Question

In my application I am trying to make a virtual attribute that’s a date_select in my User model that associates itself to my UserPrice model’s date_select. The reason being, I am trying to have only one date dropdown list that users have to select. I plan on doing this by making the User virtual date_select update all of my UserPrice date_selects to that particular date.

I have my UserPrice model with the :purchase_date attribute:

create_table :user_prices do |t|
      t.decimal :price
      t.date :purchase_date

I have a nested form which can be shown here by looking at my UserPrice controller which also on create updates all of the UserPrices generated on the form:

UserPrices Controller

  def add_store_prices
     @a_new_user = User.new
     5.times do
        @a_new_user.user_prices.build
     end
  end

  def create
    respond_to do |format|
      if current_user.update_attributes(params[:user])
        redirect_to :back
      else
        redirect_to :back
      end
    end
  end

Then I am trying to define in the User model how to update the attributes of the :purchase_dates and also get the f.date_select field to work:

class User < ActiveRecord::Base
attr_accessible :user_prices_attributes, :all_dates
has_many :user_prices
attr_writer :all_dates

def all_dates
# @all_dates  = UserPrice :purchase_date field?
    #Needs to update the :purchase_date of the UserPrices
end

I am not exactly sure where to start. How do I define the virtual attribute :all_dates and get it to update on create all of the UserPrice’s :purchase_date attributes generated on my form?

The end result should look something like this:

<%= form_for(@a_new_user, :url => {:controller => :user_prices, :action => :create}) do |f| %>
 <%= f.error_messages %>
  <%= f.date_select :all_dates  %>
    <%= f.fields_for :user_prices do |pf| %>
      <%= pf.text_field :product_name %>
      <%= pf.text_field :store %>
      <%= pf.text_field :price %>
    <% end %>
 <%= f.submit %>
<% end %>

Thanks, really need some help with this.

EDIT

This is the error I get with the following controller code:

attr_accessor :all_dates
  after_save    :save_all_dates_to_user_prices

  protected

  def save_all_dates_to_user_prices 
    if !self.all_dates.nil?       
      self.user_prices.update_all :purchase_date => self.all_dates
    end
  end


ActiveRecord::MultiparameterAssignmentErrors in UserPricesController#create

1 error(s) on assignment of multiparameter attributes

app/controllers/user_prices_controller.rb:30:in `block in create'
app/controllers/user_prices_controller.rb:29:in `create'

"utf8"=>"✓",
 "authenticity_token"=>"fmB0kymP2vetFDoI/BB6RkyMEgsnhvf04cJ5Vu1GEaI=",
 "user"=>{"all_dates(2i)"=>"10",
 "all_dates(3i)"=>"17",
 "all_dates(1i)"=>"2011",
 "user_prices_attributes"=>{"0"=>{"product_name"=>"Cherries",
 "store"=>"4255 Alafaya Trail,
 Oviedo,
 FL 32765,
 USA",
 "price"=>"2.99"},
 "1"=>{"product_name"=>"",
 "store"=>"",
 "price"=>"5.99"},
 "2"=>{"product_name"=>"",
 "store"=>"",
 "price"=>""},
 "3"=>{"product_name"=>"",
 "store"=>"",
 "price"=>""},
 "4"=>{"product_name"=>"",
 "store"=>"",
 "price"=>""}}},
 "commit"=>"Done"}

Answer 1

You are pretty close as far as your User model goes:

class User < ActiveRecord::Base

  # See: http://gabeodess.heroku.com/posts/14
  composed_of :all_dates, :class_name => "DateTime",
    :mapping => %w(Time to_s),
    :constructor => Proc.new { |item| item },
    :converter => Proc.new { |item| item }

  after_save    :save_all_dates_to_user_prices

  protected

  def save_all_dates_to_user_prices 
    if !self.all_dates.nil?       
      self.user_prices.update_all :purchase_date => self.all_dates
    end
  end

end

I’ll leave it up to you to figure out the best way to decide when all_dates gets saved. In the example I’ve given, all_dates is used to update the User’s prices after the User is saved (during either update or create), and only when all_dates is not nil (for example, whenever an input is provided on the form).

I assume that you’ve set up your User model so that it accepts_nested_attributes_for :user_prices. I don’t quite understand why you are updating the current user in the create method of your UserPrices, but I don’t see any problems in the code itself.