Ruby offers monkey patching methods in order to change the behavior of a library if there's no better way.

We can call the method we're overriding inside our monkey patch:

class Foo
  def bar(argument)
    'Hello' + argument
  end
end 

module FooExtensions
  def bar
    super(' in my') + ' World'
  end
end

class Foo
  prepend FooExtensions # the only change to above: prepend instead of include
end

Foo.new.bar # => 'Hello in my...

Ruby's String#split returns an array of substrings from the given string. Usually, this is missing the split characters:

>> 'user@example.com'.split('@')
=> ["user", "example.com"]

If you want to join those parts later on, you might know the split character and can just use it to join explicitly.
But if you split by a regular expression (for a set of split characters) that information is lost:

>> 'user@example.com'.split(/[@\.]/)
=> ["user", "example", "com"]

You can use a capture group to make those characters ...

SSHKit 1.9.0 might fail with the following error, when trying to deploy a Rail application. Upgrading the gem to version 1.21.0 fixed the issue.

Traceback (most recent call last):
	17: from /home/user/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/sshkit-1.9.0/lib/sshkit/runners/parallel.rb:12:in `block (2 levels) in execute'
	16: from /home/user/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/sshkit-1.9.0/lib/sshkit/backends/abstract.rb:29:in `run'
	15: from /home/user/.rbenv/versions/2.5.0/lib/ruby/gems/2.5.0/gems/sshkit-1.9....

Using Ruby 1.8.7 you will not be able to use the maximum versions Rubygems 1.8.30 and Bundler 1.17.3 with https://rubygems.org/ anymore. This is a result of a server certificate on December 5th, 2020. The resulting errors will look like following:

• TypeError: can't modify frozen object
• Could not verify the SSL certificate for https://rubygems.org/*
• Bundler::Fetcher::CertificateFailureError: Could not verify the SSL certificate for https://index.rubygems.org/versions.
• `Error fetching data: hostname was not m...

When deploying a Rails application that is using Webpacker and Capistrano, there are a few configuration tweaks that optimize the experience.

Using capistrano-rails

capistrano-rails is a Gem that adds Rails specifics to Capistrano, i.e. support for Bundler, assets, and migrations. While it is designed for Asset Pipeline (Sprockets) assets, it can easily be configured for Webpacker. This brings these features to the Webpacker world:

• Automatic removal of expired assets
• Manifest backups

IRB 1.2 (shipped with Ruby 2.7, but works on 2.5+) brings pretty syntax highlighting and multiline cursor navigation. However, pasting longer contents is incredibly slow. You can fix that by disabling said features. [1]

Ruby 3.0.0-pre2 solved the issue (however, the fix does not appear to be included in IRB 1.2.6, it must be Ruby itself).

Option 1:

Add a command line flag when opening an IRB:

irb --nomultiline

This also works on modern Rails...

Git diffs show the surrounding contexts for diff hunks. It does so by applying regular expressions to find the beginning of a context. When it comes to Ruby, however, it will not find method heads and travel up to the class definition:

