The document introduces Ruby, describing its origins and key features. It discusses how Ruby was designed to be more powerful than Perl and more object-oriented than Python. It also emphasizes that Ruby aims to make programming enjoyable and help programmers be productive and happy. The document then demonstrates various Ruby concepts like classes, objects, and the interactive REPL interface.

1. Ruby 101

2. Your favorite language sucks. language sucks.

3. Ruby is the greatest language ever made.

4. Ruby is the greatest language ever made. And if you disagree, you’re wrong.

5. February 24, 1993

6. Yukihiro “Matz” Matsumoto まつもとゆきひろ

7. Yukihiro “Matz” Matsumoto “ I wanted a scripting language that was more powerful than Perl, and more object-oriented than Python. That's why I decided to design my own language.”

8. Yukihiro “Matz” Matsumoto “ I hope to see Ruby help every programmer in the world to be productive, to enjoy programming, and to be happy. “ That is the primary purpose of the Ruby language.”

9. Yukihiro “Matz” Matsumoto “ Often people, especially computer engineers, focus on the machines. They think, ‘By doing this, the machine will run faster. By doing this, the machine will run more effectively. By doing this, the machine will something something something.’ They are focusing on machines. But, in fact, we need to focus on humans.”

10. for ( var i = 0 ; i < 3 ; i ++ ) { alert ( 'Hello, world!' ); }

11. for ( var i = 0 ; i < 3 ; i ++ ) { alert ( 'Hello, world!' ); } 3 .times do puts 'Hello, world!' end

12. var people = [ 'Rob' , 'Eugene' , 'Crystal' ]; for ( var i = 0 ; i < people. length ; i ++ ) { alert (people[i] + ' loves Ruby' ); }

13. var people = [ 'Rob' , 'Eugene' , 'Crystal' ]; for ( var i = 0 ; i < people. length ; i ++ ) { alert (people[i] + ' loves Ruby' ); } [ 'Rob' , 'Eugene' , 'Crystal' ].each do | name | puts &quot;#{name} loves Ruby&quot; end

14. var today = new Date (); today. setDate (today. getDate () + 2 );

15. var today = new Date (); today. setDate (today. getDate () + 2 ); 2 .days.from_now

16. Yukihiro “Matz” Matsumoto “ Sometimes people jot down pseudo-code on paper. If that pseudo-code runs directly on their computers, it’s best, isn’t it? “ Ruby tries to be like that, like pseudo-code that runs.”

17. REPL

18. REPL Read - Eval - Print - Loop

19. REPL Read - Eval - Print - Loop irb

20. REPL Read - Eval - Print - Loop irb interactive ruby

21. rob$

22. rob$ irb

23. rob$ irbruby-1.9.2 :001 >

24. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal']

25. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal'] => [&quot;Rob&quot;, &quot;Eugene&quot;, &quot;Crystal&quot;] ruby-1.9.2 :002 >

26. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal'] => [&quot;Rob&quot;, &quot;Eugene&quot;, &quot;Crystal&quot;] ruby-1.9.2 :002 > people.length

27. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal'] => [&quot;Rob&quot;, &quot;Eugene&quot;, &quot;Crystal&quot;] ruby-1.9.2 :002 > people.length => 3 ruby-1.9.2 :003 >

28. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal'] => [&quot;Rob&quot;, &quot;Eugene&quot;, &quot;Crystal&quot;] ruby-1.9.2 :002 > people.length => 3 ruby-1.9.2 :003 > people.last

29. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal'] => [&quot;Rob&quot;, &quot;Eugene&quot;, &quot;Crystal&quot;] ruby-1.9.2 :002 > people.length => 3 ruby-1.9.2 :003 > people.last => &quot;Crystal&quot; ruby-1.9.2 :004 >

30. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal'] => [&quot;Rob&quot;, &quot;Eugene&quot;, &quot;Crystal&quot;] ruby-1.9.2 :002 > people.length => 3 ruby-1.9.2 :003 > people.last => &quot;Crystal&quot; ruby-1.9.2 :004 > people.reverse

31. rob$ irbruby-1.9.2 :001 > people = ['Rob','Eugene','Crystal'] => [&quot;Rob&quot;, &quot;Eugene&quot;, &quot;Crystal&quot;] ruby-1.9.2 :002 > people.length => 3 ruby-1.9.2 :003 > people.last => &quot;Crystal&quot; ruby-1.9.2 :004 > people.reverse => [&quot;Crystal&quot;, &quot;Eugene&quot;, &quot;Rob&quot;] ruby-1.9.2 :005 >

32. The Basics

33. count = 42

34. count = 42 amount = 23.83

35. count = 42 amount = 23.83 language = 'Ruby'

36. count = 42 amount = 23.83 language = 'Ruby' text = &quot;#{language} is the best!&quot;

