ReactiveCocoa NSSpain

Transcript

1. robb robb@robb.is ceterum_censeo

2. speakerdeck.com/robb/ reactivecocoa-nsspain

3. Let's talk about ReactiveCocoa

4. Let's talk about ReactiveCocoa state

5. evil √

6. Have you tried turning it off and on again?

7. Have you tried turning it off and on again? Have

   you tried turning it off and on again?

8. Start Okay Fail

9. Start Okay Fail power-cycle power-cycle

10. state

11. state

12. duh! " " you say

13. e.g.

14. @property (readwrite) BOOL walks; @property (readwrite) BOOL quaks; @property (readonly)

    BOOL duck;

15. duck = walks ∧ quaks

16. - (void)setWalks:(BOOL)walks { _walks = walks; self.duck = walks &&

    self.quacks; }

17. - (void)setWalks:(BOOL)walks { _walks = walks; self.duck = walks &&

    self.quacks; } - (void)setQuacks:(BOOL)quacks { _quacks = quacks; self.duck = quacks && self.walks; }

18. - (void)setWalks:(BOOL)walks { _walks = walks; self.duck = walks &&

    self.quacks; } - (void)setQuacks:(BOOL)quacks { _quacks = quacks; self.duck = quacks && self.walks; }

19. - (BOOL)duck { return self.walks && self.quacks; }

20. - (NSSet *)keyPathsForValuesAffectingDuck { return [NSSet setWithArray:@[ @"walks", @"quacks" ]];

    } - (BOOL)duck { return self.walks && self.quacks; }

21. - (BOOL)duck { return self.walks && self.quacks; } // duck

    = walks ∧ quaks

22. ReactiveCocoa

23. Functional Reactive Programming

24. Signals instead of variables

25. Pipes, not boxes

26. wtf? " " you may be thinking

27. e.g.

28. RAC(self, duck) = [RACSignal combineLatest:@[ RACObserve(self, walks), RACObserve(self, quacks) ]

    reduce:^(NSNumber *walks, NSNumber *quacks) { return @(walks.boolValue && quacks.boolValue); }]:

29. RAC(self, duck) = [RACSignal combineLatest:@[ RACObserve(self, walks), RACObserve(self, quacks) ]

    reduce:^(NSNumber *walks, NSNumber *quacks) { return @(walks.boolValue && quacks.boolValue); }]:

30. RAC(self, duck) = [RACSignal combineLatest:@[ RACObserve(self, walks), RACObserve(self, quacks) ]

    reduce:^(NSNumber *walks, NSNumber *quacks) { return @(walks.boolValue && quacks.boolValue); }]:

31. RAC(self, duck) = [RACSignal combineLatest:@[ RACObserve(self, walks), RACObserve(self, quacks) ]

    reduce:^(NSNumber *walks, NSNumber *quacks) { return @(walks.boolValue && quacks.boolValue); }]:

32. RAC(self, duck) = [RACSignal combineLatest:@[ RACObserve(self, walks), RACObserve(self, quacks) ]

    reduce:^(NSNumber *walks, NSNumber *quacks) { return @(walks.boolValue && quacks.boolValue); }]:

33. // and it even does KVO! RAC(self, duck) = [RACSignal

    combineLatest:@[ RACObserve(self, walks), RACObserve(self, quacks) ] reduce:^(NSNumber *walks, NSNumber *quacks) { return @(walks.boolValue && quacks.boolValue); }]:

34. & walks talks duck

35. & walks talks duck

36. & walks talks duck

37. & walks talks duck

38. & walks talks duck

39. RACSignal

40. -(RACDisposable * )subscribe:(id<RACSubscriber> )obj; RACSignal

41. <RACSubscriber>

42. - (void)sendNext:(id)value; <RACSubscriber>

43. - (void)sendNext:(id)value; - (void)sendCompleted; <RACSubscriber>

44. - (void)sendNext:(id)value; - (void)sendCompleted; - (void)sendError:(NSError *)error; <RACSubscriber>

45. so what?

46. Powerful toolset

47. map

48. filter

49. fold

50. write declarative code

51. e.g.

52. Your name Your email address Sign Up Newsletter

53. Newsletter Your name Your email address Sign Up

54. Newsletter Your email address Sign Up robb

55. Newsletter Sign Up robb robb

56. Newsletter Sign Up robb @robb.is Sign Up robb

57. Your name Your email address Sign Up validate that looks

    familiar! Newsletter

58. - (void)viewDidLoad { [super viewDidLoad]; [self.username addTarget:self action:@selector(textFieldTextDidChange:) forControlEvents:UIControlEventAllEditingEvents]; [self.email

    addTarget:self action:@selector(textFieldTextDidChange:) forControlEvents:UIControlEventAllEditingEvents]; } help!

