...transactions and locking. Examples will be given for the ActiveRecord ORM (from Ruby on Rails), but apply to all technologies. Use transactions to group related changes Use a transaction to...
...than a single database row, you should always use a transaction. Note that in Rails, ActiveRecord::Base#save automatically opens a transaction. Hence changes you make in callbacks, nested attributes...
...the need for manual intervention that might destabilize or even crash the application. As Rails does not set a timeout on database statements by default, the following query will run...
...statement_timeout"=>"10s"}] begin ActiveRecord::Base.connection.execute("SELECT pg_sleep(15)") rescue ActiveRecord::QueryCanceled => e Rails.logger.error("Query was canceled: #{e.message}") end Adjust or disable the timeout for a single transaction:
Rails includes a way to see what an e-mail will look like. Integration to RSpec All you need to do is implement a preview-class in spec/mailers/previews/notifier_preview.rb: class NotifierPreview...
end end And adapt the preview load path in your application.rb: config.action_mailer.preview_path = "#{Rails.root}/spec/mailers/previews" # For Rails < 7.1 config.action_mailer.preview_paths << "#{Rails.root}/spec/mailers/previews" # For Rails >= 7.1 Then a preview will...
git_source(:github) { |repo| "https://github.com/#{repo}.git" } ruby "2.7.6" gem "rails", "~> 7.0.6" gem "sqlite3", "~> 1.4" gem "puma", "~> 5.0" This blocks automatic updates of rails, sqlite3 and puma...
git_source(:github) { |repo| "https://github.com/#{repo}.git" } ruby "2.7.6" gem "rails" gem "sqlite3" gem "puma" All gems are easily updateable with bundle update Good source "https://rubygems.org...
Rails 3, 4, 5, 6 config/application.rb config/environment.rb before the initialize! call (we don't usually edit this file) The current environment, e.g. environments/production.rb Gems Vendored plugins All initializers in config/initializers...
...initialize! call (we don't usually edit this file) Your own code from app Rails 2 Code in config/preinitializer.rb (if it exists) environment.rb, code above the Rails::Initializer.run block (put...
...test using Capybara::Session#save_and_open_page and Capybara::Session#save_screenshot. Use Rails' built-in screenshot module If you want to avoid an external gem and use system...
...tests, you can also use Rails' built-in ScreenshotHelper module available for Rails >= 5. Including assets in HTML screenshots for prettier presentation Note Capybara takes two kinds of screenshots: a...
Debugging performance issues in your Rails app can be a tough challenge. To get more detailed insights consider using the rack-mini-profiler gem. Setup with Unpoly Add the following...
...up.link.config.noFollowSelectors.push('.profiler-results a') document.addEventListener('up:link:follow', () => { if (window.MiniProfiler !== undefined) { window.MiniProfiler.pageTransition() } }) } # config/initializers/rack_mini_profiler.rb if Rails.env.development? Rails.application.config.to_prepare do Rack::MiniProfiler.config.position = 'top-right' # positon widget top-right Rack::MiniProfiler.config.skip_paths = [ # ignore...
...for consumption in browsers. Webpacker is a wrapper around webpack that handles integration with Rails. This is a short introduction. Installation If you haven't already, you need to install...
...x is still current! in your Gemfile. Run bundle install Finally, run bundle exec rails webpacker:install Alternatively, you can add webpacker from the start when creating a new Rails...
...an empty exclusion list returns no records at all! See below for better implementations. Rails 4+ Use the .not method to let Rails do the logic # Good User.where.not(id: []).to...
=> SELECT "users".* FROM "users" WHERE "users"."id" NOT IN (1, 2) Rails < 4 Before Rails 4, you needed to work around this yourself: # Good excluded_ids.blank? ? User.all : User.where("id...
TL;DR PostgreSQL handles Rails 4+ text and string columns the same. Some libraries may still reflect on the column type and e.g. render differently sized text fields. PostgreSQL offers...
...costs. In most situations text or character varying should be used instead. Up to Rails 3, the column type string defaulted to creating a varchar column limited to 255 characters...
...DELETE. Redirect responses to GET and POST will be followed with a GET. The Rails form_for helper will use a workaround to send POST requests with a _method param...
