Type-safe Web APIs with Protocol Buffers in Swift

1. Type-safe Web APIs with Protocol Buffers in Swift 1 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

2. Hi, I'm Yusuke @kitasuke 2 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

3. I'm going to talk about... → What Protocol Buffers are 3 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

4. I'm going to talk about... → What Protocol Buffers are → Pros and Cons 4 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

5. I'm going to talk about... → What Protocol Buffers are → Pros and Cons → Where to start 5 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

6. Web APIs 6 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

7. JSON7 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

8. HTTP Request JSON ➡ Data 8 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

9. let json = ["id": 1] let data = try? JSONSerialization.data(withJSONObject: json, options: .prettyPrinted) var request = URLRequest(url: url) request.httpBody = data 9 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

10. HTTP Response Data ➡ JSON 10 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

11. // {"user": {"name": "Yusuke"}} URLSession.shared.dataTask(with: request) { (data, _, _) in let json = (try? JSONSerialization.jsonObject(with: data!, options: .allowFragments)) as? [AnyHashable: Any] let user = json?["user"] as? [AnyHashable: Any] let name = user?["name"] as? String } 11 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

12. {"isTyped": false, "status": "disappointed"} 12 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

13. [AnyHashable: Any] 13 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

14. Any? 14 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

15. ! 15 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

16. Protocol Buffersa.k.a protobuf 16 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

17. Protocol buffers are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler. — Google 17 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

18. Serialization format - think JSON, but smaller, faster and safer — Yusuke 18 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

19. Serialization Format 19 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

20. Why are Protocol Buffers a big deal? 20 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

22. let json = ["id": 1] let data = try? JSONSerialization.data(withJSONObject: json, options: .prettyPrinted) var request = URLRequest(url: url) request.httpBody = data 22 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

24. HTTP Request UserRequest ➡ Data 24 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

25. // custom type let userRequest = UserRequest.with { $0.id = 1 } let body = try? body.serializedData() var request = URLRequest(url: url) request.httpBody = body 25 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

27. // {"user": {"name": "Yusuke"}} URLSession.shared.dataTask(with: request) { (data, _, _) in let json = (try? JSONSerialization.jsonObject(with: data!, options: .allowFragments)) as? [AnyHashable: Any] let user = json?["user"] as? [AnyHashable: Any] let name = user?["name"] as? String } 27 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

29. HTTP Response Data ➡ UserResponse 29 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

30. // UserResponse(user: User(name: "Yusuke")) URLSession.shared.dataTask(with: request) { (data, _, _) in // custom type guard let response: UserResponse = try? UserResponse(serializedData: data!) else { // error return } let user = response.user let name = user.name } 30 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

31. Protobuf( isTyped: true, status: .satisfied ) 31 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

32. ! 32 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

33. But how do they work? 33 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

34. protobuf for Swift apple/swift-protobuf 34 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

35. "But we still use Objective-C !" 35 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

36. protobuf google/protobuf 36 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

37. 1. Deﬁne message types 2. Generate code 3. Serialize/Deserialize 37 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

39. Message types deﬁne data structures in .proto ﬁles 39 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

40. Message types have key- value pairs 40 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

41. 41 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

42. user.proto syntax = "proto3"; // protoc version message User { int32 id = 1; // field number string name = 2; string introduction = 3; string photoUrl = 4; ParticipantType participantType = 5; enum ParticipantType { Speaker = 0; Attendee = 1; } } 42 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

43. talk.proto syntax = "proto3"; import "user.proto"; message Talk { int32 id = 1; string title = 2; string desc = 3; User speaker = 4; repeated string tags = 5; // Array } 43 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

45. protobuf compiler generates code from .proto ﬁle 45 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

46. Basic types Int32, UInt32, Int64, UInt64, Bool, Float, Double, String, Array, Dictionary, Data 46 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

47. Supported languages C, C++, C#, Erlang, Go, Haskell, Java, Javascript, Objective-C, Perl, PHP, Python, Ruby, Rust, Scala, Swift etc. 47 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

