Add JSONP support for MappingJackson2MessageConverter

Issue: SPR-9899

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

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2002-2014 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.servlet.mvc.method.annotation;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.json.MappingJacksonValue;
+import org.springframework.http.server.ServerHttpRequest;
+import org.springframework.http.server.ServerHttpResponse;
+import org.springframework.http.server.ServletServerHttpRequest;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
+
+import javax.servlet.http.HttpServletRequest;
+import java.util.Collection;
+
+/**
+ * A convenient base class for a {@code ResponseBodyInterceptor} to instruct the
+ * {@link org.springframework.http.converter.json.MappingJackson2HttpMessageConverter
+ * MappingJackson2HttpMessageConverter} to serialize with JSONP formatting.
+ *
+ * <p>Sub-classes must specify the query parameter name(s) to check for the name
+ * of the JSONP callback function.
+ *
+ * <p>Sub-classes are likely to be annotated with the {@code @ControllerAdvice}
+ * annotation and auto-detected or otherwise must be registered directly with the
+ * {@code RequestMappingHandlerAdapter} and {@code ExceptionHandlerExceptionResolver}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 4.1
+ */
+public abstract class AbstractJsonpResponseBodyInterceptor extends AbstractMappingJacksonResponseBodyInterceptor {
+
+	private final String[] jsonpQueryParamNames;
+
+
+	protected AbstractJsonpResponseBodyInterceptor(Collection<String> queryParamNames) {
+		Assert.isTrue(!CollectionUtils.isEmpty(queryParamNames), "At least one query param name is required");
+		this.jsonpQueryParamNames = queryParamNames.toArray(new String[queryParamNames.size()]);
+	}
+
+
+	@Override
+	protected void beforeBodyWriteInternal(MappingJacksonValue bodyContainer, MediaType contentType,
+			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
+
+		HttpServletRequest servletRequest = ((ServletServerHttpRequest) request).getServletRequest();
+
+		for (String name : this.jsonpQueryParamNames) {
+			String value = servletRequest.getParameter(name);
+			if (value != null) {
+				MediaType contentTypeToUse = getContentType(contentType, request, response);
+				response.getHeaders().setContentType(contentTypeToUse);
+				bodyContainer.setJsonpFunction(value);
+				return;
+			}
+		}
+	}
+
+	/**
+	 * Return the content type to set the response to.
+	 * This implementation always returns "application/javascript".
+	 * @param contentType the content type selected through content negotiation
+	 * @param request the current request
+	 * @param response the current response
+	 * @return the content type to set the response to
+	 */
+	protected MediaType getContentType(MediaType contentType, ServerHttpRequest request, ServerHttpResponse response) {
+		return new MediaType("application", "javascript");
+	}
+
+}

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

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2002-2014 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.servlet.mvc.method.annotation;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
+import org.springframework.http.converter.json.MappingJacksonValue;
+import org.springframework.http.server.ServerHttpRequest;
+import org.springframework.http.server.ServerHttpResponse;
+
+/**
+ * A convenient base class for {@code ResponseBodyInterceptor} implementations
+ * that customize the response before JSON serialization with
+ * {@link org.springframework.http.converter.json.MappingJackson2HttpMessageConverter
+ * MappingJackson2HttpMessageConverter}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 4.1
+ */
+public abstract class AbstractMappingJacksonResponseBodyInterceptor implements ResponseBodyInterceptor {
+
+
+	protected AbstractMappingJacksonResponseBodyInterceptor() {
+	}
+
+
+	@SuppressWarnings("unchecked")
+	@Override
+	public final <T> T beforeBodyWrite(T body, MediaType contentType,
+			Class<? extends HttpMessageConverter<T>> converterType,
+			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
+
+		if (!MappingJackson2HttpMessageConverter.class.equals(converterType)) {
+			return body;
+		}
+		MappingJacksonValue container = getOrCreateContainer(body);
+		beforeBodyWriteInternal(container, contentType, returnType, request, response);
+		return (T) container;
+	}
+
+	/**
+	 * Wrap the body in a {@link MappingJacksonValue} value container (for providing
+	 * additional serialization instructions) or simply cast it if already wrapped.
+	 */
+	protected MappingJacksonValue getOrCreateContainer(Object body) {
+		return (body instanceof MappingJacksonValue) ? (MappingJacksonValue) body : new MappingJacksonValue(body);
+	}
+
+	/**
+	 * Invoked only if the converter type is {@code MappingJackson2HttpMessageConverter}.
+	 */
+	protected abstract void beforeBodyWriteInternal(MappingJacksonValue bodyContainer, MediaType contentType,
+			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response);
+
+
+}

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

@@ -19,42 +19,40 @@ package org.springframework.web.servlet.mvc.method.annotation;
 import com.fasterxml.jackson.annotation.JsonView;
 import org.springframework.core.MethodParameter;
 import org.springframework.http.MediaType;
-import org.springframework.http.converter.HttpMessageConverter;
-import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
 import org.springframework.http.converter.json.MappingJacksonValue;
 import org.springframework.http.server.ServerHttpRequest;
 import org.springframework.http.server.ServerHttpResponse;
 import org.springframework.util.Assert;
 
 /**
- * A {@code ResponseBodyInterceptor} implementation that adds support for the
- * Jackson {@code @JsonView} annotation on a Spring MVC {@code @RequestMapping}
- * or {@code @ExceptionHandler} method.
+ * A {@code ResponseBodyInterceptor} implementation that adds support for
+ * Jackson's {@code @JsonView} annotation declared on a Spring MVC
+ * {@code @RequestMapping} or {@code @ExceptionHandler} method. The serialization
+ * view specified in the annotation will be passed in to the
+ * {@code MappingJackson2HttpMessageConverter} which will then use it to
+ * serialize the response body with.
  *
  * @author Rossen Stoyanchev
  * @since 4.1
+ *
+ * @see com.fasterxml.jackson.databind.ObjectMapper#writerWithView(Class)
  */
-public class JsonViewResponseBodyInterceptor implements ResponseBodyInterceptor {
+public class JsonViewResponseBodyInterceptor extends AbstractMappingJacksonResponseBodyInterceptor {
 
 
 	@Override
-	@SuppressWarnings("unchecked")
-	public <T> T beforeBodyWrite(T body, MediaType contentType, Class<? extends HttpMessageConverter<T>> converterType,
+	protected void beforeBodyWriteInternal(MappingJacksonValue bodyContainer, MediaType contentType,
 			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
 
-		if (!MappingJackson2HttpMessageConverter.class.equals(converterType)) {
-			return body;
-		}
-
 		JsonView annotation = returnType.getMethodAnnotation(JsonView.class);
 		if (annotation == null) {
-			return body;
+			return;
 		}
 
 		Assert.isTrue(annotation.value().length != 0,
 				"Expected at least one serialization view class in JsonView annotation on " + returnType);
 
-		return (T) new MappingJacksonValue(body, annotation.value()[0]);
+		bodyContainer.setSerializationView(annotation.value()[0]);
 	}
 
 }