Since no one was answering to my post in the GSoC forum I'll try it here

For OpenID support I implemented a DataObjectDecorator, but I couldn't figure out how I can add a custom validator to it. I need to ensure that the entered OpenID is unique so that only one user account is linked to a specific OpenID. Is that somehow possible?

At the moment I prevent duplicate OpenIDs by using a unique-index, but no error message will be shown.

Is there any way to implement a validator for DataObjectDecorators or handle such database errors ("Duplicate entry 'http://markus-lanthaler.myopenid.com/' for key 2")?

This would help me a lot to complete OpenID support!

Thanks for you reply Lakshan!

> I saw in ForumRole.php, implemented a ForumMember validator extending
> Member_Validator and overriding the getValidator function inside ForumRole.
>
> Similarly can't you extend the Member_Validator and add php() function with necessary
> validation which is to executed server-side ?

That was also my first thought and so I tried that already but unfortunately that is code that isn't executed at all.
It doesn't do anything in the ForumRole so that code is also buggy..

I forgot to post a bug report about that to the bugs forum (will do that now).

Edit: I posted it to the bugs forum and created a ticket.

OK, I fixed that problem in r40925. It's not the best (scalable) solution but it works for the moment and Hayden said that I should not change the core's validation behavior at the moment.