ResponseMapping

The <ResponseMapping> element provides an instance of the HTTPResponseMappingStrategy interface that produces result attributes from a web service response, in real time, using a script. The supplied script is expected to consume the HttpResponse instance and produce any desired results. It may raise exceptions if necessary.

For simple use cases, the HttpClientSupport class includes a number of toString methods that can translate the entire response into a string using appropriate character set handling and while enforcing size limits. This supports chunked responses for which the server doesn't know the actual size ahead of time, which is common with web services.

In addition, note that Javascript interpreters include a JSON object that automates the parsing of JSON data.

Schema Name and Location

The <ResponseMapping> element is a configuration element of type ScriptType. Both the element and its type are defined in the urn:mace:shibboleth:2.0:resolver namespace, the schema for which is located at http://shibboleth.net/schema/idp/shibboleth-attribute-resolver.xsd.

The following sections describe the attributes and elements of the ScriptType type.

Attributes

An element of type ScriptType has the following XML attributes:

language          

If the customObjectRef attribute is present, the result of the referenced Spring bean is made available to the script in a variable named custom. This is in addition to the normal script context discussed below.

Child Elements

An element of type ScriptType has the following child elements:

<Script>

<ScriptFile>

The script may be stored in a local file (with <ScriptFile>) or written inline (with <Script>). An inline script should be wrapped with a CDATA section to prevent interpretation of any special XML characters that may be included in the script.

Script Context

As enumerated below, several variables are available in the template context.

Unlike a lot of the scripted versions of objects across the system, there is no direct access to the ProfileRequestContext tree that exposes the state of the request. However, it's easy to get access to it by using a servlet request attribute named "opensamlProfileRequestContext". You can inject the servlet request object through the customObjectRef hook (set it to "shibboleth.HttpServletRequest").

Example

The example illustrates a JSON-based web service. Some of the error handling in the JSON structure is elided, but it illustrates that the response data can be trivially turned into native Javascript objects with a couple of lines of code, and the rest is mechanical.

<ResponseMapping>
	<Script>
	<![CDATA[
	var HashSet = Java.type("java.util.HashSet");
	var HttpClientSupport = Java.type("net.shibboleth.utilities.java.support.httpclient.HttpClientSupport");
	var IdPAttribute = Java.type("net.shibboleth.idp.attribute.IdPAttribute");
	var StringAttributeValue = Java.type("net.shibboleth.idp.attribute.StringAttributeValue");
 
	// Limits length to 64k
	var body = HttpClientSupport.toString(response.getEntity(), "UTF-8", 65536);
	var result = JSON.parse(body);

	var attr = new IdPAttribute("grouperGroup");
	var values = new HashSet();
	if (result.wsGroups != null) {
		for (var i=0; i<result.wsGroups.length; i++) {
			values.add(new StringAttributeValue(result.wsGroups[i].name));
		}
	}
	attr.setValues(values);
	]]>
	</Script>
</ResponseMapping>