37. count = 42 amount = 23.83 language = 'Ruby' text = &quot;#{language} is the best!&quot; people = [ 'Rob' , 'Eugene' , 'Crystal' ]

38. count = 42 amount = 23.83 language = 'Ruby' text = &quot;#{language} is the best!&quot; people = [ 'Rob' , 'Eugene' , 'Crystal' ] person = { :name => 'Rob' , :gender => 'male' }

39. count = 42 amount = 23.83 language = 'Ruby' text = &quot;#{language} is the best!&quot; people = [ 'Rob' , 'Eugene' , 'Crystal' ] person = { :name => 'Rob' , :gender => 'male' } this = true

40. count = 42 amount = 23.83 language = 'Ruby' text = &quot;#{language} is the best!&quot; people = [ 'Rob' , 'Eugene' , 'Crystal' ] person = { :name => 'Rob' , :gender => 'male' } this = true that = false

41. count = 42 amount = 23.83 language = 'Ruby' text = &quot;#{language} is the best!&quot; people = [ 'Rob' , 'Eugene' , 'Crystal' ] person = { :name => 'Rob' , :gender => 'male' } this = true that = false nothing = nil

42. [ 'Rob' , 'Eugene' , 'Crystal' ].each do | name | puts &quot;#{name} loves Ruby&quot; end

43. [ 'Rob' , 'Eugene' , 'Crystal' ].each do | name | puts &quot;#{name} loves Ruby&quot; end Iterators

44. [ 'Rob' , 'Eugene' , 'Crystal' ].each do | name | puts &quot;#{name} loves Ruby&quot; end Iterators each find collect each_with_index reject inject

45. $ ( 'li' ).each( function (index) { alert ( 'index=' + index); });

46. $ ( 'li' ).each( function (index) { alert ( 'index=' + index); }); an_array.each do | item | puts &quot;item=#{item}&quot; end

47. Loops?

48. Conditionals

49. if person.has_red_hair? Sun .burn person end

50. if person.has_red_hair? Sun .burn person end unless car.sugar_in_gas_tank? car.start end

51. if person.has_red_hair? Sun .burn person end unless car.sugar_in_gas_tank? car.start end 15 .times { wash_hands } if person.ocd?

52. if person.has_red_hair? Sun .burn person end unless car.sugar_in_gas_tank? car.start end 15 .times { wash_hands } if person.ocd? car.accelerate unless TrafficLight .is_red?

53. if just_worked_out and date_tonight take_a_shower end

54. if just_worked_out and date_tonight take_a_shower end if love_mom or just_drunk get_a_tattoo end

55. if just_worked_out and date_tonight take_a_shower end if love_mom or just_drunk get_a_tattoo end if taco_bell? and not pepto_bismol_nearby? get_to_bathroom! end

56. !

57. airlines = [ 'Southwest' , 'United' , 'Delta' ]

58. airlines = [ 'Southwest' , 'United' , 'Delta' ] airlines.reverse => [ 'Delta' , 'United' , 'Southwest' ]

59. airlines = [ 'Southwest' , 'United' , 'Delta' ] airlines.reverse => [ 'Delta' , 'United' , 'Southwest' ] puts airlines => [ 'Southwest' , 'United' , 'Delta' ]

60. airlines = [ 'Southwest' , 'United' , 'Delta' ] airlines.reverse => [ 'Delta' , 'United' , 'Southwest' ] puts airlines => [ 'Southwest' , 'United' , 'Delta' ] airlines.reverse! => [ 'Delta' , 'United' , 'Southwest' ]

61. airlines = [ 'Southwest' , 'United' , 'Delta' ] airlines.reverse => [ 'Delta' , 'United' , 'Southwest' ] puts airlines => [ 'Southwest' , 'United' , 'Delta' ] airlines.reverse! => [ 'Delta' , 'United' , 'Southwest' ] puts airlines => [ 'Delta' , 'United' , 'Southwest' ]

62. everything is an object

63. ‘ Rob’.class

64. ‘ Rob’.class => String

65. ‘ Rob’.class => String 42.class

66. ‘ Rob’.class => String 42.class => Fixnum

67. ‘ Rob’.class => String 42.class => Fixnum (23.45).class

68. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float

69. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class

70. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass

71. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class

72. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass

73. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class

74. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class

75. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class

76. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class

77. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass

78. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass => Module

79. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass => Module Module.superclass

80. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass => Module Module.superclass => Object

81. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass => Module Module.superclass => Object Object.superclass

82. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass => Module Module.superclass => Object Object.superclass => BasicObject

83. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass => Module Module.superclass => Object Object.superclass => BasicObject BasicObject.superclass

84. ‘ Rob’.class => String 42.class => Fixnum (23.45).class => Float true.class => TrueClass nil.class => NilClass String.class => Class Class.class => Class Class.superclass => Module Module.superclass => Object Object.superclass => BasicObject BasicObject.superclass => nil

