[Apache] Basic Authentication Settings for Passenger

Adding Basic auth to an Apache + Passenger VirtualHost with htpasswd.

How to Fix 'An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue.' in bundle install

How to fix mysql2 gem's native extension build error by pointing bundler to openssl's ldflags.

[RubyGems] Could not find xxx in any of the sources

Fixing Bundler's 'Could not find gem in sources' by matching the version available on RubyGems.

[Ruby on Rails] Solution for 'An error occurred while installing pg (1.4.5), and Bundler cannot continue.' [macOS Edition]

How to fix pg gem install errors on macOS by installing libpq with Homebrew and updating PATH.

[Capistrano] Deploy by specifying a specific branch or commit

A quick memo for deploying a specific branch or commit with Capistrano's -S flag.

[Ruby] cannot load such file -- ci/reporter/rake/rspec

Rescue ci_reporter's LoadError in Rakefile so Capistrano's assets:precompile survives in production.

[Capistrano] Recipe for executing rake tasks

A Capistrano recipe for invoking rake tasks on a remote server, with a namespace-collision workaround.

[Ruby] For file uploads, use 'CarrierWave'

Notes on the CarrierWave gem for file uploads in Rails, plus how to test uploads with RSpec.

[Ruby] How to Register Local Files with CarrierWave

A short memo on registering a local file with a CarrierWave uploader via store!.

[CircleCI 2.0] Rails 5.x Fix for bundler: failed to load command: rspec ~ NoMethodError: undefined method `captures' for nil:NilClass Error

Fixing the CircleCI 2.0 rspec captures-nil error on Rails 5.x by dropping the test-split step from config.yml.

[CircleCI 2.0] Rails 5.x + Webpacker Configuration Job Setup Method for Running Rspec Tests

A working config.yml for running Rspec on Rails 5.x + Webpacker on CircleCI 2.0's free plan, with notes on the gotchas.

[Column] Interview with Ruby on Rails Creator David Heinemeier Hansson - Dan Kogai's Meeting with Alpha Geeks

A pointer to Dan Kogai's DHH interview on gihyo.jp, plus a note on rereading 37signals' Rework.

How to Enable Facebook App Cookies in IE

Fix third-party cookie loss in Facebook iframe apps on IE by sending a P3P policy header (Rails / PHP).

To Install with Version Specification Using gem install, Add the --version= Option

Use `gem install <name> --version=X.Y.Z` to install a specific gem version instead of the latest.

[Haml] Solution for "syntax error, unexpected keyword_ensure, expecting keyword_end" Error

Fixing a Haml keyword_ensure syntax error caused by missing indentation inside an if branch.

How to Add Heroku Buildpacks to Build in Node.js, Ruby on Rails Order

Reordering Heroku buildpacks to Node.js before Ruby so Yarn and Webpacker install cleanly, via app.json and the CLI.

How to Write a Procfile to Use Ruby on Rails 5 on Heroku's Free Tier

A Procfile for Rails 5 on Heroku's free tier, plus a walkthrough of puma's thread, port, and environment options.

Summary of Commonly Used Commands and Flow for Web App Development with Heroku + Ruby on Rails 3.2

Commands and workflow for building and deploying a Rails 3.2 app to Heroku's Cedar stack, end to end.

[Heroku] Solution for rake assets:precompile Error in Rails 3.2 Apps

Fixing the rake assets:precompile error on Heroku by tweaking application.rb in a Rails 3.2 app.

How to Build an Authenticated Staging Environment with Heroku + Rails

Build a Basic-auth-protected Rails staging environment on Heroku alongside your production app.

[Rails] How to Redo db:migrate to Heroku's Default PostgreSQL

Three ways to force db:migrate to run again on Heroku when rake db:reset is not available.

[Heroku][Rails] How to Install New Relic Add-on [Cedar Stack]

Installing the New Relic add-on into a Rails 3.2.5 app on Heroku's Cedar stack.

[Heroku][Rails] Always Run bundle install After Editing Gemfile

Always run bundle install after editing the Gemfile so Gemfile.lock stays in sync when you push to Heroku.

