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...

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.

If you get requests with values for formats like this:

{:locale=>[:de], :formats=>["../../../../../../../../../../etc/services{{"], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby, :coffee, :haml]}

or fails like this:

Invalid query parameters: invalid %-encoding (../../../../../../../../../etc/passwd%%0000.html)

Someone tries to exploit CVE-2019-5418.
If you use the latest Rails (or latest Rails LTS) you're...

It is quite easy to migrate from CoffeeScript to ES6. You can use decaffeinate to convert your CoffeeScript source to modern JavaScript.

Install decaffeinate globally:

npm install -g decaffeinate

Call decaffeinate on each .coffee file, relaxing some options to get the most modern (and concise) JS:

decaffeinate file.coffee --use-cs2 --loose --optional-chaining --logical-assignment

Tip

If you use Babel and see errors while decaffeinati...

In a nutshell: return statements inside blocks cause a method's return value to change. This is by design (and probably not even new to you, see below) -- but can be a problem, for example for the capture method of Rails.

Consider these methods:

def stuff
  puts 'yielding...'
  yield
  puts 'yielded.'
  true
end

We can call our stuff method with a block to yield. It works like t...

If you struggle with a /boot partition that is too small for updates, and you are too intimidated by the way to resize your /boot partition, there might be an easier fix:

It is possible to configure a better compression algorithm for the images in /boot. To do this, edit /etc/initramfs-tools/initramfs.conf and change the existing line to

COMPRESS=xz

Then rebuild the images using

sudo update-initramfs -u -k all

If you get an error during the last step, please immediately get help, because otherwise...

Along with a number of other cool new features and performance improvements, Ruby 2.6 added function composition to the Proc and Method classes. Today we’ll take a look at how this allows us to use some functional programming goodness in our Ruby code.

Some older Node modules rely on window.jQuery to be present. One suggested solution is to use this config in the app/config/webpack/environment.js:

const { environment } = require('@rails/webpacker')
const webpack = require('webpack')

environment.plugins.prepend(
  'Provide',
  new webpack.ProvidePlugin({
    $: 'jquery',
    jQuery: 'jquery',
    'window.jQuery': 'jquery'
  })
)

module.exports = environment

This will work. But a side effect is that the fo...

When you want to UPDATE a table with information from an associated table, you can JOIN the associated table into the statement.

Example

Let's say you have a database schema where an Employee belongs_to :department:

+-----------------+
| Employee        |                   +------------+
|-----------------| n               1 | Department |
| email           |-------------------|------------+
| department_id   |                   | name       |
+-----------------+                   +------------+

Because of perfo...

PostCSS is a tool for transforming styles with JS plugins. In Webpacker you can configure the plugins and their settings via the postcss.config.js file. Make sure that postcss-loader is part of your package.json.

module.exports = {
  plugins: [
    require('postcss-import'),
    require('postcss-flexbugs-fixes'),
    require('postcss-preset-env')({
      autoprefixer: {
        flexbox: 'no-2009'
      },
      stage: 3
    })
  ]
}

Note: Stage 3 means you can use all CSS features that ar...

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...

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...

Rails understands a :limit options when you create columns in a migration. Its meaning depends on the column type, and sometimes the supplied value.

The documentation states that :limit sets the column length to the number of characters for string and text columns, and to the number of bytes for binary and integer columns.

Using it

This is nice since you may want a bigint column to store really long numbers in it. You can just create it by ...

All the hidden and not hidden features of Git and GitHub.

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...

Rails' ActiveSupport::TimeWithZone objects have both a timezone code and offset, e.g. Thu, 28 Mar 2019 16:00:00 CET +01:00. Ruby's stdlib TZInfo also has time zones, but with different identifiers.
Unfortunately, not all timezone codes can be used to parse strings or to move time objects into another time zone.

Some timezone codes like CET are supported by ActiveSupport extensions like String#in_time_zone, while many codes will actually not work:

>> '2019-03-01 12:00'.in_time_zone('PST')
ArgumentError (Invalid Timezone: PST)
...

Reverting a commit means creating a new commit that undoes the old changes.

Imagine the following commit history:

* commit_sha3 [Story-ID 1] Fixup for my feature 
* commit_sha2 [Story-ID 5] Other feature
* commit_sha1 [Story-ID 1] My feature 

You can revert a single commit using the following syntax:

git revert commit_sha2

To revert changes that are split across multiple commits, use the --no-commit flag.

git revert --no-commit commit_sha3
git revert --no-commit commit_sha1
git commit -m "Revert Story 1"