59. - (void)textFieldTextDidChange:(UITextField *)field { BOOL validUsername = self.username.text.length > 0;

    NSRange at = [self.email.text rangeOfString:@"@"]; BOOL validEmail = at.location != NSNotFound; self.signupButton.enabled = validUsername && validEmail; }

60. - (void)textFieldTextDidChange:(UITextField *)field { BOOL validUsername = self.username.text.length > 0;

    NSRange at = [self.email.text rangeOfString:@"@"]; BOOL validEmail = at.location != NSNotFound; self.signupButton.enabled = validUsername && validEmail; }

61. ReactiveCocoa

62. RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ self.name.rac_textSignal self.email.rac_textSignal ] reduce:^(NSString *name,

    NSString *email) { NSRange at = [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]:

63. RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ self.name.rac_textSignal self.email.rac_textSignal ] reduce:^(NSString *name,

    NSString *email) { NSRange at = [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]:

64. RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ self.name.rac_textSignal self.email.rac_textSignal ] reduce:^(NSString *name,

    NSString *email) { NSRange at = [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]:

65. RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ self.name.rac_textSignal self.email.rac_textSignal ] reduce:^(NSString *name,

    NSString *email) { NSRange at = [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]:

66. Your name Your email address Sign Up validate Newsletter

67. Newsletter Your name Your email address Sign Up

68. Newsletter Sign Up robb

69. Newsletter Sign Up robb robb@robb.is Sign Up

70. Let's talk about

71. Let's talk about Asynchrony

72. [client logInWithSuccess:^{ [client loadMeUserWithSuccess:^(SPUser *me) { [client loadFilesForUser:me withSuccess:^(NSArray *files)

    { NSLog(@"Help me, " "I'm trapped in callback hell!"); } error:^(NSError *error) { // Handle failure } } error:^(NSError *error) { // Handle failure }]; } error:^(NSError *error) { // Handle failure }]; omg, why?!

73. Let's fix this

74. 1. HTTP Client

75. @interface SPHTTPClient : AFHTTPClient - (RACSignal *)enqueueRequest:(NSURLRequest *)req; @end

76. [self enqueueHTTPRequestOperation:operation]; - (RACSignal *)enqueueRequest:(NSURLRequest *)req { return [RACSignal createSignal:^(id<RACSubscriber>

    subscriber) { AFHTTPRequestOperation *operation; operation = [self HTTPRequestOperationWithRequest:req success:^(id operation, id response) { [subscriber sendNext:response]; [subscriber sendCompleted]; } failure:^(id operation, NSError *error) { [subscriber sendError:error]; }];

77. [self enqueueHTTPRequestOperation:operation]; - (RACSignal *)enqueueRequest:(NSURLRequest *)req { return [RACSignal createSignal:^(id<RACSubscriber>

    subscriber) { AFHTTPRequestOperation *operation; operation = [self HTTPRequestOperationWithRequest:req success:^(id operation, id response) { [subscriber sendNext:response]; [subscriber sendCompleted]; } failure:^(id operation, NSError *error) { [subscriber sendError:error]; }];

78. - (RACSignal *)enqueueRequest:(NSURLRequest *)req { return [RACSignal createSignal:^(id<RACSubscriber> subscriber) {

    AFHTTPRequestOperation *operation; operation = [self HTTPRequestOperationWithRequest:req success:^(id operation, id response) { [subscriber sendNext:response]; [subscriber sendCompleted]; } failure:^(id operation, NSError *error) { [subscriber sendError:error]; }]; [self enqueueHTTPRequestOperation:operation];

79. - (RACSignal *)enqueueRequest:(NSURLRequest *)req { return [RACSignal createSignal:^(id<RACSubscriber> subscriber) {

    AFHTTPRequestOperation *operation; operation = [self HTTPRequestOperationWithRequest:req success:^(id operation, id response) { [subscriber sendNext:response]; [subscriber sendCompleted]; } failure:^(id operation, NSError *error) { [subscriber sendError:error]; }]; [self enqueueHTTPRequestOperation:operation];

80. - (RACSignal *)enqueueRequest:(NSURLRequest *)req { return [RACSignal createSignal:^(id<RACSubscriber> subscriber) {

