Question

I used a global variable in my app for passing information before. But I got a problem and thanks everyone here suggested me to store those data in session with database.

I tried, but I found that I can’t access the session variable in Model. I googled and knew this is the Model normal behavior, RoR won’t pass the session variable to Model.

So, I would like to use that session variable in validation and also the controller….

1. how to pass the value of the
   session variable into Models? or

2. is there any other method for my
   use case? I need a variable storing
   a value, which is required in all
   MVCs, and should be independent
   between different concurrent users.

Thanks everyone. 🙂

Answer 1

If I understand you correctly, a session variable changes the way you validate the model. I believe the correct solution for this is the following:

class Blog < ActiveRecord::Base
  attr_accessor :validate_title

  validate_presence_of :title, :if => :validate_title
end

class BlogsController < ApplicationController
  def new
    @blog = Blog.new
    @blog.validate_title = session[:validate_title]
  end
end

The code has not been testet, but that’s the idea. The if argument can be the name of a method and you can do whatever you want in there. You can have various validation modes if you want. For example:

class Blog < ActiveRecord::Base
  attr_accessor :validation_mode

  validate_presence_of :title, :if => :validate_title

  def validate_title
    validation_mode == "full" or validation_mode == "only_title"
  end
end

class BlogsController < ApplicationController
  def new
    @blog = Blog.new
    @blog.validate_mode = session[:validate_mode]
  end
end

For more information, read the guide on validation.