Ruby on Rails: extending ActiveRecord::Errors

In Ruby on Rails, where does one put the code from this snippet in http://gist.github.com/376389? I want to extend ActiveRecord::Errors with the code that's available there so I can merge error messages.

Is this something for ApplicationController? or for lib?

Paste from github.com

# monkey patch gleaned from http://dev.rubyonrails.org/attachment/ticket/11394/merge_bang_errors.patch
module ActiveRecord
  class Errors

    def merge!(errors, options={})
      fields_to_merge = if only=options[:only]
        only
      elsif except=options[:except]
        except = [except] unless except.is_a?(开发者_StackOverflow中文版Array)
        except.map!(&:to_sym)
        errors.entries.map(&:first).select do |field|
          !except.include?(field.to_sym)
        end
      else
        errors.entries.map(&:first)
      end
      fields_to_merge = [fields_to_merge] unless fields_to_merge.is_a?(Array)
      fields_to_merge.map!(&:to_sym)

      errors.entries.each do |field, msg|
        add field, msg if fields_to_merge.include?(field.to_sym)
      end
    end
  end
end

You can just drop that into any ruby file in your initializers directory (create a new one, name it whatever you want). Rails runs all of the files in there every time it is booted, and will extend Errors at that time.

This question is stale but if you want to do something similar in rails 3.x you can drop this in a file in your config/initializers/ directory:

# monkey patch gleaned from http://dev.rubyonrails.org/attachment/ticket/11394/merge_bang_errors.patch

module ActiveModel
  class Errors
    def merge!(errors, options={})
      return if errors.blank? || errors.first.size < 2

      fields_to_merge = if only=options[:only]
        only
      elsif except=options[:except]
        except = [except] unless except.is_a?(Array)
        except.map!(&:to_sym)
        errors.entries.map(&:first).select do |field|
          !except.include?(field.to_sym)
        end
      else
        errors.entries.map(&:first)
      end
      fields_to_merge = [fields_to_merge] unless fields_to_merge.is_a?(Array)
      fields_to_merge.map!(&:to_sym)

      errors.entries.each do |field, msg|
        add field, msg if fields_to_merge.include?(field.to_sym)
      end
    end
  end
end