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?
The only way I know about is to use the augmentDatabase() method to add an unique-index to the database (adding it to extraDBFields() 'indexes' doesn't work) but in that way I can't output an error-message.
OK, I fixed it in r38854 (and added also defaults to it). But this doesn't help to solve my problem :-(
Now I can prevent that duplicate entries are created, but no error message will be shown since an database error occurs.. 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")?