  */
 public class ServletWebRequestTests {
 
@@ -116,113 +114,4 @@ public class ServletWebRequestTests {
 		assertNull(request.getNativeResponse(MultipartRequest.class));
 	}
 
-	@Test
-	public void checkNotModifiedTimestampForGET() {
-		long currentTime = new Date().getTime();
-		servletRequest.setMethod("GET");
-		servletRequest.addHeader("If-Modified-Since", currentTime);
-
-		assertTrue(request.checkNotModified(currentTime));
-		assertEquals(304, servletResponse.getStatus());
-	}
-
-	@Test
-	public void checkModifiedTimestampForGET() {
-		long currentTime = new Date().getTime();
-		long oneMinuteAgo  = currentTime - (1000 * 60);
-		servletRequest.setMethod("GET");
-		servletRequest.addHeader("If-Modified-Since", oneMinuteAgo);
-
-		assertFalse(request.checkNotModified(currentTime));
-		assertEquals(200, servletResponse.getStatus());
-		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
-	}
-
-	@Test
-	public void checkNotModifiedTimestampForHEAD() {
-		long currentTime = new Date().getTime();
-		servletRequest.setMethod("HEAD");
-		servletRequest.addHeader("If-Modified-Since", currentTime);
-
-		assertTrue(request.checkNotModified(currentTime));
-		assertEquals(304, servletResponse.getStatus());
-	}
-
-	@Test
-	public void checkModifiedTimestampForHEAD() {
-		long currentTime = new Date().getTime();
-		long oneMinuteAgo  = currentTime - (1000 * 60);
-		servletRequest.setMethod("HEAD");
-		servletRequest.addHeader("If-Modified-Since", oneMinuteAgo);
-
-		assertFalse(request.checkNotModified(currentTime));
-		assertEquals(200, servletResponse.getStatus());
-		assertEquals(""+currentTime, servletResponse.getHeader("Last-Modified"));
-	}
-
-	@Test
-	public void checkNotModifiedTimestampWithLengthPart() {
-		long currentTime = Date.parse("Wed, 09 Apr 2014 09:57:42 GMT");
-		servletRequest.setMethod("GET");
-		servletRequest.addHeader("If-Modified-Since", "Wed, 09 Apr 2014 09:57:42 GMT; length=13774");
-
-		assertTrue(request.checkNotModified(currentTime));
-		assertEquals(304, servletResponse.getStatus());
-	}
-
-	@Test
-	public void checkModifiedTimestampWithLengthPart() {
-		long currentTime = Date.parse("Wed, 09 Apr 2014 09:57:42 GMT");
-		servletRequest.setMethod("GET");
-		servletRequest.addHeader("If-Modified-Since", "Wed, 08 Apr 2014 09:57:42 GMT; length=13774");
-
-		assertFalse(request.checkNotModified(currentTime));
-		assertEquals(200, servletResponse.getStatus());
-		assertEquals("" + currentTime, servletResponse.getHeader("Last-Modified"));
-	}
-
-	@Test
-	public void checkNotModifiedETagForGET() {
-		String eTag = "\"Foo\"";
-		servletRequest.setMethod("GET");
-		servletRequest.addHeader("If-None-Match", eTag );
-
-		assertTrue(request.checkNotModified(eTag));
-		assertEquals(304, servletResponse.getStatus());
-	}
-
-	@Test
-	public void checkModifiedETagForGET() {
-		String currentETag = "\"Foo\"";
-		String oldEtag = "Bar";
-		servletRequest.setMethod("GET");
-		servletRequest.addHeader("If-None-Match", oldEtag);
-
-		assertFalse(request.checkNotModified(currentETag));
-		assertEquals(200, servletResponse.getStatus());
-		assertEquals(currentETag, servletResponse.getHeader("ETag"));
-	}
-
-	@Test
-	public void checkNotModifiedETagForHEAD() {
-		String eTag = "\"Foo\"";
-		servletRequest.setMethod("HEAD");
-		servletRequest.addHeader("If-None-Match", eTag );
-
-		assertTrue(request.checkNotModified(eTag));
-		assertEquals(304, servletResponse.getStatus());
-	}
-
-	@Test
-	public void checkModifiedETagForHEAD() {
-		String currentETag = "\"Foo\"";
-		String oldEtag = "Bar";
-		servletRequest.setMethod("HEAD");
-		servletRequest.addHeader("If-None-Match", oldEtag);
-
-		assertFalse(request.checkNotModified(currentETag));
-		assertEquals(200, servletResponse.getStatus());
-		assertEquals(currentETag, servletResponse.getHeader("ETag"));
-	}
-
 }

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/context/PortletWebRequest.java

@@ -162,6 +162,17 @@ public class PortletWebRequest extends PortletRequestAttributes implements Nativ
 		return false;
 	}
 
+	/**
+	 * Last-modified handling not supported for portlet requests:
+	 * As a consequence, this method always returns {@code false}.
+	 *
+	 * @since 4.2
+	 */
+	@Override
+	public boolean checkNotModified(String etag, long lastModifiedTimestamp) {
+		return false;
+	}
+
 	@Override
 	public String getDescription(boolean includeClientInfo) {
 		PortletRequest request = getRequest();