Building Resilient API Clients

Transcript

1. Building!Resilient!API!Clients !KyleFuller

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5. Building!Resilient!API!Clients

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12. How$does$it$work?

13. GET /questions

14. DELETE /questions/{id}

15. GET /questions/{id}

16. POST /questions/{id}/choices/{choice_id}

17. POST /questions

18. Applica'on*was*built*from*an*out3 of3band*specifica'on

19. Tight&Coupling

20. We#want#to#change#something.

21. /v1

22. /v2

23. Move%Fast%and%Break&Things

24. Move%Fast%and%Break%Things

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27. "Each&version&will&remain&for&at&least& 2&years&from&release."

28. Eventually*have*to*switch

29. API$Team$maintains$legacy$API

30. Move%Fast%and%Break&Nothing

31. REST

32. What%is%REST?

33. “An$cipa$ng*change*is*one*of*the* central*themes*of*REST”

34. REST%is%not... • CRUD • Pre)y+URLs • JSON • HTTP+"Verbs" •

    Rou9ng

35. It’s%not%about%exposing%your% database%via%an%API

36. These%are%implementa)on%details

37. Representa)onal,State,Transfer

38. Transfer(State(from(Server(to(Client?

39. Ques%on(Resource

40. HATEOAS

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42. Hypermedia*as*the*Engine*of* Applica6on*State

43. Ques%ons • create • list

44. Ques%on • delete • choices

45. Choice • vote

46. Teaching)the)client)the)seman.c) meaning)of)the)domain

47. Without'knowledge'about'the' implementa3on'details

48. Root questions

49. Ques%on delete

50. Choice vote

51. Ques%on create • ques&on • choices

52. Why$are$we$not$doing$this?

53. Hyperdrive

54. One$Does$Not$Simply$Use$JSON

55. HAL$+$Siren

56. HAL Hypertext(Applica.on(Language

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58. HAL { "_links": { "self": { "self": "/questions/1" } }

    }

59. HAL { "_embedded": { "choices": [ { "_links": { "self":

    { "self": "/questions/1/choices/1" } }, "choice": "Swift", "votes": 2048 } ] } }
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61. Siren { "actions": [ { "name": "vote", "href": "/questions/1/choices/3", "method":

    "POST" } ] }

62. Siren { "actions": [ { "name": "create", "fields": [ {

    "name": "question", "type": "text", "title": "Question" }, { "name": "choices", "type": "array[text]", "title": "Choices" } ], "method": "POST", "type": "application/json", "href": "/questions" } ] }

63. API$Blueprint$+$Hyperdrive

64. apiblueprint.org

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67. hyperdrive.enter("https://polls.apiblueprint.org/") { result }

68. representor

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70. representor • a#ributes • transi,ons

71. representor • a#ributes • transi,ons • representors

72. if let questions = representor.transitions["questions"] { }

73. hyperdrive.request(questions) { result in }

74. if let questions = representor.representors["questions"] { map(questions, viewQuestion) }

75. } else { println("Looks like there are no questions yet.")

    }

76. func viewQuestion(question:Representor<HTTPTransition>) { println(question.attributes["question"]) if let choices = question.representors["choices"] {

    map(choices, viewChoice) } else { println("-> This question does not have any choices.") } if let delete = question.transitions["delete"] { // User may delete this question } }

77. func viewChoice(choice:Representor<HTTPTransition>) { let text = choice.attributes["choice"] let votes =

    choice.attributes["votes"] println('-> \(text) (\(votes))') if let vote = choice.transitions["vote"] { // User may vote on this choice } }

78. hyperdrive.request(vote)

79. if let create = questions.transitions["create"] { // We may create

    a new question for attribute in create.attributes { // Creation takes `attribute.name` } } else { // Gracefully handle the lack of being able to create a question }

80. Why?

81. Change'business'rules

82. Remove&transi-ons

83. Add#transi*ons

84. Coupling

85. TaaS Toaster(as(a(Service

86. Toaster(Applica.on

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90. Demo

91. How$does$API$Blueprint$work?

92. ## Questions Collection [/questions] ### List All Questions [GET] +

    Relation: questions + Response 200 (application/json) + Attributes (array[Question])

93. ### Create a New Question [POST] + Relation: create +

    Request (application/json) + Attributes + question (string, required) - The question + choices (array[string]) - A collection of choices. + Response 201 (application/json) + Attributes (Question)

94. ## Question [/questions/{question_id}] + Attributes + question: `Favourite programming language?`

    (string, required) + published_at: `2014-11-11T08:40:51.620Z` (string) - An ISO8601 date when the question was published + choices (array[Choice], required) - An array of Choice objects

95. { "id": 1, "question": "Favourite programming language?", "choices": [ {

    "id": 1, "choice": "Swift", "votes": 128 }, { "id": 2, "choice": "Objective-C", "votes": 2 } ] }

96. ### Delete a Question [DELETE] + Relation: delete + Response

    204

97. ## Choice [/questions/{question_id}/choices/{choice_id}] + Attributes + choice: Swift (string, required)

    + votes: 0 (number, required)

98. ### Vote on a Choice [POST] This action allows you

    to vote on a question's choice. + Relation: vote + Response 201

99. Conclusion • Move&Faster • Write&Less&Code • Don't&Break&Things • Embrace&Change

100. Move%Fast,%Break%Nothing

101. the$hypermedia$project!/!Hyperdrive the$hypermedia$project!/!representor*swi- !apiaryio!/!polls'app apiaryio!/!polls'api

102. Ques%ons?

103. fuller.li/slides !KyleFuller