Introduction

Most of the time it is a tedious task to apply a code style guide to an existing code base as there are likely to be a lot of conflicts. At makandra we are using makandra-rubocop to have code style checks. Here is some advice on how to add makandra-rubocop efficiently.

Note

RubyMine by default has a Rubocop inspection with rules that we don't always agree with. We recommend replacing this with makandra-rubocop or disabling the inspection.
...

I got this error after upgrading Ruby from 2.4.5 to 2.6.4 when I opened the Rails console - rails server still worked.

Running via Spring preloader in process 14679
Loading development environment (Rails 5.2.2.1)
Traceback (most recent call last):
.../lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/application.rb:175:in 'fork': No such file to load -- irb/encoding_aliases.rb (LoadError)
.../lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/application.rb:175:in 'fork': undefined method 'reject!' for nil:NilClass (NoMethodError)
.../li...

When using Chrome for Selenium tests, the chromedriver binary will be used to control Chrome. To debug problems that stem from Selenium's Chrome and/or Chromedriver, you might want to enable logging for the chromedriver itself. Here is how.

Option 1: Use Selenium::WebDriver::Service

In your test setup, you may already have something like Capybara::Selenium::Driver.new(@app, browser: :chrome, options: ...), especially when passing options like device emulation.

Similar to options, simply add an extra key service and pass an inst...

With this gem your transaction blocks raise an error when they have side effects that cannot be rolled back.

By default it checks whether you're connecting with HTTP, queuing a Sidekiq job or sending an e-mail within a transaction. You can add custom checks, too.

Found in this RubyGuides article.

The ruby sass gem also installs a command line tool to convert to and from SCSS. Use it for a directory of .scss-files like

sass-convert -R assets/stylesheets --from scss --to sass

Rails is split into a large number of (sub-) frameworks.

The most important and central of those are

• activesupport (extends the Ruby standard library)
• activerecord / activemodel (ORM for Rails)
• actionview / actionpack (controller / views)
• actionmailer (sends mails)

However, there are also some more situational frameworks included, such as

• actioncable (real time communications using websockets)
• actionmailbox (receives mails)
• actiontext (support for WYSIWYG text editor)
• activejob (background jobs)
• activestorage (file uplo...

When upgrading Clearance, pay attention whether the password hashing strategy might have changed. Old clearance versions (< 1.0) used SHA1-encrypted passwords by default. Current versions default to BCrypt.

If you simply upgrade without taking this into account, users will get a BCrypt::Errors::InvalidHash when trying to sign in. Your tests will not notice this, since they create new users for each scenario.

To fix it, you'll either have to force all users to reset their passwords, or you can allow old users to keep signing in with t...

webpack is a very powerful asset bundler written in node.js to bundle (ES6) JavaScript modules, stylesheets, images, and other assets 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 node.js and Yarn.

Then, put

gem 'webpacker', '~> 4.x' # check if 4.x is still cu...

RubyMine comes with a nice way to grep through your project's files: The finder (ctrl + shift + f). Don't be discouraged about the notice 100+ matches in n+ files if your searched keyword is too general or widely used in your project.

RubyMine comes with a few ways to narrow down the resulting list, don't hesitate to apply those filters to speed up your search. Your keybinding might vary based on your personal settings.

File mask (alt + k)

If you already know the file extension of your ...

The gem json fails to install for Ruby 2.5 if you use a version equal or below 1.8.3.

Run bundle update json --conservative to solve this issue.

The backtrace you will encounter looks like this:

Building native extensions. This could take a while...
ERROR:  Error installing json:
	ERROR: Failed to build gem native extension.

    current directory: /home/user/.rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/json-1.8.3/ext/json/ext/generator
/home/user/.rbenv/versions/2.5.3/bin/ruby -I /home/user/.rbenv/versions/2.5.3/lib/ruby/si...

Travis changed their default distribution from Ubuntu 14.04 (trusty) to 16.04 (precise). This might break your test setup for new builds.

You can solve this issue by freezing your test distribution in the .travis.yml to Ubuntu 14.04 until you have the time to solve all the issues you will have in 16.04:

dist: trusty

Error details

Here are few indicators that you ran into this issue:

Connection to the PostgreSQL database does not work anymore

Your travis-ci builds might have started failing on the usual

psql -c...

