HOWTOs for Ruby on Rails and JavaScript

Rails: How to get URL params without routing parameters (or vice versa)

Rails merges query string, request body, and routing data in params; request.query_parameters and request.path_parameters separate URL values from route data.

Edit

Rails Env Widget

A small helper adds a dismissible on-screen badge showing the current Rails environment to prevent confusion between development, test, and production.

rails_env_widget_helper.rb

Edit

Cucumber step to pick a datetime in Rails' horrible datetime_select

datetime_select creates a clumsy date and time chooser in Rails; a visual picker is usually better, but a Cucumber step can still drive it.

Edit

Rails index route for resources named after uncountable substantives

Uncountable Rails resources break normal route helpers and form handling. resource can still expose the index action through a special _index_path helper.

markembling.info

Edit

dusen and edge_rider gems no longer depend on Rails

dusen 0.4.8 and edge_rider 0.2.3 no longer require Rails, while still depending on ActiveRecord, making them usable with Sinatra and other non-Rails apps.

Edit

Rails: Invoking a view helper from the console

Call view helpers from the Rails console via helper or an ActionView::Base instance when a helper depends on templates.

Edit

Rails 4.1+ automatically detects the :inverse_of an association

Rails 4.1 infers association inverses automatically, but failures are silent and extra options can block detection. Setting :inverse_of manually remains safer.

guides.rubyonrails.org

Edit

OR-ing query conditions on Rails 4 and 3.2

Rails 4 and 3.2 lack ActiveRecord::Relation#or for combining query conditions; activerecord_any_of provides any_of and none_of for cleaner disjunctive filters.

github.com

Edit

Rails 3.1 error message: Could not find a JavaScript runtime

Fresh Rails 3.1 apps can fail on boot when ExecJS cannot locate a JavaScript runtime, and adding a runtime gem to the Gemfile removes the error.

Edit

Subscribe to Rails security mailing list without Google account

Subscribe to the Ruby on Rails security mailing list without a Google account by using a direct boxsubscribe URL instead of the web interface.

Edit

How to enable Rails' file_fixture helper in FactoryBot

FactoryBot factories do not get Rails' file_fixture helper by default; including RSpec Rails file fixture support makes file_fixture available and sets the fixture path.

Edit

How to disable Rails raising errors on pending migrations in development

Rails 4 can block page loads in development when migrations are pending, which interrupts experimenting with a new migration. Setting config.active_record.migration_error to false disables the check.

Edit

Fix Rubygems warning: Gem.source_index is deprecated, use Specification

Rubygems updates can flood legacy Rails apps with Gem::SourceIndex deprecation warnings. SlimGems or upgrading Rails 2.3.11 to 2.3.12+ reduces the noise.

Edit

Use non-ASCII characters on IRB and Rails consoles with RVM and Mac OS X

Missing readline support prevents non-ASCII input in IRB or Rails consoles on Mac with RVM; reinstalling Ruby with readline enables 8-bit characters.

Edit

Retrieve the SQL query a scope would produce in ActiveRecord

Get the SQL generated by an ActiveRecord scope without executing it; Rails 3 uses to_sql, while Rails 2 needs a backport or construct_finder_sql.

Edit

Use the Ruby debugger on Rails 2 script/runner scripts

Rails 3+ script/runner debugging needs rdebug because --debugger is gone; Ruby-debug must be available and required to enter the debugger from a script.

Edit

Fix error: rails console - no such file to load -- readline

rails console fails with no such file to load -- readline when Ruby was built without readline support. Reinstalling Ruby with the readline development library available restores console input.

Edit