[Heroku] How to Change WebServer from WEBrick to thin - [Rails 3.x on Heroku/Cedar]

Move a Rails 3.x app on Heroku Cedar off WEBrick and onto the more production-friendly thin server.

[Heroku] Ruby on Rails 4 + Mongoid + MongoHQ '500 Internal Server Error'

Fixing the Mongoid ':consistency is an unknown option' 500 error on Heroku by trimming mongoid.yml.

Heroku Recommended Free Add-ons

Free Heroku add-ons worth enabling early: Papertrail, Rollbar, SendGrid, and Deploy Hooks.

[Heroku] SendGrid Email Sending Configuration Method for Rails 5.x

Wire up the SendGrid Heroku add-on to Rails 5.x ActionMailer and send a test email from the console.

Procedure to Install Redmine on Heroku

Deploy Redmine 1.2.3 to Heroku with .gems pins and attachment paths routed to /tmp/.

Steps to Build Ruby on Rails Development Environment on Mac [Ruby 1.8.7]

Setting up a Rails development environment on macOS with the system Ruby 1.8.7, RubyGems, Rails, and SQLite3.

[Mac] Installing Ruby and Rails with RVM

How to install Ruby and Rails on Mac with RVM, pulling in dependencies through Homebrew.

[Heroku][Rails] NewRelic - Web Application Performance Measurement and Operations Monitoring

Adding the NewRelic addon to a Rails + Heroku app for performance monitoring.

[Ruby] "libiconv is missing" Error During nokogiri Installation with bundle install

Fixing the 'libiconv is missing' error during bundle install of nokogiri with bundle config build.nokogiri.

[Ruby] WARNING: Nokogiri was built against LibXML version 2.7.3, but has dynamically loaded 2.7.8

Fixing the Nokogiri vs LibXML version mismatch warning by reinstalling libxml2 libraries via Homebrew.

[Ruby] Development HTTP Server 'Pow' by 37signals

Using 37signals' Pow — a zero-config Rack dev server for macOS — with Rails and Sinatra apps.

[Rails] Differences Between Routing in Version 2 and 3

A side-by-side comparison of Ruby on Rails 2 and 3 routing DSL with concrete examples.

[Rails3.0] When Scaffold-Generated Delete (Destroy) Links Don't Work, Check if jquery_ujs.js or rails.js is Loaded

Rails 3.0 Destroy links not firing? Check that jquery_ujs.js is loaded via the jquery-rails gem.

[Rails 3.1.0] ActionView::Template::Errror (application.css isn't precompiled)

Fixing the Rails 3.1 application.css isn't precompiled error on Heroku by setting config.assets.compile = true.

[Ruby on Rails 3.1] How to Enable Autoload for Custom Libraries in the lib Directory

Re-enable autoload for lib/ in Rails 3.1 by adding paths to config.autoload_paths in application.rb.

[Rails] Editing scaffold.css to Make Tables More Readable

Make Rails 3.1 scaffold tables more readable by adding a border class to scaffold.css.

How to Change the Root Route from routes.rb in Rails 3

Change the Rails 3 root route with the root directive and delete public/index.html.

[Ruby on Rails] How to Display Confirmation Dialog After Pressing Form Submit Button

Pass a :confirm message to submit_tag in Rails 3.1 to show a confirmation dialog on submit.

[Ruby on Rails 4] group :assets do … end is Deprecated

Rails 4 removed the group :assets block from Gemfile — delete it when upgrading from Rails 3.

Steps to Create Ruby on Rails 5 and Deploy to Heroku

End-to-end steps for spinning up a Rails 5 app and deploying it to Heroku with Heroku Postgres.

Ruby on Rails + Rspec + Capybara Initial Setup

Set up RSpec and Capybara in Rails 5 and run your first Feature test end-to-end.

Rails 5.x + Webpacker + React.js Development Environment Setup

How I set up a Rails 5.x + Webpacker + React.js development environment, from rails new through hot reload and yarn start.

Redux Development Environment Setup on Rails 5.x + React.js + Webpacker

Adding Redux to a Rails 5.x + Webpacker + React.js environment via yarn add.

