Problem migrating to Shibboleth IdP v3 from v2 using a custom login filter

[Peter Schober]

* Simone Avogadro <simone.avogadro at gmail.com> [2015-10-16 13:57]:
>   Our custom authentication is basically a servlet filter which sits on top
> of:
> 
>    - /Authn/*
>    - /profile/SAML2/Unsolicited/SSO
>    - /profile/SAML2/Redirect/SSO
> 
>  and wraps request/response to provide a Principal

I think the proper way to do this was the "external authentication"
mechanis, both for v2 and v3. The docs for v3 are here:
https://wiki.shibboleth.net/confluence/display/IDP30/ExternalAuthnConfiguration
-peter