Rabl for a nested hash of ActiveRecord collections - ruby-on-rails

Question

I have a few ActiveRecord objects like City, Country, State etc. My controller action is like (as a representative example):
def get_data
#data = {
cities: City.limit(2),
countries: Country.limit(2),
states: State.limit(2),
version: 1000
}
respond_with #data
end
I want to render a JSON like:
{
data: {
country: [{id: 1, name: 'a'}, {id: 2, name: 'b'}],
state: [{id: 1, name: 'p'}, {id: 2, name: 'q'}],
city: [{id: 1, name: 'x'}, {id: 2, name: 'y'}],
version: 1000
}
}
(Please note singular keys for collections, Please do not suggest changes to the JSON structure, as it is fixed.)
What should be the rabl template for this? I have been breaking my head on this for hours.

Answer 1

if i were you i will not even care to go to rabl template for this because what your are creating with this code:
#data = {
cities: City.limit(2),
countries: Country.limit(2),
states: State.limit(2),
version: 1000
}
is the final output , not the individual components.
you can just replace this with:
render :json => {
:data => {
cities: City.limit(2).map{ |c|{:id => c[:id] },
countries: Country.limit(2).map{ |c|{:id => c[:id] },
states: State.limit(2).map{ |c|{:id => c[:id] },
version: 1000
}
}
its not a best use case for rabl , but if you still want it to load via rabl this below code in the get_data.json.rabl will do just fine.
node :data do
{
:version_number => #data[:version_number],
:country => #data[:countries].map{ |c|{:id => c[:id] , :name => c[:name]} }
:state => #data[:states].map{ |s|{:id => s[:id] , :name => s[:name]} }
:city => #data[:city].map{ |c|{:id => c[:id] , :name => c[:name]} }
}
end