Render :json with extra data

Question

I have a model called Todo and I render this:

format.json { render :json => @todo }

Each Todo belongs_to a List. I want to add the value

Answer 1

You may want to capture the value of the JSON data, and then modify it.

format.json { render :json => JSON::parse(@todo.to_json).merge("list" => { "completion_percentage" => 63 }).to_json }

Answer 2

To refine Brandon's answer, try using:

render :json => @todo.attributes.merge({list: { "completion_percentage" => 63 }})

Answer 3

Just so others are aware, calling @todo.attributes will pull off custom methods on attributes. E.g., if you have in your Todo model a method

    def written_date
      self.written_date = self.written_date.utc.beginning_of_day
    end 

And an attribute called written_date on the Todo Model, only the attribute will come back that is stored in the database.

And you except the custom method to come back when you call @todo.attributes, it will not.