Monkey patch to fix JSON error decoding in ActiveResource 3

active_resource_errors.rb

# Monkey patch to fix Rails JSON error decoding
# https://gist.github.com/2244799
class ActiveResource::Errors
  
  def from_json(json, save_cache = false)
    clear unless save_cache
    
    decoded = ActiveSupport::JSON.decode(json)
    
    if decoded.is_a?(Hash)
      # Hash from Rails 3
      errors = decoded['errors']
    else
      # Array from Rails 2
      errors = {}
      for attr, value in decoded
        (errors[attr] ||= []) << value
      end
    end
    
    for attr, list in errors
      list.each{|error| add(attr, error) }
    end
  end
end