Adds :callback option to to_json for Array, Hash and ActiveRecord::Base.

json_callbacks.rb

# Adds :callback option to to_json for Array, Hash and ActiveRecord::Base.  Usage:
#   user = User.find(:first)
#   user.to_json(:callback => "foo")
#   => foo({"user":{"name":"The Dude"}})
# There's probably a much better way to do this - would love ideas / improvements!

class Array
  alias orig_to_json to_json
  def to_json(*a)
	callback = nil
	if a[0] && !a[0][:callback].blank?
		callback = a[0][:callback]
		a[0].delete(:callback)
	end
    r = self.orig_to_json(a[0])
	if callback
      r = "#{callback}(#{r})"
    end
    r
  end 	
end

class Hash
  alias orig_to_json to_json
  def to_json(*a)
	callback = nil
	if a[0] && !a[0][:callback].blank?
		callback = a[0][:callback]
		a[0].delete(:callback)
	end
    r = self.orig_to_json(a[0])
	if callback
      r = "#{callback}(#{r})"
    end
    r
  end 
end

class ActiveRecord::Base
  alias orig_to_json to_json
  def to_json(*a)
	callback = nil
	if a[0] && !a[0][:callback].blank?
		callback = a[0][:callback]
		a[0].delete(:callback)
	end
    r = self.orig_to_json(a[0])
	if callback
      r = "#{callback}(#{r})"
    end
    r
  end
end