Write and use GraphQL middleware

Originally posted here: https://speakerdeck.com/alexandersaenko/write-and-use-graphql-middleware

Доклад включает в себя:
- Ретроспективу опыта написания GraphQL middleware (прокси-сервера между REST API и мобильным приложением) для iOS-проекта
- Анализ преимуществ и недостатков технологии
- Lessons learned использования GraphQL в production

This talk was made for CocoaHeads Kyiv #14 which took place Oct 6 2018.

Transcript

1. GRAPHQL MIDDLEWARE WRITE AND USE
2. ALEXANDER SAENKO
3. AGENDA
4. GRAPHQL ▸ Data query and manipulation language ▸ Open Source ▸ Created by Facebook ▸ 10k stars on GitHub ▸ Always* backward-compatible
5. WHEN TO USE?
7. { "id": 118, "status": 0, "name": "The text you need", "due_date": 1498861069, "created_date": 1498256269, "updated_date": 1498741329, "description": "Something you definitely don't need", "is_modified": 1, "modified_by": "Alexander Saenko", "tasks": [ { "id": 38, "name": "The first task", "description": "Something about the task"}, { "id": 41, "name": "The second task", "description": "Something about the second task" } ] }
8. { "id": 118, "status": 0, "name": "The text you need", "due_date": 1498861069, "created_date": 1498256269, "updated_date": 1498741329, "description": "Something you definitely don't need", "is_modified": 1, "modified_by": "Alexander Saenko", "tasks": [ { "id": 38, "name": "The first task", "description": "Something about the task"}, { "id": 41, "name": "The second task", "description": "Something about the second task" } ] }
9. { "id": 118, "status": 0, "name": "The text you need", "due_date": 1498861069, "created_date": 1498256269, "updated_date": 1498741329, "description": "Something you definitely don't need", "is_modified": 1, "modified_by": "Alexander Saenko", "tasks_count": 2 [ { "id": 38, "name": "The first task", "description": "Something about the task"}, { "id": 41, "name": "The second task", "description": "Something about the second task" } ] }
10. { "id": 118, "status": 0, "name": "The text you need", "updated_date": 1498741329, "tasks_count": 2 }
11. struct TableModel: Codable { let id: Int let status: Bool let name: String let updatedDate: Date let tasksCount: Int enum CodingKeys:String, CodingKey { case id case status case name case updatedDate = "updated_date" case tasksCount = "tasks_count" } }
12. struct TableModel: Codable { let id: Int let status: Bool let name: String let updatedDate: Date let tasksCount: Int enum CodingKeys:String, CodingKey { case id case status case name case updatedDate = "updated_date" case tasksCount = "tasks_count" } }
13. type TableModel { id: Int! status: Boolean! name: String! updatedDate: Date! tasksCount: Int! }
14. export function TableModel(data) { return { id () { return data.id; }, status() { return data.status; }, name() { return data.name; }, updatedDate() { return new Date(data.updated_date * 1000); }, tasksCount() { return data.tasks.length; } } }
15. { "id": 118, "status": 0, "name": "The text you need", "updatedDate": 1498741329, "tasksCount": 2 } struct TableModel: Codable { let id: Int let status: Bool let name: String let updatedDate: Date let tasksCount:Int }
16. { "id": 118, "status": 0, "is_completed": false, "name": "The text you need", "updated_date": 1498741329, "tasks_count": 2 }
17. type TableModel { id: Int! status: Boolean! @deprecated isCompleted: Boolean! name: String! updatedDate: Date! tasksCount: Int! }
18. export function TableModel(data) { return { id () { return data.id; }, status() { return data.is_completed; }, isCompleted() { return data.is_completed; }, name() { return data.name; }, updatedDate() { return new Date(data.updated_date * 1000); }, tasksCount() { return data.tasks_count; } } }
19. WHEN TO USE ▸ No breaking changes in API ▸ Client-driven API ▸ Minimum network pressure
20. PROS & CONS
21. 0 0+1 JAVASCRIPT
24. + https://code.visualstudio.com
25. 0+1 1 WRAP REST API
26. type Patient { id: String! code: String! name: String! group: String! }
27. export function Patient(data) { return { __typeName: "Patient", id() { return data.id; }, code() { return data.id_code; }, name() { return data.first_name + ' ' + data.last_name; }, group() { return data.last_name ? data.last_name.trimLeft().charAt(0).toUpperCase() : data.first_name.trimLeft().charAt(0).toUpperCase(); } } }
28. 1+1 1 DATA LOADERS
29. BATCHING AND CACHING https://github.com/facebook/dataloader
30. time: 0.724 URL: /api/user time: 0.71 URL: /api/vacancies time: 0.772 URL: /api/user time: 1.116 URL: /api/invitations time: 1.125 URL: /api/counters/1 time: 1.126 URL: /api/friends time: 1.12 URL: /api/counters/1
31. export default function createLoaders(fetchFn) { return { User: new DataLoader(async (keys) => { return Promise.all(keys.map(async () => { const response = await fetchFn(‘get’, `/api/user`); return await response.json(); })); }), Counters: new DataLoader((keys) => { return Promise.all(keys.map(async (id) => { const response = await fetchFn('get', `/api/counters/${id}`; return await response.json(); }); }) }
32. return { schema, rootValue: { id: ‘viewer’, loaders: createLoaders(fetchFn), }, };
33. ...
 type: userType, resolve: async (rootValue) => { const {loaders} = rootValue; const user = await loaders.UserProfile.load(‘me’); const user1 = await loaders.UserProfile.load(‘me’); return user; }
 
 ... type: counterType, resolve: async (rootValue) => { const {loaders} = rootValue; const counter = await loaders.Counters.load(1); const counter1 = await loaders.Counters.load(1); return counter1; }
 ...
34. time: 0.584 URL: /api/user time: 0.669 URL: /api/vacancies time: 0.982 URL: /api/invitations time: 0.622 URL: /api/counters/1 time: 0.716 URL: /api/friends https://medium.com/@ven_korolev/make-applications-faster-with-a-dataloader-library-from-facebook-dec67d15e415
35. 2 1+1 AUTHORIZATION
36. return { schema: schema, context: { loaders: root.loaders(request.headers.authorization), token: request.headers.authorization }, graphiql: true }
37. return { schema: schema, context: { loaders: root.loaders(request.headers.authorization), token: request.headers.authorization }, graphiql: true }
39. return { schema: schema, context: { loaders: root.loaders(request.headers.authorization), token: request.headers.authorization }, graphiql: true }
43. 2 2+1 SWIFT QUERY
44. static let query = """ query { patients { id code name group } } """ struct Response: Decodable { let patients: [Patient] struct Patient: Decodable { let id: String let code: String let name: String let group: String } }
45. static func query(id: String) -> String { return """ query { case(id: "\(id)") { id code status created { date } updated patient { name } treatmentPath { name } } } """ }
46. 2 3+1 FILE UPLOAD
49. 2+1 4 ONBOARDING
53. 3+1 4 MAINTENANCE
54. http://appreviewtimes.com/
57. 4 4 FINAL RESULTS
58. LESSONS LEARNED
59. TYPESCRIPT FROM THE BEGINNING
60. IDEMPOTENCE
61. EXPERIMENTAL SANDBOX
62. YES, I WILL USE IT AGAIN
63. THANK YOU!