class-for-form.rb

%w[ rubygems nokogiri open-uri ].each {|lib| require lib }

# Usage:
#   MyClass = make_me_a_class "http://some/url"
#
# See the irb-example.rb below
#
# Note: you don't *have* to set a constant with this method but 
#       if you just use a regular variable, the class won't know 
#       it's name.  Ruby classes get their name from their constant's name.
#
def make_me_a_class url_with_form
  
  # go get the URL
  doc = Nokogiri::HTML open(url_with_form).read

  # grab the first <form> if it exists
  if first_form = doc.css('form').first

    # grab the <input>, <select>, <textarea> fields for this form, if any
    fields = first_form.css('input, select, textarea')
    unless fields.empty?

      # make a new Class
      klass = Class.new

      # for each field, add an attr_accessor to the class using the field's name attribute
      fields.each do |field|
        begin
          klass.send :attr_accessor, field[:name]
        rescue Exception => ex
          # if a field's name has brackets in it or is nil or anything like that, attr_accessor will fail
          puts "Couldn't create valid accessor for #{field[:name].inspect}"
        end 
      end 

      # return the new class!
      return klass
    end 
  end 
end

irb-example.rb

>> GoogleForm = make_me_a_class 'http://www.google.com'
=> GoogleForm
>> GoogleForm.instance_methods - Object.instance_methods
=> ["hl=", "btnG", "btnG=", "q", "q=", "ie", "ie=", "btnI", "btnI=", "source", "source=", "hl"]
>> GistForm = make_me_a_class 'https://gist.github.com'
Couldn't create valid accessor for nil
>> GistForm.instance_methods - Object.instance_methods
=> ["page=", "q", "q=", "page"]
>> TwitterForm = make_me_a_class 'http://twitter.com'
=> TwitterForm
>> TwitterForm.instance_methods - Object.instance_methods
=> ["commit", "commit=", "q", "q=", "authenticity_token", "authenticity_token="]