85. Class, Object, Module and all other classes are instances of a class Class . Class, Module and Object have a circular dependency as they are in the core of the OO model

86. Introspection

87. 42.methods

88. 42.methods [:!, :!=, :!~, :%, :&, :*, :**, :+, :+@, :-, :-@, :/, :<, :<<, :<=, :<=>, :==, :===, :=~, :>, :>=, :>>, :[], :^, :__id__, :__send__, :abs, :abs2, :angle, :arg, :between?, :ceil, :chr, :class, :clone, :coerce, :conj, :conjugate, :define_singleton_method, :denominator, :display, :div, :divmod, :downto, :dup, :enum_for, :eql?, :equal?, :even?, :extend, :fdiv, :floor, :freeze, :frozen?, :gcd, :gcdlcm, :hash, :i, :imag, :imaginary, :initialize_clone, :initialize_dup, :inspect, :instance_eval, :instance_exec, :instance_of?, :instance_variable_defined?, :instance_variable_get, :instance_variable_set, :instance_variables, :integer?, :is_a?, :kind_of?, :lcm, :magnitude, :method, :methods, :modulo, :next, :nil?, :nonzero?, :numerator, :object_id, :odd?, :ord, :phase, :polar, :pred, :private_methods, :protected_methods, :public_method, :public_methods, :public_send, :quo, :rationalize, :real, :real?, :rect, :rectangular, :remainder, :respond_to?, :respond_to_missing?, :round, :send, :singleton_class, :singleton_method_added, :singleton_methods, :size, :step, :succ, :taint, :tainted?, :tap, :times, :to_c, :to_enum, :to_f, :to_i, :to_int, :to_r, :to_s, :truncate, :trust, :untaint, :untrust, :untrusted?, :upto, :zero?, :|, :~]

89. 42.methods [:!, :!=, :!~, :%, :&, :*, :**, :+, :+@, :-, :-@, :/, :<, :<<, :<=, :<=>, :==, :===, :=~, :>, :>=, :>>, :[], :^, :__id__, :__send__, :abs, :abs2, :angle, :arg, :between?, :ceil, :chr, :class, :clone, :coerce, :conj, :conjugate, :define_singleton_method, :denominator, :display, :div, :divmod, :downto, :dup, :enum_for, :eql?, :equal?, :even?, :extend, :fdiv, :floor, :freeze, :frozen?, :gcd, :gcdlcm, :hash, :i, :imag, :imaginary, :initialize_clone, :initialize_dup, :inspect, :instance_eval, :instance_exec, :instance_of?, :instance_variable_defined?, :instance_variable_get, :instance_variable_set, :instance_variables , :integer?, :is_a?, :kind_of?, :lcm, :magnitude, :method, :methods, :modulo, :next, :nil?, :nonzero?, :numerator, :object_id, :odd?, :ord, :phase, :polar, :pred, :private_methods , :protected_methods, :public_method, :public_methods , :public_send, :quo, :rationalize, :real, :real?, :rect, :rectangular, :remainder, :respond_to? , :respond_to_missing?, :round, :send , :singleton_class, :singleton_method_added, :singleton_methods, :size, :step, :succ, :taint, :tainted?, :tap, :times, :to_c, :to_enum, :to_f, :to_i, :to_int, :to_r, :to_s, :truncate, :trust, :untaint, :untrust, :untrusted?, :upto, :zero?, :|, :~]

90. var method = 'first_name' eval ( 'person.' + method)

91. var method = 'first_name' eval ( 'person.' + method) method = 'first_name' person.send(method)

92. 2 + 2

93. 2 + 2 2.+(2)

94. 2 + 2 2.+(2) 2.send('+',2)

95. Syntactic Sugar

96. 2 == 2

97. 2 == 2 2.==(2)

98. 2 == 2 2.==(2) 2.send('==',2)

99. Ruby removes the cruft

100. car = Vehicle . new ( 'honda' , 'civic' , { :interior => 'beige' }) car = Vehicle . new 'honda' , 'civic' , :interior => 'beige'

101. Beautiful code

102. class Person attr_accessor 'gender' , 'eyes' , 'chin' , 'name' def initialize ( gender,eyes,chin ) @gender = gender @eyes = eyes @chin = chin end end

103. class Person attr_accessor 'gender' , 'eyes' , 'chin' , 'name' def initialize ( gender,eyes,chin ) @gender = gender @eyes = eyes @chin = chin end end rob = Person . new 'male' , 'blue' , 'square'

104. class Person attr_accessor 'gender' , 'eyes' , 'chin' , 'name' def initialize ( gender,eyes,chin ) @gender = gender @eyes = eyes @chin = chin end end rob = Person . new 'male' , 'blue' , 'square' aimee = Person . new 'female' , 'brown' , 'cleft'

