si-http:outbound-gateway gives HttpMessageNotWritableException for Integer

[alpheratz]

I am building a very simple spike for http:outbound-gateway.

My app is configured as follows:

<si:gateway id="httpGateway" service-interface="bob.Gateway" default-reply-channel="httpGatewayReply" default-request-channel="httpGatewayRequest"/>

<si:channel id="httpGatewayReply"/>
<si:channel id="httpGatewayRequest"/>

<si-http:outbound-gateway
            url="http://localhost:8080/Grails/test/index"
            request-channel="httpGatewayRequest"
            http-method="POST"
            request-timeout="2000"
            reply-channel="httpGatewayReply"
            expected-response-type="java.lang.String"
            auto-startup="true"
            charset="UTF-8"
            />

The interface is:

package bob

public interface Gateway {
  String calculateShippingCost(Map s)
}

The test app is:

package bob

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SIHttpTest {
  public static void main(String[] args) {
    def config = new ClassPathXmlApplicationContext("spring-config.xml");

    def gateway = (Gateway)config.getBean('httpGateway')
    println "Calling Gateway stuff..."
    println gateway.calculateShippingCost([fromLoc: "Brisbane", toLoc: 'Darwin', nItems: 1])
    println "Done."
  }
}

When I run this I get the following (excerpted) stack trace:

org.springframework.integration.MessageHandlingException: HTTP request execution failed for URI [http://localhost:8080/Grails/test/index]
	at org.springframework.integration.http.outbound.HttpRequestExecutingMessageHandler.handleRequestMessage(HttpRequestExecutingMessageHandler.java:243)
	at org.springframework.integration.handler.AbstractReplyProducingMessageHandler.handleMessageInternal(AbstractReplyProducingMessageHandler.java:98)
...
Caused by: org.springframework.http.converter.HttpMessageNotWritableException: Could not write request: no suitable HttpMessageConverter found for request type [java.lang.Integer]
	at org.springframework.http.converter.FormHttpMessageConverter.writePart(FormHttpMessageConverter.java:292)
...
Exception in thread "main" org.springframework.integration.MessageHandlingException: HTTP request execution failed for URI [http://localhost:8080/Grails/test/index]
	at org.springframework.integration.http.outbound.HttpRequestExecutingMessageHandler.handleRequestMessage(HttpRequestExecutingMessageHandler.java:243)
...
Caused by: org.springframework.http.converter.HttpMessageNotWritableException: Could not write request: no suitable HttpMessageConverter found for request type [java.lang.Integer]
	at org.springframework.http.converter.FormHttpMessageConverter.writePart(FormHttpMessageConverter.java:292)
	at
...

All is OK if I alter to test app to remove the integer map entry, thus:

    println gateway.calculateShippingCost([fromLoc: "Brisbane", toLoc: 'Darwin'])

It's also OK if I treat nItems as a string:

    println gateway.calculateShippingCost([fromLoc: "Brisbane", toLoc: 'Darwin', nItems: '1'])

This is surprising to me.

Do I need to create a converter for Integer?

Thoughts/guidance/suggestions gratefully accepted.

Cheers,

Alph

[oleg.zhurakousky]

Thank you
I was able to reproduce and it does seem strange to me that it could not convert it automatically. Let me look closer, i'll reply shortly.

[alpheratz]

Sorry to nag Oleg, but did you find anything in your investigations? Is there a workaround?

Cheers,

Alph

[oleg.zhurakousky]

Yeah, the default HttpMessageConvereters do not handle integers. One of the engineers of that functionality (in RestTemplate) is on vacation, so I have to wait till he gets back to get the answer. Part of the issue i think is because there is no way to submit Integer from the form. It will always come as a String. So i would suggest to do that (wrap int to string as you did before). Let me know.