A simple, standardized way to build and use Service Objects (aka Commands) in Ruby
A simple, standardized way to build and use Service Objects (aka Commands) in Ruby
Add this line to your application's Gemfile:
gem 'simple_command'
And then execute:
$ bundle
Or install it yourself as:
$ gem install simple_command
Here's a basic example of a command that authenticates a user
# define a command class class AuthenticateUser # put SimpleCommand before the class' ancestors chain prepend SimpleCommand include ActiveModel::Validationsoptional, initialize the command with some arguments
def initialize(email, password) @email = email @password = password end
mandatory: define a #call method. its return value will be available
through #result
def call if user = User.find_by(email: @email)&.authenticate(@password) return user else errors.add(:base, :failure) end nil end end
in your locale file ```yaml
en: activemodel: errors: models: authenticate_user: failure: Wrong email or password ```
Then, in your controller:
class SessionsController < ApplicationController def create # initialize and execute the command # NOTE: `.call` is a shortcut for `.new(args).call` command = AuthenticateUser.call(session_params[:email], session_params[:password])# check command outcome if command.success? # command#result will contain the user instance, if found session[:user_token] = command.result.secret_token redirect_to root_path else flash.now[:alert] = t(command.errors.full_messages.to_sentence) render :new end
end
private
def session_params params.require(:session).permit(:email, :password) end end
Make the spec file
spec/commands/authenticate_user_spec.rblike:
describe AuthenticateUser do subject(:context) { described_class.call(username, password) }describe '.call' do context 'when the context is successful' do let(:username) { 'correct_user' } let(:password) { 'correct_password' }
it 'succeeds' do expect(context).to be_success end end context 'when the context is not successful' do let(:username) { 'wrong_user' } let(:password) { 'wrong_password' } it 'fails' do expect(context).to be_failure end end
end end
git checkout -b my-new-feature)
git commit -am 'Add some feature')
git push origin my-new-feature)