[Rails] AbstractController::DoubleRenderError

Fixing Rails 3.1's AbstractController::DoubleRenderError by adding `and return` after the first render.

[Ruby on Rails] Email Sending Process with Action Mailer

How to configure Rails' Action Mailer to send email via Gmail SMTP.

[Ruby on Rails] ActionDispatch::Cookies::CookieOverflow error

Fixing Rails' CookieOverflow error by moving the session store off cookies onto ActiveRecord or Redis.

[Ruby on Rails] How to Use Helper Methods in ActionMailer Views

Using add_template_helper to make custom helpers available inside ActionMailer views.

[Rails] Correspondence Between ActiveRecord and DB Data Types

A quick reference for how ActiveRecord column types map to native PostgreSQL and MySQL types.

[Ruby on Rails] find with ActiveRecord::RecordNotFound

Avoiding ActiveRecord::RecordNotFound by preferring find_by_id, which returns nil, over find.

[Ruby on Rails] How to Apply Row Locking with ActiveRecord (Optimistic Lock, Pessimistic Lock)

Reference links for learning ActiveRecord's optimistic and pessimistic row locking.

[Ruby on Rails] How to Implement Setters and Getters in ActiveRecord

Two ways to implement custom setters and getters on ActiveRecord models with define_method.

[Ruby on Rails] How to use acts_as_list

Reference links for using acts_as_list with jQuery UI Sortable in Rails.

[Ruby on Rails] How to Add Foreign Key Columns to Other Tables (add_column, references)

Adding foreign key columns in Rails migrations, for both new tables and existing ones.

[Ruby on Rails] How to Configure Amazon SES (Simple Email Service)

Setting up Amazon SES over SMTP in Rails 3.2.5 with the aws-ses gem.

[Ruby on Rails] How to use arel_table

Reference links for learning how to use Rails' arel_table.

[Ruby on Rails] How to Specify Paths for Loading Images in JavaScript and CSS Files

How to reference images from JS/CSS under Rails' Asset Pipeline, using ThickBox as an example.

[Ruby on Rails] How to Set Basic Authentication for Non-Development Environments

Configuring Rails to apply Basic auth in production and staging while skipping it in development.

[Ruby on Rails] Setting Conditions for before_filter

Reference links for setting conditions on before_filter in Ruby on Rails.

[Ruby on Rails] Use blank? or present? instead of nil? to check model attributes

Use blank? or present? instead of nil? when checking Rails model attributes.

[Ruby on Rails] Presence Validation for Boolean Type

Validate Rails Boolean columns with inclusion: {in: [true, false]} instead of presence.

[Ruby on Rails] About .build and build_xxx

.build vs build_xxx in Rails, and how build differs from new for has_one associations.

[Ruby on Rails] Permission Management and Authorization with "cancan" is Convenient

Reference links for introducing the cancan authorization gem into a Rails app.

[Ruby on Rails] How to Change Default Values of Database Columns

Change a column's default value in Rails with change_column_default in a migration.

[Ruby on Rails] CSV Import/Export

Reference links and notes for CSV import/export in Ruby on Rails.

[Ruby on Rails] How to get the current URL (including parameters)

Getting the current URL with url_for(params) in Rails 3, plus adding and removing query parameters.

[Ruby on Rails] How to Initialize and Reset Database ~ rake db:reset and rake db:migrate:reset

rake db:reset vs rake db:migrate:reset in Rails, and when to reach for each.

Register initial data from CSV files with rails db:seed

Manage rails db:seed initial data as per-model CSV files and run seeds per model.

[Ruby on Rails] Reference Articles for User Authentication Engine "Devise"

Reference articles for introducing Devise into a Ruby on Rails application.

[Ruby on Rails] Overriding Devise's current_user method

Overriding Devise's current_user with alias_method to always include the user's Role.

[Ruby] How to Get Currently Logged-in User ID with User Authentication Engine "Devise"

Getting the currently logged-in user's ID from Devise via current_user.id.