    AFHTTPRequestOperation *operation; operation = [self HTTPRequestOperationWithRequest:req success:^(id operation, id response) { [subscriber sendNext:response]; [subscriber sendCompleted]; } failure:^(id operation, NSError *error) { [subscriber sendError:error]; }]; [self enqueueHTTPRequestOperation:operation];

81. [self enqueueHTTPRequestOperation:operation]; return [RACDisposable disposableWithBlock:^{ [operation cancel]; }]; }]; createSignal:^(id<RACSubscriber>

    subscriber) { AFHTTPRequestOperation *operation; operation = [self HTTPRequestOperationWithRequest:req success:^(id operation, id response) { [subscriber sendNext:response]; [subscriber sendCompleted]; } failure:^(id operation, NSError *error) { [subscriber sendError:error]; }];

82. [self enqueueHTTPRequestOperation:operation]; return [RACDisposable disposableWithBlock:^{ [operation cancel]; }]; }]; createSignal:^(id<RACSubscriber>

    subscriber) { AFHTTPRequestOperation *operation; operation = [self HTTPRequestOperationWithRequest:req success:^(id operation, id response) { [subscriber sendNext:response]; [subscriber sendCompleted]; } failure:^(id operation, NSError *error) { [subscriber sendError:error]; }];

83. 2. API interaction

84. - (RACSignal *)fetchMeUser return [[self.client getPath:@"/me"] flattenMap:^(id JSON) { NSError

    *error; SPUser *user = [SPUser userWithJSON:JSON error:&error]; if (user == nil) { return [RACSignal error:error]; } else { return [RACSignal return:user]; } }]; }

85. - (RACSignal *)fetchMeUser return [[self.client getPath:@"/me"] flattenMap:^(id JSON) { NSError

    *error; SPUser *user = [SPUser userWithJSON:JSON error:&error]; if (user == nil) { return [RACSignal error:error]; } else { return [RACSignal return:user]; } }]; }

86. - (RACSignal *)fetchMeUser return [[self.client getPath:@"/me"] flattenMap:^(id JSON) { NSError

    *error; SPUser *user = [SPUser userWithJSON:JSON error:&error]; if (user == nil) { return [RACSignal error:error]; } else { return [RACSignal return:user]; } }]; }

87. - (RACSignal *)fetchMeUser return [[self.client getPath:@"/me"] flattenMap:^(id JSON) { NSError

    *error; SPUser *user = [SPUser userWithJSON:JSON error:&error]; if (user == nil) { return [RACSignal error:error]; } else { return [RACSignal return:user]; } }]; }

88. - (RACSignal *)fetchMeUser return [[self.client getPath:@"/me"] flattenMap:^(id JSON) { NSError

    *error; SPUser *user = [SPUser userWithJSON:JSON error:&error]; if (user == nil) { return [RACSignal error:error]; } else { return [RACSignal return:user]; } }]; } check out Mantle!

89. - (RACSignal *)fetchMeUser return [[self.client getPath:@"/me"] flattenMap:^(id JSON) { NSError

    *error; SPUser *user = [SPUser userWithJSON:JSON error:&error]; if (user == nil) { return [RACSignal error:error]; } else { return [RACSignal return:user]; } }]; }

90. - (RACSignal *)fetchMeUser return [[self.client getPath:@"/me"] flattenMap:^(id JSON) { NSError

    *error; SPUser *user = [SPUser userWithJSON:JSON error:&error]; if (user == nil) { return [RACSignal error:error]; } else { return [RACSignal return:user]; } }]; }

91. 3. Putting it together

92. [[[[client logIn] then:^{ return [client fetchMeUser]; }] flattenMap:^(SPUser *me) {

    return [client fetchFilesForUser:me]; }] subscribeNext:^(NSArray *files) { NSLog(@"Files: %@", files); } error:^(NSError *error) { // Handle error }];

93. [[[[client logIn] then:^{ return [client fetchMeUser]; }] flattenMap:^(SPUser *me) {

    return [client fetchFilesForUser:me]; }] subscribeNext:^(NSArray *files) { NSLog(@"Files: %@", files); } error:^(NSError *error) { // Handle error }];

94. [[[[client logIn] then:^{ return [client fetchMeUser]; }] flattenMap:^(SPUser *me) {

    return [client fetchFilesForUser:me]; }] subscribeNext:^(NSArray *files) { NSLog(@"Files: %@", files); } error:^(NSError *error) { // Handle error }];

95. [[[[client logIn] then:^{ return [client fetchMeUser]; }] flattenMap:^(SPUser *me) {

    return [client fetchFilesForUser:me]; }] subscribeNext:^(NSArray *files) { NSLog(@"Files: %@", files); } error:^(NSError *error) { // Handle error }];

