GraphQL at Facebook

GraphQL at Facebook
Dan Schafer
ReactEurope, 2 June 2016
https://www.react-europe.org/

1. Facebook’s GraphQL Stack Dan Schafer
3. { me { name } }
4. { "me": { "name": "Daniel Schafer" } } { me { name } }
5. { me { name profilePicture { width height url } } }
6. { "me": { "name": "Daniel Schafer", "profilePicture": { "width": 50, "height": 50, "url": "https://cdn/50.jpg" } } } { me { name profilePicture { width height url } } }
7. query Q { me { name birthday teammates { name birthday } } }
8. query Q { me { name birthday teammates { name birthday } } } { "me": { "name": "Daniel Schafer", "birthday": "Jan 17", "teammates": [ { "name": "Lee Byron", "birthday": "Dec 18" }, { "name": "Laney Kuenzel", "birthday": "Jan 25" } ] } }
9. query Q { me { ...BasicInfo teammates { ...BasicInfo } } } fragment BasicInfo on User { name birthday } { "me": { "name": "Daniel Schafer", "birthday": "Jan 17", "teammates": [ { "name": "Lee Byron", "birthday": "Dec 18" }, { "name": "Laney Kuenzel", "birthday": "Jan 25" } ] } }
10. graphql.org
11. GraphQL: How?
12. How do I implement authorization? How do I make GraphQL efficient? How do I cache my results?
13. How do I implement authorization? How do I make GraphQL efficient? How do I cache my results?
14. How do I implement authorization? How do I make GraphQL efficient? How do I cache my results?
15. Facebook’s GraphQL Stack
17. Think Graphs, not Endpoints
18. Single Source of Truth
19. Thin API layer
20. Authorization
22. “A Todo Item can only be seen by its creator.”
23. What is a Todo Item?
24. http://api.todoapp.com/todo/4
25. http://api.todoapp.com/todo/4 Too interface-specific
26. SELECT * FROM todoitems WHERE id = 4
27. SELECT * FROM todoitems WHERE id = 4 GET todoitem:4
28. SELECT * FROM todoitems WHERE id = 4 Storage Detail GET todoitem:4
29. External Interfaces Storage Layer
30. External Interfaces Business Logic Storage Layer
31. External Interfaces Business Logic Storage Layer
32. GraphQL Business Logic Storage Layer
33. What is a Todo Item?
34. class TodoItem { constructor(id: number, title: string, isDone: boolean) { this.id = id; this.title = title; this.isDone = isDone; } };
35. http://sujaytrivedi.blogspot.com/2015/03/object-oriented-programming-oop-in-c.html
36. https://upload.wikimedia.org/wikipedia/commons/b/b8/Policy_Admin_Component_Diagram.PNG
37. class TodoItem { constructor(id: number, title: string, isDone: boolean) { this.id = id; this.title = title; this.isDone = isDone; } };
38. Single Source of Truth
39. class TodoItem { constructor(data: TodoItemData) { this.id = data.id; this.title = data.title; this.isDone = data.isDone; } // Single source of truth for fetching static async gen(id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable return data ? new TodoItem(data) : null; } }
40. Implementing Authorization
41. class TodoItem { // Single source of truth for fetching static async gen(id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable return data ? new TodoItem(data) : null; } }
42. class TodoItem { // Single source of truth for fetching static async gen(id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable // Single source of truth for authorization return data ? new TodoItem(data) : null; } }
43. class TodoItem { // Single source of truth for fetching static async gen(id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable if (data === null) return null; const canSee = checkCanSee(data); return canSee ? new TodoItem(data) : null; } }
44. class TodoItem { // Single source of truth for fetching static async gen(id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable if (data === null) return null; const canSee = checkCanSee(data); return canSee ? new TodoItem(data) : null; } } function checkCanSee(data: Object) { // A Todo Item can only be seen by its creator }
45. class TodoItem { // Single source of truth for fetching static async gen(id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable if (data === null) return null; const canSee = checkCanSee(data); return canSee ? new TodoItem(data) : null; } } function checkCanSee(data: Object) { return (data.creatorID === /* authenticated user ID */); }
46. class TodoItem { // Single source of truth for fetching static async gen(id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable if (data === null) return null; const canSee = checkCanSee(data); return canSee ? new TodoItem(data) : null; } } function checkCanSee(data: Object) { return (data.creatorID === /* authenticated user ID */); }
47. class TodoItem { // Single source of truth for fetching static async gen( viewer: Viewer, id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable if (data === null) return null; const canSee = checkCanSee(data); return canSee ? new TodoItem(data) : null; } } function checkCanSee(data: Object) { return (data.creatorID === /* authenticated user ID */); }
48. class TodoItem { // Single source of truth for fetching static async gen( viewer: Viewer, id: number): Promise<?TodoItem> { const data = await Redis.get("ti:" + id); // Nullable if (data === null) return null; const canSee = checkCanSee(viewer, data); return canSee ? new TodoItem(data) : null; } } function checkCanSee(viewer: Viewer, data: Object) { return (data.creatorID === viewer.userID); }
49. class TodoItem { static async gen( viewer: Viewer, id: number): Promise<?TodoItem>; // No other public constructors } class TodoList { static async gen( viewer: Viewer, id: number): Promise<?TodoList>; // No other public constructors }
50. Authorization in GraphQL
51. todoItem: { type: TodoItemType, resolve: (obj) => /* ??? */ }
52. todoItem: { type: TodoItemType, resolve: (obj) => /* ??? */ } // ... graphql(schema, "{todoItem}");
53. todoItem: { type: TodoItemType, resolve: (obj) => TodoItem.gen(viewer, id) } // ... graphql(schema, "{todoItem}");
