What I Learned from Short Ruby Newsletter (#128)

I subscribed to the Short Ruby Newsletter a long time ago. I love it because it contains tons of interesting examples of Ruby and Ruby on Rails code that I would want to use in my apps. In every edition, I read about so many things which are new to me and might be useful.

Sadly, I always read the newsletter but never remember or use the cool new things. However, I decided to make a change, I took notes of the things that I found interesting and were new to me and thought I would write a small summary.

Here’s what I learned in #128:

Pattern Matching

You can pattern match time in ruby:

require 'time'

time = Time.now

case time
in { month: 1, day: 1|2 }
puts "This year is going to be great 🌟"
in { month: (1..3) }
puts "I should take it a little slow though, not tire myself 🤔"
in { month: (4..6) }
puts "What?? it's April already! 🥵"
in { month: (7..11) }
puts "No, I had no resolutions this year 🙂‍↔️"
in { month: 12, day: (20...31) }
puts "Next year is going to be great 🌟"
end

The above is possible because Time implements the deconstruct_keys method

You can implement the same technique to pattern match other objects.

You can use pattern matching to bind variables from Arrays and Hashes:

case [1,2]
in Integer => a, Integer
  puts a #-> 1
end

case [1,2]
in a, Integer
  puts a #-> 1
end

case {a: 1, b: 2}
in a:, b:
  puts a #-> 1
  puts b #-> 2
end

case {a: 1, b: 2}
in a:, b: String
  # Raises NoMatchingPatternError
end

Use the ^ pin operator to prevent variable overriding:

expectation = 18
case [1, 2]
in ^expectation, *rest
  "matched. expectation was: #{expectation}"
else
  "not matched. expectation was: #{expectation}"
end

There is also a standalone expression version of pattern matching:

slug = { slug: "admin" }

if slug in { slug: String => role }
  puts role #=> admin
end

Message Verifier

Use ActiveSupport::MessageVerifier to

• generate secure tokens for urls: password reset links, email confirmation links

Rails.application.message_verifier(:password_reset).generate([@user.id, 5.minutes.from_now])

id, time = Rails.application.message_verifier(:password_reset).verify(cookies[:password_reset])
if time.future?
  self.current_user = User.find(id)
end

This is not an encrypted string though. If you need encryption use: Message Encryptor

Select Aliases

You can specify column aliases using the Select query method.

users = User.select(email: :login_email)
users.first.login_email

VNC sessions

A VNC session is used to remotely control the GUI of another computer. wiki

You can use a VNC session to play games in another computer!

I’m hugely grateful to the Short Ruby Newsletter team for curating these insights. My biggest lesson is learning pattern matching and I can’t wait to triage my codebase to look for places I can use it!