Add ContentNegotiationManagerFactoryBean

The new FactoryBean facilitates the creation of a
ContentNegotiationManager in XML configuration.

Issue: SPR-8420

spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBean.java

+/*
+ * Copyright 2002-2012 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.accept;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Properties;
+
+import javax.servlet.ServletContext;
+
+import org.springframework.beans.factory.FactoryBean;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.http.MediaType;
+import org.springframework.util.CollectionUtils;
+
+/**
+ * A factory providing convenient access to a {@code ContentNegotiationManager}
+ * configured with one or more {@link ContentNegotiationStrategy} instances.
+ *
+ * <p>By default strategies for checking the extension of the request path and
+ * the {@code Accept} header are registered. The path extension check will perform
+ * lookups through the {@link ServletContext} and the Java Activation Framework
+ * (if present) unless {@linkplain #setMediaTypes(Map) media types} are configured.
+ *
+ * @author Rossen Stoyanchev
+ * @since 3.2
+ */
+public class ContentNegotiationManagerFactoryBean implements FactoryBean<ContentNegotiationManager>, InitializingBean {
+
+	private boolean favorPathExtension = true;
+
+	private boolean favorParameter = false;
+
+	private boolean ignoreAcceptHeader = false;
+
+	private Map<String, MediaType> mediaTypes = new HashMap<String, MediaType>();
+
+	private Boolean useJaf;
+
+	private String parameterName;
+
+	private MediaType defaultContentType;
+
+	private ContentNegotiationManager contentNegotiationManager;
+
+	/**
+	 * Indicate whether the extension of the request path should be used to determine
+	 * the requested media type with the <em>highest priority</em>.
+	 * <p>By default this value is set to {@code true} in which case a request
+	 * for {@code /hotels.pdf} will be interpreted as a request for
+	 * {@code "application/pdf"} regardless of the {@code Accept} header.
+	 */
+	public void setFavorPathExtension(boolean favorPathExtension) {
+		this.favorPathExtension = favorPathExtension;
+	}
+
+	/**
+	 * Add mappings from file extensions to media types.
+	 * <p>If this property is not set, the Java Action Framework, if available, may
+	 * still be used in conjunction with {@link #setFavorPathExtension(boolean)}.
+	 */
+	public void setMediaTypes(Properties mediaTypes) {
+		if (!CollectionUtils.isEmpty(mediaTypes)) {
+			for (Map.Entry<Object, Object> entry : mediaTypes.entrySet()) {
+				String extension = ((String) entry.getKey()).toLowerCase(Locale.ENGLISH);
+				this.mediaTypes.put(extension, MediaType.valueOf((String) entry.getValue()));
+			}
+		}
+	}
+
+	/**
+	 * Indicate whether to use the Java Activation Framework as a fallback option
+	 * to map from file extensions to media types. This is used only when
+	 * {@link #setFavorPathExtension(boolean)} is set to {@code true}.
+	 * <p>The default value is {@code true}.
+	 * @see #parameterName
+	 * @see #setMediaTypes(Map)
+	 */
+	public void setUseJaf(boolean useJaf) {
+		this.useJaf = useJaf;
+	}
+
+	/**
