Add virtual attribute

[Linus Pettersson]

Hi!

Let's say I have an app that handles a TODO list. The list has finished and unfinished items. Now I want to add two virtual attributes to the list object; the count of finished and unfinished items in the list. I also need these to be displayed in the json output.

How do I achieve that?

Best Regards

Linus

[Colin Law]

Define two scopes on List that return the finished and unfinished items then use
List.unfinished.count

Colin

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> Linus
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[Linus Pettersson]

I already have done that, like this:

def unfinished_items
   self.items.where("status = ?", false)
end

def finished_items
  self.items.where("status = ?", true)
end

So I can use the List.unfinished.... But how do I add it as attributes to the json output?

[Andrew Skegg]

Linus Pettersson <linus.pettersson@...> writes:

> So I can use the List.unfinished.... But how do I add it as attributes to
the json output?
>
>
>

Seems you are confusing search patterns with object output. Your JSON output
should already include a "status" field.

[Tower He]

Acts_as_api will help you. It is a really awesome gem.

发自我的 iPhone

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[Linus Pettersson]

Well, yes but that's not the point.

Items have a status field. Lists has many items.

When displaying a List as JSON I want it to have an attribute that counts how many finished items there are in the list and how many unfinished items there are in the list. The above methods only fetches the items, and I'd have to count the result of that of course.

[Tower He]

class TodosController < ApplicationController

  def show

    @todo = Todo.find(params[:id])

    respond_to do |format|

      format.json { render_for_api :public, :json => @todo }

    end

  end

end

class Todo < ActiveRecord::Base

  has_many items

  acts_as_api

  api_accessible :public do |t|

    t.add "items.finished_items.all", :as => finished_items

    t.add "items.unfinished_items.all", :as => unfinished_items

    t.add "items.finished_items.count", :as => num_of_finished_items

    t.add "items.unfinished_items.count", :as => num_of_unfinished_items

  end

end

class Item < ActiveRecord::Base

  belongs_to todo

  scope :finished_items, where(:status => 'finished')

  scope :unfinished_items, where(:status => 'unfinished')

  acts_as_api

end

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Tower He

[Annapoorna R]

hi..
i got prob with creating mailer in rails 3
i used rails g mailer UserMailer.. .. how to define method in usermailer....?n cal that method..?

[Colin Law]

On 4 August 2011 09:28, Annapoorna R <prapo...@gmail.com> wrote:
> hi..
> i got prob with creating mailer in rails 3
> i used rails g mailer UserMailer.. .. how to define method in
> usermailer....?n cal that method..?

What has that got to do with the subject of this thread, which is Add
virtual attribute? It is best to start a new thread for a new
subject, with a subject line that matches the question.

Colin