GH-3089: Add AmqpInGateway.replyHeadersMappedLast (#3091)

* GH-3089: Add AmqpInGateway.replyHeadersMappedLast

Fixes #3089

In some use-case we would like to control when headers from SI message
should be populated into an AMQP message.
One of the use-case is like a `SimpleMessageConverter` and its `plain/text`
for the String reply, meanwhile we know that this content is an
`application/json`.
So, with a new `replyHeadersMappedLast` we can override the mentioned
`content-type` header, populated by the `MessageConverter` with an
actual value from the message headers populated in the flow upstream

* Introduce an `AmqpInboundGateway.replyHeadersMappedLast`; expose it
on the DSL and XML level
* Use newly introduced `MappingUtils.mapReplyMessage()`
* Optimize `DefaultAmqpHeaderMapper` to not parse JSON headers at all
when `JsonHeaders.TYPE_ID` is already present (e.g. `MessageConverter`
result)
* Also skip `JsonHeaders` when we `populateUserDefinedHeader()`

**Cherry-pick to 5.1.x**

* * Fix language and package typos
* Add missed `@param` in JavaDoc of the `AmqpBaseInboundGatewaySpec.batchingStrategy()`
* Extract a `RabbitTemplate` `MessageConverter` to use for reply messages
conversion - pursue a backward compatibility

Author: artembilan

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/config/AmqpInboundGatewayParser.java

@@ -30,6 +30,7 @@
  * @author Mark Fisher
  * @author Gary Russell
  * @author Artem Bilan
+ *
  * @since 2.1
  */
 public class AmqpInboundGatewayParser extends AbstractAmqpInboundAdapterParser {
@@ -48,6 +49,8 @@ protected void configureChannels(Element element, ParserContext parserContext, B
 		IntegrationNamespaceUtils.setReferenceIfAttributeDefined(builder, element, "request-channel");
 		IntegrationNamespaceUtils.setReferenceIfAttributeDefined(builder, element, "reply-channel");
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "default-reply-to");
+		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "reply-headers-last",
+				"replyHeadersMappedLast");
 	}
 
 }

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/dsl/AmqpBaseInboundGatewaySpec.java

@@ -138,4 +138,29 @@ public S recoveryCallback(RecoveryCallback<?> recoveryCallback) {
 		return _this();
 	}
 
+	/**
+	 * Set to true to bind the source message in the headers.
+	 * @param bindSourceMessage true to bind.
+	 * @return the spec.
+	 * @since 5.1.9
+	 * @see AmqpInboundGateway#setBindSourceMessage(boolean)
+	 */
+	public S bindSourceMessage(boolean bindSourceMessage) {
+		this.target.setBindSourceMessage(bindSourceMessage);
+		return _this();
+	}
+
+	/**
+	 * When mapping headers for the outbound (reply) message, determine whether the headers are
+	 * mapped before the message is converted, or afterwards.
+	 * @param replyHeadersMappedLast true if reply headers are mapped after conversion.
+	 * @return the spec.
+	 * @since 5.1.9
+	 * @see AmqpInboundGateway#setReplyHeadersMappedLast(boolean)
+	 */
+	public S replyHeadersMappedLast(boolean replyHeadersMappedLast) {
+		this.target.setReplyHeadersMappedLast(replyHeadersMappedLast);
+		return _this();
+	}
+
 }

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/inbound/AmqpInboundGateway.java

