ActiveModel supplies an errors object that behaves similar to a Hash. It can be used to add errors to a...
Greg Molnar has written a neat article about creating a single-file Rails app. This is not meant for production use but can be useful to try things out, e.g...
...when hunting down a bug or embedding a Rails app into the tests of a gem. What you do is basically: Put everything (gems, application config, database migrations, models, controllers...
...you have a maintenance script where you want to iterate over all ActiveRecord models. Rails provides this out of the box: # script/maintenance_task.rb # Load all models eagerly, otherwise you might only...
Rails.application.eager_load! ApplicationRecord.descendants.select(&:table_exists?).each do |model| # ... end Caution If you iterate over individual records, please provide a progress indicator: See https://makandracards.com/makandra/625369-upload-run-scripts-production Caution
Sometimes you need to remove high Unicode characters from a string, so all characters have a code point between 0...
All columns of a model's database table are automagically available through accessors on the Active Record object.
Concurrent counter increments are a race-condition trap. The Rails idiom (load the record, increment in Ruby, save) breaks under concurrent writes. Between the read and the write, another transaction...
...using ActiveStorage's disk service. This means that stored files are served by your Rails application, and every request to a file results in (at least!) one non-trivial log...
...an example of what loading a single in an example application writes to the Rails log. Started GET "/rails/active_storage/blobs/redirect/..." for ::1 at ... Processing by ActiveStorage::Blobs::RedirectController#show as SVG...
By default, Rails' validates_uniqueness_of does not consider "username" and "USERNAME" to be a collision. If you use MySQL this will lead to issues, since string comparisons are case...
...may fail with an SQL error due to duplicate index key. You can change Rails' behaviour, by saying class User < ActiveRecord::Base validates_uniqueness_of :name, case_sensitive: false
...groups are a useful RSpec feature. Unfortunately the default directory structure generated by rspec-rails has no obvious place to put them. I recommend storing them like this: spec/models/shared_examples/foo.rb spec/models/shared_examples/bar.rb...
...those shared examples available to all specs, put the following into your spec_helper.rb (for rails 4 in rails_helper.rb), above the RSpec.configure block: Dir[Rails.root.join("spec/models/shared_examples/**/*.rb")].each {|f| require f...
Rails' fragment caching caches subtrees of an HTML document tree. While constructing that tree though, it can be really hard to keep track of whether some code is run in...
...a caching context. Fortunately, Rails 7 brings two helpers that simplify this. Note that these helpers are all about Rails' fragment caching and not about downstream caching (i.e. Cache-Control...
if 'foo' =~ /foo/ puts $LAST_MATCH_INFO[1] # => foo end Require pitfall in Rails The English library is not loaded by default in Rails. So you or another library...
TL;DR: Pannellum is a small (~56 kB, own WebGL renderer, no three.js) equirectangular panorama viewer. The npm package has...
...posts with a limited number of tags. The following chapters explain different approaches in Rails, how you can assign such an association via HTML forms. In most cases you want...
...with assignable values. The basic setup for all options looks like this: config/routes.rb Rails.application.routes.draw do root "posts#index" resources :posts, except: [:show, :destroy] end db/migrate/20230510093740_create_posts.rb class CreatePosts < ActiveRecord::Migration...
...scope :all_tags, -> (tags){ where('tags @> ARRAY[?]', tags) } end Document.create(title: "PostgreSQL", tags: ["pg","rails"]) Document.any_tags('pg') Document.all_tags(['pg', 'rails']) Migration: class CreateDocuments < ActiveRecord::Migration def change
Rails' Strong Parameters enable you to allow only specific values from request params to e.g. avoid mass assignment. Usually, you say something like params.permit(:email, :password) and any extra parameters...
...after_logout idp_sign_out] end Unsafe redirect when trying to log out Since Rails 7 you need to pass allow_other_host: true to redirect_to to allow a...
...so that a tcp connection is used instead of a socket connection. Configure rails application to use the database development: adapter: mysql2 database: projectname_development encoding: utf8mb4 collation: utf8mb4_unicode...
tl;dr Prefer request specs over end-to-end tests (Capybara) to joyfully test file downloads! Why? Testing file downloads
It is very common to parse dates from strings. It seems obvious to use Date.parse for this job. However this...
...in any structure. While its flexibility is great, there is no syntactic sugar in Rails yet. Thus, you need to manually query the database. Demo # Given a Task model with...
When internationalizing your Rails app, you'll be replacing strings like 'Please enter your name' with t('.name_prompt'). You will be adding keys to your config/locales/*.yml files over...
So you want to organize your I18n using multiple .yml files but your Rails 4.1 application simply won't use any extra files in development? Spring is to blame.
...gem with strategy :transaction, after_commit callbacks will not be fired in your tests. Rails 5+ Rails 5 has a fix for this issue and no further action is needed...
...Rails 3, Rails 4 Add the gem test_after_commit to your test group in the Gemfile and you are done. You don't need to change the database strategy...
Since Rails 7 you are able to encrypt database information with Active Record. Using Active Record Encryption will store an attribute as string in the database. And uses JSON for...
...need to configure your Active Record Encryption keys manually in the config/application.rb: config.active_record.encryption.primary_key = Rails.application.secrets.dig(:active_record_encryption, :primary_key) config.active_record.encryption.deterministic_key = Rails.application.secrets.dig(:active_record_encryption, :deterministic_key) config.active_record.encryption.key_derivation...