54. todoItem: { type: TodoItemType, args: { id: { type: GraphQLID } }, resolve: (obj, {id}) => TodoItem.gen(viewer, id) } // ... graphql(schema, "{todoItem(id: 4)}");
55. todoItem: { type: TodoItemType, args: { id: { type: GraphQLID } }, resolve: (obj, {id}, viewer) => TodoItem.gen(viewer, id) } // ... graphql(schema, "{todoItem(id: $id)}", viewer);
56. todoItem: { type: TodoItemType, args: { id: { type: GraphQLID } }, resolve: (obj, {id}, viewer) => TodoItem.gen(viewer, id) } // ... graphql(schema, "{todoItem(id: $id)}", viewer);
57. todoItem: { type: TodoItemType, args: { id: { type: GraphQLID } }, resolve: (obj, {id}, viewer) => TodoItem.gen(viewer, id) } // ... const viewer = Viewer.fromAuthToken(request.auth_token); graphql(schema, "{todoItem(id: $id)}", viewer);
58. Efficiency
59. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } }
60. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 GET u:3 GET u:4 GET u:5 GET u:6 GET u:7 GET u:8 GET u:9 GET u:10 GET u:11 GET u:12 redis.log
61. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 GET u:3 GET u:4 GET u:5 GET u:6 GET u:7 GET u:8 GET u:9 GET u:10 GET u:11 GET u:12 redis.log
62. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 GET u:3 GET u:4 GET u:5 GET u:6 GET u:7 GET u:8 GET u:9 GET u:10 GET u:11 GET u:12 redis.log
63. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 GET u:3 GET u:4 GET u:5 GET u:6 GET u:7 GET u:8 GET u:9 GET u:10 GET u:11 GET u:12 redis.log
64. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 GET u:2 GET u:3 GET u:4 GET u:5 GET u:6 GET u:8 GET u:9 GET u:10 GET u:11 GET u:12 redis.log
65. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 GET u:2 GET u:3 GET u:4 GET u:5 GET u:6 GET u:1 GET u:5 GET u:7 GET u:8 GET u:9 redis.log
66. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 -1 GET u:3 GET u:4 GET u:5 GET u:6 GET u:7 GET u:8 GET u:9 GET u:10 GET u:11 GET u:12 redis.log
67. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 GET u:3 GET u:4 GET u:5 GET u:6 GET u:7 redis.log
68. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 MGET u:2 u:3 u:4 u:5 u:6 MGET u:8 u:9 u:10 u:11 u:12 redis.log
69. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 MGET u:2 u:3 u:4 u:5 u:6 MGET u:1 u:5 u:7 u:8 u:9 redis.log
70. Implementing Batching in GraphQL
71. Implementing Batching in GraphQL
72. DataLoader
73. https://github.com/facebook/dataloader
74. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "m:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await Redis.get("u:" + id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } }
75. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "m:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await Redis.get("u:" + id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } }
76. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "u:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await Redis.get("u:" + id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } }
77. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "u:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await userDataLoader.load(id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } }
78. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 MGET u:2 u:3 u:4 u:5 u:6 MGET u:1 u:5 u:7 u:8 u:9 redis.log
79. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 MGET u:2 u:3 u:4 u:5 u:6 MGET u:1 u:5 u:7 u:8 u:9 redis.log
80. Caching
81. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "u:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await userDataLoader.load(id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } }
82. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "u:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await userDataLoader.load(id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } }
83. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 MGET u:2 u:3 u:4 u:5 u:6 MGET u:1 u:5 u:7 u:8 u:9 redis.log
84. { me { name bestFriend { name } friends(first: 5) { name bestFriend { name } } } } GET u:1 GET u:2 LRANGE friends:1 0 5 MGET u:2 u:3 u:4 u:5 u:6 MGET u:1 u:5 u:7 u:8 u:9 redis.log
85. Clients?
86. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "m:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await userDataLoader.load(id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } getID(): number { return this.id; } }
87. const userDataLoader = new DataLoader( ids => Redis.mget(ids.map(id => "m:" + id)) ); class User { static async gen(v: Viewer, id: number): Promise<?User> { const rawData = await userDataLoader.load(id); // Do authorization ... return rawData === null ? new TodoItem(rawData) : null; } getID(): number { return this.id; } }
88. const userType = new GraphQLObjectType({ name: 'User', fields: () => ({ id: { type: GraphQLID, resolve: (user) => user.getID() } }) });
89. { me { id profilePhoto { id } } }
90. { me { id profilePhoto { id } } } { me: { id: "1", profilePhoto: { id: "1" } } }
91. What do we want in IDs?
92. Unique Cache Key
93. Globally Unique Cache Key
94. Globally Unique Cache Key Refetch Identifier
95. Globally Unique Cache Key Refetch Identifier Client Comprehension?
96. Globally Unique Cache Key Refetch Identifier Client Comprehension?
97. Globally Unique Cache Key Refetch Identifier Opaque to Clients
98. const userType = new GraphQLObjectType({ name: 'User', fields: () => ({ id: { type: GraphQLID, resolve: (user) => user.getID() } }) });
99. const userType = new GraphQLObjectType({ name: 'User', fields: () => ({ id: { type: GraphQLID, resolve: (user) => base64("user:" + user.getID()) } }) });
100. { me { id profilePhoto { id } } }
101. { me { id profilePhoto { id } } } { me: { id: "dXNlcjoxCg==", profilePhoto: { id: "cGhvdG86MQo=" } } }
102. Facebook’s GraphQL Stack
103. Think Graphs, not Endpoints
104. Single Source of Truth
105. Thin API layer
106. graphql.org