Grails custom validation scenarios - forms

Question

I just started looking at grails, I used to work mainly with PHP before, so my question is what is the best way of adding custom validation scenarios to a form. So lets say we have all the constraints in the domain but under a certain controller action where a form is bound to the domain we want to add an extra custom validation of some sort (for argument sakes, lets say we have a date and only in this scenario it should be more than 2 weeks in the future). Whats the best approach of doing that?
Thanks!

Answer 1

For you requirement you can using a Command Object with constraints:
#grails.validation.Validateable
class CommandObject {
Date date
static constraints = {
date(/*constraint here*/)
}
}
Edit:
Concerning your second question, yes you can share constraints from your domain object to your command object using importFrom [EntityName], see the example from the doc:
Domain object:
class User {
String firstName
String lastName
String passwordHash
static constraints = {
firstName blank: false, nullable: false
lastName blank: false, nullable: false
passwordHash blank: false, nullable: false
}
}
Command object:
class UserCommand {
String firstName
String lastName
String password
String confirmPassword
static constraints = {
importFrom User
password blank: false, nullable: false
confirmPassword blank: false, nullable: false
}
}
Sharing Constraints

Answer 2

I suggest you do the form validation using jquery before it reaches the controller. If you want, you can also do individual validation on the gsp itself (ei. checking that the input field is required, accepts only emails, accepts integer only etc.). You can even do this on the controller. But I think form validation using jquery is already enough :)