验证虚拟属性的存在

Question

I have custom action called add_roles in a controller and a related form view with a virtual attribute called :role_name. I want to validate the presence of :role_name but it doesn't work:

This is the controller:

Class StaffsController < InheritedResources::Base
  def roles
    @staff=Staff.find params[:id]
  end

  def add_roles    
    @staff=Staff.find params[:id]
    role_name=params[:staff][:role_name] #this field must be present
    @staff.add_role Role.find(role_name).name
    redirect_to staff_path(@staff)
  end
end

This is the model:

class Staff < ActiveRecord::Base
  attr_accessible :email, :name, :surname
  attr_accessor :role_name

  validates_presence_of :role_name

  validate do |staff|
    if staff.role_name.blank?
      staff.errors[:base] << "INVALID"
    end
  end
end

This is the view:

<%= simple_form_for @staff, url: :add_roles_staff do |f| %>
    <%= f.input :role_name, as: :select, collection: Role.global %>
    <%= f.button :submit %>
<% end %>

The correct behavior is if I don't select the select box :role_name the form shows me an error, but now it isn't working. The form doesn't show me any error.

Answer 1

check out our staff model to see if validation is working if triggered by hand:

s = Staff.new
s.valid?
s.role_name='role'
s.valid? 

my guess is this works. if that is the case your validation never triggered, probably because you dont save the model (as you only change a virtual attribute). so my guess is just trigger validation explicitly.

However there is such a fundamental flaw in your code, that validation not working seems to be a minor problem: You should make the association between staff and his role explicitly on the database. At thge moment the virtual attribute will not survive a request/response lifecycle. As soon as you redirect out of the controller, that change is forever lost.

HTH

and by the way validates_presence_of :role_name does what you define below again:

validate do |staff|
  if staff.role_name.blank?
    staff.errors[:base] << "INVALID"
  end
end

so just delete that code