+	 * Indicate whether a request parameter should be used to determine the
+	 * requested media type with the <em>2nd highest priority</em>, i.e.
+	 * after path extensions but before the {@code Accept} header.
+	 * <p>The default value is {@code false}. If set to to {@code true}, a request
+	 * for {@code /hotels?format=pdf} will be interpreted as a request for
+	 * {@code "application/pdf"} regardless of the {@code Accept} header.
+	 * <p>To use this option effectively you must also configure the MediaType
+	 * type mappings via {@link #setMediaTypes(Map)}.
+	 * @see #setParameterName(String)
+	 */
+	public void setFavorParameter(boolean favorParameter) {
+		this.favorParameter = favorParameter;
+	}
+
+	/**
+	 * Set the parameter name that can be used to determine the requested media type
+	 * if the {@link #setFavorParameter} property is {@code true}.
+	 * <p>The default parameter name is {@code "format"}.
+	 */
+	public void setParameterName(String parameterName) {
+		this.parameterName = parameterName;
+	}
+
+	/**
+	 * Indicate whether the HTTP {@code Accept} header should be ignored altogether.
+	 * If set the {@code Accept} header is checked at the
+	 * <em>3rd highest priority</em>, i.e. after the request path extension and
+	 * possibly a request parameter if configured.
+	 * <p>By default this value is set to {@code false}.
+	 */
+	public void setIgnoreAcceptHeader(boolean ignoreAcceptHeader) {
+		this.ignoreAcceptHeader = ignoreAcceptHeader;
+	}
+
+	/**
+	 * Set the default content type.
+	 * <p>This content type will be used when neither the request path extension,
+	 * nor a request parameter, nor the {@code Accept} header could help determine
+	 * the requested content type.
+	 */
+	public void setDefaultContentType(MediaType defaultContentType) {
+		this.defaultContentType = defaultContentType;
+	}
+
+	public void afterPropertiesSet() throws Exception {
+		List<ContentNegotiationStrategy> strategies = new ArrayList<ContentNegotiationStrategy>();
+
+		if (this.favorPathExtension) {
+			PathExtensionContentNegotiationStrategy strategy = new PathExtensionContentNegotiationStrategy(this.mediaTypes);
+			if (this.useJaf != null) {
+				strategy.setUseJaf(this.useJaf);
+			}
+			strategies.add(strategy);
+		}
+
+		if (this.favorParameter) {
+			ParameterContentNegotiationStrategy strategy = new ParameterContentNegotiationStrategy(this.mediaTypes);
+			strategy.setParameterName(this.parameterName);
+			strategies.add(strategy);
+		}
+
+		if (!this.ignoreAcceptHeader) {
+			strategies.add(new HeaderContentNegotiationStrategy());
+		}
+
+		if (this.defaultContentType != null) {
+			strategies.add(new FixedContentNegotiationStrategy(this.defaultContentType));
+		}
+
+		ContentNegotiationStrategy[] array = strategies.toArray(new ContentNegotiationStrategy[strategies.size()]);
+		this.contentNegotiationManager = new ContentNegotiationManager(array);
+	}
+
+	public Class<?> getObjectType() {
+		return ContentNegotiationManager.class;
+	}
+
+	public boolean isSingleton() {
+		return true;
+	}
+
+	public ContentNegotiationManager getObject() throws Exception {
+		return this.contentNegotiationManager;
+	}
+
+}

