Support HTTP HEAD

Issue: SPR-13130

spring-web/src/main/java/org/springframework/web/cors/CorsConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -340,6 +340,7 @@ public class CorsConfiguration {
 		}
 		if (allowedMethods.isEmpty()) {
 			allowedMethods.add(HttpMethod.GET.name());
+			allowedMethods.add(HttpMethod.HEAD.name());
 		}
 		List<HttpMethod> result = new ArrayList<HttpMethod>(allowedMethods.size());
 		boolean allowed = false;

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -144,7 +144,10 @@ public class ShallowEtagHeaderFilter extends OncePerRequestFilter {
 	protected boolean isEligibleForEtag(HttpServletRequest request, HttpServletResponse response,
 			int responseStatusCode, InputStream inputStream) {
 
-		if (responseStatusCode >= 200 && responseStatusCode < 300 && HttpMethod.GET.matches(request.getMethod())) {
+		String method = request.getMethod();
+		if (responseStatusCode >= 200 && responseStatusCode < 300 &&
+				(HttpMethod.GET.matches(method) || HttpMethod.HEAD.matches(method))) {
+
 			String cacheControl = null;
 			if (servlet3Present) {
 				cacheControl = response.getHeader(HEADER_CACHE_CONTROL);

spring-web/src/test/java/org/springframework/web/cors/CorsConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -24,7 +24,10 @@ import org.junit.Test;
 
 import org.springframework.http.HttpMethod;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 /**
  * Unit tests for {@link CorsConfiguration}.
@@ -176,7 +179,7 @@ public class CorsConfigurationTests {
 
 	@Test
 	public void checkMethodAllowed() {
-		assertEquals(Arrays.asList(HttpMethod.GET), config.checkHttpMethod(HttpMethod.GET));
+		assertEquals(Arrays.asList(HttpMethod.GET, HttpMethod.HEAD), config.checkHttpMethod(HttpMethod.GET));
 		config.addAllowedMethod("GET");
 		assertEquals(Arrays.asList(HttpMethod.GET), config.checkHttpMethod(HttpMethod.GET));
 		config.addAllowedMethod("POST");
@@ -189,7 +192,7 @@ public class CorsConfigurationTests {
 		assertNull(config.checkHttpMethod(null));
 		assertNull(config.checkHttpMethod(HttpMethod.DELETE));
 		config.setAllowedMethods(new ArrayList<>());
-		assertNull(config.checkHttpMethod(HttpMethod.HEAD));
+		assertNull(config.checkHttpMethod(HttpMethod.POST));
 	}
 
 	@Test

spring-web/src/test/java/org/springframework/web/cors/DefaultCorsProcessorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -171,7 +171,7 @@ public class DefaultCorsProcessorTests {
 		this.conf.addAllowedOrigin("*");
 		this.processor.processRequest(this.conf, request, response);
 		assertEquals(HttpServletResponse.SC_OK, response.getStatus());
-		assertEquals("GET", response.getHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS));
+		assertEquals("GET,HEAD", response.getHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS));
 	}
 
 	@Test

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/RequestMethodsRequestCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -36,6 +36,10 @@ import org.springframework.web.bind.annotation.RequestMethod;
  */
 public final class RequestMethodsRequestCondition extends AbstractRequestCondition<RequestMethodsRequestCondition> {
 
+	private static final RequestMethodsRequestCondition HEAD_CONDITION =
+			new RequestMethodsRequestCondition(RequestMethod.HEAD);
+
+
 	private final Set<RequestMethod> methods;
 
 
@@ -98,17 +102,24 @@ public final class RequestMethodsRequestCondition extends AbstractRequestConditi
 		if (this.methods.isEmpty()) {
 			return this;
 		}
-		RequestMethod incomingRequestMethod = getRequestMethod(request);
-		if (incomingRequestMethod != null) {
+		RequestMethod requestMethod = getRequestMethod(request);
+		if (requestMethod != null) {
 			for (RequestMethod method : this.methods) {
-				if (method.equals(incomingRequestMethod)) {
+				if (method.equals(requestMethod)) {
 					return new RequestMethodsRequestCondition(method);
 				}
 			}
+			if (isHeadRequest(requestMethod) && getMethods().contains(RequestMethod.GET)) {
+				return HEAD_CONDITION;
+			}
 		}
 		return null;
 	}
 