@@ -23,8 +23,6 @@
 import org.springframework.amqp.core.Address;
 import org.springframework.amqp.core.AmqpTemplate;
 import org.springframework.amqp.core.Message;
-import org.springframework.amqp.core.MessagePostProcessor;
-import org.springframework.amqp.core.MessageProperties;
 import org.springframework.amqp.rabbit.core.RabbitTemplate;
 import org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer;
 import org.springframework.amqp.rabbit.listener.api.ChannelAwareMessageListener;
@@ -38,14 +36,14 @@
 import org.springframework.integration.amqp.support.AmqpMessageHeaderErrorMessageStrategy;
 import org.springframework.integration.amqp.support.DefaultAmqpHeaderMapper;
 import org.springframework.integration.amqp.support.EndpointUtils;
+import org.springframework.integration.amqp.support.MappingUtils;
 import org.springframework.integration.gateway.MessagingGatewaySupport;
 import org.springframework.integration.support.ErrorMessageUtils;
 import org.springframework.messaging.MessageChannel;
 import org.springframework.retry.RecoveryCallback;
 import org.springframework.retry.support.RetrySynchronizationManager;
 import org.springframework.retry.support.RetryTemplate;
 import org.springframework.util.Assert;
-import org.springframework.util.StringUtils;
 
 import com.rabbitmq.client.Channel;
 
@@ -71,9 +69,11 @@ public class AmqpInboundGateway extends MessagingGatewaySupport {
 
 	private final boolean amqpTemplateExplicitlySet;
 
-	private volatile MessageConverter amqpMessageConverter = new SimpleMessageConverter();
+	private MessageConverter amqpMessageConverter = new SimpleMessageConverter();
 
-	private volatile AmqpHeaderMapper headerMapper = DefaultAmqpHeaderMapper.inboundMapper();
+	private MessageConverter templateMessageConverter = this.amqpMessageConverter;
+
+	private AmqpHeaderMapper headerMapper = DefaultAmqpHeaderMapper.inboundMapper();
 
 	private Address defaultReplyTo;
 
@@ -83,6 +83,8 @@ public class AmqpInboundGateway extends MessagingGatewaySupport {
 
 	private boolean bindSourceMessage;
 
+	private boolean replyHeadersMappedLast;
+
 	public AmqpInboundGateway(AbstractMessageListenerContainer listenerContainer) {
 		this(listenerContainer, new RabbitTemplate(listenerContainer.getConnectionFactory()), false);
 	}
@@ -110,6 +112,9 @@ private AmqpInboundGateway(AbstractMessageListenerContainer listenerContainer, A
 		this.messageListenerContainer.setAutoStartup(false);
 		this.amqpTemplate = amqpTemplate;
 		this.amqpTemplateExplicitlySet = amqpTemplateExplicitlySet;
+		if (this.amqpTemplateExplicitlySet && this.amqpTemplate instanceof RabbitTemplate) {
+			this.templateMessageConverter = ((RabbitTemplate) this.amqpTemplate).getMessageConverter();
+		}
 		setErrorMessageStrategy(new AmqpMessageHeaderErrorMessageStrategy());
 	}
 
@@ -125,6 +130,7 @@ public void setMessageConverter(MessageConverter messageConverter) {
 		this.amqpMessageConverter = messageConverter;
 		if (!this.amqpTemplateExplicitlySet) {
 			((RabbitTemplate) this.amqpTemplate).setMessageConverter(messageConverter);
+			this.templateMessageConverter = messageConverter;
 		}
 	}
 
@@ -187,6 +193,24 @@ public void setBindSourceMessage(boolean bindSourceMessage) {
 		this.bindSourceMessage = bindSourceMessage;
 	}
 
+	/**
+	 * When mapping headers for the outbound (reply) message, determine whether the headers are
+	 * mapped before the message is converted, or afterwards. This only affects headers
+	 * that might be added by the message converter. When false, the converter's headers
+	 * win; when true, any headers added by the converter will be overridden (if the
+	 * source message has a header that maps to those headers). You might wish to set this
+	 * to true, for example, when using a
+	 * {@link org.springframework.amqp.support.converter.SimpleMessageConverter} with a
+	 * String payload that contains json; the converter will set the content type to
+	 * {@code text/plain} which can be overridden to {@code application/json} by setting
+	 * the {@link AmqpHeaders#CONTENT_TYPE} message header. Default: false.
+	 * @param replyHeadersMappedLast true if reply headers are mapped after conversion.
+	 * @since 5.1.9
+	 */
+	public void setReplyHeadersMappedLast(boolean replyHeadersMappedLast) {
+		this.replyHeadersMappedLast = replyHeadersMappedLast;
+	}
+
 	@Override
 	public String getComponentType() {
 		return "amqp:inbound-gateway";
@@ -331,7 +355,7 @@ private org.springframework.messaging.Message<Object> convert(Message message, C
 