@@ -24,7 +24,7 @@ class TicketPdf # <=== Actually expected here: the method definition
     ApplicationController.render(
       "tickets/index.html.haml",
       layout: "tickets",
-      assigns: { tickets: tickets }
+      assigns: { tickets: tickets, event_name: event_name }
     )
   end
 end
```...

If you have installed Rubocop in your project, RubyMine can show you Rubocop violations immediately in your editor. You probably already know this feature.

Example

Enable/Disable marking

If your RubyMine does not show you any violations, although there are some, you may have to enable the setting first.

To do so, open Navigate -> Search Everywhere -> Actions (Or use the shortcut CTRL + SHIFT + A) and type in "rubocop", then you should see some...

curl-to-ruby is a handy tool that converts your curl command to ruby code that uses the Net::HTTP library.

Example

curl -X POST -d
  "grant_type=password&email=email&password=password"
  localhost:3000/oauth/token

will output to:

require 'net/http'
require 'uri'

uri = URI.parse("http://localhost:3000/oauth/token")
request = Net::HTTP::Post.new(uri)
request.set_form_data(
  "email" => "email",
  "grant_type" => "password",
  "password" => "password",
)

req_options =...

In Rubocop you might notice the cop Style/CaseEquality for e.g. this example:

def foo(expected, actual)
  expected === actual
end

In case expected is a Regex, it suggests to change it to the following pattern:

def foo(expected, actual)
  expected.match?(actual)
end

In case expected is a Regex or a String, you need to keep ===. Otherwise the actual expression is always converted to a regular expression.

# For expected === actual
foo('Test(s)', 'Test(s)') #=> true

# For expected.match?(actual)
foo('Test(...

Here is a short summary of Cucumber hooks in Ruby taken from https://github.com/cucumber/cucumber-ruby. Note that the BeforeStep is currently not existing in the Ruby implementation of Cucumber.

Before hooks run before the first step of each scenario.

Before do |scenario|
  ...
end

After hooks run after the last step of each scenario, even when the step result is failed, undefined, pending or skipped.

...

We currently test most of our gems on Travis CI, but want to migrate those tests to Github Actions. This is a step-by-step guide on how to do this.

Note that this guide requires the gem to use gemika.

1. Go to a new "ci" branch:

   git checkout -b ci
   

2. Update gemika to version >= 0.5.0 in all your Gemfiles.
3. Have gemika generate a Github Actions workflow definition by running

   mkdir -p .github/workflows; bundle exec rake gemika:generate_github_actions_workflow > .github/workf...
   

On some of our older projects, we use the mysql2 gem. Unfortunately, versions 0.2.x (required for Rails 2.3) and versions 0.3.x (required for Rails 3.2) can no longer be installed on Ubuntu 20.04. Trying this either leads to errors when compiling the native extension, or a segfaults when using it.

For Rails 4.2, mysql2 version 0.4.10 seems to work okay. If you still have issues, upgrade to 0.5.x, which should be compatible.

To install it, you have to switch the mysql2 gem to our fork. In your Gemfile, ...

The sidekiq-rate-limiter gem allows rate-limiting Sidekiq jobs and works like a charm. However, it needs to be integrated on a per-worker basis.

If you want to limit a whole queue instead, and if your requirements are simple enough, you can do it via a Sidekiq middleware yourself.

Here is an example that limits concurrency of the "mailers" queue to 1. It uses a database mutex via the [with_advisory_lock](https://github.com/ClosureTree/wit...

If you're using the webdrivers gem and VCR together, depending on your configuration, VCR will yell at you regulary.
The webdrivers gem tries to update your webdrivers on your local machine. To do so, it checks the internet for newer versions, firing an HTTP-request to e.g. https://chromedriver.storage.googleapis.com

You can "fix" this in multiple ways:

1. Update your drivers on your machine with
   RAILS_ENV=test rake webdrivers:chromedriver:update

2. Ignore the driver update-URL in your ...

Pagy is a gem for pagination.
They make some bold claims:

Pagy is the ultimate pagination gem that outperforms the others in each and every benchmark and comparison.

Maybe this is worth trying out.

If you want to get the path of a file relative to another, you can use the expand_path method with either the constant __FILE__ or the method __dir__. Read this card for more information about __FILE__ and __dir__.

Example

Structure:

.
├── bin
│   ├── format_changelog
├── CHANGELOG.md

bin/format_changelog:

#!/usr/bin/env ruby

changelog_path = ? # How to get the path to ../CHANGELOG.md independent of the working dir of the caller
changelog = File.read(changelog_path)

# ... further actions...

To find a version containing the regular expression foo in the history of any branch:

git grep foo $(git rev-list --all)

You may also limit the search to a file extension, e.g. Ruby files (.rb) like this:

git grep foo $(git rev-list --all) -- *.rb

Ruby Jard provides a rich Terminal UI that visualizes everything your need, navigates your program with pleasure, stops at matter places only, reduces manual and mental efforts.

This is an extract from the linked article. It shows an approach on how to implement encrypted passwords with the AWS Key Management Service (KMS).

For most applications it's enough to use a hashed password with a salt (e.g. the gem devise defaults to this).

Upon password creation

1. Generate hash as hash of password + salt.

2. Encrypt the hash with a public key from KMS (you can store the public key in your server code).

3. In your database sto...

Rails 5.2+ supports "verbose query logs" where it shows the source of a query in the application log.
Normally, it looks like this:

  User Load (0.5ms)  SELECT "users".* FROM "users" WHERE ...
  ↳ app/controllers/users_controller.rb:42:in `load_users'

However, you may encounter ActiveRecord's LogSubscriber as the source for all/most queries which is not helpful at all:

  User Load (0.5ms)  SELECT "users".* FROM "users" WHERE ...
  ↳ activerecord (6.0.3.3) lib/active_record/log_subscriber.rb:100:in `debug'

While th...

When you use Sentry to monitor exceptions, an important feature is Sentry's error grouping mechanism. It will aggregate similar error "events" into one issue, so you can track and monitor it more easily. Grouping is especially important when you try to silence certain errors.

It is worth understanding how Sentry's grouping mechanism works.

The default grouping mechanism

The exact algorithm has changed over time, and Sentry will keep using the algorithm t...

In Ruby on Rails, all the routes of a given application can be found within the config/routes.rb file.
You add more and more routes in this file as your project grows.

The problem here is that this file potentially becomes very complicated to manage over the time.
That’s why it’s important to find a way to order and maintain your routes.

See: Clean your Rails routes: grouping

Sometimes the routes.rb grows very fast and each line adds mo...