Ability to access parameters from HTTP GET inbound requests when constructing outbound calls [INT-1677]

[spring-operator]

Neil Chaudhuri opened INT-1677 and commented

REST HTTP GET requests contain parameters in the path and in the query string. Currently, Spring Integration captures path parameters like id in the following example

<http:inbound-gateway     id="documentByIdInboundGateway"
                          request-channel="documentByIdRequestChannel"
                          reply-channel="documentByIdReplyChannel"
                          name="/documents/{id}"
                          supported-methods="GET"/>

DEBUG [BeanNameUrlHandlerMapping.lookupHandler] Matching patterns for request [/documents/1232332] are [/documents/{id}]
DEBUG [BeanNameUrlHandlerMapping.lookupHandler] URI Template variables for request [/documents/1232332] are {id=1232332}

However, it is impossible to access these URI template variables in order to construct an outbound call from them. The is a feature request for an API to retrieve the id from above for the following outbound call for example:

<http:outbound-gateway     id="documentByIdTargetAdapter"
                           url="http://localhost:8080/myapp/documents/{id}"
                           http-method="GET"
                           request-channel="documentByIdRequestChannel"
                           reply-channel="targetDocumentByIdReplyChannel"
                           expected-response-type="com.myapp.Document"
                           charset="UTF-8"
                           header-mapper="jsonHeaderMapper">

Of course, the outbound request could be of any kind and not just a REST call.

Incidentally, it is unclear what the current Spring Integration behavior is for query parameters. Regardless, this feature request applies to all inbound REST parameters.

---

Affects: 2.0 Final

Reference URL: http://forum.springsource.org/showthread.php?t=99493

Issue Links:

• Investigate possible implementation of SpringIntegrationServlet that would map its handler based on the arbitrary attribute (e.g., 'path') rather than beanName for non-MVC cases [INT-2102] #6088 Investigate possible implementation of SpringIntegrationServlet that would map its handler based on the arbitrary attribute (e.g., 'path') rather than beanName for non-MVC cases
  ("is depended on by")
• Document using the "path" attribute with HTTP inbound adapters [INT-2443] #6422 Document using the "path" attribute with HTTP inbound adapters

2 votes, 1 watchers

[spring-operator]

Tom Greasley commented

I recently made small changes to a copy of HttpRequestHandlingEndpointSupport such that the query params and URI template variables were added to the message header rather than the body, regardless of the method GET or POST. It made things a lot more flexible. The only thing I was not happy with was not being able to create a null message body for GET requests, I used a new Object() instead.

[spring-operator]

Andrew Berman commented

Is there any movement on this issue? I've run into the same thing where I need to get the parameter from the URL. I see the request URL, but like the reporter mentioned in the forum, it's really clunky to be parsing that in the context xml. Ideally, something like pathParams["myparam"] would be perfect.

[spring-operator]

Oleg Zhurakousky commented

Actually I've been looking into that and similar requirement recently, so we'll do something with it for 2.1. Meanwhile you can add transformer in between the inbound and outbound and extract the required values.

[spring-operator]

Vigil Bose commented

This feature is very crucial for our project since we have a collection of REST based Spring Integration powered services that cater to various requests from different clients. So look forward to having a clean solution to extract URI variables from the inbound http gateway or inbound http adapter.

[spring-operator]

Oleg Zhurakousky commented

This might have already been resolved as part of #5347.

<int-http:outbound-channel-adapter id="fullConfig"
			url="http://localhost/test2/{foo}"
			http-method="GET"
			. . .">
		<int-http:uri-variable name="foo" expression="headers.bar"/>
</int-http:outbound-channel-adapter>

Please take a look and let us know

[spring-operator]

Mark Fisher commented

The requirement for this issue is actually related to inbound requests.

[spring-operator]

Oleg Zhurakousky commented

The example below shows how it could be accomplished.

<inbound-channel-adapter id="inboundAdapterWithExpressions" 
	                         path="/fname/{f}/lname/{l}"
	                         channel="requests"
							 mapped-request-headers="foo,bar"
							 payload-expression="#pathVariables.f">
		<header name="lname" expression="#pathVariables.l"/>
	</inbound-channel-adapter>