+	private boolean isHeadRequest(RequestMethod requestMethod) {
+		return (requestMethod != null && RequestMethod.HEAD.equals(requestMethod));
+	}
+
 	private RequestMethod getRequestMethod(HttpServletRequest request) {
 		try {
 			return RequestMethod.valueOf(request.getMethod());

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/HttpEntityMethodProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -170,7 +170,9 @@ public class HttpEntityMethodProcessor extends AbstractMessageConverterMethodPro
 		Object body = responseEntity.getBody();
 		if (responseEntity instanceof ResponseEntity) {
 			outputMessage.setStatusCode(((ResponseEntity<?>) responseEntity).getStatusCode());
-			if (HttpMethod.GET == inputMessage.getMethod() && isResourceNotModified(inputMessage, outputMessage)) {
+			HttpMethod method = inputMessage.getMethod();
+			boolean isGetOrHead = (HttpMethod.GET == method || HttpMethod.HEAD == method);
+			if (isGetOrHead && isResourceNotModified(inputMessage, outputMessage)) {
 				outputMessage.setStatusCode(HttpStatus.NOT_MODIFIED);
 				// Ensure headers are flushed, no body should be written.
 				outputMessage.flush();

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/condition/RequestMethodsRequestConditionTests.java

@@ -32,6 +32,7 @@ import static org.springframework.web.bind.annotation.RequestMethod.POST;
 
 /**
  * @author Arjen Poutsma
+ * @author Rossen Stoyanchev
  */
 public class RequestMethodsRequestConditionTests {
 
@@ -61,6 +62,25 @@ public class RequestMethodsRequestConditionTests {
 		assertEquals(Collections.singleton(GET), actual.getContent());
 	}
 
+	@Test
+	public void methodHeadMatch() throws Exception {
+		RequestMethodsRequestCondition condition = new RequestMethodsRequestCondition(GET, POST);
+		MockHttpServletRequest request = new MockHttpServletRequest("HEAD", "/foo");
+		RequestMethodsRequestCondition actual = condition.getMatchingCondition(request);
+
+		assertNotNull(actual);
+		assertEquals("GET should also match HEAD", Collections.singleton(HEAD), actual.getContent());
+	}
+
+	@Test
+	public void methodHeadNoMatch() throws Exception {
+		RequestMethodsRequestCondition condition = new RequestMethodsRequestCondition(POST);
+		MockHttpServletRequest request = new MockHttpServletRequest("HEAD", "/foo");
+		RequestMethodsRequestCondition actual = condition.getMatchingCondition(request);
+
+		assertNull("HEAD should match only if GET is declared", actual);
+	}
+
 	@Test
 	public void noDeclaredMethodsMatchesAllMethods() {
 		RequestCondition condition = new RequestMethodsRequestCondition();

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/ServletAnnotationControllerHandlerMethodTests.java

@@ -19,7 +19,6 @@ package org.springframework.web.servlet.mvc.method.annotation;
 import java.beans.PropertyEditorSupport;
 import java.io.IOException;
 import java.io.Serializable;
-import java.io.UnsupportedEncodingException;
 import java.io.Writer;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
@@ -968,7 +967,7 @@ public class ServletAnnotationControllerHandlerMethodTests extends AbstractServl
 	public void httpEntity() throws ServletException, IOException {
 		initServletWithControllers(ResponseEntityController.class);
 