spring-web/src/test/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBeanTests.java

+/*
+ * Copyright 2002-2012 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.accept;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Properties;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.http.MediaType;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.context.request.ServletWebRequest;
+
+/**
+ * Test fixture for {@link ContentNegotiationManagerFactoryBean} tests.
+ * @author Rossen Stoyanchev
+ */
+public class ContentNegotiationManagerFactoryBeanTests {
+
+	private ContentNegotiationManagerFactoryBean factoryBean;
+
+	private NativeWebRequest webRequest;
+
+	private MockHttpServletRequest servletRequest;
+
+	@Before
+	public void setup() {
+		this.factoryBean = new ContentNegotiationManagerFactoryBean();
+		this.servletRequest = new MockHttpServletRequest();
+		this.webRequest = new ServletWebRequest(this.servletRequest);
+	}
+
+	@Test
+	public void defaultSettings() throws Exception {
+		this.factoryBean.afterPropertiesSet();
+		ContentNegotiationManager manager = this.factoryBean.getObject();
+
+		this.servletRequest.setRequestURI("/flower.gif");
+
+		assertEquals("Should be able to resolve file extensions by default",
+				Arrays.asList(MediaType.IMAGE_GIF), manager.resolveMediaTypes(this.webRequest));
+
+		this.servletRequest.setRequestURI("/flower?format=gif");
+		this.servletRequest.addParameter("format", "gif");
+
+		assertEquals("Should not resolve request parameters by default",
+				Collections.emptyList(), manager.resolveMediaTypes(this.webRequest));
+
+		this.servletRequest.setRequestURI("/flower");
+		this.servletRequest.addHeader("Accept", MediaType.IMAGE_GIF_VALUE);
+
+		assertEquals("Should resolve Accept header by default",
+				Arrays.asList(MediaType.IMAGE_GIF), manager.resolveMediaTypes(this.webRequest));
+	}
+
+	@Test
+	public void addMediaTypes() throws Exception {
+		Properties mediaTypes = new Properties();
+		mediaTypes.put("json", MediaType.APPLICATION_JSON_VALUE);
+		this.factoryBean.setMediaTypes(mediaTypes);
+
+		this.factoryBean.afterPropertiesSet();
+		ContentNegotiationManager manager = this.factoryBean.getObject();
+
+		this.servletRequest.setRequestURI("/flower.json");
+		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON), manager.resolveMediaTypes(this.webRequest));
+	}
+
+	@Test
+	public void favorParameter() throws Exception {
+		this.factoryBean.setFavorParameter(true);
+		this.factoryBean.setParameterName("f");
+
+		Properties mediaTypes = new Properties();
+		mediaTypes.put("json", MediaType.APPLICATION_JSON_VALUE);
+		this.factoryBean.setMediaTypes(mediaTypes);
+
+		this.factoryBean.afterPropertiesSet();
+		ContentNegotiationManager manager = this.factoryBean.getObject();
+
+		this.servletRequest.setRequestURI("/flower");
+		this.servletRequest.addParameter("f", "json");
+
+		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON), manager.resolveMediaTypes(this.webRequest));
+	}
+
+	@Test
+	public void ignoreAcceptHeader() throws Exception {
+		this.factoryBean.setIgnoreAcceptHeader(true);
+		this.factoryBean.afterPropertiesSet();
+		ContentNegotiationManager manager = this.factoryBean.getObject();
+
+		this.servletRequest.setRequestURI("/flower");
+		this.servletRequest.addHeader("Accept", MediaType.IMAGE_GIF_VALUE);
+
+		assertEquals(Collections.emptyList(), manager.resolveMediaTypes(this.webRequest));
+	}
+
+	@Test
+	public void setDefaultContentType() throws Exception {
+		this.factoryBean.setDefaultContentType(MediaType.APPLICATION_JSON);
+		this.factoryBean.afterPropertiesSet();
+		ContentNegotiationManager manager = this.factoryBean.getObject();
+
+		assertEquals(Arrays.asList(MediaType.APPLICATION_JSON), manager.resolveMediaTypes(this.webRequest));
+	}
+
+}

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/ContentNegotiationConfigurer.java

@@ -35,11 +35,10 @@ import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
 /**
  * Helps with configuring a {@link ContentNegotiationManager}.
  *
- * <p>By default the extension of the request path extension is checked first and
- * the {@code Accept} is checked second. The path extension check will perform a
- * look up in the media types configured via {@link #setMediaTypes(Map)} and
- * will also fall back to {@link ServletContext} and the Java Activation Framework
- * (if present).
+ * <p>By default strategies for checking the extension of the request path and
+ * the {@code Accept} header are registered. The path extension check will perform
+ * lookups through the {@link ServletContext} and the Java Activation Framework
+ * (if present) unless {@linkplain #setMediaTypes(Map) media types} are configured.
  *
  * @author Rossen Stoyanchev
  * @since 3.2
@@ -72,6 +71,16 @@ public class ContentNegotiationConfigurer {
 		return this;
 	}
 
