I want to add several custom fields to my posts. I want them to be mandatory. Also I want to be able to validate each field.
Example: Each post should have a version number and a URL poiting to a zip file. I want to verify that the version number doesn't have any space. Only digits and dots are allowed. The URL should start with "http://" and end with ".zip"
If any value is incorrect the post should not be saved.
Is there a plugin that can handle mandatory and validated custom fields? I've only found the Custom Field GUI which doesn't solve my problem.