<p>What is the "canonical" way to access the MessageContext from a PayloadEndpoint?</p>

<p>We are using <a href="http://static.springframework.org/spring-ws/sites/1.5/apidocs/org/springframework/ws/server/endpoint/PayloadEndpoint.html" rel="nofollow noreferrer">PayloadEndpoint</a> and <a href="http://static.springframework.org/spring-ws/sites/1.5/apidocs/org/springframework/ws/server/endpoint/AbstractMarshallingPayloadEndpoint.html" rel="nofollow noreferrer">AbstractMarshallingPayloadEndpoint</a> which do not expose the MessageContext to their invoke / invokeinternal methods, but will now need to access the HTTP request parameters.</p>

Easiest way I can think of: create a 'wrapper' endpoint which implements
MessageEndpoint
. Then you can extract your request parameters and pass them down to your actual endpoint.
You could store the request variables in a ThreadLocal so the original endpoint can access them.