+	/**
+	 * Add mappings from file extensions to media types.
+	 * <p>If this property is not set, the Java Action Framework, if available, may
+	 * still be used in conjunction with {@link #setFavorPathExtension(boolean)}.
+	 */
+	public ContentNegotiationConfigurer addMediaType(String extension, MediaType mediaType) {
+		this.mediaTypes.put(extension, mediaType);
+		return this;
+	}
+
 	/**
 	 * Add mappings from file extensions to media types.
 	 * <p>If this property is not set, the Java Action Framework, if available, may

spring-webmvc/src/test/java/org/springframework/web/servlet/config/MvcNamespaceTests.java

@@ -452,7 +452,7 @@ public class MvcNamespaceTests {
 
 	@Test
 	public void testCustomContentNegotiationManager() throws Exception {
-		loadBeanDefinitions("mvc-config-content-negotiation-manager.xml", 14);
+		loadBeanDefinitions("mvc-config-content-negotiation-manager.xml", 12);
 
 		RequestMappingHandlerMapping mapping = appContext.getBean(RequestMappingHandlerMapping.class);
 		ContentNegotiationManager manager = mapping.getContentNegotiationManager();

spring-webmvc/src/test/resources/org/springframework/web/servlet/config/mvc-config-content-negotiation-manager.xml

@@ -7,23 +7,12 @@
 
 	<mvc:annotation-driven content-negotiation-manager="contentNegotiationManager" />
 
-	<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManager">
-		<constructor-arg>
-			<list>
-				<ref bean="pathExtensionStrategy" />			
-				<ref bean="headerStrategy" />			
-			</list>
-		</constructor-arg>
+	<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean">
+		<property name="mediaTypes">
+			<value>
+				xml=application/rss+xml
+			</value>
+		</property>
 	</bean>
 
-	<bean id="pathExtensionStrategy" class="org.springframework.web.accept.PathExtensionContentNegotiationStrategy">
-		<constructor-arg>
-			<map>
-				<entry key="xml" value="application/rss+xml" />
-			</map>
-		</constructor-arg>
-	</bean>
-	
-	<bean id="headerStrategy" class="org.springframework.web.accept.HeaderContentNegotiationStrategy" />
-
 </beans>

src/reference/docbook/mvc.xml

@@ -4503,25 +4503,20 @@ public class WebConfig extends WebMvcConfigurerAdapter {
   }
 }</programlisting>
 
-     <para>In XML you'll need to use the <code>content-negotiation-manager</code> property:</para>
+     <para>In XML you'll need to use the <code>content-negotiation-manager</code>
+     property of <code>annotation-driven</code>:</para>
 
 		<programlisting language="xml">&lt;mvc:annotation-driven content-negotiation-manager="contentNegotiationManager" /&gt;
 
-&lt;bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManager"&gt;
-    &lt;constructor-arg&gt;
-        &lt;list&gt;
-            &lt;ref bean="pathExtensionStrategy" /&gt;
-            &lt;bean id="headerStrategy" class="org.springframework.web.accept.HeaderContentNegotiationStrategy"/&gt;
-        &lt;/list&gt;
-    &lt;/constructor-arg&gt;
-&lt;/bean&gt;
-
-&lt;bean id="pathExtensionStrategy" class="org.springframework.web.accept.PathExtensionContentNegotiationStrategy"&gt;
-    &lt;constructor-arg&gt;
-        &lt;map&gt;
-            &lt;entry key="xml" value="application/rss+xml" /&gt;
-        &lt;/map&gt;
-    &lt;/constructor-arg&gt;
+&lt;bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManagerFactoryBean"&gt;
+    &lt;property name="favorPathExtension" value="false" /&gt;
+    &lt;property name="favorParameter" value="true" /&gt;
+    &lt;property name="mediaTypes" &gt;
+        &lt;value&gt;
+            json=application/json
+            xml=application/xml
+        &lt;/value&gt;
+    &lt;/property&gt;
 &lt;/bean&gt;</programlisting>
 
 	</section>