Ruby Batteries Included

RUBY
BATTERIES
INCLUDED
Ruby Can Standard Library,
And So Can You!

View Slide

HOW MANY GEMS DOES IT
TAKE TO BUILD AN APP?

View Slide

$ grep gem Gemﬁle -c

View Slide

$ grep gem Gemﬁle -c
135

View Slide

THE STANDARD LIBRARY
http://ruby-doc.org/

View Slide

CORE VS STD-LIB

View Slide

ﬁnd `ruby -e 'puts $:.join(" ")'` -iname '*.rb' -exec
grep -E '^\w*class ' {} \; | sort | uniq | wc -l

View Slide

OKAY, NOT ALL OF THEM
•Bed Basics
•Bath Performance
•Beyond Beyond

View Slide

View Slide

http://www.ﬂickr.com/photos/austinevan/3368444745/

View Slide

Set

View Slide

Set
require 'set'

View Slide

Set
require 'set'
s = Set.new([1, 2, 3, 1, 1, 1])
puts s.inspect
# => #

View Slide

Enumerable

View Slide

Enumerable
class MyFileChanger
include Enumerable
File = Struct.new(:name, :content)
def initialize
@files = []
end
def <<(filename)
content = ::File.read(filename)
@files << File.new(filename, content)
self
end
def each
@files.each do |file|
yield([file.name, file.content])
end
end
end

View Slide

Enumerable
class MyFileChanger
include Enumerable
def initialize
@files = []
end
def <<(filename)
self
end
def each
end
end
end
files = MyFileChanger.new
files << '/etc/profile' << '/etc/bashrc'
files.each_with_index do |(name, content), index|
puts "#{index}. #{name} is #{content.bytesize} bytes"
end
names = files.map do |(name, content)|
name
end
puts names.inspect
size = files.reduce(0) do |sum, (name, content)|
sum + content.bytesize
end
puts size

View Slide

Enumerable
class MyFileChanger
include Enumerable
def initialize
@files = []
end
def <<(filename)
self
end
def each
end
end
end
files = MyFileChanger.new
files << '/etc/profile' << '/etc/bashrc'
files.each_with_index do |(name, content), index|
puts "#{index}. #{name} is #{content.bytesize} bytes"
end
names = files.map do |(name, content)|
name
end
puts names.inspect
size = files.reduce(0) do |sum, (name, content)|
sum + content.bytesize
end
puts size
0. /etc/proﬁle is 189 bytes
1. /etc/bashrc is 745 bytes
["/etc/proﬁle", "/etc/bashrc"]
934

View Slide

Enumerator

View Slide

Enumerator
a = [1, 2, 3]
a.each { |n| puts n }
Enumerator.new(a).each { |n| puts n }

View Slide

Enumerator
a = [1, 2, 3]
naturals = Enumerator.new do |y|
n = 1
loop do
y << n
n += 1
end
end
odds = Enumerator.new do |y|
naturals.each do |n|
y << n if n % 2 != 0
end
end

View Slide

Enumerator
a = [1, 2, 3]
n = 1
loop do
y << n
n += 1
end
end
y << n if n % 2 != 0
end
end
class Integer
def prime?
return false if self < 2
max = Math.sqrt(self).floor
(2..max).none? { |n| self % n == 0 }
end
end
primes = Enumerator.new do |y|
y << 2
odds.each do |n|
y << n if n.prime?
end
end

View Slide

Enumerator
a = [1, 2, 3]
n = 1
loop do
y << n
n += 1
end
end
y << n if n % 2 != 0
end
end
class Integer
def prime?
return false if self < 2
max = Math.sqrt(self).floor
(2..max).none? { |n| self % n == 0 }
end
end
primes = Enumerator.new do |y|
y << 2
odds.each do |n|
y << n if n.prime?
end
end
puts primes.take(10).inspect
# => [2, 3, 5, 7, 11, 13, 17, 19, 23, 29]

View Slide

SimpleDelegator

View Slide

SimpleDelegator
require 'delegate'

View Slide

SimpleDelegator
require 'delegate'
class FancyString < SimpleDelegator
def fancy?
self == 'fancy'
end
end

View Slide

SimpleDelegator
require 'delegate'
def fancy?
self == 'fancy'
end
end
s = FancyString.new('fancy')
puts s.fancy? # => true

View Slide

SimpleDelegator
require 'delegate'
def fancy?
self == 'fancy'
end
end
s = FancyString.new('fancy')
puts s.fancy? # => true
puts s.length # => 5

View Slide

Forwardable

View Slide

Forwardable
require 'forwardable'

View Slide

Forwardable
FancyString = Struct.new(:str) do
extend Forwardable
# Single delegation
def_delegator :str, :length, :fancy_length
# Multiple delegations
def_delegators :str, :include?, :match
end

View Slide

Forwardable
extend Forwardable
# Single delegation
end
s = FancyString.new('Hello!')