105. class Person attr_accessor 'gender' , 'eyes' , 'chin' , 'name' def initialize ( gender,eyes,chin ) @gender = gender @eyes = eyes @chin = chin end end rob = Person . new 'male' , 'blue' , 'square' aimee = Person . new 'female' , 'brown' , 'cleft'

106. class Person def + ( other_person ) gene_pool = [ self ,other_person] Person . new selection(gene_pool, 'gender' ), selection(gene_pool, 'eyes' ), selection(gene_pool, 'chin' ) end def selection ( gene_pool,feature ) return gene_pool[rand(gene_pool.size)].send feature end private 'selection' end

107. baby = rob + aimee

108. baby = rob + aimee baby.name = 'Jack'

110. baby = rob + aimee baby.name = 'Jack' baby.name=( 'Jack' )

111. baby = rob + aimee baby.name = 'Jack' baby.name=( 'Jack' ) baby.inspect

112. baby = rob + aimee baby.name = 'Jack' baby.name=( 'Jack' ) baby.inspect #<Person:0x0000010083fdf0 @gender=&quot;male&quot;, @eyes=&quot;blue&quot;, @chin=&quot;cleft&quot;, @name=&quot;Jack&quot;>

113. “ When I am working on a problem I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong.” — R. Buckminster Fuller

114. return gene_pool[rand(gene_pool.size)].send feature

115. return gene_pool[rand(gene_pool.size)].send feature class Array def random return self [rand( self .length)] end end

116. return gene_pool[rand(gene_pool.size)].send feature class Array def random return self [rand( self .length)] end end return gene_pool.random.send feature

117. unless []. respond_to ? 'random' class Array def random return self [rand( self .length)] end end end

118. Monkey Patching!!1!one!!!

119. David Heinemeier Hansson (DHH) “ Why Ruby” http://confreaks.net/system/assets/datas/694/original/431-rubyconf2010-keynote-why-ruby-small.mp4?1291226733

120. “ UNIX was not designed to stop its users from doing stupid things, as that would also stop them from doing clever things.” — Doug Gwyn

121. “ There is not now, nor has there ever been, nor will there ever be, any programming language in which it is the least bit difficult to write bad code.” — Anonymous

122. class Array def random return self [rand( self .length)] end end class Person attr_accessor 'gender' , 'eyes' , 'chin' , 'name' def initialize ( gender,eyes,chin ) @gender = gender @eyes = eyes @chin = chin end def + ( other_person ) gene_pool = [ self ,other_person] Person . new selection(gene_pool, 'gender' ), selection(gene_pool, 'eyes' ), selection(gene_pool, 'chin' ) end def selection ( gene_pool,feature ) return gene_pool.random.send feature end private 'selection' end

123. using System;using System.Collections.Concurrent;using System.Collections.Specialized;using System.ComponentModel.Composition;using System.Diagnostics;using System.IO;using System.IO.Compression;using System.Net;using System.Text.RegularExpressions;using System.Threading;using System.Linq;using Newtonsoft.Json;using NLog;using Raven.Abstractions.Data;using Raven.Abstractions.Exceptions;using Raven.Abstractions.MEF;using Raven.Http.Abstractions;using Raven.Http.Exceptions;using Raven.Http.Extensions;using Formatting = Newtonsoft.Json.Formatting;namespace Raven.Http{ public abstract class HttpServer : IDisposable { private const int MaxConcurrentRequests = 192; protected readonly IResourceStore DefaultResourceStore; protected readonly IRavenHttpConfiguration DefaultConfiguration; private readonly ThreadLocal<string> currentTenantId = new ThreadLocal<string>(); private readonly ThreadLocal<IResourceStore> currentDatabase = new ThreadLocal<IResourceStore>(); private readonly ThreadLocal<IRavenHttpConfiguration> currentConfiguration = new ThreadLocal<IRavenHttpConfiguration>(); protected readonly ConcurrentDictionary<string, IResourceStore> ResourcesStoresCache = new ConcurrentDictionary<string, IResourceStore>(StringComparer.InvariantCultureIgnoreCase); private readonly ConcurrentDictionary<string, DateTime> databaseLastRecentlyUsed = new ConcurrentDictionary<string, DateTime>();

124. public int NumberOfRequests { get { return Thread.VolatileRead(ref physicalRequestsCount); } } [ImportMany] public OrderedPartCollection<AbstractRequestResponder> RequestResponders { get; set; } public IRavenHttpConfiguration Configuration { get { return DefaultConfiguration; } } public abstract Regex TenantsQuery { get; } private HttpListener listener; private static readonly Logger logger = LogManager.GetCurrentClassLogger(); private int reqNum; // concurrent requests // we set 1/4 aside for handling background tasks private readonly SemaphoreSlim concurretRequestSemaphore = new SemaphoreSlim(MaxConcurrentRequests); private Timer databasesCleanupTimer; private int physicalRequestsCount; public bool HasPendingRequests { get { return concurretRequestSemaphore.CurrentCount != MaxConcurrentRequests; } } protected HttpServer(IRavenHttpConfiguration configuration, IResourceStore resourceStore) {