48. Swift features → struct, not class → enum RawValue is Int → Default value is set 48 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

50. user.proto syntax = "proto3"; // protoc version message User { int32 id = 1; // field number string name = 2; string introduction = 3; string photoUrl = 4; ParticipantType participantType = 5; enum ParticipantType { Speaker = 0; Attendee = 1; } } 50 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

51. user.pb.swift // struct struct User: SwiftProtobuf.Message, ... { init() {} enum Type: SwiftProtobuf.Enum { typealias RawValue = Int // always Int case speaker // = 0 case participant // = 1 case UNRECOGNIZED(Int) } // property has default value var id: Int32 = 0 var name: String = "" var introduction: String = "" var photoURL: String = "" var participantType: User.ParticipantType = .speaker } 51 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

52. talk.proto syntax = "proto3"; import "user.proto"; message Talk { int32 id = 1; string title = 2; string desc = 3; User speaker = 4; repeated string tags = 5; // Array } 52 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

53. talk.pb.swift struct Talk: SwiftProtobuf.Message, ... { init() {} var id: Int32 = 0 var title: String = "" var speaker: User = User() var desc: String = "" var tags: [String] = [] } 53 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

55. User.java public static final class User extends Message<User, User.Builder> { public final Integer id; public final String name; public final String introduction; public final String photoUrl; public final ParticipantType participantType; } 55 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

56. Talk.java public final class Talk extends Message<Talk, Talk.Builder> { public final Integer id; public final String title; public final User speaker; public final String summary; public final List<String> tags; } 56 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

58. user.pb.go type User_Type int32 const ( User_Speaker User_ParticipantType = 0 User_Attendee User_ParticipantType = 1 ) type User struct { ID int32 ˆprotobuf:"varint,1,opt,name=id,proto3" json:"id,omitempty"ˆ Name string ˆprotobuf:"bytes,2,opt,name=name,proto3" json:"name,omitempty"ˆ Introduction string ˆprotobuf:"bytes,3,opt,name=introduction,proto3" json:"introduction,omitempty"ˆ PhotoURL string ˆprotobuf:"bytes,4,opt,name=photoUrl,proto3" json:"photoUrl,omitempty"ˆ Type User_Type ˆprotobuf:"varint,5,opt,name=type,proto3,enum=api.User_Type" json:"type,omitempty"ˆ } 58 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

59. talk.pb.go type Talk struct { ID int32 ˆprotobuf:"varint,1,opt,name=id,proto3" json:"id,omitempty"ˆ Title string ˆprotobuf:"bytes,2,opt,name=title,proto3" json:"title,omitempty"ˆ Speaker *User ˆprotobuf:"bytes,3,opt,name=speaker" json:"speaker,omitempty"ˆ Summary string ˆprotobuf:"bytes,4,opt,name=summary,proto3" json:"summary,omitempty"ˆ Tags []string ˆprotobuf:"bytes,5,rep,name=tags" json:"tags,omitempty"ˆ } 59 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

60. One message type ⬇ Multiple languages code 60 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

61. Less communication, More collaboration with other platforms 61 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

62. 1. Deﬁne message types 2. Generate source ﬁles 3. Serialize/Deserialize 62 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

63. Serialization public func serializedData(partial: Bool = default) throws -> Data public func jsonString() throws -> String public func textFormatString() throws -> String 63 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

64. let user = User.with { $0.id = 1 $0.type = .speaker $0.name = "kitasuke" } let talk = Talk.with { $0.id = 1 $0.title = "Type-safe Web APIs with Protocol Buffers in Swift" $0.speaker = user $0.tags = ["swift", "iOS", "protocol-buffers", "ioscon", "type-safe"] } let data = try? talk.serializedData() 64 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

65. Deserialization public convenience init(serializedData data: Data, extensions: SwiftProtobuf.ExtensionSet? = default, partial: Bool = default) throws public convenience init(jsonString: String) throws public convenience init(textFormatString: String, extensions: SwiftProtobuf.ExtensionSet? = default) throws 65 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

