Why use Ruby and Rails?
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This document provides an overview of Ruby and Rails. It notes that Ruby was created in Japan by Yukihiro Matsumoto in 1993. Rails was created in Denmark by David Heinemeier Hansson in 2004 to build the BaseCamp application. It compares package ecosystems across languages and frameworks, demonstrating that RubyGems has the most packages of the listed options. It also shows multiple ways to write the same program in Ruby and discusses best practices like testing, short methods, and extracting duplicate logic.
![MANY WAYS TO DO IT
n = 15!
!
n.times{|i| puts " "*(n-i-1) + "*"*(i*2+1)}!
!
Java:!
class Test { public static void main(String args[]) {} }!
!
!
!
!
!
!
!](https://image.slidesharecdn.com/ror-fri-2014-140109093339-phpapp02/85/Why-use-Ruby-and-Rails-16-320.jpg)
!
key + 1!
end!
obj[1] # => 2!
!
def []=(key, value)!
whatevz!
end!
obj[1] = 2!](https://image.slidesharecdn.com/ror-fri-2014-140109093339-phpapp02/85/Why-use-Ruby-and-Rails-19-320.jpg)
![def clients!
User.where(user_type: "client")!
end!
!
def days_until_next_week(date)!
8 - date.cwday!
end!
!
def next_week_start(after_date)!
after_date + days_until_next_week(after_date).days!
end!
def payments_next_week!
payments = []!
!
User.where(user_type: "client").each do |user|!
next_week_start = Date.today + (8 Date.today.cwday).days!
next_week_end = next_week_start + 7.days!
payments = user.payments.where("due_on >= ? AND
due_on < 1.week.from_now", next_week_start,
next_week_end)!
payments.each do |payment|!
next if payment.due_on.saturday? ||
payment.due_on.sunday?!
payments << payment!
end!
end!
end!
!
def week_end(week_start)!
week_start + 7.days!
end!
!
def client_payments_between(client, range)!
client.payments!
.where("due_on >= ?", range.first)!
.where("due_on < ?", range.last)!
end!
!
def client_payments_next_week(client)!
start_day = next_week_start(Date.today)!
client_payments_between(client,!
start_day..week_end(start_day))!
end!
!
def payment_on_weekend?(payment)!
payment.due_on.saturday? || payment.due_on.sunday?!
end!
!
def payments_next_week!
clients.flat_map do |client|!
client_payments_next_week(client).reject do |payment|!
payment_on_weekend?(payment)!
end!
end!
end!](https://image.slidesharecdn.com/ror-fri-2014-140109093339-phpapp02/85/Why-use-Ruby-and-Rails-21-320.jpg)
Why use Ruby and Rails?
- 1. RUBY (AND RAILS) Jan Berdajs @mrbrdo
- 2. RUBY • Japan • Yukihiro Matsumoto a.k.a. Matz • 24. Feb. 1993 • Matz is nice and so we are nice (MINASWAN)
- 3. RAILS • Denmark • David Heinemeier Hansson a.k.a DHH • BaseCamp / 37 signals • July 2004 • “The best frameworks are in my opinion extracted, not envisioned. And the best way to extract is first to actually do.”
- 6. PACKAGES ASP.NET NuGet: PHP Pear: Packagist/Composer: Python PyPI: Node.JS NPM: Ruby RubyGems: 17,770 ! 595 21,754 38,607 53,740 68,500 ! Honorable mention: Java, Scala: Maven etc, too many to count
- 8. MANY WAYS TO DO IT n = 15! ! (1..n).each do |i|! n_zvezdic = (i - 1) * 2 + 1! n_presledkov = n - i! ! (1..n_presledkov).each do! putc " "! end! ! (1..n_zvezdic).each do! putc "*"! end! ! putc "n"! end! !
- 9. MANY WAYS TO DO IT n = 15! ! (1..n).each do |i|! n_zvezdic = (i - 1) * 2 + 1! n_presledkov = n - i! ! n_presledkov.times do! print " "! end! ! n_zvezdic.times do! print "*"! end! ! print "n"! end! !
- 10. MANY WAYS TO DO IT n = 15! ! (1..n).each do |i|! n_zvezdic = (i - 1) * 2 + 1! n_presledkov = n - i! ! print " " * n_presledkov! ! ! ! print "*" * n_zvezdic! ! ! ! print "n"! end! !
- 11. MANY WAYS TO DO IT n = 15! ! (1..n).each do |i|! n_zvezdic = (i - 1) * 2 + 1! n_presledkov = n - i! ! puts " " * n_presledkov + "*" * n_zvezdic! ! ! ! ! ! ! ! ! end! !
- 12. MANY WAYS TO DO IT n = 15! ! n.times do |i|! n_zvezdic = i * 2 + 1! n_presledkov = n - i - 1! ! puts " " * n_presledkov + "*" * n_zvezdic! end! ! ! ! ! ! ! ! ! !