125. DefaultResourceStore = resourceStore; DefaultConfiguration = configuration; configuration.Container.SatisfyImportsOnce(this); foreach (var requestResponder in RequestResponders) { requestResponder.Value.Initialize(() => currentDatabase.Value, () => currentConfiguration.Value, () => currentTenantId.Value, this); } } #region IDisposable Members public void Dispose() { databasesCleanupTimer.Dispose(); if (listener != null && listener.IsListening) listener.Stop(); foreach (var documentDatabase in ResourcesStoresCache) { documentDatabase.Value.Dispose(); } } #endregion public void Start() { listener = new HttpListener(); string virtualDirectory = DefaultConfiguration.VirtualDirectory; if (virtualDirectory.EndsWith(&quot;/&quot;) == false) virtualDirectory = virtualDirectory + &quot;/&quot;; listener.Prefixes.Add(&quot;http://&quot; + (DefaultConfiguration.HostName ?? &quot;+&quot;) + &quot;:&quot; + DefaultConfiguration.Port + virtualDirectory);

126. switch (DefaultConfiguration.AnonymousUserAccessMode) { case AnonymousUserAccessMode.None: listener.AuthenticationSchemes = AuthenticationSchemes.IntegratedWindowsAuthentication; break; case AnonymousUserAccessMode.All: listener.AuthenticationSchemes = AuthenticationSchemes.IntegratedWindowsAuthentication | AuthenticationSchemes.Anonymous; listener.AuthenticationSchemeSelectorDelegate = request => { if(request.RawUrl.StartsWith(&quot;/admin&quot;,StringComparison.InvariantCultureIgnoreCase)) return AuthenticationSchemes.IntegratedWindowsAuthentication; return AuthenticationSchemes.Anonymous; }; break; case AnonymousUserAccessMode.Get: listener.AuthenticationSchemes = AuthenticationSchemes.IntegratedWindowsAuthentication | AuthenticationSchemes.Anonymous; listener.AuthenticationSchemeSelectorDelegate = request => { return IsGetRequest(request.HttpMethod, request.Url.AbsolutePath) ? AuthenticationSchemes.Anonymous | AuthenticationSchemes.IntegratedWindowsAuthentication : AuthenticationSchemes.IntegratedWindowsAuthentication; }; break; default: throw new ArgumentException(&quot;Cannot understand access mode: &quot; + DefaultConfiguration.AnonymousUserAccessMode); } databasesCleanupTimer = new Timer(CleanupDatabases, null, TimeSpan.FromMinutes(1), TimeSpan.FromMinutes(1)); listener.Start(); listener.BeginGetContext(GetContext, null); }

127. private void CleanupDatabases(object state) { var databasesToCleanup = databaseLastRecentlyUsed .Where(x=>(DateTime.Now - x.Value).TotalMinutes > 10) .Select(x=>x.Key) .ToArray(); foreach (var db in databasesToCleanup) { DateTime _; databaseLastRecentlyUsed.TryRemove(db, out _); IResourceStore database; if(ResourcesStoresCache.TryRemove(db, out database)) database.Dispose(); } } private void GetContext(IAsyncResult ar) { IHttpContext ctx; try { ctx = new HttpListenerContextAdpater(listener.EndGetContext(ar), DefaultConfiguration); //setup waiting for the next request listener.BeginGetContext(GetContext, null); } catch (InvalidOperationException) { // can't get current request / end new one, probably // listner shutdown return; } catch (HttpListenerException) { // can't get current request / end new one, probably // listner shutdown return; }

128. if (concurretRequestSemaphore.Wait(TimeSpan.FromSeconds(5)) == false) { HandleTooBusyError(ctx); return; } try { Interlocked.Increment(ref physicalRequestsCount); HandleActualRequest(ctx); } finally { concurretRequestSemaphore.Release(); } } public void HandleActualRequest(IHttpContext ctx) { var sw = Stopwatch.StartNew(); bool ravenUiRequest = false; try { ravenUiRequest = DispatchRequest(ctx); } catch (Exception e) { HandleException(ctx, e); if (ShouldLogException(e)) logger.WarnException(&quot;Error on request&quot;, e); } finally { try { FinalizeRequestProcessing(ctx, sw, ravenUiRequest); } catch (Exception e) { logger.ErrorException(&quot;Could not finalize request properly&quot;, e); }

