Spring Integration Bridge - Request Headers - spring-integration

Question

I have a SI application that uses Bridge to bridge some channels. I want the request headers to be copied through the bridge. When I debugged the application, I found that the BridgeHandler has a method which sets copyRequestHeaders() to false.
public class BridgeHandler extends AbstractReplyProducingMessageHandler {
#Override
public String getComponentType() {
return "bridge";
}
#Override
protected Object handleRequestMessage(Message<?> requestMessage) {
return requestMessage;
}
#Override
protected boolean shouldCopyRequestHeaders() {
return false;
}
}
I want to change this to keep it true. I looked up Bridge's XSD and it doesnt seem to support any entry to alter this, nor does it take a reference to a custom bridge handler bean.
What are my options now? Any suggestions would be helpful.
spring-config.xml:
<beans:import resource="classpath*:spring/rabbit.xml" />
<beans:import resource="classpath*:spring/router.xml" />
<beans:import resource="classpath*:spring/file_persister.xml" />
<beans:import resource="classpath*:spring/transformer.xml" />
<!-- Rabbit to Router -->
<int:bridge id="rabbitBridge" input-channel="rabbitInboundChannel" output-
channel="routerInputChannel" />
rabbit.xml:
<int:channel id="rabbitInboundChannel" />
<rabbit:connection-factory id="amqpConnectionFactoryInbound"
host="${rabbit.host}" port="${rabbit.port}"
username="${rabbit.username}" password="${rabbit.password}" channel-cache-
size="${rabbit.channelCacheSize}"
connection-factory="rabbitConnectionFactoryInbound" />
<beans:bean id="rabbitConnectionFactoryInbound"
class="com.rabbitmq.client.ConnectionFactory">
<beans:property name="requestedHeartbeat"
value="${rabbit.requestedHeartBeat}" />
</beans:bean>
<!-- Inbound Adapter to AMQP RabbitMq -->
<int-amqp:inbound-channel-adapter id="rabbitMQInboundChannelAdapter"
channel="rabbitInboundChannel" concurrent-
consumers="${rabbit.concurrentConsumers}" task-executor="rabbit-
executor" connection-factory="amqpConnectionFactoryInbound"
message-converter="byteArrayToStringConverter" queue-
names="${rabbit.queue}" error-channel="errorChannelId"
prefetch-count="${rabbit.prefetchCount}" />
<header-enricher input-channel="rabbitInboundChannel" output-
channel="rabbitLoggingChannel">
<int:header name="Operation" value="${operation.rabbit}" overwrite="true" />
**<int:header name="GUID" expression="#{ 'T(java.util.UUID).randomUUID().toString()' }" />**
<int:header name="operationStartTime" expression="#{ 'T(java.lang.System).currentTimeMillis()' }" />
</header-enricher>
<int:channel id="rabbitLoggingChannel">
<int:interceptors>
<int:wire-tap channel="loggerChannel" />
</int:interceptors>
</int:channel>
<task:executor id="rabbit-executor" rejection-policy="CALLER_RUNS" pool-
size="${rabbit.poolSize}" queue-capacity="${rabbit.queueSize}" />
router.xml:
<int:channel id="routerInputChannel" />
<int:header-enricher input-channel="routerInputChannel" output-
channel="routerLoggingChannel">
<int:header name="Operation" value="${operation.router}" overwrite="true"
/>
<int:header name="file_name" expression="headers['GUID'] + '.xml'" />
<int:header name="operationStartTime" expression="#{
'T(java.lang.System).currentTimeMillis()' }" overwrite="true" />
<int:error-channel ref="errorChannelId" />
</int:header-enricher>
<int:recipient-list-router id="recipientListRouter" input-
channel="routerInputChannel">
<int:recipient channel="filePersistChannel" selector-expression="new
String(payload).length()>0" />
<int:recipient channel="transformerInputChannel" />
</int:recipient-list-router>
<int:channel id="routerLoggingChannel">
<int:interceptors>
<int:wire-tap channel="loggerChannel" />
</int:interceptors>
</int:channel>
Logging O/P:
2017-04-24 13:26:33,360 [rabbit-executor-4] INFO
Operation="RABBIT_INBOUND_ADAPTER" Status="Success" DurationMs="0"
GUID="8d5c67c8-a0fb-4a7e-99dc-f545159dde7e"
2017-04-24 13:26:33,361 [rabbit-executor-4] INFO Operation="ROUTER"
Status="Success" DurationMs="0" GUID=" "
2017-04-24 13:26:33,364 [rabbit-executor-4] INFO Operation="FILE_PERSISTER"
Status="Success" DurationMs="3" GUID=" "
2017-04-24 13:26:33,381 [rabbit-executor-5] INFO
Operation="ORDER_EVENT_TRANSFORMER" Status="Success" DurationMs="27"
GUID=" "
If you notice, the GUID header which gets set in rabbit.xml is not propogated to router.xml, hence the log has empty GUID. Without the bridge, the GUID gets printed.

Answer 1

You don't need to do that. The <bridge> is based on the BridgeHandler which logic is very transparent:
#Override
protected Object handleRequestMessage(Message<?> requestMessage) {
return requestMessage;
}
So, it is obvious - your request headers are transferred, just because the whole requestMessage travels to the outputMessage.
The logic behind that method is like:
protected Message<?> createOutputMessage(Object output, MessageHeaders requestHeaders) {
AbstractIntegrationMessageBuilder<?> builder = null;
if (output instanceof Message<?>) {
if (!this.shouldCopyRequestHeaders()) {
return (Message<?>) output;
}
builder = this.getMessageBuilderFactory().fromMessage((Message<?>) output);
}
else if (output instanceof AbstractIntegrationMessageBuilder) {
builder = (AbstractIntegrationMessageBuilder<?>) output;
}
else {
builder = this.getMessageBuilderFactory().withPayload(output);
}
if (this.shouldCopyRequestHeaders()) {
builder.copyHeadersIfAbsent(requestHeaders);
}
return builder.build();
}
Since our output is Message and we don't copyRequestHeaders(), nothing is changed and everything is good for you.
I wonder what makes you to come to us with such an issue, because there is just no issue.
confused