96. [[[[client logIn] then:^{ return [client fetchMeUser]; }] flattenMap:^(SPUser *me) {

    return [client fetchFilesForUser:me]; }] subscribeNext:^(NSArray *files) { NSLog(@"Files: %@", files); } error:^(NSError *error) { // Handle error }];

97. [[[[client logIn] then:^{ return [client fetchMeUser]; }] flattenMap:^(SPUser *me) {

    return [client fetchFilesForUser:me]; }] subscribeNext:^(NSArray *files) { NSLog(@"Files: %@", files); } error:^(NSError *error) { // Handle error }];

98. [[[[client logIn] then:^{ return [client fetchMeUser]; }] flattenMap:^(SPUser *me) {

    return [client fetchFilesForUser:me]; }] subscribeNext:^(NSArray *files) { NSLog(@"Files: %@", files); } error:^(NSError *error) { // Handle error }];

99. UI&IO

100. UI+IO

101. Your name Your email address Sign Up Newsletter

102. Your name Your email address Sign Up validate Newsletter

103. Your name Your email address Sign Up validate Newsletter

104. , why me? oh boy

105. self.name.rac_textSignal self.email.rac_textSignal reduce:^(NSString *name, NSString *email) { NSRange at =

     [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]; RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ ]

106. self.name.rac_textSignal self.email.rac_textSignal reduce:^(NSString *name, NSString *email) { NSRange at =

     [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]; RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ ]

107. validName, validEmail reduce:^(NSString *name, NSString *email) { NSRange at =

     [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]; reduce:^(NSString *name, NSString *email) { NSRange at = [email rangeOfString:@"@"]; return @(at.location != NSNotFound && name.length > 0); }]; RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ ]

108. reduce:^(NSString *name, NSString *email) { NSRange at = [email rangeOfString:@"@"];

     return @(at.location != NSNotFound && name.length > 0); }]; validName, validEmail RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ ]

109. reduce:^(NSNumber *name, NSNumber *email) { return @(name.boolValue && email.boolValue); }];

     validName, validEmail map:^(NSString *name) { return @(name.length > 0); }]; RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ ]

110. RACSignal *validName = [self.name.rac_textSignal map:^(NSString *name) { return @(name.length >

     0); }]; reduce:^(NSNumber *name, NSNumber *email) { validName, validEmail RAC(self.signUpButton, enabled) = [RACSignal combineLatest:@[ ] RACSignal *validEmail = [[self.email.rac_textSignal map:^(NSString *email) { return [[client validateEmail:email] startWith:@NO]; }] switchToLatest];

111. RACSignal *validName = [self.name.rac_textSignal map:^(NSString *name) { return @(name.length >

     0); }]; RACSignal *validEmail = [[self.email.rac_textSignal map:^(NSString *email) { return [[client validateEmail:email] startWith:@NO]; }] switchToLatest];

112. RACSignal *validEmail = [[self.email.rac_textSignal map:^(NSString *email) { return [[client validateEmail:email]

     startWith:@NO]; }] switchToLatest]; RACSignal *validName = [self.name.rac_textSignal map:^(NSString *name) { return @(name.length > 0); }];

113. RACSignal *validEmail = [[self.email.rac_textSignal map:^(NSString *email) { return [[client validateEmail:email]

     startWith:@NO]; }] switchToLatest]; RACSignal *validName = [self.name.rac_textSignal map:^(NSString *name) { return @(name.length > 0); }];

114. Your name Your email address Sign Up validate Newsletter

115. Newsletter Your name Your email address Sign Up

116. Newsletter Sign Up robb

117. Newsletter Sign Up robb robb@robb.is

118. Newsletter Sign Up robb robb@robb.is Sign Up

119. Recap

120. Recap + Declarative code

121. Recap + Declarative code + Easy handling of asynchronous tasks

122. Recap + Declarative code + Easy handling of asynchronous tasks

     + Great Composition

123. Recap + Declarative code + Easy handling of asynchronous tasks

     + Great Composition − Conceptual overhead

124. Recap + Declarative code + Easy handling of asynchronous tasks

     + Great Composition − Conceptual overhead − Debugging can get tricky

125. Recap (dtrace support coming soon) + Declarative code + Easy

     handling of asynchronous tasks + Great Composition − Conceptual overhead − Debugging can get tricky

126. Qs?

127. Thanks!

128. iPhone 5 Setch Template courtesy of Denis Rojčyk Cloud icon

     curtesy of Dmitry Baranovskiy, from The Noun Project