Ruby-on-rails – How to configure Ruby on Rails with no database

This is really late, but here's how you can find where a method is defined:

http://gist.github.com/76951

# How to find out where a method comes from.
# Learned this from Dave Thomas while teaching Advanced Ruby Studio
# Makes the case for separating method definitions into
# modules, especially when enhancing built-in classes.
module Perpetrator
  def crime
  end
end

class Fixnum
  include Perpetrator
end

p 2.method(:crime) # The "2" here is an instance of Fixnum.
#<Method: Fixnum(Perpetrator)#crime>

If you're on Ruby 1.9+, you can use source_location

require 'csv'

p CSV.new('string').method(:flock)
# => #<Method: CSV#flock>

CSV.new('string').method(:flock).source_location
# => ["/path/to/ruby/1.9.2-p290/lib/ruby/1.9.1/forwardable.rb", 180]

Note that this won't work on everything, like native compiled code. The Method class has some neat functions, too, like Method#owner which returns the file where the method is defined.

EDIT: Also see the __file__ and __line__ and notes for REE in the other answer, they're handy too. -- wg

Now, the accepted way to set the humanized names and custom error messages is to use locales.

# config/locales/en.yml
en:
  activerecord:
    attributes:
      user:
        email: "E-mail address"
    errors:
      models:
        user:
          attributes:
            email:
              blank: "is required"

Now the humanized name and the presence validation message for the "email" attribute have been changed.

Validation messages can be set for a specific model+attribute, model, attribute, or globally.