Introduction to GraphQL

My OpenFest presentation about GraphQL.

(Video: https://www.youtube.com/watch?v=-dAI5tSSPGA)

Transcript

1. Introduction to GraphQL Radoslav Stankov 08/10/2015
2. Radoslav Stankov @rstankov http://rstankov.com
 http://blog.rstankov.com http://github.com/rstankov
12. GET /api/posts?date=2015-10-31 { id: 1, title: "Post title", tagline: "Post headline", votes_count: 1, comments_count: 1, url: '/category/slug', thumbnail_url: 'assets.producthunt.com/uuid', hunter_id: 1 }
15. GET /api/users/1 { id: 1, name: 'User Name', handle: 'user_name', avatar_url: 'assets.producthunt.com/uuid' }
16. Rest Client Rest Server
17. Rest Client Rest Server /api/posts?date=2015-10-31
18. Rest Client Rest Server /api/posts?date=2015-10-31 /api/users/{x} (for X users)
19. Rest Client Rest Server /api/posts?date=2015-10-31 /api/users/{x} (for X users)
20. …approach 2
21. GET /api/posts?date=2015-10-31 { id: 1, title: "Post title", tagline: "Post headline", votes_count: 1, comments_count: 1, url: '/category/slug', thumbnail_url: 'assets.producthunt.com/uuid', hunter: { id: 1, name: 'User Name', handle: 'user_name', avatar_url: 'assets.producthunt.com/uuid' } }
28. GET /api/posts?date=2015-10-31 { id: 1, title: "Post title", tagline: "Post headline", votes_count: 1, comments_count: 1, url: '/category/slug', thumbnail_url: 'assets.producthunt.com/uuid', hunter: { id: 1, name: 'User Name', handle: 'user_name', avatar_url: 'assets.producthunt.com/uuid' }, makers: [{ id: 2, name: 'Second User', handle: 'second_user', avatar_url: 'assets.producthunt.com/uuid' }] }
32. GET /api/posts?date=2015-10-31 { id: 1, title: "Post title", tagline: "Post headline", votes_count: 1, comments_count: 1, url: '/category/slug', thumbnail_url: 'assets.producthunt.com/uuid', hunter: { id: 1, name: 'User Name', handle: 'user_name', avatar_url: 'assets.producthunt.com/uuid' }, makers: [{ id: 2, name: 'Second User', handle: 'second_user', avatar_url: 'assets.producthunt.com/uuid' }], platform: [{ name: 'iPhone', }, { name: 'Mac', }, { name: 'Web', }] }
35. …approach 3
37. Rest Client Rest Server
38. Rest Client Rest Server endpoint 1 feature 1
39. Rest Client Rest Server endpoint 1 feature 1 endpoint 2 feature 2
40. Rest Client Rest Server endpoint 1 feature 1 endpoint 2 feature 2 endpoint 3 feature 3
41. Rest Client Rest Server endpoint 1 feature 1 endpoint 2 feature 2 endpoint 3 feature 3 endpoint N feature N
48. { id: 1, title: "Post title", tagline: "Post headline", votes_count: 1, hunter: { id: 1, avatar_url: 'assets.producthunt.com/uuid' }, makers: [{ id: 2, avatar_url: 'assets.producthunt.com/uuid' }] }
49. { id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } }
51. GET /graphql Request Body Response Body
52. 
 query { post(id: 1){ id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } } } GET /graphql Request Body Response Body
53. 
 query { post(id: 1){ id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } } } GET /graphql Request Body Response Body
54. 
 query { post(id: 1){ id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } } } GET /graphql Request Body Response Body { "data": { "post": { "id": 1, "title": "title", "tagline": "tagline", "votes_count": 0, "hunter": { "id": 1, "avatar_url": "assets.producthu }, "makers": [ { "id": 1, "avatar_url": "assets.product } ] } } }
55. It’s that simple
56. 
 https://facebook.github.io/graphql

57. GraphQL is a query language created by Facebook in 2012 which provides a common interface between the client and the server for data fetching and manipulations. The client asks for various data from the GraphQL server via queries.
58. Architecture 
 GraphQL Library
 (Per-Language)
 
 Type
 Definitions
 
 Application
 Code

59. GraphQL • Single endpoint • Not just a library • Application-Layer Protocol • Server agnostic • Strongly-typed • Client-specified queries • Hierarchical
60. Tries to solve • N+1 API queries • API response bloat • Documentation • Ad Hoc Endpoints • Structure issues
61. QueryType = GraphQL::ObjectType.define do name 'Query' description 'The query root for this schema' field :post do type PostType description 'The post' argument :id, types.Int, 'Post id' resolve -> (obj, args, context) do Post.find args['id'] end end end Ruby Example
62. PostType = GraphQL::ObjectType.define do name 'Post' field :id, types.Int field :title, types.String field :tagline, types.String field :votes_count, types.Int field :comments_count, types.Int field :thumbnail_url, types.String field :hunter do type -> { UserType } resolve -> (obj, args, context) do obj.user end end field :makers do type -> { types[UserType] } resolve -> (obj, args, context) do obj.makers end end end Ruby Example
63. Query 
 query { post(id: 1){ id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } } } { "data": { "post": { "id": 1, "title": "title", "tagline": "tagline", "votes_count": 0, "hunter": { "id": 1, "avatar_url": "assets.producthun }, "makers": [ { "id": 1, "avatar_url": "assets.producth } ] } } }
64. Mutation 
 mutation { createUser(name: "Rado") { id } } { "data": { "createSpeaker": { "id": 2 } } }
65. Documentation 
 query { __schema { types { name fields { name type { name kind ofType { name kind } } } } } } { "data": { "__schema": { "types": [ { "name": "Query", "fields": [ { "name": "user", "type": { "name": "Non-Null", "kind": "NON_NULL", "ofType": { "name": "User", "kind": "OBJECT" } } }, { "name": "post", "type": { "name": "Non-Null", "kind": "NON_NULL", "ofType": { "name": "Post", "kind": "OBJECT" } } } ] },
66. { id hunter: { id name
 small_avatar_url: avatar_url(size: 100)
 big_avatar_url: avatar_url(size: 400) } } Cool tricks
67. query withFragments { user(id: 4) { friends(first: 10) { ...friendFields } mutualFriends(first: 10) { ...friendFields } } } fragment friendFields on User { id name profilePic(size: 50) } Cool tricks
68. 
 https://facebook.github.io/react

69. 
 https://facebook.github.io/relay

71. PostContainer = Relay.createContainer(Post, { fragments: { post: () => Relay.QL` fragment on Post { id title tagline votes_count } `, }, }); Relay
72. Demo
73. Issues • New, just a draft specification • Mutations are weird • Best practices and solutions • Large datasets
75. https://speakerdeck.com/rstankov/introduction-to-graphql
76. https://github.com/rstankov/talks-code
79. @rstankov Thanks :)
80. Questions?