IDP3 HTTP-Artifact form encoding

[Wibke Börger]

Hi Scott,

>> Is there a way to change this behaviour so that the artifact will be put
>> in a form and sent via POST?
>
> The underlying class supports it, we are not currently exposing that in the configuration.

I looked at HTTPArtifactEncoder and adjusted the bean definition for 
shibboleth.Encoders.SAML2ArtifactEncoder so that it uses postEncoding 
and gets the VelociytEngine. But there's a bug in HTTPArtifactEncoder's 
postEncode method: the OutputStreamWriter is never flushed. Adding 
outWriter.flush(); fixes that and then the post encoding of the artifact 
works.

Wibke