When installing a gem you can use version comparators like >= or ~>. That way it is possible to fetch the latest version of Bundler 1 with this command:

gem install bundler -v '~>1'

How to install bundler for Ruby < 2.3 is a common usecase where you might need Bundler 1.

Cucumber up to version 2 had a neat feature called Step Argument Transforms which was dropped in favor of Cucumber 3 ParameterTypes. While I strongly encourage you to drop your legacy Transforms when upgrading to Cucumber 3, it might not always be possible due to their different design.
This is a guide on how to keep the exact same functionality of your old Transforms while writing them in the style of new `Paramet...

Until Capybara 2, node finders that accept a text option were able to find nodes based on rendered text, even if it spans over multiple elements in the HTML. Imagine a page that includes this HTML:

<div class='haystack'>
  Hi!
  <br>
  Try to match me.
</div>

Even though the text is separated by a <br> tag in the HTML, it is matched until Capybara 2 which used to "squish" text prior to the comparison.

# Capyabara 1 or 2
page.find(...

To keep JavaScript sources small, it can sometimes make sense to split your webpack bundles. For example, if your website uses some large JavaScript library – say TinyMCE – which is only required on some selected pages, it makes sense to only load that library when necessary.

In modern webpack this is easily doable by using the asynchronous import function.

Say we have an unpoly compiler that sets up TinyMCE like this (code is somewhat simplified):

// TinyMCE as part of the main bundle!

import tinymce from 'tinymce/tinymce'

// U...

We're always striving towards keeping our website's JavaScript as small as possible.

If you're using webpack(er), you can use the webpack-bundle-analyzer plugin to get a good overview, which of your JavaScript modules take up how much space, and where you can optimize.

To use it, add it via npm or yarn

yarn add webpack-bundle-analyzer

Then add this to your environment.js:

// Uncomment this code to show statistics of bundle sizes. Generated file will automatically...

Tod is a gem for working with daytimes. That's a tuple of (hour, minute second) without a day, month or year.

Another additional gem?

Thus SQL has a time datatype for storing time of day in the format hh:mm:ss, neither Ruby nor Rails themselves offer an elegant way to deal with day times.

Time and DateTime both handle daytime values AND calendar date, using them to only store the time of day will end in inconsistent and thus confusing data, e. g. Time.new will initialize with the current Time in your Timezone, `DateTime.n...

This is a short overview of things that are required to upgrade a project from the Asset Pipeline to Webpacker. Expect this upgrade to take a few days even the diff is quite small afterwards.

Preparations

1. Find all libraries that are bundled with the asset pipeline. You can check the application.js and the application.css for require and import statements. The source of a library is most often a gem or a vendor directory.
2. Find an working example for each library in the application and write it down.
3. Find out the ver...

Many mail clients do not support external style sheets. Some even require all styling inline, which means you'll have to do your styling inline. For Rails applications, you can use Roadie or premailer, which lets you keep your well-structured CSS files and do the inlining for you.

See Designing HTML email

Since Roadie is now in passive maintenance mode, we go with premailer:

Include premailer in your Gemfile:

gem 'premailer-ra...

While deploying an Ruby update to an old application these days, we encountered the following misleading error:

*** [err :: some-host.makandra.de] You are trying to install in deployment mode after changing
*** [err :: some-host.makandra.de] your Gemfile. Run `bundle install` elsewhere and add the
*** [err :: some-host.makandra.de] updated Gemfile.lock to version control.
*** [err :: some-host.makandra.de] 
*** [err :: some-host.makandra.de] You have deleted from the Gemfile:
*** [err :: some-host.makandra.de] *

We found out a newe...

When we want to use our own (or bought) fonts in an application with Webpack(er), we have two options. We can

• put the fonts directly into your Webpack's assets folder or
• write an npm package with an own sass file that can be imported from the Webpack manifest.

Load fonts from your assets folder

The first option turns out to be straightforward: Import the stylesheets in the index.js of the pack you're using:

// webpack_source_path/application/index.js

import './stylesheets/reset'
import...

Webpacker is Rails' way of integrating Webpack, and version 4 has been released just a few days ago, allowing us to use Webpack 4.

I successfully upgraded an existing real-world Webpack 3 application. Below are notes on everything that I encountered.
Note that we prefer not using the Rails asset pipeline at all and serving all assets through Webpack for the sake of consistency.

Preparations

• Remove version locks in Gemfile for webpacker
• Remove version locks in package.json for webpack and webpack-dev-server
• Install by ca...