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Ugrading from 4.2 to 5.0

• Rails 5.0 requires ruby version 2.2.2+
  • Current version: 2.3.1
• All models inherit from ApplicationRecord
  • Create app/models/application_record.rb with the following code:

  class ApplicationRecord < ActiveRecord::Base
    self.abstract_class = true
  end
  

  • Make sure all your models inherit from it!
• before callbacks would return false in ActiveRecord and ActiveModel and thereby halting the entire execution chain.
  • Callback chains must be explicitly halted by calling throw(:abort)
  • Add to config/application.rb: ActiveSupport.halt_callback_chains_on_return_false = false
• ActiveJob now inherits from ApplicationJob
  • Create app/jobs/application_job.rb add the following code

  class ApplicationJob < ActiveJob::Base
  end
  

  • Make sure all job classes inherit from it.
• If using assigns and assert_template in controller tests add gem 'rails-controller-testing' to gemfile
• Uploading files using ActionDispatch::Http::UploadFile replace with Rack::Test::UploadedFile
• Autoloading is now disabled after booting in Production Environment, if need to be set use: Rails.application.config.enable_dependency_loading = true
• ActiveModel::Serializers::Xml has been extracted into a gem: gem 'activemodel-serializers-xml'
• Support for mysql has been removed, use mysql2
• Use rails instead of rake for running tasks and tests
• Calling params will now return an object instead of a hash.
  • If using params.permit then no changes are needed.
  • Otherwise, you will need to convert params.permit([:proceed_to, :return_to]).to_h
• protect_from_forgery defaults to prepend: false
• Default template handler is now RAW. Always specify the extension of your file to be parsed by an appropriate template handler
• Add wildcard for template dependencies
• content_tag_for and div_for have been removed in favor of just using content_tag, to continue using the older view helper methods add the gem gem 'record_tag_helper', '~> 1.0' to gemfile
• The protected_attributes gem is no longer supported in Rails 5!
• The activerecord-deprecated_finders gem is no longer supported in Rails 5!
• Test cases are now ran randomly instead of sorted, to revert to sorted:

# config/environments/test.rb
Rails.application.configure do
  config.active_support.test_order = :sorted
end

• ActionController::Live became a concern!
  • If ActionController::Live is included in another module that is included in your controller, then you should extend the module with ActiveSupport::Concern

Framework Defaults

• belongs_to will now trigger a validation error by default if there is no association present
  • Can be turned off per association by using : optional: true
  • For all associations, place LOC inside an initializer: config.active_record.belongs_to_required_by_default = true
• Per-form CSRF tokens: when activated every form in your app will each have their own CSRF token that is specific to that action and method for that form: config.action_controller.per_form_csrf_tokens = true
• For additional CSRF protection, you can configure your app to check if the HTTP Origin header should be checked against the site's origin: config.action_controller.forgery_protection_origin_check = true
• Default mailer queue name is mailers, you can change it with this configuration: config.action_mailer.deliver_later_queue_name = :new_queue_name
• Support for fragment caching in your config: config.action_mailer.perform_caching = true
• Control how the schema is dumped: config.active_record.dump_schemas = :all
• Configure SSL options to enable HSTS with subdomains: config.ssl_options = { hsts: { subdomains: true } }
• Ruby 2.4: allows you to preserve the timezone of the reciever: ActiveSupport.to_time_preserves_timezone = false
• It is recommended that you do not set columns equal to a String, but pass a Hash instead, which will be converted to and from a JSON string automatically

Ugrading from 5.0 to 5.1

• If app uses HashWithIndifferentAccess class, move to using ActiveSupport::HashWithIndifferentAccess
• In config/secrets.yml all keys are now loaded as symbols, using strings should be changed!

Ugrading from 5.1 to 5.2

• Rails 5.2 adds bootsnap gem (which reduces boot time of app)
  • app:update sets it up in boot.rb, use it then add to gemfile
  • No need to use it then change the boot.rb
• Expiry info is imbedded in ecrypted or signed cookies, which makes the cookies incompatible with Rails older than 5.2
  • If you require cookies to be read by 5.1 and prior: Rails.application.config.action_dispatch.use_authenticated_cookie_encryption: false

Updating Steps

Check current ruby version

• Make sure the version of ruby meets the version specified by the version of rails

Make minor upgrades

• If upgrading a major version of rails (ex. rails 5 to rails 6)
  • Make sure to incrementally increase the version and check the site to see where it breaks (from 5 to 5.2 to 5.x until 6.0)

Update gemfile to the version of Rails

• gem 'rails', ~> '6.0' for example
• In terminal, run bundle update rails
• Fix and update gemfile dependencies
• Update configrations by running rails app:update
• Take a look at the new_framework_defaults.rb file to uncomment any modified settings

Upgrading from 5.2 to 6

Webpacker

• Now is the default javascript compiler for rails 6, but is not automatically included: add to gemfile: gem 'webpacker'
  • then run bin/rails webpacker:install

Force SSL

• force_ssl in controllers has been deprecated and will be removed in 6.1

Purpose and expiry metadata

• has been moved to within signed/encrypted cookie
• Rails.application.config.action_dispatch.use_cookies_with_metadata to false

NPM packages have been moved to within @rails scope

• if the following packages were instgalled via npm/yarn

actioncable   → @rails/actioncable
activestorage → @rails/activestorage
rails-ujs     → @rails/ujs

• they are now included within rails

Actioncable API has been converted to ES6 Syntax

• If using actioncable, make the following changes:

ActionCable.WebSocket = MyWebSocket
ActionCable.adapters.WebSocket = MyWebSocket

ActionCable.logger = myLogger
ActionCable.adapters.logger = myLogger

ActionCable.startDebugging()
ActionCable.logger.enabled = true

ActionCable.stopDebugging()
ActionCable.logger.enabled = false

ActionDispatch::Response#content_type

• calling .content_type now returns the charset
• use .media_type to return just the mime type

config.hosts setting

• allows you to add hosts when in development environment

# config/environments/development.rb
config.hosts << "example.com"
# can also use regexp:
config.hosts << /[a-zA-Z0-9].example.com/

---

Autoloading

• files classes, and modules are now automatically loaded using zeitwerk
  • zeitwerk autoloads or eager loads all files in your app so that no require_directive statements are needed

# config/application.rb
config.load_defaults 6.0

# if upgrdaing from older version of rails
# config/application.rb
config.autoloader :zeitwerk 

Autoload paths

app/models
app/models/concerns

• app/models/concerns/foo.rb can now be defined as Foo and not Concerns::Foo
• concerns folder has now been added to the autoload path (assumed as root directory, namespace has been ignored)
• When working with an API set up, files like app/api/base.rb, usually defined as Api::Base will now be defined as just Base
  • rails adds all subdirectories of app/ to the autoload paths
  • to keep that naming convention, remove the desired path from the auto- load path:

ActiveSupport::Dependencies.autoload_paths.delete("#{Rails.root}/app/api")

• Always use classes or modules when defining constants
• One class per file, unless nested within module
• config.cache_classes = false to turn enable reloading in the test env
• Bootsnap should be atleast version 1.4.2
• You can use classic mode instead of zeitwerk by:

# config/application.rb
config.load_defaults 6.0
config.autoloader = :classic

---

Active Storage

* `has_many_attached` used to append new files to the collection
* new behavior: overwrites the current collection
* use `attach` to add new attachments without overwriting the existing ones