-		MockHttpServletRequest request = new MockHttpServletRequest("PUT", "/foo");
+		MockHttpServletRequest request = new MockHttpServletRequest("POST", "/foo");
 		String requestBody = "Hello World";
 		request.setContent(requestBody.getBytes("UTF-8"));
 		request.addHeader("Content-Type", "text/plain; charset=utf-8");
@@ -980,7 +979,7 @@ public class ServletAnnotationControllerHandlerMethodTests extends AbstractServl
 		assertEquals(requestBody, response.getContentAsString());
 		assertEquals("MyValue", response.getHeader("MyResponseHeader"));
 
-		request = new MockHttpServletRequest("PUT", "/bar");
+		request = new MockHttpServletRequest("GET", "/bar");
 		response = new MockHttpServletResponse();
 		getServlet().service(request, response);
 		assertEquals("MyValue", response.getHeader("MyResponseHeader"));
@@ -1748,6 +1747,30 @@ public class ServletAnnotationControllerHandlerMethodTests extends AbstractServl
 		assertEquals("view", response.getForwardedUrl());
 	}
 
+	@Test
+	public void httpHead() throws ServletException, IOException {
+		initServletWithControllers(ResponseEntityController.class);
+
+		MockHttpServletRequest request = new MockHttpServletRequest("HEAD", "/baz");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		getServlet().service(request, response);
+
+		assertEquals(200, response.getStatus());
+		assertEquals("MyValue", response.getHeader("MyResponseHeader"));
+		assertEquals(4, response.getContentLength());
+		assertTrue(response.getContentAsByteArray().length == 0);
+
+		// Now repeat with GET
+		request = new MockHttpServletRequest("GET", "/baz");
+		response = new MockHttpServletResponse();
+		getServlet().service(request, response);
+
+		assertEquals(200, response.getStatus());
+		assertEquals("MyValue", response.getHeader("MyResponseHeader"));
+		assertEquals(4, response.getContentLength());
+		assertEquals("body", response.getContentAsString());
+	}
+
 
 	/*
 	 * Controllers
@@ -3019,25 +3042,27 @@ public class ServletAnnotationControllerHandlerMethodTests extends AbstractServl
 	@Controller
 	public static class ResponseEntityController {
 
-		@RequestMapping("/foo")
-		public ResponseEntity<String> foo(HttpEntity<byte[]> requestEntity) throws UnsupportedEncodingException {
+		@RequestMapping(path = "/foo", method = RequestMethod.POST)
+		public ResponseEntity<String> foo(HttpEntity<byte[]> requestEntity) throws Exception {
 			assertNotNull(requestEntity);
 			assertEquals("MyValue", requestEntity.getHeaders().getFirst("MyRequestHeader"));
-			String requestBody = new String(requestEntity.getBody(), "UTF-8");
-			assertEquals("Hello World", requestBody);
 
-			HttpHeaders responseHeaders = new HttpHeaders();
-			responseHeaders.set("MyResponseHeader", "MyValue");
-			return new ResponseEntity<String>(requestBody, responseHeaders, HttpStatus.CREATED);
+			String body = new String(requestEntity.getBody(), "UTF-8");
+			assertEquals("Hello World", body);
+
+			URI location = new URI("/foo");
+			return ResponseEntity.created(location).header("MyResponseHeader", "MyValue").body(body);
 		}
 
-		@RequestMapping("/bar")
-		public ResponseEntity<String> bar() {
-			HttpHeaders responseHeaders = new HttpHeaders();
-			responseHeaders.set("MyResponseHeader", "MyValue");
-			return new ResponseEntity<String>(responseHeaders, HttpStatus.NOT_FOUND);
+		@RequestMapping(path = "/bar", method = RequestMethod.GET)
+		public ResponseEntity<Void> bar() {
+			return ResponseEntity.notFound().header("MyResponseHeader", "MyValue").build();
 		}
 
+		@RequestMapping("/baz")
+		public ResponseEntity<String> baz() {
+			return ResponseEntity.ok().header("MyResponseHeader", "MyValue").body("body");
+		}
 	}
 
 	@Controller