define-easy-handler has some pretty extensive features for accepting GET/POST parameters, but when it comes to validating those parameters, and possibly returning errors to the client, it seems like the only viable thing to do is write a standard handler function and work with get-parameters* and post-parameters* directly.
Does anyone have any experience to share in this direction? How is everyone handling more complex form validation and error reporting? Has there ever been any talk of a small external library for doing validation?
Eric