ruby-patterns

Ruby Patterns

Project Structure

Gem Layout

my_gem/
├── lib/
│   ├── my_gem.rb              # Entry point, require sub-files
│   └── my_gem/
│       ├── version.rb
│       ├── configuration.rb
│       ├── client.rb
│       └── errors.rb
├── spec/
│   ├── spec_helper.rb
│   ├── my_gem/
│   │   └── client_spec.rb
│   └── fixtures/
├── bin/
│   └── console              # IRB with gem loaded
├── sig/                     # RBS type signatures
├── Gemfile
├── Rakefile
├── my_gem.gemspec
├── .rubocop.yml
└── .ruby-version

Rails Standard Structure

app/
├── controllers/
│   ├── application_controller.rb
│   └── api/v1/
│       └── users_controller.rb
├── models/
│   ├── application_record.rb
│   ├── user.rb
│   └── concerns/
│       └── searchable.rb
├── services/
│   └── users/
│       ├── create_service.rb
│       └── import_service.rb
├── jobs/
│   └── user_sync_job.rb
├── mailers/
├── serializers/
│   └── user_serializer.rb
└── views/
config/
├── routes.rb
├── database.yml
├── initializers/
│   ├── sidekiq.rb
│   └── cors.rb
└── environments/
db/
├── migrate/
├── schema.rb
└── seeds.rb
spec/
├── rails_helper.rb
├── spec_helper.rb
├── models/
├── requests/
├── services/
├── factories/
│   └── users.rb
└── support/
    └── shared_examples/

Gemfile Best Practices

source "https://rubygems.org"

ruby "~> 3.3"

gem "rails", "~> 7.2"
gem "pg"
gem "puma", ">= 6.0"
gem "sidekiq", "~> 7.0"
gem "redis", ">= 5.0"

group :development, :test do
  gem "rspec-rails"
  gem "factory_bot_rails"
  gem "faker"
  gem "debug"
  gem "rubocop-rails", require: false
  gem "rubocop-rspec", require: false
end

group :test do
  gem "shoulda-matchers"
  gem "webmock"
  gem "vcr"
  gem "simplecov", require: false
end

---

Idioms / Code Style

Blocks, Procs, and Lambdas

# Block -- yielded to, not stored
def with_retry(attempts: 3)
  attempts.times do |i|
    return yield
  rescue StandardError => e
    raise if i == attempts - 1
    sleep(2**i)
  end
end

with_retry { http_client.get("/data") }

# Proc -- flexible arity, returns from enclosing method
validator = Proc.new { |val| val.to_s.strip.length > 0 }

# Lambda -- strict arity, returns from itself
transform = ->(x) { x.to_s.downcase.strip }
words = ["Hello ", " WORLD"].map(&transform)

# Method reference
names = users.map(&:name)
valid = values.select(&method(:valid?))