http-inbound-adapter: How is view-name used?

[skram]

Problem solved! See solution below:

For some reason, I can't make the view-name work for inbound-channel-adapter in Spring Integration. How do you exactly used this.

By the way the documentation is too stingy in explaining the usage of this feature. The closest I got is from this thread: http://forum.springsource.org/showth...r-view-problem

I got a view resolver and dispatcher servlet. From my service I have two results: a valid result and an exception. Is it possible to return a view name that will map to a valid response and another view name that will map to an exception.

How? Thanks

Here are my configs:

integration.xml

<http:inbound-channel-adapter channel="INBOUND-HTTP" name="/test" supported-methods="POST" 
		view-name="plain" />

<bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" 
    		p:prefix="/WEB-INF/jsp/" p:suffix=".jsp"/>

web.xml

<servlet>
		<servlet-name>Multipart</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/applicationContext.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

[skram]

By the way I get a 404 whenever the view-name is specified. But when I removed it, I get the usual 200 Ok status.

[skram]

Problem solved

It turns out you need to configure the web.xml correctly and declare an appropriate view resolver.

For reference, I'm posting the solution here:

Here's my web.xml

	<servlet>
		<servlet-name>Multipart</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/applicationContext.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<servlet-mapping>
		<servlet-name>Multipart</servlet-name>
		<url-pattern>/upload</url-pattern>
	</servlet-mapping>

	<servlet-mapping>
		<servlet-name>Multipart</servlet-name>
		<url-pattern>/plain</url-pattern>
	</servlet-mapping>

/upload - This is the entry point for our application
/plain - This is the view returned by the application

spring-integration.xml:

	<int:channel id="INBOUND-HTTP" />
	<int:channel id="REPLY"/>

	<http:inbound-gateway request-channel="INBOUND-HTTP" name="/upload" supported-methods="POST, GET" 
		reply-channel="REPLY" view-name="plain" />
	
	<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver" p:order="1">
		<property name="defaultViews">
			<list>
				<bean class="org.springframework.web.servlet.view.json.MappingJacksonJsonView" />
			</list>
		</property>
</bean>

Alternatively, you can declare the http inbound gateway as:

	<bean id="httpInbound" class="org.springframework.integration.http.inbound.HttpRequestHandlingController" name="/upload">
		<constructor-arg value="true" /> 
		<property name="requestChannel" ref="INBOUND-HTTP" />
  		<property name="replyChannel" ref="REPLY" />
		<property name="viewName" value="plain" />
		<property name="supportedMethodNames">
			<list>
				<value>POST</value>
			</list>
		</property>
	</bean>

Notice the view-name (or viewName depending if you're using the standard bean or namespace support) corresponds to the servlet mapping. And we've declared a ContentNegotiatingViewResolver and MappingJacksonJsonView which will convert the final response as JSON view.

If we want a JSP to be returned, we must declare an InternalResourceViewResolver

	<bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver" 
    		p:prefix="/WEB-INF/jsp/" p:suffix=".jsp"/>

And make sure you have a plain.jsp declared in the WEB-INF/jsp folder. The name must match the view-name and the servlet-mapping URL pattern.

I just wished that the Spring Integration reference was more transparent in explaining this feature. (By the way it took me 8 hours to figure this out starting from 8pm to 5am ...yep I didn't sleep until I was able to get this out).

When I have the extra time, I will be uploading a tutorial about this to my blog at http://krams915.blogspot.com

[vbose]

Thank you so much for the solution. The SI reference document lacks documentation in this regard. I have been badly looking for help and luckily I found this one.

[ejkp]

<bean id="httpInbound" class="org.springframework.integration.http.inbound.HttpRequestHandlingController" name="/upload">
		<constructor-arg value="true" /> 
		<property name="requestChannel" ref="INBOUND-HTTP" />
  		<property name="replyChannel" ref="REPLY" />
		<property name="viewName" value="plain" />
		<property name="supportedMethodNames">
			<list>
				<value>POST</value>
			</list>
		</property>
	</bean>

in the above declaration

<constructor-arg value="true" />

tells spring to expect reply and not to send the 200 response code. how do i do the same when i use the method below ? ??

<http:inbound-gateway request-channel="INBOUND-HTTP" name="/upload" supported-methods="POST, GET" 
		reply-channel="REPLY" view-name="plain" />

i wish the spring documentation had consistent examples for each topic and i am new to this.

[Mark Fisher]

The namespace support is a higher-level way of configuring the underlying beans (think of it as a domain-specific language where the "domain" is EIP). As such, there is not always a one-to-one mapping between the elements and classes OR a one-to-one mapping between attributes and properties. Sometimes the *presence* of a particular type of element drives underlying property values, and that is the case here...

The use of "inbound-gateway" does indicate that it should expect a reply while "inbound-channel-adapter" indicates that it does NOT expect a reply.

With Spring Integration adapters, "gateway" always means request/reply (bidirectional) while "channel-adapter" means one-way either inbound OR outbound (unidirectional).

Hope that helps.
-Mark

[ejkp]

<http:inbound-channel-adapter channel="INBOUND-HTTP" name="/test" supported-methods="POST" 
		view-name="plain" />

i used the above declaration for the gateway

this is the flow gateway->service-acitvator (injects a id)->splitter->router->aggregator-> return to client

all i get his the response code, no content. i am just pushing a string to the channel, is that enough?

[Wrangler]

<http:inbound-channel-adapter channel="INBOUND-HTTP" name="/test" supported-methods="POST" 
		view-name="plain" />

i used the above declaration for the gateway

this is the flow gateway->service-acitvator (injects a id)->splitter->router->aggregator-> return to client

all i get his the response code, no content. i am just pushing a string to the channel, is that enough?

Since you are stating you want to use a "gateway" to return a response, you should be using:
int-http:inbound-gateway instead of http:inbound-channel-adapter.