Revert "Cache Control only written if not set"

This reverts commit 242b831f20c11171975c1e2bdd50c9ae1cdbf445.
Spring MVC fixed the issue we were working around and the changes
in Spring Security were unreliable.

Fixes gh-3975

web/src/main/java/org/springframework/security/web/header/HeaderWriterFilter.java

@@ -15,17 +15,15 @@
  */
 package org.springframework.security.web.header;
 
-import java.io.IOException;
-import java.util.List;
+import org.springframework.util.Assert;
+import org.springframework.web.filter.OncePerRequestFilter;
 
 import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
-
-import org.springframework.security.web.util.OnCommittedResponseWrapper;
-import org.springframework.util.Assert;
-import org.springframework.web.filter.OncePerRequestFilter;
+import java.io.IOException;
+import java.util.*;
 
 /**
  * Filter implementation to add headers to the current response. Can be useful to add
@@ -58,52 +56,12 @@ public class HeaderWriterFilter extends OncePerRequestFilter {
 	@Override
 	protected void doFilterInternal(HttpServletRequest request,
 			HttpServletResponse response, FilterChain filterChain)
-					throws ServletException, IOException {
+			throws ServletException, IOException {
 
-		HeaderWriterResponse headerWriterResponse = new HeaderWriterResponse(request,
-				response, this.headerWriters);
-		try {
-			filterChain.doFilter(request, headerWriterResponse);
-		}
-		finally {
-			headerWriterResponse.writeHeaders();
+		for (HeaderWriter headerWriter : headerWriters) {
+			headerWriter.writeHeaders(request, response);
 		}
+		filterChain.doFilter(request, response);
 	}
 
-	static class HeaderWriterResponse extends OnCommittedResponseWrapper {
-		private final HttpServletRequest request;
-		private final List<HeaderWriter> headerWriters;
-
-		HeaderWriterResponse(HttpServletRequest request, HttpServletResponse response,
-				List<HeaderWriter> headerWriters) {
-			super(response);
-			this.request = request;
-			this.headerWriters = headerWriters;
-		}
-
-		/*
-		 * (non-Javadoc)
-		 *
-		 * @see org.springframework.security.web.util.OnCommittedResponseWrapper#
-		 * onResponseCommitted()
-		 */
-		@Override
-		protected void onResponseCommitted() {
-			writeHeaders();
-			this.disableOnResponseCommitted();
-		}
-
-		protected void writeHeaders() {
-			if (isDisableOnResponseCommitted()) {
-				return;
-			}
-			for (HeaderWriter headerWriter : this.headerWriters) {
-				headerWriter.writeHeaders(this.request, getHttpResponse());
-			}
-		}
-
-		private HttpServletResponse getHttpResponse() {
-			return (HttpServletResponse) getResponse();
-		}
-	}
 }

web/src/main/java/org/springframework/security/web/header/writers/CacheControlHeadersWriter.java

@@ -15,20 +15,14 @@
  */
 package org.springframework.security.web.header.writers;
 
-import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
 
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-
 import org.springframework.security.web.header.Header;
-import org.springframework.security.web.header.HeaderWriter;
-import org.springframework.util.ReflectionUtils;
 
 /**
- * Inserts headers to prevent caching if no cache control headers have been specified.
- * Specifically it adds the following headers:
+ * A {@link StaticHeadersWriter} that inserts headers to prevent caching. Specifically it
+ * adds the following headers:
  * <ul>
  * <li>Cache-Control: no-cache, no-store, max-age=0, must-revalidate</li>
  * <li>Pragma: no-cache</li>
@@ -38,47 +32,21 @@ import org.springframework.util.ReflectionUtils;
  * @author Rob Winch
  * @since 3.2
  */
-public final class CacheControlHeadersWriter implements HeaderWriter {
-	private static final String EXPIRES = "Expires";
-	private static final String PRAGMA = "Pragma";
-	private static final String CACHE_CONTROL = "Cache-Control";
-
-	private final Method getHeaderMethod;
-
-	private final HeaderWriter delegate;
+public final class CacheControlHeadersWriter extends StaticHeadersWriter {
 
