Form validation in Ruby

[jonjendev]

Does anybody know if it is possible to validate the forms in Ruby?
According to the Jenkins wiki, this is what's supposed to be
implemented (FIELD is supposed to be exchanged for the field name):

public FormValidation doCheckFIELD(@QueryParameter String value) {
    if(looksOk(value))
        return FormValidation.ok();
    else
        return FormValidation.error("There's a problem here");
}

How would you do this in Ruby? How do you handle the QueryParameter?
The @ would make it an intstance variable. (What is a Queryparameter?)

Any help would be much appreciated!

/Jonatan

[jonjendev]

I'm gonna add some information!

I'm developing a Jenkins plugin in Ruby. You're supposed to be able to
configure every node that connects to the server so that an email is
sent to a specified address when the node loses its connection to the
master. 'EmailNodeProperty' adds a field to enter an email address:

    #
    # Save an email property for every node
    #
    class EmailNodeProperty < Jenkins::Slaves::NodeProperty
        require 'java'
        import 'hudson.util.FormValidation'

        display_name "Email notification"

        attr_accessor :email

        def initialize(attrs = {})
            @email = attrs['email']
        end

        def doCheckEmail value
            puts "  ENP.doCheckEmail:#{value}"
        end
    end

When you configure a node, there's a field named 'email' where you can
enter an email address. I want this field to be validated when you
enter an address.

When you save the configuration, an 'EmailNodeProperty' is created
whence (that's right) you can access the email address.

'MyComputerListener's 'offline' method gets called when a node loses
its connection:

    class MyComputerListener
        include Jenkins::Slaves::ComputerListener
        include Jenkins::Plugin::Proxy

        def online(computer, listener)
        end

        def offline(computer)
            #Do nothing when the Master shuts down
            if computer.to_s.match('Master') == nil
                list = computer.native.getNode().getNodeProperties()
                proxy = list.find {"EmailNodeProperty"}
                if proxy.is_a?(Jenkins::Plugin::Proxy)
                    rubyObject = proxy.getTarget()
                    email = rubyObject.email #<= Accesses the email
from EmailNodeProperty
                end
            end
            [...]
        end
    end

'MyComputerListener' finds the email address and sends an email.

Does anybody know if it is possible to validate the form in Ruby?
According to the Jenkins wiki (https://wiki.jenkins-ci.org/display/
JENKINS/Basic+guide+to+Jelly+usage+in+Jenkins), this is what's
supposed to be implemented (FIELD is supposed to be exchanged for the
field name, so I guess it should be 'doCheckEmail'):

    public FormValidation doCheckFIELD(@QueryParameter String value) {
        if(looksOk(value))
            return FormValidation.ok();
        else
            return FormValidation.error("There's a problem here");
    }

How would you do this in Ruby? Where should the method be implemented?
In 'EmailNodeProperty' or in 'MyComputerListener'? How do you handle
the QueryParameter? The @ would make it an intstance variable in Ruby.
(What is a Queryparameter?)

Any help would be much appreciated!

/Jonatan