129. protected virtual bool ShouldLogException(Exception exception) { return true; } private void FinalizeRequestProcessing(IHttpContext ctx, Stopwatch sw, bool ravenUiRequest) { LogHttpRequestStatsParams logHttpRequestStatsParam = null; try { logHttpRequestStatsParam = new LogHttpRequestStatsParams( sw, ctx.Request.Headers, ctx.Request.HttpMethod, ctx.Response.StatusCode, ctx.Request.Url.PathAndQuery); } catch (Exception e) { logger.WarnException(&quot;Could not gather information to log request stats&quot;, e); } ctx.FinalizeResonse(); sw.Stop(); if (ravenUiRequest || logHttpRequestStatsParam == null) return; LogHttpRequestStats(logHttpRequestStatsParam); ctx.OutputSavedLogItems(logger); } private void LogHttpRequestStats(LogHttpRequestStatsParams logHttpRequestStatsParams) { // we filter out requests for the UI because they fill the log with information // we probably don't care about them anyway. That said, we do output them if they take too // long.

130. if (logHttpRequestStatsParams.Headers[&quot;Raven-Timer-Request&quot;] == &quot;true&quot; && logHttpRequestStatsParams.Stopwatch.ElapsedMilliseconds <= 25) return; var curReq = Interlocked.Increment(ref reqNum); logger.Debug(&quot;Request #{0,4:#,0}: {1,-7} - {2,5:#,0} ms - {5,-10} - {3} - {4}&quot;, curReq, logHttpRequestStatsParams.HttpMethod, logHttpRequestStatsParams.Stopwatch.ElapsedMilliseconds, logHttpRequestStatsParams.ResponseStatusCode, logHttpRequestStatsParams.RequestUri, currentTenantId.Value); } private void HandleException(IHttpContext ctx, Exception e) { try { if (e is BadRequestException) HandleBadRequest(ctx, (BadRequestException)e); else if (e is ConcurrencyException) HandleConcurrencyException(ctx, (ConcurrencyException)e); else if (TryHandleException(ctx, e)) return; else HandleGenericException(ctx, e); } catch (Exception) { logger.ErrorException(&quot;Failed to properly handle error, further error handling is ignored&quot;, e); } } protected abstract bool TryHandleException(IHttpContext ctx, Exception exception);

131. private static void HandleTooBusyError(IHttpContext ctx) { ctx.Response.StatusCode = 503; ctx.Response.StatusDescription = &quot;Service Unavailable&quot;; SerializeError(ctx, new { Url = ctx.Request.RawUrl, Error = &quot;The server is too busy, could not acquire transactional access&quot; }); } private static void HandleGenericException(IHttpContext ctx, Exception e) { ctx.Response.StatusCode = 500; ctx.Response.StatusDescription = &quot;Internal Server Error&quot;; SerializeError(ctx, new { Url = ctx.Request.RawUrl, Error = e.ToString() }); } private static void HandleBadRequest(IHttpContext ctx, BadRequestException e) { ctx.SetStatusToBadRequest(); SerializeError(ctx, new { Url = ctx.Request.RawUrl, e.Message, Error = e.Message }); }

132. private static void HandleConcurrencyException(IHttpContext ctx, ConcurrencyException e) { ctx.Response.StatusCode = 409; ctx.Response.StatusDescription = &quot;Conflict&quot;; SerializeError(ctx, new { Url = ctx.Request.RawUrl, e.ActualETag, e.ExpectedETag, Error = e.Message }); } protected static void SerializeError(IHttpContext ctx, object error) { var sw = new StreamWriter(ctx.Response.OutputStream); new JsonSerializer().Serialize(new JsonTextWriter(sw) { Formatting = Formatting.Indented, }, error); sw.Flush(); } private bool DispatchRequest(IHttpContext ctx) { if (AssertSecurityRights(ctx) == false) return false; SetupRequestToProperDatabase(ctx); CurrentOperationContext.Headers.Value = ctx.Request.Headers; try { OnDispatchingRequest(ctx); if (DefaultConfiguration.HttpCompression) AddHttpCompressionIfClientCanAcceptIt(ctx);

133. AddAccessControlAllowOriginHeader(ctx); foreach (var requestResponderLazy in RequestResponders) { var requestResponder = requestResponderLazy.Value; if (requestResponder.WillRespond(ctx)) { requestResponder.Respond(ctx); return requestResponder.IsUserInterfaceRequest; } } ctx.SetStatusToBadRequest(); if (ctx.Request.HttpMethod == &quot;HEAD&quot;) return false; ctx.Write( @&quot;<html> <body> <h1>Could not figure out what to do</h1> <p>Your request didn't match anything that Raven knows to do, sorry...</p> </body></html>&quot;); } finally { CurrentOperationContext.Headers.Value = new NameValueCollection(); currentDatabase.Value = DefaultResourceStore; currentConfiguration.Value = DefaultConfiguration; } return false; } protected virtual void OnDispatchingRequest(IHttpContext ctx){}

