rails.md

Rails conventions

App behavior should be configured via environment variables

When implementing new features, it should not depend on current RAILS_ENV value, but environment variable(s) specific to the feature.

• Avoid modifying config/environments/*.rb, and keep default Rails configuration (this will also help when updating Rails)
• Avoid testing:
  • Rails.env.development?
  • Rails.env.production?
  • Rails.env.test?

Examples:

# bad:
module MyRailsApp
  class Application < Rails::Application
    if Rails.env.production?
      config.middleware.use Rack::Attack
    end
  end
end

# good:
module MyRailsApp
  class Application < Rails::Application
    if ENV.key? "RACK_ATTACK_ENABLED"
      config.middleware.use Rack::Attack
    end
  end
end

Routing

Format segregation

Actual format segregation should be performed based on the HTTP Accept header (Accept: application/json), not based on a URL suffix (/resource.json).

A unique resource should only be requested on a unique URL, which is why we should avoid extension-based routing as much as possible.

# bad
GET /resources.html
GET /resources.json

# bad
GET /resources       [Accept: text/html]
GET /api/resources   [Accept: application/json]

# good
GET /resources       [Accept: text/html]
GET /resources       [Accept: application/json]

This can be achieved in Rails using the following router configuration:

Rails.application.routes.draw do
  concern :resources do
    resources :posts
    resources :comments
  end

  scope format: ENV.key?("ALLOW_FORMAT_FROM_URL") ? nil : false do
    scope module: :api, constraints: ->(req) { req.format == :json } do
      concerns :resources
    end
    concerns :resources
  end
end