 		private void process(Message message, org.springframework.messaging.Message<Object> messagingMessage) {
 			setAttributesIfNecessary(message, messagingMessage);
-			final org.springframework.messaging.Message<?> reply = sendAndReceiveMessage(messagingMessage);
+			org.springframework.messaging.Message<?> reply = sendAndReceiveMessage(messagingMessage);
 			if (reply != null) {
 				Address replyTo;
 				String replyToProperty = message.getMessageProperties().getReplyTo();
@@ -342,39 +366,23 @@ private void process(Message message, org.springframework.messaging.Message<Obje
 					replyTo = AmqpInboundGateway.this.defaultReplyTo;
 				}
 
-				MessagePostProcessor messagePostProcessor =
-						message1 -> {
-							MessageProperties messageProperties = message1.getMessageProperties();
-							String contentEncoding = messageProperties.getContentEncoding();
-							long contentLength = messageProperties.getContentLength();
-							String contentType = messageProperties.getContentType();
-							AmqpInboundGateway.this.headerMapper.fromHeadersToReply(reply.getHeaders(),
-									messageProperties);
-							// clear the replyTo from the original message since we are using it now
-							messageProperties.setReplyTo(null);
-							// reset the content-* properties as determined by the MessageConverter
-							if (StringUtils.hasText(contentEncoding)) {
-								messageProperties.setContentEncoding(contentEncoding);
-							}
-							messageProperties.setContentLength(contentLength);
-							if (contentType != null) {
-								messageProperties.setContentType(contentType);
-							}
-							return message1;
-						};
+				org.springframework.amqp.core.Message amqpMessage =
+						MappingUtils.mapReplyMessage(reply, AmqpInboundGateway.this.templateMessageConverter,
+								AmqpInboundGateway.this.headerMapper,
+								message.getMessageProperties().getReceivedDeliveryMode(),
+								AmqpInboundGateway.this.replyHeadersMappedLast);
 
 				if (replyTo != null) {
-					AmqpInboundGateway.this.amqpTemplate.convertAndSend(replyTo.getExchangeName(),
-							replyTo.getRoutingKey(), reply.getPayload(), messagePostProcessor);
+					AmqpInboundGateway.this.amqpTemplate.send(replyTo.getExchangeName(), replyTo.getRoutingKey(),
+							amqpMessage);
 				}
 				else {
 					if (!AmqpInboundGateway.this.amqpTemplateExplicitlySet) {
 						throw new IllegalStateException("There is no 'replyTo' message property " +
 								"and the `defaultReplyTo` hasn't been configured.");
 					}
 					else {
-						AmqpInboundGateway.this.amqpTemplate.convertAndSend(reply.getPayload(),
-								messagePostProcessor);
+						AmqpInboundGateway.this.amqpTemplate.send(amqpMessage);
 					}
 				}
 			}

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/support/DefaultAmqpHeaderMapper.java

@@ -105,7 +105,7 @@ protected DefaultAmqpHeaderMapper(String[] requestHeaderNames, String[] replyHea
 	 */
 	@Override
 	protected Map<String, Object> extractStandardHeaders(MessageProperties amqpMessageProperties) {
-		Map<String, Object> headers = new HashMap<String, Object>();
+		Map<String, Object> headers = new HashMap<>();
 		try {
 			String appId = amqpMessageProperties.getAppId();
 			if (StringUtils.hasText(appId)) {
@@ -325,24 +325,23 @@ else if (allHeaders != null) {
 			amqpMessageProperties.setUserId(userId);
 		}
 