[Ruby on Rails] How to Display Error Messages for Devise Login Process

Adding alert output to Devise's sessions/new view to show login error messages.

[Ruby on Rails] Created update_without_password! Method in Devise that Raises Exception on Save Failure

A record of adding an exception-raising update_without_password! method that Devise itself does not provide, defined on the User model.

[Ruby on Rails] Determine production/development Environment with Rails.env

Sample code notes for checking production/development environments with Rails.env in Ruby on Rails.

[Ruby on Rails] URL Encoding (url_encode) in ERB

Notes on URL-encoding strings inside ERB with the url_encode helper and its short form u.

[Ruby on Rails] Converting .erb Files to .haml Using erb2haml

Notes on batch-converting .erb view templates to .haml with haml-rails, erb2haml, and rake haml:replace_erbs.

[Ruby on Rails] "erb2haml" for Converting erb to haml

Notes on converting erb view files to haml using the erb2haml gem and rake haml:convert_erbs.

[Ruby][FactoryGirl] Could not find a valid mapping for #&lt;User

A record of running into the "Could not find a valid mapping for User" error with FactoryGirl and Devise.

[Rails][FactoryGirl] Error: Factory already registered: xxx

A short note on the "Factory already registered: xxx" error raised by FactoryGirl.

[Ruby on Rails] How to Set favicon.ico with favicon_link_tag

Notes on setting favicon.ico in a Rails app via the favicon_link_tag helper.

Deploy a Rails App to Fly.io and Get Preview Environments for Every Pull Request

Using Fly.io and GitHub Actions, you can automatically build isolated preview environments with PostgreSQL for every PR in your Rails app. This guide covers deployment to the Tokyo region (nrt) and the full GitHub Actions workflow setup.

[Ruby on Rails] Setting for Always Using HTTPS Connection: config.force_ssl = true

Notes on enabling config.force_ssl = true in production.rb to force HTTPS connections in Rails.

[Ruby on Rails] form_for and form helper summary

A personal cheat sheet of Ruby on Rails form_for and form helpers such as f.select.

[Ruby on Rails] How to Format Time and Set Initial Values in Input Forms

Notes on prefilling a form field with a strftime-formatted DateTime via text_field's value option.

[Ruby on Rails] Controller Creation and Naming Conventions

Notes on how CamelCase vs under_scored names behave with rails generate controller.

[Ruby on Rails] How to Get Current Controller Name and Action Name in Views

Notes on reading controller.controller_name and controller.action_name from a Rails view.

[Ruby on Rails][Haml] Use Backslashes for Line Breaks in Text Mail

Notes on using backslashes (\) to add line breaks inside Haml text-mail templates.

Haml Tips

Handy Haml tips: conditional class names and repeating ul/li output with in_groups_of.

[Ruby on Rails] How to use helper methods in controllers and models

How to call Rails helper methods from controllers and models by including ActionView::Helpers.

[Ruby on Rails] ArgumentError (invalid byte sequence in US-ASCII)

Fixing `ArgumentError (invalid byte sequence in US-ASCII)` in Rails by adding `# encoding: utf-8` to the file header.

[Ruby on Rails] Converting line breaks to br tags

A custom Rails helper for converting line breaks to br tags, without the p tags that simple_format inserts.

[Ruby on Rails] How to create many-to-many relationship tables

Reference links for setting up many-to-many relationship tables in Ruby on Rails.

[Ruby on Rails] How to Skip Creating Test::Unit Files When Creating an App

Use `rails new APP -T` to skip Test::Unit file generation in Rails 3.2 when you plan to use RSpec.

[Ruby on Rails] PDFKit doesn't work with NoMethodError (undefined method `chomp' for nil:NilClass): error

Fixing PDFKit's `chomp` nil error on CentOS + Passenger by exporting PATH via a ruby_wrapper script.

[Ruby on Rails] How to change title for each page

Per-page title and meta tags in Rails using content_for and yield, with ERB and Haml examples.

[Ruby on Rails] The pluck Method is Convenient for Creating Single-Column Arrays

Use Rails 3.2's `pluck` to fetch a single-column array — shorter and faster than `map(&:column)`.

