MethodStruct

Facilitates extracting large methods into objects - see Usage. For a more in-depth treatment of the refactoring see http://sourcemaking.com/refactoring/replace-method-with-method-object. You can also take a look at http://www.bunsch.pl/2014/10/14/wrangling-service-objects-with-method_struct/ for an exmaple of usage in a Rails app.

Installation

Add this line to your application's Gemfile:

gem 'method_struct'

And then execute:

$ bundle

Or install it yourself as:

$ gem install method_struct

Usage

Say you have this:

class UsersController
  def create
    User.create(:email => params[:email], :name => params[:name])
    Mailer.registration_email(params[:email]).deliver
  end
end

You can change it into this:

class Registrator < MethodStruct.new(:email, :name)
  def call
    create_user!
    send_email!
  end

  private
  def create_user!
    User.create(:email => email, :name => name)
  end

  def send_email!
    Mailer.registration_email(:email).deliver
  end
end

class UsersController
  def create
    Registrator.call(params[:email], params[:name])
    # Or
    Registrator.call(:email => params[:email], :name => params[:name])
    # Or - thanks to ruby changing [] into .call
    Registrator[params[:email], params[:name]]
  end
end

You can also specify a different method name like so:

class Registrator < MethodStruct.new(:email, :name, :method_name => :register)
  def register
    # ...
  end
end

class UsersController
  def create
    Registrator.register(params[:email], params[:name])
  end
end

You can use :require_all => true if you want to verify that all arguments have been specified or :require_presence => true to verify that all arguments are non-nil. Global defaults for these options can be changed like so:

MethodStruct::Defaults.set(
  :require_presence => true,
  :method_name => :do_it
)

Method struct currently also supports a do syntax, but it is discouraged (and may get depracated) due to odd constant scoping. Example:

Registrator = MethodStruct.new(:email, :name) do
  REGISTRATION_PATH = "/register" # this is now a top-level constant

  def call
    ...
  end
end

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Copyright and license

Copyright 2020 Zendesk

Licensed under the Apache License, Version 2.0