-		Map<String, String> jsonHeaders = new HashMap<String, String>();
-
-		for (String jsonHeader : JsonHeaders.HEADERS) {
-			Object value = getHeaderIfAvailable(headers, jsonHeader, Object.class);
-			if (value != null) {
-				headers.remove(jsonHeader);
-				if (value instanceof Class<?>) {
-					value = ((Class<?>) value).getName();
-				}
-				jsonHeaders.put(jsonHeader.replaceFirst(JsonHeaders.PREFIX, ""), value.toString());
-			}
-		}
-
 		/*
 		 * If the MessageProperties already contains JsonHeaders, don't overwrite them here because they were
 		 * set up by a message converter.
 		 */
 		if (!amqpMessageProperties.getHeaders().containsKey(JsonHeaders.TYPE_ID.replaceFirst(JsonHeaders.PREFIX, ""))) {
+			Map<String, String> jsonHeaders = new HashMap<>();
+
+			for (String jsonHeader : JsonHeaders.HEADERS) {
+				Object value = getHeaderIfAvailable(headers, jsonHeader, Object.class);
+				if (value != null) {
+					headers.remove(jsonHeader);
+					if (value instanceof Class<?>) {
+						value = ((Class<?>) value).getName();
+					}
+					jsonHeaders.put(jsonHeader.replaceFirst(JsonHeaders.PREFIX, ""), value.toString());
+				}
+			}
 			amqpMessageProperties.getHeaders().putAll(jsonHeaders);
 		}
 
@@ -361,8 +360,9 @@ protected void populateUserDefinedHeader(String headerName, Object headerValue,
 			MessageProperties amqpMessageProperties) {
 		// do not overwrite an existing header with the same key
 		// TODO: do we need to expose a boolean 'overwrite' flag?
-		if (!amqpMessageProperties.getHeaders().containsKey(headerName)
-				&& !AmqpHeaders.CONTENT_TYPE.equals(headerName)) {
+		if (!amqpMessageProperties.getHeaders().containsKey(headerName) &&
+				!AmqpHeaders.CONTENT_TYPE.equals(headerName) &&
+				!headerName.startsWith(JsonHeaders.PREFIX)) {
 			amqpMessageProperties.setHeader(headerName, headerValue);
 		}
 	}

spring-integration-amqp/src/main/java/org/springframework/integration/amqp/support/MappingUtils.java

@@ -30,6 +30,8 @@
  * Utility methods used during message mapping.
  *
  * @author Gary Russell
+ * @author Artem Bilan
+ *
  * @since 4.3
  *
  */
@@ -40,7 +42,7 @@ private MappingUtils() {
 	}
 