View Slide

Forwardable
extend Forwardable
# Single delegation
end
puts s.fancy_length # => 6
puts s.include?('!') # => true

View Slide

Forwardable
extend Forwardable
# Single delegation
end
puts s.fancy_length # => 6
puts s.include?('!') # => true
puts s.bytesize # => NoMethodError

View Slide

View Slide

Benchmark

View Slide

Benchmark
require 'benchmark'
results = Benchmark.measure do
1_000_000.times { |i| i.to_s }
GC.start
end
puts results
# => 0.480000 0.010000 0.490000 ( 0.487643)

View Slide

Benchmark
require 'benchmark'
results = Benchmark.measure do
1_000_000.times { |i| i.to_s }
GC.start
end
puts results
# => 0.480000 0.010000 0.490000 ( 0.487643)
n = 5000000
# Simple benchmark
Benchmark.bm do |x|
x.report { for i in 1..n; a = "1"; end }
x.report { n.times do ; a = "1"; end }
x.report { 1.upto(n) do ; a = "1"; end }
end

View Slide

Benchmark

View Slide

Benchmark
# Nice reporting labels
Benchmark.bm(10) do |x|
x.report('for:') { for i in 1..n; a = "1"; end }
x.report('times:') { n.times do ; a = "1"; end }
x.report('upto:') { 1.upto(n) do ; a = "1"; end }
end
# Warmup
Benchmark.bmbm(10) do |x|
x.report('for:') { for i in 1..n; a = "1"; end }
x.report('times:') { n.times do ; a = "1"; end }
x.report('upto:') { 1.upto(n) do ; a = "1"; end }
end

View Slide

RubyVM
http://timelessrepo.com/tailin-ruby

View Slide

RubyVM
def acc(i, n, result)
if i == -1
result
else
acc(i - 1, n + result, n)
end
end
def fib(i)
acc(i, 1, 0)
end
puts fib(10000)
# => stack level too deep (SystemStackError)
http://timelessrepo.com/tailin-ruby

View Slide

RubyVM::InstructionSequence

View Slide

RubyVM::InstructionSequence.compile_option = {
:tailcall_optimization => true,
:trace_instruction => false
}

View Slide

}
RubyVM::InstructionSequence.new(<<-EOF).eval
if i == -1
result
else
end
end
def fib(i)
acc(i, 1, 0)
end
EOF

View Slide

}
RubyVM::InstructionSequence.new(<<-EOF).eval
if i == -1
result
else
end
end
def fib(i)
acc(i, 1, 0)
end
EOF
puts fib(10000)
# => A number with 2090 digits

View Slide

Fiddle

View Slide

Fiddle
require 'fiddle'
include Fiddle

View Slide

Fiddle
require 'fiddle'
include Fiddle
libm = DL.dlopen('/usr/lib/libm.dylib')

View Slide

Fiddle
require 'fiddle'
include Fiddle
f = libm['sqrt']

View Slide

Fiddle
require 'fiddle'
include Fiddle
f = libm['sqrt']
args = [TYPE_DOUBLE]

View Slide

Fiddle
require 'fiddle'
include Fiddle
f = libm['sqrt']
ret = TYPE_DOUBLE

View Slide

Fiddle
require 'fiddle'
include Fiddle
f = libm['sqrt']
ret = TYPE_DOUBLE
sqrt = Function.new(f, args, ret)

View Slide

Fiddle
require 'fiddle'
include Fiddle
f = libm['sqrt']
ret = TYPE_DOUBLE
sqrt = Function.new(f, args, ret)
puts sqrt.call(81) # => 9.0

View Slide

WeakRef

View Slide

WeakRef
require 'weakref'
bightml = WeakRef.new(read_html('http://
bigpage.com/'))
puts bightml # => "..."
puts bightml.weakref_alive? # => true

View Slide

WeakRef
require 'weakref'
bigpage.com/'))
GC.start

View Slide

WeakRef
require 'weakref'
bigpage.com/'))
GC.start
puts bightml.weakref_alive? # => false

View Slide

http://www.ﬂickr.com/photos/bobcanada/4506301467/

View Slide

SecureRandom

View Slide

SecureRandom
require 'securerandom'

View Slide

SecureRandom
puts SecureRandom.base64
# => 9d4va7k0/XhK2EqYMXJ2jg==

View Slide

SecureRandom
puts SecureRandom.hex
# => 9e70e038fc7faf20106c304854c21b8a

View Slide

SecureRandom
# => 9e70e038fc7faf20106c304854c21b8a
puts SecureRandom.random_bytes.inspect
# => "r>0\xD1\xA4\x00t&\x82\xFCEl_\x17w\xF1"

View Slide

SecureRandom
# => 9e70e038fc7faf20106c304854c21b8a
puts SecureRandom.random_number
# => 0.47149176126339587

