Rails 5 (API-only) Notes

notes.md

The following are some notes I put together while working on a Rails 5 (API-only) application, after having been away from Ruby/Rails for some time. Maybe they'll be useful to others, too?

Testing

• Inheriting from MiniTest::Unit::TestCase (e.g. class SendOnboardingNotCompleteReminderEmailWorkerTest < MiniTest::Unit::TestCase, as provided by Sidekiq generator) results in: ArgumentError: unknown command 'i'. Use: class SendOnboardingNotCompleteReminderEmailWorkerTest < ActiveSupport::TestCase instead.

• timecop-like funcionality is baked into ActiveSupport

  include ActiveSupport::Testing::TimeHelpers

  travel_to(1.day.ago) {}

• FactoryBot values are static unless set using a block: confirmed_at { Time.now }

ActiveRecord

• enums can be very useful, especially during early iterations/spikes.
• class with foreign_key uses belongs_to; using has_one will result in "must exist" error
• has_many :through requires has_many :through_join_table
• find record which contains an array which contains at least one of a list of arguments

    query = "array[?] && things"    
    things = ["papers", "books"]    
    Stuff.find_by(query, things)

Vim Rails

Vim Rails' intelligent file navigation is very useful and quickly becomes something you wish was available for every language/framework/library. The mnemonics are also very intuitive and once you know them, they'll likely Just Work for models/tests/controllers/etc.

My favorite commands and some notes:

• :Emigrate edits the latest migration (I was aware of this command but not what the E stood for)
• :Smigration open the latest migration in a new split
• :Emodel if executed while editing UsersController will open UserModel

Sidekiq

• You can't pass kwargs to a Sidekiq worker

Misc

• I've found the following helper to be very useful for setting required global variables (using ENV vars) from within initializers:

  # lib/helpers.rb
  fetch_from_env_or_fail = lambda { |key|  ENV.fetch(key) { fail "#{key} is required." }}
  
  # config/initializers/redis.rb
  REDIS_HOST = fetch_from_env_or_fail.("REDIS_HOST")
  

• JSONPlaceholder is very useful for simulating external services