5 hidden gems of the Ruby Standard Library

Rubyconf Portugal 2015, Braga

Transcript

1. 5 hidden gems in the ruby standard library sergio gil·iamserg.io·@porras
4. ruby is old
5. its standard library big
7. Work
11. ❤❤❤ ❤ ❤❤❤ ❤❤ ❤❤❤
12. ❤ “Fame”
13. ❤ “Fame” CSV JSON Logger Benchmark
14. ❤ “Fame” CSV JSON Logger Benchmark REXML RSS RINDA
15. ❤ “Fame” CSV JSON Logger Benchmark REXML RSS RINDA ¯\_(ツ)_/¯
16. ❤ “Fame” CSV JSON Logger Benchmark REXML RSS RINDA ??? ¯\_(ツ)_/¯
17. ❤ “Fame” CSV JSON Logger Benchmark REXML RSS RINDA ??? ¯\_(ツ)_/¯
18. net/http
24. buggy
25. buggy slow
26. buggy slow lack of features
27. buggy slow lack of features confusing api
28. no one ❤ it
29. no one it
33. set
34. {,,,}
35. it doesn’t keep order
36. it doesn’t keep order It doesn’t support duplicates
37. it doesn’t keep order It doesn’t support duplicates it’s very fast at finding elements
38. it doesn’t keep order It doesn’t support duplicates it’s very fast at finding elements doesn ’ t ma tter some times fast is nice, I like fast!
40. Array#include?
41. Array#include? Array#uniq
42. BLACKLISTED_IPS = %w( 42.100.119.12 61.103.82.121 86.26.59.70 ... 114.28.117.113 79.45.68.85 ) def blacklisted?(ip) BLACKLISTED_IPS.include?(ip) end blacklisted?('79.45.68.85')
43. require 'set' BLACKLISTED_IPS = Set.new %w( 42.100.119.12 61.103.82.121 86.26.59.70 ... 114.28.117.113 79.45.68.85 ) def blacklisted?(ip) BLACKLISTED_IPS.include?(ip) end blacklisted?('79.45.68.85')
44. +--------+--------+ |items | win | +--------+--------+ |100 | x3 | |1000 | x60 | |10000 | x450 | |1000000 | x40000 | +--------+--------+
45. > (Set.new([1, 2, 3]) + Set.new([3, 4, 5])) - Set.new([1, 3, 5]) #=> #<Set: {2, 4}>
46. Queue
48. require "thread"
49. list.each do |item| do_something(item) end
50. list.each do |item| do_something_slow(item) end
51. list.map do |item| Thread.new do do_something(item) end end.each(&:join)
52. huge_list.map do |item| Thread.new do do_something(item) end end.each(&:join)
53. huge_list.map do |item| Thread.new do do_something(item) end end.each(&:join) huge_list = File.open('huge.txt')
55. num_workers = 20 queue = Queue.new threads = num_workers.times.map do Thread.new do until (item = queue.pop) == :END do_something(item) end end end list.each { |item| queue << item } num_workers.times { queue << :END } threads.each(&:join)
56. num_workers = 20 queue = SizedQueue.new(num_workers * 2) threads = num_workers.times.map do Thread.new do until (item = queue.pop) == :END do_something(item) end end end list.each { |item| queue << item } num_workers.times { queue << :END } threads.each(&:join)
57. Rake
58. utilities for managing files and dependencies
59. utilities for managing files and dependencies part of the standard library since 1.9
60. Rake::FileList A DSL for file name patterns
61. files = Dir.glob("{lib,spec}/**/*.rb") files << "Rakefile" if File.exists?("Rakefile") files.reject! { |f| f =~ /example\.rb$/ }
62. require 'rake/file_list' files = Rake::FileList.new do |files| files.add("lib/**/*.rb") files.add("spec/**/*.rb") files.add("Rakefile") files.exclude(/example\.rb$/) end
63. Rake::FileTask clever timestamp based file dependencies
64. Rake::FileTask.define_task('checksum.md5' => files) do |t| system "cat #{files.join(' ')} | md5 > checksum.md5" end.invoke
65. $ touch "lib/hello world.rb"
66. $ touch "lib/hello world.rb" $ ruby md5.rb
67. $ touch "lib/hello world.rb" $ ruby md5.rb Calculating md5 sum cat: lib/hello: No such file or directory cat: world.rb: No such file or directory
68. shellwords
69. shell command line parsing
70. require "shellwords" Shellwords.split('um dois três "trinta e um"') #=> ["um", "dois", "três", "trinta e um"]
71. filename = "Sergio's notes.txt" system "cat #{filename}"
72. filename = "Sergio's notes.txt" system "cat #{filename}" sh: -c: line 0: unexpected EOF while looking for matching `'' sh: -c: line 1: syntax error: unexpected end of file
73. filename = "Sergio's notes.txt" system "cat #{Shellwords.escape(filename)}"
74. Rake::FileTask.define_task('checksum.md5' => files) do |t| system "cat #{Shellwords.shelljoin(files)} | md5 > checksum.md5" end.invoke
75. FIDDLE
76. NATIVE EXTENSIONS