...Fix on the client: Make a POST request with method override The default configuration Rails and Sinatra includes a Rack middleware that lets you control the HTTP method used for...
I recently stumbled upon the Rails feature composed_of. One of our applications dealt with a lot of addresses and they were implemented as 7 separate columns in the DB...
...enforced that. Because I used a regular class, I had to build it myself. The Rails-native readonly is sadly only available with ActiveRecord, not with ActiveModel. It would have...
...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...
...can never change them without forcing users to empty their cache. Note By default Rails sends a header Cache-Control: max-age=0, private, must-revalidate with all responses, including...
...cached by browsers. You do need to pay attention if you redirect outside of Rails, e.g. via your web server configuration. Dealing with incorrectly cached redirects The only fix is...
Empty CSPs with send_file If you use send_file from a Rails controller, you can send potentially dangerous files with an inline disposition iff you also send...
...would execute active content): Content-Disposition: attachment If you use send_file from a Rails controller, the default disposition is attachment. You can also set it explicitly: send_file @attachment.path...
...lot more gems than you think. E.g. when you do this: bundle update cucumber-rails ... you might think this will only update cucumber-rails. But it actually updates cucumber-rails...
...breaking API changes. Which is all the time. In the example above updating cucumber-rails will give you Capybara 2.0 (because capybara is a dependency of cucumber-rails), which will...
...shoulda-matchers gem gives you some RSpec matchers to test the application of standard Rails validations. Under the hood should-matchers uses the same recipe as outlined above (set invalid...
...screen_name is not a palindrome. Since that check is not possible with standard Rails validations, we write a custom validation method like this: class User < ActiveRecord::Base validate :validate...
...add support for parallel tests. You can easily do that by setting config.root: config.root = "#{Rails.public_path}/system/#{Rails.env}#{ENV['TEST_ENV_NUMBER']}".freeze For debugging purposes (e.g. trying to hunt...
...separate environment. You you could read from an ENV variable instead of using your Rails.env. Suggested configuration In total, here is a suggested configuration that you can put into config/initializers/carrierwave.rb...
...comparison can often be seen with simple string comparison like so. # ❌ Not recommended if Rails.version > '6.1.7.8' || RUBY_VERSION > '3.1.4' raise Error, 'please check if the monkey patch below is still...
...comparison above works by coincidence. But chances are that you are not: For example, Rails version 6.1.10.8 would not raise an error in the code block above, because in an...
...of form.fields_for. You forgot to use accepts_nested_attributes in the containing model. Rails won't complain, but nothing will work. In particular, nested_form.object will be nil.
You are not setting the inverse_of for a has_many through association. Rails will then not be able to process a collection assignment, since it can't find...
...config/initializers/searchkick.rb (or wherever you have configured your Searchkick settings) add: SEARCHKICK_CLIENT_TYPE = case Rails.env when 'production', 'staging', 'development', 'test' :elasticsearch else :opensearch end Searchkick.client_type = ENV.fetch('SEARCHKICK_CLIENT_TYPE...
...SEARCHKICK_CLIENT_TYPE).to_sym ENV['OPENSEARCH_URL'] ||= case Rails.env when 'production' OPENSEARCH_PRODUCTION_SERVER when 'staging' OPENSEARCH_STAGING_SERVER else 'http://opensearch:9200' # docker container name end
...model validation that restricts its length. There are two motivations for this: In modern Rails, database types :string and :text no longer have a relevant size limit. Without a validation...
...malicious user can quickly exhaust the hard drive of your database server. In legacy Rails (or database schemas migrated from legacy Rails), database types :string and :text had a database...
Recent rails security updates have shown that people make incorrect assumptions about the possible contents of the params hash. Just don't make any! Treat it as what it is...
.../pages/edit?foo --> params == {:foo => nil} /pages/edit?foo[] --> params == {:foo => [nil]} # at least in older rails 3 and in rails 2.x Be especially wary about stuff like User.find_by_password...
...but give sub-classes a way to override values without affecting the parent class. Rails has many helpers for this such as class_attribute and class_inheritable_accessor. Unfortunately their...
...semantics are hard to understand, the helpers available differ for different versions of Rails and the behavior is subtly different. Make sure you read and understand the API before using...