View Slide

SecureRandom
# => 9e70e038fc7faf20106c304854c21b8a
# => 0.47149176126339587
puts SecureRandom.random_number(50)
# => 37

View Slide

SecureRandom
# => 9e70e038fc7faf20106c304854c21b8a
# => 0.47149176126339587
puts SecureRandom.random_number(50)
# => 37
puts SecureRandom.uuid
# => 3a34412c-4798-4985-9a43-7d36a6e0d116

View Slide

GServer

View Slide

GServer
require 'gserver'

View Slide

GServer
require 'gserver'
class RandomServer < GServer
def serve(io)
cmd = io.read(4).strip
case cmd
when 'hex' then io.puts(SecureRandom.hex)
when 'uuid' then io.puts(SecureRandom.uuid)
end
end
end

View Slide

GServer
require 'gserver'
class RandomServer < GServer
def serve(io)
cmd = io.read(4).strip
case cmd
when 'hex' then io.puts(SecureRandom.hex)
when 'uuid' then io.puts(SecureRandom.uuid)
end
end
end
server = RandomServer.new(10101)
server.start
server.join

View Slide

Kernel#spawn

View Slide

Kernel#spawn
def capture(cmd)
r, w = IO.pipe
pid = spawn(cmd, :out => w)
w.close
Process.wait(pid)
r.read
ensure
r.close
end
output = capture('randomizer')
print output

View Slide

Shellwords

View Slide

Shellwords
require 'shellwords'

View Slide

Shellwords
pattern = '; rm -rf /; '
capture("randomizer #{pattern.shellescape} /dev/*")

View Slide

Shellwords
# Assuming our capture function could take *args
like system

View Slide

Shellwords
# Assuming our capture function could take *args
like system
capture('randomizer', pattern, '/dev/*') # => Nope

View Slide

PStore

View Slide

PStore
require 'pstore'
store = PStore.new('randomizer', thread_safe = true)
store.ultra_safe = true

View Slide

PStore
require 'pstore'
store.transaction do
store['App'] = 'The Randomizer'
store[:randoms] ||= []
store[:randoms] << Randomizer.uuid
end

View Slide

PStore
require 'pstore'
end
puts store[:randoms].inspect # => ["901dcd24-fa10-4194-b25b-8ad49bc875fb"]
end

View Slide

PStore
require 'pstore'
end
end
store[:randoms] = []
store.abort # Or an Exception
end

View Slide

PStore
require 'pstore'
end
end
store[:randoms] = []
store.abort # Or an Exception
end
end

View Slide

I heard you like testing...

View Slide

MiniTest

View Slide

MiniTest
require 'minitest/autorun'
class MathTest < MiniTest::Unit::TestCase
def test_addition
assert_equal 2, 1 + 1
end
end
describe Integer do
it 'should subtract' do
(1 - 1).must_equal(0)
end
end

View Slide

MiniTest
require 'minitest/autorun'
class MathTest < MiniTest::Unit::TestCase
def test_addition
assert_equal 2, 1 + 1
end
end
describe Integer do
it 'should subtract' do
(1 - 1).must_equal(0)
end
end
describe 'Mocks' do
it 'should mock things' do
mock = MiniTest::Mock.new
mock.expect(:length, 10)
mock.length.must_equal(10)
mock.verify
end
end

View Slide

Other Fun Things
• OptionParser/optparse, GetoptLong/getoptlong
• Two command line option parsers!
• WEBrick => require ‘webrick’
• Threaded HTTP server.
• Rss => require ‘rss’
• Parse and generate RSS feeds. In the stdlib. wat.

View Slide

Other Fun Things
• Drb => require ‘drb’
• Distributed object system.
• Find => require ‘find’
• Recursively iterate the ﬁlesystem.
• Ripper => require ‘ripper’
• Parse ruby ﬁles

View Slide

Other Fun Things
• ThreadsWait => require ‘thwait’
• Wait for a bunch of threads, block called for each when it ﬁnishes.
• Queue/SizedQueue => require ‘thread’
• << things in, #pop things out.
• MonitorMixin => require ‘monitor’
• Thread safety with synchronize block.

View Slide

Other Fun Things
• Net::POP3 => require ‘net/pop’
• Talk POP3 email.
• Net::IMAP => require ‘net/imap’
• Talk IMAP email.
• Net::SMTP => require ‘net/smtp’
• Talk to SMTP servers.

View Slide

Other Fun Things
• Net::FTP => require ‘net/ftp’
• Talk FTP
• Net::HTTP => require ‘net/http’
• Talk HTTP

View Slide

View Slide

THANKS!!
@darkhelmetlive
darkhelmet
verboselogging.com
GetYardstick.com
https://www.makesets.com/the-ruby-standard-library

View Slide

Ruby Batteries Included

Ruby Batteries Included

Daniel Huckstep

Other Decks in Programming

Featured

Transcript