require 'active_support/concern' require 'rails/generators/actions/create_migration' module Rails module Generators # Holds common methods for migrations. It assumes that migrations has the # [0-9]*_name format and can be used by another frameworks (like Sequel) # just by implementing the next migration version method. module Migration extend ActiveSupport::Concern attr_reader :migration_number, :migration_file_name, :migration_class_name module ClassMethods def migration_lookup_at(dirname) #:nodoc: Dir.glob("#{dirname}/[0-9]*_*.rb") end def migration_exists?(dirname, file_name) #:nodoc: migration_lookup_at(dirname).grep(/\d+_#{file_name}.rb$/).first end def current_migration_number(dirname) #:nodoc: migration_lookup_at(dirname).collect do |file| File.basename(file).split("_").first.to_i end.max.to_i end def next_migration_number(dirname) #:nodoc: raise NotImplementedError end end def create_migration(destination, data, config = {}, &block) action Rails::Generators::Actions::CreateMigration.new(self, destination, block || data.to_s, config) end def set_migration_assigns!(destination) destination = File.expand_path(destination, self.destination_root) migration_dir = File.dirname(destination) @migration_number = self.class.next_migration_number(migration_dir) @migration_file_name = File.basename(destination, '.rb') @migration_class_name = @migration_file_name.camelize end # 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. # # migration_template "migration.rb", "db/migrate/add_foo_to_bar.rb" def migration_template(source, destination, config = {}) source = File.expand_path(find_in_source_paths(source.to_s)) set_migration_assigns!(destination) context = instance_eval('binding') dir, base = File.split(destination) numbered_destination = File.join(dir, ["%migration_number%", base].join('_')) create_migration numbered_destination, nil, config do ERB.new(::File.binread(source), nil, '-', '@output_buffer').result(context) end end end end end