 	/**
-	 * Map an o.s.Message to an o.s.a.core.Message. When using a
+	 * Map an o.s.m.Message to an o.s.a.core.Message. When using a
 	 * {@link ContentTypeDelegatingMessageConverter}, {@link AmqpHeaders#CONTENT_TYPE} and
 	 * {@link MessageHeaders#CONTENT_TYPE} will be used for the selection, with the AMQP
 	 * header taking precedence.
@@ -54,25 +56,64 @@ private MappingUtils() {
 	public static org.springframework.amqp.core.Message mapMessage(Message<?> requestMessage,
 			MessageConverter converter, AmqpHeaderMapper headerMapper, MessageDeliveryMode defaultDeliveryMode,
 			boolean headersMappedLast) {
+
+		return doMapMessage(requestMessage, converter, headerMapper, defaultDeliveryMode, headersMappedLast, false);
+	}
+
+	/**
+	 * Map a reply o.s.m.Message to an o.s.a.core.Message. When using a
+	 * {@link ContentTypeDelegatingMessageConverter}, {@link AmqpHeaders#CONTENT_TYPE} and
+	 * {@link MessageHeaders#CONTENT_TYPE} will be used for the selection, with the AMQP
+	 * header taking precedence.
+	 * @param replyMessage the reply message.
+	 * @param converter the message converter to use.
+	 * @param headerMapper the header mapper to use.
+	 * @param defaultDeliveryMode the default delivery mode.
+	 * @param headersMappedLast true if headers are mapped after conversion.
+	 * @return the mapped Message.
+	 * @since 5.1.9
+	 */
+	public static org.springframework.amqp.core.Message mapReplyMessage(Message<?> replyMessage,
+			MessageConverter converter, AmqpHeaderMapper headerMapper, MessageDeliveryMode defaultDeliveryMode,
+			boolean headersMappedLast) {
+
+		return doMapMessage(replyMessage, converter, headerMapper, defaultDeliveryMode, headersMappedLast, true);
+	}
+
+	private static org.springframework.amqp.core.Message doMapMessage(Message<?> message,
+			MessageConverter converter, AmqpHeaderMapper headerMapper, MessageDeliveryMode defaultDeliveryMode,
+			boolean headersMappedLast, boolean reply) {
+
 		MessageProperties amqpMessageProperties = new MessageProperties();
 		org.springframework.amqp.core.Message amqpMessage;
 		if (!headersMappedLast) {
-			headerMapper.fromHeadersToRequest(requestMessage.getHeaders(), amqpMessageProperties);
+			mapHeaders(message.getHeaders(), amqpMessageProperties, headerMapper, reply);
 		}
 		if (converter instanceof ContentTypeDelegatingMessageConverter && headersMappedLast) {
-			String contentType = contentTypeAsString(requestMessage.getHeaders());
+			String contentType = contentTypeAsString(message.getHeaders());
 			if (contentType != null) {
 				amqpMessageProperties.setContentType(contentType);
 			}
 		}
-		amqpMessage = converter.toMessage(requestMessage.getPayload(), amqpMessageProperties);
+		amqpMessage = converter.toMessage(message.getPayload(), amqpMessageProperties);
 		if (headersMappedLast) {
-			headerMapper.fromHeadersToRequest(requestMessage.getHeaders(), amqpMessageProperties);
+			mapHeaders(message.getHeaders(), amqpMessageProperties, headerMapper, reply);
 		}
-		checkDeliveryMode(requestMessage, amqpMessageProperties, defaultDeliveryMode);
+		checkDeliveryMode(message, amqpMessageProperties, defaultDeliveryMode);
 		return amqpMessage;
 	}
 
+	private static void mapHeaders(MessageHeaders messageHeaders, MessageProperties amqpMessageProperties,
+			AmqpHeaderMapper headerMapper, boolean reply) {
+
+		if (reply) {
+			headerMapper.fromHeadersToReply(messageHeaders, amqpMessageProperties);
+		}
+		else {
+			headerMapper.fromHeadersToRequest(messageHeaders, amqpMessageProperties);
+		}
+	}
+
 	private static String contentTypeAsString(MessageHeaders headers) {
 		Object contentType = headers.get(AmqpHeaders.CONTENT_TYPE);
 		if (contentType instanceof MimeType) {

spring-integration-amqp/src/main/resources/org/springframework/integration/amqp/config/spring-integration-amqp-5.1.xsd

@@ -239,6 +239,18 @@
 							</xsd:documentation>
 						</xsd:annotation>
 					</xsd:attribute>
+					<xsd:attribute name="reply-headers-last">
+						<xsd:annotation>
+							<xsd:documentation>
+								Whether reply headers are mapped before or after conversion from a messaging Message to
+								a spring amqp Message. Set to true, for example, if you wish to override the
+								contentType header set by the converter.
+							</xsd:documentation>
+						</xsd:annotation>
+						<xsd:simpleType>
+							<xsd:union memberTypes="xsd:boolean xsd:string" />
+						</xsd:simpleType>
+					</xsd:attribute>
 				</xsd:extension>
 			</xsd:complexContent>
 		</xsd:complexType>