Deploy a Rails App to Railway and Get Preview Environments for Every Pull Request

Using Railway's PR Preview Environments, you can automatically build isolated preview environments with PostgreSQL for every PR in your Rails app. It only requires a single railway.json file and Dashboard configuration — no GitHub Actions needed.

[Rails] Solving the 'rake aborted! no such file to load -- pg' Error with rake db:migrate Command

Fix `rake db:migrate` failing with `no such file to load -- pg` by swapping sqlite3 for pg in your Gemfile.

[Ruby on Rails] 'Ransack' - Easily Create Complex Search Forms

Introducing the Ransack gem for building complex Rails search forms, with reference links.

[Ruby on Rails] How to Redirect Facebook External Access to Facebook Page App

Detecting off-Facebook access in Rails via `params[:signed_request]` and redirecting to the on-Facebook page app.

[Rails] The Cause of redirect_to Not Working Was a Half-Width Space in the URL

`redirect_to` failed silently in Rails because a Facebook OAuth scope URL contained a stray half-width space.

[Ruby on Rails] How to limit default actions with 'only' while adding custom actions

Restrict Rails `resources` with `only:` and still add a custom collection action like `search`.

[Ruby on Rails] File Upload Methods in RSpec

A list of file-upload helper methods available when testing Rails controllers with RSpec.

[Ruby on Rails] How to use seed-fu for easy seed data addition and management

Using the seed-fu gem to manage Rails seed data under `db/fixtures/`, with a CSV import example.

[Ruby on Rails] Separating seed_fu by Environment

Splitting seed_fu fixtures into per-environment directories and switching them with FIXTURE_PATH.

[Rails] How to Set Time Zone to Japan Standard Time (JST)

How to switch a Rails app's time zone from UTC to Japan Standard Time (JST).

[Ruby on Rails][SQLite3] SQLException: Cannot add a NOT NULL column with default value NULL

The cause of the SQLite3 NOT NULL column error in Rails migrations, and two ways to fix it.

[Ruby] Internationalization (i18n) for state_machine

Localizing state_machine state and event names via i18n YAML and human_state_name.

[Ruby on Rails] Error: Range unspecified. Specify the :in, :within, :maximum, :minimum, or :is option.

The Range unspecified error from validates length was caused by a typo in minimum / maximum.

[Ruby on Rails] How to Not Check nil with validates numericality

Pass allow_nil: true to validates numericality to skip validation for empty input.

[Ruby on Rails] 'ValidatesTimeliness' for Date and Time Validation

Setting up ValidatesTimeliness for Rails date/time validation, with i18n messages and custom formats.

[Rails] How to Get View Image URLs from Within a Controller

Using view_context.image_path inside a Rails controller to resolve a full asset URL.

[Ruby] 'will_paginate' for adding pagination functionality

will_paginate helper options and localizing its labels through a locale YAML file.

[Ruby on Rails] Grouping validations using with_options

Using with_options to group conditional Active Record validations under a single :if block.

Ruby on Rails4 + Mongoid + RSpec

Bootstrapping a Rails 4 app with Mongoid and RSpec, including DatabaseCleaner wiring.

RailsCasts - Features Many Ruby on Rails Tutorial Videos and Code

Introducing RailsCasts — Ruby on Rails tips explained with video screencasts and code.

[Ruby] How to Use Ransack's sort_link with Nested Resources

Passing controller / action / parent id in a hash so Ransack's sort_link works with nested resources.

[Redmine] Encoding::CompatibilityError (incompatible character encodings: UTF-8 and ASCII-8BIT):

Fixed Redmine 1.2.3's Encoding::CompatibilityError by switching Ruby from 1.9.2 to the required 1.8.7.

Reading the Official Site is Sufficient for Redmine Initial Configuration

Redmine's official docs are enough for the initial configuration — no other reference needed.

Site to Check Ruby, Rails, Rack Versions Required When Installing Redmine

A memo on the official RedmineInstall page that lists the Ruby / Rails / Rack versions required for each Redmine release.

