module Rails::Generators::Migration

Holds common methods for migrations. It assumes that migrations have the [0-9]*_name format and can be used by other frameworks (like Sequel) just by implementing the next migration version method.

Attributes

migration_class_name[R]

migration_file_name[R]

migration_number[R]

Public Instance Methods

create_migration(destination, data, config = {}, &block) Show source

# File railties/lib/rails/generators/migration.rb, line 35
def create_migration(destination, data, config = {}, &block)
  action Rails::Generators::Actions::CreateMigration.new(self, destination, block || data.to_s, config)
end

migration_template(source, destination, config = {}) Show source

# File railties/lib/rails/generators/migration.rb, line 56
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
    if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
      ERB.new(::File.binread(source), trim_mode: "-", eoutvar: "@output_buffer").result(context)
    else
      ERB.new(::File.binread(source), nil, "-", "@output_buffer").result(context)
    end
  end
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"

set_migration_assigns!(destination) Show source

# File railties/lib/rails/generators/migration.rb, line 39
def set_migration_assigns!(destination)
  destination = File.expand_path(destination, 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