Rest Webservice using Spring Integration HTTP inbound gateway

[amitso]

Hi,

I am trying to expose a rest webservice using HTTP inbound gateway. I am not able to access the "retailer" path variable in the service activator.

I am using Spring 3.0.6 and Spring integration 2.0.5 RELEASE.

Please help, I tried googling but I am not able to find any suitable sample which will give me this pathvariable access.

I have created following things.

1. Inbound Channel
2. Outbound Channel
3. Inbound Gateway
4. Service Activator

Following is the configuration I have created.

WEB.xml

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
	<servlet>
		<servlet-name>businessIntegration</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/spring/servlet-context.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>businessIntegration</servlet-name>
		<url-pattern>/*</url-pattern>
	</servlet-mapping>
</web-app>

servlet-context.xml

	<bean name="auditLogGateway" class="uk.co.fresca.api.common.auditlog.AuditLogGateway"></bean>

	<!-- findAll Log -->
	<int:channel id="findAllLogsInboundChannel" />
	<int-http:inbound-gateway request-channel="findAllLogsInboundChannel" name="/findLogs/{retailer}/{product}"  mapped-request-headers="Accept-Charset:utf-8" supported-methods="GET" reply-channel="findAllLogsTransformedChannel"/>
	<int:service-activator expression="@auditLogGateway.fetchAllLogs(#pathVariables.retailer)" id="findLogs" input-channel="findAllLogsInboundChannel" output-channel="findAllLogsOutboundChannel" >
	</int:service-activator>
	<int:channel id="findAllLogsOutboundChannel"></int:channel>
	<int:object-to-json-transformer input-channel="findAllLogsOutboundChannel" output-channel="findAllLogsTransformedChannel"></int:object-to-json-transformer>
	<int:channel id="findAllLogsTransformedChannel"></int:channel>

	public Message<List> fetchAllLogs(String retailer){
		System.out.println(retailer);
		Message<List> retMessage = new GenericMessage<List>(new ArrayList());
		return retMessage;
	}

[Mark Fisher]

The support for path variables in a Spring Integration HTTP *inbound* adapter is actually new in version 2.1 (which is approaching RC1 very soon). The outbound adapters supported *setting* path vars in 2.0.x, but to grab values from the inbound URI, you will need to use 2.1.

Here's what you can do in 2.1:

1. use "path" instead of "name" as an attribute on the adapter and rely on the same path var syntax that you have already.
2. add a "payload-expression" attribute OR 1 or more <header/> subelements with "expression" attributes themselves
3. within the expressions, grab any path var values as such: #pathVariables.foo

Hope that helps.
-Mark

[amitso]

Thanks Mark,

This helped a lot. I am trying the same example with 2.1, I will come back with some good news.

Thanks,

Amit Solankurkar

[amitso]

Hi Mark,

Thanks a lot!!

I have changed the libraries to 2.1.0.M3 and it is working. I am setting the pathVariables in the header and getting them from header in service activator.

Following is the configuration changed, posting for other's use.


servlet-config.xml

	<bean name="controller" class="uk.co.fresca.HomeController"></bean>

	<int:channel id="inCh"></int:channel>
	<int:channel id="outCh"></int:channel>
	<int-http:inbound-gateway request-channel="inCh" reply-channel="outCh" name="/findlogs/{retailer}/{product}" path="/findlogs/{retailer}/{product}" mapped-request-headers="accept-charset:utf-8">
		<int-http:header name="retailer" expression="#pathVariables.retailer"/>
	</int-http:inbound-gateway>
	<int:service-activator input-channel="inCh" output-channel="outCh" ref="controller" method="process">
	</int:service-activator>

In service activator retailer value can be taken from the header.


One small help, not on priority,

how to pass this param as a payload expression. I tried changing the payload-expression of the inbound gateway in many ways but not successful.

[Mark Fisher]

Are you saying you tried payload-expression="#pathVariables.retailer"?

That should work, but maybe you need to ensure that the request-payload-type is configured.

[amitso]

Hi Mark,

I tried payload-expression="#pathVariables.retailer" and it is working fine, as I have a input message type if String.

public String process(<Message<String> retailer){
System.out.println(retailer); -- This is printing the retailer value correctly.
}

but if I want to use multiple pathvariables then I am planning to use a custom request payload to which I can assign the values. Is there any way to do it?

Thanks again for the prompt response.