generators 的生成

一般在我们想要的模块的文件夹名(如: make_voteable)下有：

1.想要生成的放在模板文件的文件夹： templates
2.放置rails generate xxx 命令的文件(如：make_voteable_generator.rb)

在‘放置rails generate xxx 命令的文件‘通常有require 'rails/generators/想要的命令 一般为：

    autoload :Actions,               'rails/generators/actions'
    autoload :ActiveModel,         'rails/generators/active_model'
    autoload :Migration,             'rails/generators/migration'
    autoload :NamedBase,         'rails/generators/named_base'
    autoload :ResourceHelpers,   'rails/generators/resource_helpers'
    autoload :TestCase,              'rails/generators/test_case'

这里面的一个或几个。你想生成什么类型的文件？？

而模板文件比较‘死’，一般来说你想要什么就写什么即可。

（一般来说 rails 插件里的 generators 与其它代码是‘无关的’，也就是说它们是独立的。生成代码可以与其它代码完全没有联系！）

==== 分隔线 === 3个常用方法

在这xyz_generator.rb文件中一定有source_root(path=nil)方法

source_root(path=nil) 方法源代码：

# File railties/lib/rails/generators/base.rb, line 25
def self.source_root(path=nil)
  @_source_root = path if path
  @_source_root ||= default_source_root
end

还有
migration_template(source, destination=nil, config={})上方法经常用到，需记住！源代码为：

      # Creates a migration template at the given destination. The difference
      # to the default template method is that the migration version is appended
      # to the destination file name.
      #
      # The migration version, migration file name, migration class name are
      # available as instance variables in the template to be rendered.
      #
      # ==== Examples
      #
      #   migration_template "migration.rb", "db/migrate/add_foo_to_bar.rb"
      #
      def migration_template(source, destination=nil, config={})
        destination = File.expand_path(destination || source, self.destination_root)

        migration_dir = File.dirname(destination)
        @migration_number     = self.class.next_migration_number(migration_dir)
        @migration_file_name  = File.basename(destination).sub(/\.rb$/, '')
        @migration_class_name = @migration_file_name.camelize

        destination = self.class.migration_exists?(migration_dir, @migration_file_name)

        if !(destination && options[:skip]) && behavior == :invoke
          if destination && options.force?
            remove_file(destination)
          elsif destination
            raise Error, "Another migration is already named #{@migration_file_name}: #{destination}"
          end
          destination = File.join(migration_dir, "#{@migration_number}_#{@migration_file_name}.rb")
        end

        template(source, destination, config)
      end

此外，还有这个copy_file(src, dest, preserve = false, dereference = true)。这个为Ruby代码！