134. private void SetupRequestToProperDatabase(IHttpContext ctx) { var requestUrl = ctx.GetRequestUrlForTenantSelection(); var match = TenantsQuery.Match(requestUrl); if (match.Success == false) { currentTenantId.Value = Constants.DefaultDatabase; currentDatabase.Value = DefaultResourceStore; currentConfiguration.Value = DefaultConfiguration; } else { var tenantId = match.Groups[1].Value; IResourceStore resourceStore; if(TryGetOrCreateResourceStore(tenantId, out resourceStore)) { databaseLastRecentlyUsed.AddOrUpdate(tenantId, DateTime.Now, (s, time) => DateTime.Now); if (string.IsNullOrEmpty(Configuration.VirtualDirectory) == false && Configuration.VirtualDirectory != &quot;/&quot;) { ctx.AdjustUrl(Configuration.VirtualDirectory + match.Value); } else { ctx.AdjustUrl(match.Value); } currentTenantId.Value = tenantId; currentDatabase.Value = resourceStore; currentConfiguration.Value = resourceStore.Configuration; } else { throw new BadRequestException(&quot;Could not find a database named: &quot; + tenantId); } } }

135. protected abstract bool TryGetOrCreateResourceStore(string name, out IResourceStore database); private void AddAccessControlAllowOriginHeader(IHttpContext ctx) { if (string.IsNullOrEmpty(DefaultConfiguration.AccessControlAllowOrigin)) return; ctx.Response.AddHeader(&quot;Access-Control-Allow-Origin&quot;, DefaultConfiguration.AccessControlAllowOrigin); } private static void AddHttpCompressionIfClientCanAcceptIt(IHttpContext ctx) { var acceptEncoding = ctx.Request.Headers[&quot;Accept-Encoding&quot;]; if (string.IsNullOrEmpty(acceptEncoding)) return; // gzip must be first, because chrome has an issue accepting deflate data // when sending it json text if ((acceptEncoding.IndexOf(&quot;gzip&quot;, StringComparison.InvariantCultureIgnoreCase) != -1)) { ctx.SetResponseFilter(s => new GZipStream(s, CompressionMode.Compress, true)); ctx.Response.AddHeader(&quot;Content-Encoding&quot;,&quot;gzip&quot;); } else if (acceptEncoding.IndexOf(&quot;deflate&quot;, StringComparison.InvariantCultureIgnoreCase) != -1) { ctx.SetResponseFilter(s => new DeflateStream(s, CompressionMode.Compress, true)); ctx.Response.AddHeader(&quot;Content-Encoding&quot;, &quot;deflate&quot;); } } private bool AssertSecurityRights(IHttpContext ctx) { if (DefaultConfiguration.AnonymousUserAccessMode == AnonymousUserAccessMode.None && IsInvalidUser(ctx)) { ctx.SetStatusToUnauthorized(); return false; }

136. IHttpRequest httpRequest = ctx.Request; if (DefaultConfiguration.AnonymousUserAccessMode == AnonymousUserAccessMode.Get && IsInvalidUser(ctx) && IsGetRequest(httpRequest.HttpMethod, httpRequest.Url.AbsolutePath) == false ) { ctx.SetStatusToUnauthorized(); return false; } return true; } protected virtual bool IsGetRequest(string httpMethod, string requestPath) { return (httpMethod == &quot;GET&quot; || httpMethod == &quot;HEAD&quot;); } private static bool IsInvalidUser(IHttpContext ctx) { return (ctx.User == null || ctx.User.Identity == null || ctx.User.Identity.IsAuthenticated == false); } public void ResetNumberOfRequests() { Interlocked.Exchange(ref reqNum, 0); Interlocked.Exchange(ref physicalRequestsCount, 0); } }} 517 lines of code

137. webserver = TCPServer . new ( '127.0.0.1' , 3000 ) while (session = webserver.accept) session.print &quot;HTTP/1.1 200/OK Content-type:text/html &quot; request = session.gets filename = request.match( / (.*?) / )[ 1 ] filename = 'index.html' if filename == '' begin session.print File .read(filename) rescue Errno :: ENOENT session.print 'File not found' end session.close end

138. “ There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies and the other way is to make it so complicated that there are no obvious deficiencies.” — C.A.R. Hoare

139. class Person def + ( other_person ) gene_pool = [ self ,other_person] Person . new selection(gene_pool, 'gender' ), selection(gene_pool, 'eyes' ), selection(gene_pool, 'chin' ) end def selection ( gene_pool,feature ) return gene_pool[rand(gene_pool.size)].send feature end private 'selection' end

140. class Person def + ( other_person ) gene_pool = [ self ,other_person] Person . new selection(gene_pool, 'gender' ), selection(gene_pool, 'eyes' ), selection(gene_pool, 'chin' ) end def selection ( gene_pool,feature ) return gene_pool[rand(gene_pool.size)].send feature end private 'selection' end

141. class Person def + ( other_person ) gene_pool = [ self ,other_person] Person . new selection(gene_pool, 'gender' ), selection(gene_pool, 'eyes' ), selection(gene_pool, 'chin' ) end def selection ( gene_pool,feature ) return gene_pool[rand(gene_pool.size)].send feature end private 'selection' end

142. Implicit return Any statement in Ruby returns the value of the last evaluated expression

143. ruby-1.9.2 :001 > puts 'Hello, world!'