- 13. MANY WAYS TO DO IT n = 15! ! n.times{|i| puts " "*(n-i-1) + "*"*(i*2+1)}! ! ! ! ! ! ! ! ! !
- 14. MANY WAYS TO DO IT n = 15! ! (1..n).each do |i|! n_zvezdic = (i - 1) * 2 + 1! n_presledkov = n - i! ! (1..n_presledkov).each do! putc " "! end! ! (1..n_zvezdic).each do! putc "*"! end! ! putc "n"! end! !
- 15. MANY WAYS TO DO IT n = 15! ! n.times{|i| puts " "*(n-i-1) + "*"*(i*2+1)}! ! ! ! ! ! ! ! ! !
- 16. MANY WAYS TO DO IT n = 15! ! n.times{|i| puts " "*(n-i-1) + "*"*(i*2+1)}! ! Java:! class Test { public static void main(String args[]) {} }! ! ! ! ! ! ! !
- 17. MANY WAYS TO DO IT n = 15! ! n.times{|i| puts " "*(n-i-1) + "*"*(i*2+1)}! ! ! ! ! ! ! ! ! !
- 18. JUST COOL Date.today.thursday? # => true! ! 10.seconds.ago # => 2014-01-09 09:15:10 +0100! ! 10.even? # => true! ! 102.megabytes + 24.kilobytes + 10.bytes # => 106,979,338! ! 10 + 1 # => 11! ! class Fixnum! def +(i)! 42! end! end! ! 10 + 1 # => 42!
- 19. JUST COOL def alive?! state != :dead! end! ! def clear!! everything.remove! end! ! def setting=(value)! raise "invalid value" unless value == 42! end! obj.setting = 5! ! def [](key)! key + 1! end! obj[1] # => 2! ! def []=(key, value)! whatevz! end! obj[1] = 2!
- 20. BEST PRACTICES Short methods, self-commenting code + readability + testing ! You only need comments when you know your code is written so bad that people won’t understand it.
- 21. def clients! User.where(user_type: "client")! end! ! def days_until_next_week(date)! 8 - date.cwday! end! ! def next_week_start(after_date)! after_date + days_until_next_week(after_date).days! end! def payments_next_week! payments = []! ! User.where(user_type: "client").each do |user|! next_week_start = Date.today + (8 Date.today.cwday).days! next_week_end = next_week_start + 7.days! payments = user.payments.where("due_on >= ? AND due_on < 1.week.from_now", next_week_start, next_week_end)! payments.each do |payment|! next if payment.due_on.saturday? || payment.due_on.sunday?! payments << payment! end! end! end! ! def week_end(week_start)! week_start + 7.days! end! ! def client_payments_between(client, range)! client.payments! .where("due_on >= ?", range.first)! .where("due_on < ?", range.last)! end! ! def client_payments_next_week(client)! start_day = next_week_start(Date.today)! client_payments_between(client,! start_day..week_end(start_day))! end! ! def payment_on_weekend?(payment)! payment.due_on.saturday? || payment.due_on.sunday?! end! ! def payments_next_week! clients.flat_map do |client|! client_payments_next_week(client).reject do |payment|! payment_on_weekend?(payment)! end! end! end!
- 22. BEST PRACTICES Testing ! ! ! ! describe "#decline!" do! subject { create :booking }! context "without reason" do! before { subject.decline! }! its(:status) { should == "declined" }! its(:declined?) { should be_true }! end! context "with reason" do! before { subject.decline!("REASON!") }! its(:status) { should == "declined" }! its(:declined?) { should be_true }! its(:status_reason) { should == "REASON!" }! end! end!
- 23. BEST PRACTICES TEST FIRST => great object interfaces/APIs Write how you want to use it, before you implement it.
- 24. BEST PRACTICES Don’t repeat yourself! Extract duplicate logic # user.rb! ! # file1.rb! ! User.where(user_type: ! # file2.rb! ! "client").first! User.where(user_type: "client", active: false).first! class User! def self.client! where(user_type: "client")! end! end! ! # file1.rb! ! User.client.first! ! # file2.rb! ! User.client.where(active: false).first!
- 25. BEST PRACTICES Don’t repeat yourself! Extract duplicate logic # user.rb! ! class User! def self.client! where(user_type: "client")! end! end! # file1.rb! ! User.where(user_type: ! # file2.rb! ! "client").first! ! # file1.rb! User.where(user_type: "client", active: false).first! ! User.client.first! ! # file2.rb! 2 places to fix 1 place to fix ! User.client.where(active: false).first! + easier to test
- 26. BEST PRACTICES Convention over configuration Sensible defaults
- 27. MY STUFF
- 32. MY JOB STUFF @ D-LABS
- 36. QUESTIONS