 	/**
 	 * Creates a new instance
 	 */
 	public CacheControlHeadersWriter() {
-		this.delegate = new StaticHeadersWriter(createHeaders());
-		this.getHeaderMethod = ReflectionUtils.findMethod(HttpServletResponse.class,
-				"getHeader", String.class);
-	}
-
-	@Override
-	public void writeHeaders(HttpServletRequest request, HttpServletResponse response) {
-		if (hasHeader(response, CACHE_CONTROL) || hasHeader(response, EXPIRES)
-				|| hasHeader(response, PRAGMA)) {
-			return;
-		}
-		this.delegate.writeHeaders(request, response);
-	}
-
-	private boolean hasHeader(HttpServletResponse response, String headerName) {
-		if (this.getHeaderMethod == null) {
-			return false;
-		}
-		return ReflectionUtils.invokeMethod(this.getHeaderMethod, response,
-				headerName) != null;
+		super(createHeaders());
 	}
 
 	private static List<Header> createHeaders() {
 		List<Header> headers = new ArrayList<Header>(2);
-		headers.add(new Header(CACHE_CONTROL,
+		headers.add(new Header("Cache-Control",
 				"no-cache, no-store, max-age=0, must-revalidate"));
-		headers.add(new Header(PRAGMA, "no-cache"));
-		headers.add(new Header(EXPIRES, "0"));
+		headers.add(new Header("Pragma", "no-cache"));
+		headers.add(new Header("Expires", "0"));
 		return headers;
 	}
 }

web/src/test/java/org/springframework/security/web/header/HeaderWriterFilterTests.java

@@ -15,32 +15,21 @@
  */
 package org.springframework.security.web.header;
 
-import java.io.IOException;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.verify;
+
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
 
-import javax.servlet.FilterChain;
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
-
 import org.springframework.mock.web.MockFilterChain;
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpServletResponse;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.mockito.Matchers.any;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.verifyNoMoreInteractions;
-import static org.mockito.Mockito.verifyZeroInteractions;
+import org.springframework.security.web.header.HeaderWriter;
+import org.springframework.security.web.header.HeaderWriterFilter;
 
 /**
  * Tests for the {@code HeadersFilter}
@@ -71,8 +60,8 @@ public class HeaderWriterFilterTests {
 	@Test
 	public void additionalHeadersShouldBeAddedToTheResponse() throws Exception {
 		List<HeaderWriter> headerWriters = new ArrayList<HeaderWriter>();
-		headerWriters.add(this.writer1);
-		headerWriters.add(this.writer2);
+		headerWriters.add(writer1);
+		headerWriters.add(writer2);
 
 		HeaderWriterFilter filter = new HeaderWriterFilter(headerWriters);
 
@@ -82,34 +71,9 @@ public class HeaderWriterFilterTests {
 
 		filter.doFilter(request, response, filterChain);
 
-		verify(this.writer1).writeHeaders(request, response);
-		verify(this.writer2).writeHeaders(request, response);
+		verify(writer1).writeHeaders(request, response);
+		verify(writer2).writeHeaders(request, response);
 		assertThat(filterChain.getRequest()).isEqualTo(request); // verify the filterChain
 																	// continued
 	}
-
-	// gh-2953
-	@Test
-	public void headersDelayed() throws Exception {
-		HeaderWriterFilter filter = new HeaderWriterFilter(
-				Arrays.<HeaderWriter>asList(this.writer1));
-
-		MockHttpServletRequest request = new MockHttpServletRequest();
-		MockHttpServletResponse response = new MockHttpServletResponse();
-
-		filter.doFilter(request, response, new FilterChain() {
-			@Override
-			public void doFilter(ServletRequest request, ServletResponse response)
-					throws IOException, ServletException {
-				verifyZeroInteractions(HeaderWriterFilterTests.this.writer1);
-
-				response.flushBuffer();
-
-				verify(HeaderWriterFilterTests.this.writer1).writeHeaders(
-						any(HttpServletRequest.class), any(HttpServletResponse.class));
-			}
-		});
-
-		verifyNoMoreInteractions(this.writer1);
-	}
 }

web/src/test/java/org/springframework/security/web/header/writers/CacheControlHeadersWriterTests.java

@@ -15,32 +15,19 @@
  */
 package org.springframework.security.web.header.writers;
 
-import java.util.Arrays;
+import static org.assertj.core.api.Assertions.assertThat;
 
-import javax.servlet.http.HttpServletResponse;
+import java.util.Arrays;
 
 import org.junit.Before;
 import org.junit.Test;
-import org.junit.runner.RunWith;
-import org.powermock.core.classloader.annotations.PrepareOnlyThisForTest;
-import org.powermock.modules.junit4.PowerMockRunner;
-
 import org.springframework.mock.web.MockHttpServletRequest;
 import org.springframework.mock.web.MockHttpServletResponse;
-import org.springframework.util.ReflectionUtils;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.mockito.Matchers.anyString;
-import static org.mockito.Mockito.doThrow;
-import static org.mockito.Mockito.when;
-import static org.powermock.api.mockito.PowerMockito.spy;
 