144. ruby-1.9.2 :001 > puts 'Hello, world!'Hello, world! => nil ruby-1.9.2 :002 >

145. ruby-1.9.2 :001 > puts 'Hello, world!'Hello, world! => nil ruby-1.9.2 :002 > puts('Hello, world!')

146. ruby-1.9.2 :001 > puts 'Hello, world!'Hello, world! => nil ruby-1.9.2 :002 > puts('Hello, world!')Hello, world! => nil ruby-1.9.2 :003 >

147. Blabber Talk to your servers via IM

149. gems

150. rob$

151. rob$ gem install rails

152. rob$ gem install rails rob$ gem install httparty json

153. require 'rubygems' require 'json' require 'httparty'

154. rob$ irbruby-1.9.2 :001 >

155. rob$ irbruby-1.9.2 :001 > HTTParty

156. rob$ irbruby-1.9.2 :001 > HTTPartyNameError: uninitialized constant Object::HTTParty from (irb):1 from /Users/rob/.rvm/rubies/ruby-1.9.2-p180/bin/irb:16:in `<main>'ruby-1.9.2 :002 >

157. rob$ irbruby-1.9.2 :001 > HTTPartyNameError: uninitialized constant Object::HTTParty from (irb):1 from /Users/rob/.rvm/rubies/ruby-1.9.2-p180/bin/irb:16:in `<main>'ruby-1.9.2 :002 > require 'httparty'

158. rob$ irbruby-1.9.2 :001 > HTTPartyNameError: uninitialized constant Object::HTTParty from (irb):1 from /Users/rob/.rvm/rubies/ruby-1.9.2-p180/bin/irb:16:in `<main>'ruby-1.9.2 :002 > require 'httparty' => true ruby-1.9.2 :003 >

159. rob$ irbruby-1.9.2 :001 > HTTPartyNameError: uninitialized constant Object::HTTParty from (irb):1 from /Users/rob/.rvm/rubies/ruby-1.9.2-p180/bin/irb:16:in `<main>'ruby-1.9.2 :002 > require 'httparty' => true ruby-1.9.2 :003 > HTTParty

160. rob$ irbruby-1.9.2 :001 > HTTPartyNameError: uninitialized constant Object::HTTParty from (irb):1 from /Users/rob/.rvm/rubies/ruby-1.9.2-p180/bin/irb:16:in `<main>'ruby-1.9.2 :002 > require 'httparty' => true ruby-1.9.2 :003 > HTTParty => HTTParty ruby-1.9.2 :004 >

161. Questions?

162. Workshop

163. Command line interface to the Active.com Search API

164. It should:

170. Example

171. What you need to know

172. Required Gems require 'json' require 'httparty'

173. Search API Endpoint http://api.amp.active.com/search? v=json& k=keywords& m=meta:channel%3DRunning& api_key=wuhmn9ye94xn3xnteudxsavw

174. HTTP call HTTParty.get(url)

175. Parse JSON JSON.parse(text) HTTP call HTTParty.get(url)

176. Get user input user_input = gets

177. Get user input user_input = gets Remove newlines user_input.chomp

178. Get user input user_input = gets Print to STDOUT print 'text'puts 'text' Remove newlines user_input.chomp

179. Iterate through array with index my_array.each_with_index do |item,i| puts “#{item} is at position #{i}” end

180. Exit exit 0 Iterate through array with index my_array.each_with_index do |item,i| puts “#{item} is at position #{i}” end

182. Questions?

183. require 'json' require 'httparty' HTTParty.get(url) JSON.parse(text) user_input = gets print 'text' puts 'text' user_input.chomp my_array.each_with_index do |item,i| puts “#{item} is as position #{i}” end http://api.amp.active.com/search? v=json& k=keywords& m=meta:channel%3DRunning& api_key= wuhmn9ye94xn3xnteudxsavw exit 0

184. “ I am rarely happier than when spending an entire day programming my computer to perform automatically a task that would otherwise take me a good ten seconds to do by hand.” — Douglas Adams

185. Learning a new language

188. EGO

189. “ Would you rather be a king of fools or a student of masters?”

190. The End