GraphQL with JavaScript

My GraphQL presentation from JSTalks

Transcript

1. Implementing GraphQL with
 JavaScript Radoslav Stankov 21/10/2015
2. Radoslav Stankov @rstankov http://rstankov.com
 http://blog.rstankov.com http://github.com/rstankov
9. 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 }
12. GET /api/users/1 { id: 1, name: 'User Name', handle: 'user_name', avatar_url: 'assets.producthunt.com/uuid' }
13. Rest Client Rest Server
14. Rest Client Rest Server /api/posts?date=2015-10-31
15. Rest Client Rest Server /api/posts?date=2015-10-31 /api/users/{x} (for X users)
16. Rest Client Rest Server /api/posts?date=2015-10-31 /api/users/{x} (for X users)
17. …approach 2
18. 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' } }
25. 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' }] }
29. 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', }] }
32. …approach 3
34. Rest Client Rest Server
35. Rest Client Rest Server endpoint 1 feature 1
36. Rest Client Rest Server endpoint 1 feature 1 endpoint 2 feature 2
37. Rest Client Rest Server endpoint 1 feature 1 endpoint 2 feature 2 endpoint 3 feature 3
38. Rest Client Rest Server endpoint 1 feature 1 endpoint 2 feature 2 endpoint 3 feature 3 endpoint N feature N
45. { 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' }] }
46. { id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } }
48. GET /graphql Request Body Response Body
49. 
 query { post(id: 1){ id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } } } GET /graphql Request Body Response Body
50. 
 query { post(id: 1){ id title tagline votes_count hunter { id avatar_url } makers { id avatar_url } } } GET /graphql Request Body Response Body
51. 
 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 } ] } } }
52. It’s that simple
53. 
 https://facebook.github.io/graphql

54. 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.
55. Architecture 
 GraphQL Library
 (Per-Language)
 
 Type
 Definitions
 
 Application
 Code

56. GraphQL • Single endpoint • Not just a library • Application-Layer Protocol • Server agnostic • Strongly-typed • Client-specified queries • Hierarchical
57. Tries to solve • N+1 API queries • API response bloat • Documentation • Ad Hoc Endpoints • Structure issues
58. Code var RootQueryType = new GraphQLObjectType({ name: 'RootQueryType', fields: { post: { type: PostType, description: 'Find post by id', args: { id: { description: 'Post id' type: new GraphQLNonNull(GraphQLInt) } }, resolve: function(_, params) { return data.posts.find(params.id); } }, });
59. Code var PostType = new GraphQLObjectType({ name: 'Post', fields: function() { return { id: { type: GraphQLInt, }, title: { type: GraphQLString, }, user: { type: UserType, description: "Creator of the post", resolve: function(post) { return data.users.find(post.user_id); } }, }; } });
60. Code var [TYPE] = new GraphQLObjectType({ name: [NAME],
 description: [DESCRIPTION], fields: function() { return { [FIELD_NAME]: { description: [DESCRIPTION], deprecation: [DEPRECATION MARKER], type: [TYPE],
 args: [LIST OF FIELD ARGUMENT],
 resolve: [FUNCTION] }, } } });
61. Code var PostType = new GraphQLObjectType({ name: 'Post', fields: function() { return { id: { type: GraphQLInt,
 resolve: function(post) { return post.id; } }, user: { type: UserType, resolve: function(post) { return data.users.find(post.user_id); } }, }; } });
62. Code var PostType = new GraphQLObjectType({ name: 'Post', fields: function() { return { id: { type: GraphQLInt }, user: { type: UserType, resolve: function(post) { return data.users.find(post.user_id); } }, }; } });
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. Code var RootMutationType = new GraphQLObjectType({ name: 'RootMutationType', fields: { createPost: { type: PostType, args: { title: { type: new GraphQLNonNull(GraphQLString) }, tagline: { type: new GraphQLNonNull(GraphQLString) }, user_id: { type: new GraphQLNonNull(GraphQLInt) }, }, resolve: function(_, params) { if (!data.users.find(params.user_id)) { throw "Invalid user id - " + params.user_id; } return data.posts.create(params); }, }, }, });
66. 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" } } } ] },
67. { id hunter: { id name
 small_avatar_url: avatar_url(size: 100)
 big_avatar_url: avatar_url(size: 400) } } Cool tricks
68. Code var UserType = new GraphQLObjectType({ name: 'User', fields: function() { return { // ... some field definitions ... picture: { type: GraphQLString, args: { size: { type: GraphQLInt }, }, resolve: function(user, params) { var size = params.size || 400; return 'file.example.com/' + user.picture_uuid + "?size=" + size; } }, }; } });
69. query withFragments { user(id: 4) { friends(first: 10) { ...friendFields } mutualFriends(first: 10) { ...friendFields } } } fragment friendFields on User { id name profilePic(size: 50) } Cool tricks
70. 
 https://facebook.github.io/react

71. 
 https://facebook.github.io/relay

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