 /**
  * @author Rob Winch
  *
  */
-@RunWith(PowerMockRunner.class)
-@PrepareOnlyThisForTest(ReflectionUtils.class)
 public class CacheControlHeadersWriterTests {
 
 	private MockHttpServletRequest request;
@@ -51,79 +38,20 @@ public class CacheControlHeadersWriterTests {
 
 	@Before
 	public void setup() {
-		this.request = new MockHttpServletRequest();
-		this.response = new MockHttpServletResponse();
-		this.writer = new CacheControlHeadersWriter();
+		request = new MockHttpServletRequest();
+		response = new MockHttpServletResponse();
+		writer = new CacheControlHeadersWriter();
 	}
 
 	@Test
 	public void writeHeaders() {
-		this.writer.writeHeaders(this.request, this.response);
-
-		assertThat(this.response.getHeaderNames().size()).isEqualTo(3);
-		assertThat(this.response.getHeaderValues("Cache-Control")).isEqualTo(
-				Arrays.asList("no-cache, no-store, max-age=0, must-revalidate"));
-		assertThat(this.response.getHeaderValues("Pragma"))
-				.isEqualTo(Arrays.asList("no-cache"));
-		assertThat(this.response.getHeaderValues("Expires"))
-				.isEqualTo(Arrays.asList("0"));
-	}
-
-	@Test
-	public void writeHeadersServlet25() {
-		spy(ReflectionUtils.class);
-		when(ReflectionUtils.findMethod(HttpServletResponse.class, "getHeader",
-				String.class)).thenReturn(null);
-		this.response = spy(this.response);
-		doThrow(NoSuchMethodError.class).when(this.response).getHeader(anyString());
-		this.writer = new CacheControlHeadersWriter();
+		writer.writeHeaders(request, response);
 
-		this.writer.writeHeaders(this.request, this.response);
-
-		assertThat(this.response.getHeaderNames().size()).isEqualTo(3);
-		assertThat(this.response.getHeaderValues("Cache-Control")).isEqualTo(
+		assertThat(response.getHeaderNames().size()).isEqualTo(3);
+		assertThat(response.getHeaderValues("Cache-Control")).isEqualTo(
 				Arrays.asList("no-cache, no-store, max-age=0, must-revalidate"));
-		assertThat(this.response.getHeaderValues("Pragma"))
-				.isEqualTo(Arrays.asList("no-cache"));
-		assertThat(this.response.getHeaderValues("Expires"))
-				.isEqualTo(Arrays.asList("0"));
-	}
-
-	// gh-2953
-	@Test
-	public void writeHeadersDisabledIfCacheControl() {
-		this.response.setHeader("Cache-Control", "max-age: 123");
-
-		this.writer.writeHeaders(this.request, this.response);
-
-		assertThat(this.response.getHeaderNames()).hasSize(1);
-		assertThat(this.response.getHeaderValues("Cache-Control"))
-				.containsOnly("max-age: 123");
-		assertThat(this.response.getHeaderValue("Pragma")).isNull();
-		assertThat(this.response.getHeaderValue("Expires")).isNull();
-	}
-
-	@Test
-	public void writeHeadersDisabledIfPragma() {
-		this.response.setHeader("Pragma", "mock");
-
-		this.writer.writeHeaders(this.request, this.response);
-
-		assertThat(this.response.getHeaderNames()).hasSize(1);
-		assertThat(this.response.getHeaderValues("Pragma")).containsOnly("mock");
-		assertThat(this.response.getHeaderValue("Expires")).isNull();
-		assertThat(this.response.getHeaderValue("Cache-Control")).isNull();
-	}
-
-	@Test
-	public void writeHeadersDisabledIfExpires() {
-		this.response.setHeader("Expires", "mock");
-
-		this.writer.writeHeaders(this.request, this.response);
-
-		assertThat(this.response.getHeaderNames()).hasSize(1);
-		assertThat(this.response.getHeaderValues("Expires")).containsOnly("mock");
-		assertThat(this.response.getHeaderValue("Cache-Control")).isNull();
-		assertThat(this.response.getHeaderValue("Pragma")).isNull();
+		assertThat(response.getHeaderValues("Pragma")).isEqualTo(
+				Arrays.asList("no-cache"));
+		assertThat(response.getHeaderValues("Expires")).isEqualTo(Arrays.asList("0"));
 	}
 }