Solution for bundle/gem install rmagick error: Can't find MagickWand.h

Fixed the rmagick MagickWand.h build error by switching to Homebrew's imagemagick@6.

[RSpec] How to Send Ajax Requests in Controller Tests

A short memo on using RSpec's xhr helper to send Ajax GET and POST requests in controller specs.

[RSpec] Various ways to use Devise in test code

Rails + RSpec notes on testing Devise-protected controllers by stubbing current_user in a before block.

[RSpec] Specifying Seed File Loading Path with SeedFu.fixture_paths for SeedFu.seed

A spec_helper snippet showing how to load seeds from multiple directories via SeedFu.fixture_paths before RSpec runs.

[RSpec] Stubbing Constants with stub_const

How to stub constants in RSpec with stub_const, including nested constants under a Class or Module.

[RSpec] Stubbing Time.now

A tiny snippet for stubbing Time.now in Rails + RSpec to return a fixed timestamp.

[RSpec] Differences between stub and mock

A link roundup of references that helped me get stubs vs. mocks straight in RSpec.

[RSpec] How to Test Private Methods

How to test private methods in Rails + RSpec by invoking them via Object#send.

[Ruby] Differences between count, size, and length

A link roundup on the differences between count, size, and length in Ruby.

[Ruby] Summary of reference sites for using Foreman

Reference links for learning Foreman, the Procfile-based process manager for Ruby apps.

[Ruby] Solution for ERROR: cannot discover where libxml2 is located on your system. please make sure `pkg-config` is installed.

Fixing nokogiri's libxml2/pkg-config install error on macOS by installing the libraries with Homebrew and using system-libraries.

[Ruby] Uninstalling Passenger

Example console output for uninstalling the Phusion Passenger gem with `gem uninstall passenger`.

[Ruby] How to get User Agent

Reading the User Agent in Rails and redirecting iPhone / Android traffic to a mobile-specific page via before_filter.

[Ruby] Use 'sunspot' for full-text search engine Solr

Reference links for the sunspot gem, which connects Rails apps to the Solr full-text search engine, including RSpec testing tips.

[Ruby] Regular Expression to Check Time Format

A Ruby regex for validating HH:MM time strings, wired up as a Rails custom validator.

[Ruby] RSpec Beginner Articles Summary

A curated list of beginner references for RSpec, grouped by topic (views, requests, syntax, config).

[Ruby] Introduction to state_machine

Reference links for getting started with state_machine, a Ruby gem for managing object state transitions.

[RVM] How to Manage Ruby on Rails Versions

Managing Ruby on Rails versions with RVM by creating a dedicated gemset per Rails application.

[Ruby][RVM] mysql2.bundle: [BUG] Segmentation fault

Fixing a mysql2.bundle segmentation fault after recreating an RVM gemset by updating RVM to head.

[Ruby] Use rvmsudo instead of sudo in RVM environment

In an RVM environment, use `rvmsudo` instead of `sudo` for ruby and rails commands.

Should Shared Library Directory Be Named 'shared' or 'common'?

Should a shared-library directory be named `shared` or `common`? Linux, Rails, and Capistrano all pick `shared`.

[Ruby] Shinjuku.rb #3 Memorandum

Notes from Shinjuku.rb #3, including talks on Padrino, mocktra, and a Rails3 Recipe Book reading group.

[Ruby] How to check the Solr version installed by sunspot_solr

Checking the default Solr version of sunspot_solr via the registry.jsp URL.

[Ruby] Filtering with multiple columns from related tables using sunspot

Filtering by multiple columns on a related table in sunspot via a multi-value integer field in the searchable block.

Top Ruby Companies: Find Out Which World-Class Companies Use Ruby

Top Ruby Companies lists world-class Ruby adopters by market cap — Airbnb, Shopify, Coinbase, Block, Procore lead as of March 2024.

[Ruby][Rails] Curated Libraries and Tools Summary by WEB+DB PRESS Vol.67

A memo of curated Ruby/Rails libraries and tools by purpose from WEB+DB PRESS Vol.67.

[Ruby] How to Use will_paginate with Nested Resources

How to use will_paginate with nested resources via a params hash.