66. let talk = try? Talk(serializedData: data) let title = talk?.title let speaker = talk?.speaker let tags = talk?.tags 66 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

67. How serialization works 67 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

68. Binary Encoding 68 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

69. Key factor 1. Field number 2. Wire type 69 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

70. Field number message Talk { int32 id = 1; ← // Field number string title = 2; string desc = 3; User speaker = 4; repeated string tags = 5; } 70 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

71. Wire type Type Meaning Used For 0 Varint int32, int64, uint32, uint64, sint32, sint64, bool, enum 1 64-bit fixed64, sfixed64, double 2 Length-delimited string, bytes, embedded messages, packed repeated fields 3 (deprecated) 4 (deprecated) 5 32-bit fixed32, sfix3d32, float 71 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

72. // message type message Test1 { int32 a = 1; } test1.a = 300 // encoded message 08 96 01 08 // field number and wire type 96 01 // value which is 300 72 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

73. So small and numeric 73 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

74. High network performance 74 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

75. Demo kitasuke/SwiftProtobufSample 75 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

76. Quick Recap 76 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

77. Quick Recap → Type-safety 77 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

78. Quick Recap → Type-safety → Shared data model 78 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

79. Quick Recap → Type-safety → Shared data model → High performance 79 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

80. You might have concerns about... 80 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

81. Versioning 81 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

82. Backward compatibility → Unknown ﬁeld is ignored → Default value for missing ﬁeld 82 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

83. Backward compatibility → Unknown field is ignored → Default value for missing field as long as you don't change existing field number or wire type 83 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

84. Coexistence of protobuf & JSON 84 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

85. Absolutely you can! 85 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

86. Accept & Content-Type → application/protobuf - protobuf → application/json - JSON 86 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

87. HTTP Request var request = URLRequest(url: url) if protobuf { request.setValue("application/protobuf", forHTTPHeaderField: "Content-Type") request.setValue("application/protobuf", forHTTPHeaderField: "Accept") } else if json { request.setValue("application/json", forHTTPHeaderField: "Content-Type") request.setValue("application/json", forHTTPHeaderField: "Accept") } 87 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

88. HTTP Response URLSession.shared.dataTask(with: request) { (data, urlResponse, _) in let httpURLResponse = urlResponse as? HTTPURLResponse let contentType = httpURLResponse?.allHeaderFields["Content-Type"] as? String if contentType == "application/protobuf" { let response = try? Response(serializedData: data!) } else if contentType == "application/json" { let response = try? Response(jsonString: data!) } } 88 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

89. Sounds good so far ! 89 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

90. So, what are Cons? 90 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

91. Not human-readable → Binary data is not understandable 91 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

92. Time investment → Time consuming at the beginning → Involvement from other platforms 92 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

93. Swift version → Watch Swift version of protobuf plugin → Specify tag version if you use older version 93 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

94. Stability → Still pre-release version only for Swift → Contribute if you ﬁnd a bug ! 94 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

95. Where should we start? 95 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

96. Internal service → Easy to adapt → Small start 96 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

97. Data store → Database → NSKeyedArchiver → NSCache 97 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

98. Parsing library → JSON parser → Server side Swift 98 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

99. Conclusion 99 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

100. Conclusion → Swifty 100 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

101. Conclusion → Swifty → Consistent in Cross-platform 101 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

102. Conclusion → Swifty → Consistent in Cross-platform → Extensible 102 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

103. It's deﬁnitely worth it ! 103 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

104. Partially in Production 70M Downloads !"# 104 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

105. Credits Protocol Buffers swift-protobuf Kitura Protocol Buffers in your Kitura Apps 105 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017

106. Thank you! GitHub: https://github.com/kitasuke Demo: SwiftProtobufSample Twitter: @kitasuke Email: yusuke2759@gmail.com 106 — Type-safe Web APIs with Protocol Buffers in Swift, Yusuke Kita (@kitasuke), iOSCon 2017