77. tracting libxml2-2.9.2.tar.gz into tmp/x86_64-apple-darwin14/ports/libxml2/2.9.2... OK nning patch with /Library/Ruby/Gems/2.0.0/gems/nokogiri-1.6.6.2/ports/patches/libxml2/00 itialization-for-the-catalog-module.patch... nning 'patch' for libxml2 2.9.2... OK nning patch with /Library/Ruby/Gems/2.0.0/gems/nokogiri-1.6.6.2/ports/patches/libxml2/00 E-2014-3660-fix.patch... nning 'patch' for libxml2 2.9.2... OK nning 'configure' for libxml2 2.9.2... OK nning 'compile' for libxml2 2.9.2... ERROR, review '/Library/Ruby/Gems/2.0.0/gems/nokogi 6_64-apple-darwin14/ports/libxml2/2.9.2/compile.log' to see what happened. * extconf.rb failed *** uld not create Makefile due to some reason, probably lack of necessary braries and/or headers. Check the mkmf.log file for more details. You may ed configuration options. ovided configuration options: --with-opt-dir --without-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --without-make-prog --srcdir=. --curdir --ruby=/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby --help --clean --use-system-libraries --enable-static --disable-static --with-zlib-dir
78. LESS GLUE CODE
79. LESS GLUE CODE THIS CODE IS RUBY
80. LESS GLUE CODE THIS CODE IS RUBY NO COMPILATION STEP
81. int add(int a, int b) { return a + b; }
83. require 'fiddle' require 'fiddle/import' module MyLib extend Fiddle::Importer dlload 'libmylib.so' extern 'int add(int, int)' end
84. require 'fiddle' require 'fiddle/import' module MyLib extend Fiddle::Importer dlload 'libmylib.so' extern 'int add(int, int)' end puts MyLib.add(11, 31) #=> 42
85. class MyNum module MyLib extend Fiddle::Importer dlload 'libmylib.so' extern 'int add(int, int)' end attr_reader :value def initialize(value) @value = value end def +(other) self.class.new(MyLib.add(value, other.value)) end protected :value end p MyNum.new(5) + MyNum.new(7) #=> #<MyNum:0x007f @value=12>
86. class Whatever def initialize @pointer = MyLib.returns_a_pointer # this is a Fiddle::Pointer end def do_something(value) MyLib.uses_a_pointer(@pointer, value) end end
87. PStore
88. NoSQL anyone?
89. NoSQL anyone? the 90’s
90. (Disclaimer: I might be doing other additional things for it to work) It Works!
91. Transactions
92. Transactions Fast lookup by key
93. Transactions Fast lookup by key Flexible schema
94. Transactions Fast lookup by key Flexible schema Pluggable backends
95. require 'pstore' store = PStore.new('mydata.data')
96. [] []= fetch
97. store['hello'] = 'world'
98. store['hello'] = 'world' # PStore::Error: not in transaction
99. store.transaction do store['hello'] = 'world' end
100. store.transaction do store['hello'] end #=> "world"
101. store.transaction do store['account1'] ||= 0 store['account2'] ||= 0 store['account1'] += 1 store['account2'] -= 1 end
103. store.transaction do store[:data] = { a: 1, b: 2} end
104. store.transaction do store[:data] = { a: 1, b: 2} end store.transaction do store[:data][:a] += 10 end
105. store.transaction do store[:data] = { a: 1, b: 2} end store.transaction do store[:data][:a] += 10 end store.transaction do store[:data] end
106. store.transaction do store[:data] = { a: 1, b: 2} end store.transaction do store[:data][:a] += 10 end store.transaction do store[:data] end #=> {:a=>11, :b=>2}
107. require 'yaml/store' store = YAML::Store.new('data.yml') # rest of examples just work!
108. require 'yaml/store' store = YAML::Store.new('data.yml') # rest of examples just work! --- :data: :a: 11 :b: 2
109. require 'pstore' require 'json' class JSONStore < PStore def dump(table) JSON.dump(table) end def load(content) JSON.load(content) end end
110. store.transaction do store['data'] = { 'a' => 1, 'b' => 2 } end store.transaction do store['data']['a'] += 10 end store.transaction do store['data'] end #=> {"a"=>11, "b"=>2}
111. {"data":{"a":11,"b":2}}
112. Those are just some examples
113. Explore
114. Explore Be critical
115. Explore Be critical Don’t believe everything you hear
116. Explore Be critical Don’t believe everything you hear talk about your discoveries
117. MUito Obrigado rubyconf.pt sergio gil·iamserg.io·@porras
118. Links: http://www.mikeperham.com/2010/11/22/the-ruby-stdlib-is-a-ghetto/ http://architecturalatrocities.com/post/23659800703/the-ruby-standard-library-is-a-disgrace http://apocryph.org/archives/579 http://devblog.avdi.org/2015/09/04/poll-whats-your-favorite-ruby-http-client-library/ http://www.jstorimer.com/pages/ruby-core-classes-arent-thread-safe http://iamserg.io/writings/2014/queue-and-sized-queue/ http://blog.skylight.io/bending-the-curve-writing-safe-fast-native-gems-with-rust/ https://robm.me.uk/ruby/2014/01/25/pstore.html http://www.rubydoc.info/stdlib/set http://www.rubydoc.info/stdlib/thread/Queue http://www.rubydoc.info/stdlib/thread/SizedQueue http://www.rubydoc.info/gems/rake/Rake/FileList http://www.rubydoc.info/gems/rake/Rake/FileTask http://www.rubydoc.info/stdlib/shellwords http://www.rubydoc.info/stdlib/fiddle/Fiddle http://www.rubydoc.info/stdlib/pstore/PStore