RABL If statement

events_controller.rb

def index
    @events = Event.upcoming.all

    respond_to do |format|
      format.html # index.html.erb
      format.json { @events }
    end
  end

index.rabl

collection @events
attributes :title, :date, :time, :venue, :description, :price, :address, :featured, :catId, :link, :latitude, :longitude
node(:imageUrl){|events| events.image.url(:main)}
node(:imageThumbUrl){|events| events.image.url(:thumb)}