Building Resilient API Clients

Transcript

1. Building!Resilient!API!Clients !KyleFuller
5. Building!Resilient!API!Clients
12. How$does$it$work?
13. GET /questions
14. DELETE /questions/{id}
15. GET /questions/{id}
16. POST /questions/{id}/choices/{choice_id}
17. POST /questions
18. Applica'on*was*built*from*an*out3 of3band*specifica'on
19. Tight&Coupling
20. We#want#to#change#something.
21. /v1
22. /v2
23. Move%Fast%and%Break&Things
24. Move%Fast%and%Break%Things
27. "Each&version&will&remain&for&at&least& 2&years&from&release."
28. Eventually*have*to*switch
29. API$Team$maintains$legacy$API
30. Move%Fast%and%Break&Nothing
31. REST
32. What%is%REST?
33. “An$cipa$ng*change*is*one*of*the* central*themes*of*REST”
34. REST%is%not... • CRUD • Pre)y+URLs • JSON • HTTP+"Verbs" • Rou9ng
35. It’s%not%about%exposing%your% database%via%an%API
36. These%are%implementa)on%details
37. Representa)onal,State,Transfer
38. Transfer(State(from(Server(to(Client?
39. Ques%on(Resource
40. HATEOAS
42. Hypermedia*as*the*Engine*of* Applica6on*State
43. Ques%ons • create • list
44. Ques%on • delete • choices
45. Choice • vote
46. Teaching)the)client)the)seman.c) meaning)of)the)domain
47. Without'knowledge'about'the' implementa3on'details
48. Root questions
49. Ques%on delete
50. Choice vote
51. Ques%on create • ques&on • choices
52. Why$are$we$not$doing$this?
53. Hyperdrive
54. One$Does$Not$Simply$Use$JSON
55. HAL$+$Siren
56. HAL Hypertext(Applica.on(Language
58. HAL { "_links": { "self": { "self": "/questions/1" } } }
59. HAL { "_embedded": { "choices": [ { "_links": { "self": { "self": "/questions/1/choices/1" } }, "choice": "Swift", "votes": 2048 } ] } }
61. Siren { "actions": [ { "name": "vote", "href": "/questions/1/choices/3", "method": "POST" } ] }
62. Siren { "actions": [ { "name": "create", "fields": [ { "name": "question", "type": "text", "title": "Question" }, { "name": "choices", "type": "array[text]", "title": "Choices" } ], "method": "POST", "type": "application/json", "href": "/questions" } ] }
63. API$Blueprint$+$Hyperdrive
64. apiblueprint.org
67. hyperdrive.enter("https://polls.apiblueprint.org/") { result }
68. representor
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
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