GraphQL for Rubyists

The accompanying recording of this presentation is available here: http://rubythursday.com/talks/ruby-roundtable-graphql-relay.

Transcript

2. Hi, I’m Brooks
3. I work at !
4. let’s talk about GraphQL & Relay
5. in Ruby
6. but first
7. let’s start with APIs
8. REST APIs
9. are endpoint driven
10. are verb driven
11. !"""# verb !""""""""""""""""""""""""""""""""""""""""""""# endpoint https://api.reddit.com/r/catsstandingup.json GET
12. { "kind": "Listing", "data": { "modhash": "", "children": [ { "kind": "t3", "data": { "id": "4lyzb1", "created": 1464776494, "title": "Cat.", "author": "AcezennJames", "score": 1, "num_comments": 0, "subreddit": "CatsStandingUp", "url": "https://i.reddituploads.com/da4620368fdd4c08a17e3b2f56571889? fit=max&h=1536&w=1536&s=a7a58b1ca15529fa6dda138d12d6fb51", "permalink": "/r/CatsStandingUp/comments/4lyzb1/cat/", "thumbnail": "http://b.thumbs.redditmedia.com/uT4-uPd2Z7Jt-gVdJSswq8W5bTa9Jchfnb3GHRlhHLE.jpg", "locked": false } } ] } }
13. but, we’re Rubyists…
14. require 'net/http' require 'json' uri = URI('https://api.reddit.com/r/catsstandingup.json') response = Net::HTTP.get(uri) parsed_response = JSON.parse(response) posts = parsed_response['data']['children'] html = posts.each_with_object('') do |post, string| thumbnail = post['data']['thumbnail'] string << "<img src='#{thumbnail}' />" end File.write('cats_standing_up.html', html)
16. REST APIs
17. …for backend engineers
18. are difficult to change
19. …for implementors
20. aren’t optimized for consumption
21. { "kind": "Listing", "data": { "modhash": "", "children": [ { "kind": "t3", "data": { "id": "4lyzb1", "created": 1464776494, "title": "Cat.", "author": "AcezennJames", "score": 1, "num_comments": 0, "subreddit": "CatsStandingUp", "url": "https://i.reddituploads.com/da4620368fdd4c08a17e3b2f56571889? fit=max&amp;h=1536&amp;w=1536&amp;s=a7a58b1ca15529fa6dda138d12d6fb51", "permalink": "/r/CatsStandingUp/comments/4lyzb1/cat/", "thumbnail": "http://b.thumbs.redditmedia.com/uT4-uPd2Z7Jt-gVdJSswq8W5bTa9Jchfnb3GHRlhHLE.jpg", "locked": false } } ] } }
22. enter, GraphQL
23. What is it?
24. a Data Query Language
25. think SQL
26. not Neo4j
27. GraphQL is a specification
28. created by Facebook
29. powering all of their mobile apps
30. what does it look like?
31. { me { firstName lastName email } }
32. { me { firstName lastName email } } { "data":{ "me":{ "firstName":"Brooks", "lastName":"Swinnerton", "email":"brooks@github.com" } } }
33. !"""# verb !""""""""""""""""""""""""""""""""""""""""# endpoint https://nyc-restaurant-grades.com/graphql POST
34. { restaurant(name: "Cafe Ghia") { name buildingNumber street zipcode borough grade } } { "data": { "restaurant": { "name": "Cafe Ghia", "buildingNumber": "24", "street": "Irving Avenue", "zipcode": "11237", "borough": "BROOKLYN", "grade": "A" } } } https://nyc-restaurant-grades.com/graphql POST
35. how do you know what you can query?
36. GraphQL is introspectable
37. GraphQL is typed
39. documentation and client generation, are free
40. THIS IS THE HOLY GRAIL
41. Building a GraphQL server
42. like SQL, there are many implementations
43. let’s talk about the Ruby implementation
44. ActiveRecord::Schema.define(version: 20160605211006) do create_table "inspections"do |t| t.integer "restaurant_id" t.text "type" t.datetime "inspected_at" t.datetime "graded_at" t.integer "score" t.text "violation_description" t.text "violation_code" t.text "grade" t.datetime "created_at", null: false t.datetime "updated_at", null: false end create_table "restaurants"do |t| t.text "name" t.text "camis" t.text "building_number" t.text "street" t.text "zipcode" t.integer "borough" t.text "cuisine" t.datetime "created_at", null: false t.datetime "updated_at", null: false end end db/schema.rb
45. class Inspection < ActiveRecord::Base belongs_to :restaurant end app/models/inspection.rb
46. class Restaurant < ActiveRecord::Base enum borough: ['BRONX', 'BROOKLYN', 'MANHATTAN', 'STATEN_ISLAND', 'QUEENS'] has_many :inspections def grade return unless last_inspection last_inspection.grade end private def last_inspection inspections.where.not(grade: nil).order(inspected_at: :desc).last end end app/models/restaurant.rb
47. graphql-ruby
48. app/graph/graph/types/restaurant.rb module Graph module Types Restaurant = GraphQL::ObjectType.define do name 'Restaurant' description 'A place of business serving food in New York City' global_id_field :id field :name, !types.String, 'The doing-business-as value.' field :camis, !types.String, 'The unique identifier.' field :buildingNumber, types.String, 'The street number.', property: :building_number field :street, types.String, 'The street name.' field :zipcode, types.String, 'The zip code.' field :cuisine, types.String, 'The cuisine.' field :grade, types.String, 'The latest grade of an inspection.' end end end
49. app/graph/graph/types/inspection.rb module Graph module Types Inspection = GraphQL::ObjectType.define do name 'Inspection' description 'A NYC health inspection.' global_id_field :id field :type, types.String, 'The type of inspection.' field :violationDescription, types.String, 'The violation description.', property: :violation_description field :violationCode, types.String, 'The violation code cited.', property: :violation_code field :grade, types.String, 'The grade received.' field :score, types.Int, 'The numeric score received.' field :inspectedAt, !types.String, 'The inspection timestamp.', property: :inspected_at field :gradedAt, types.String, 'The issued grade timestamp.', property: :graded_at end end end
50. app/graph/graph/types/root_query.rb module Graph module Types RootQuery = GraphQL::ObjectType.define do name "RootQuery" description "The query root." field :restaurant do type -> { Types::Restaurant } description "Perform a search for one restaurant." argument :name, types.String resolve -> (object, arguments, context) do ::Restaurant.find_by(name: arguments['name']) end end end end end
51. { restaurant(name: "Cafe Ghia") { name buildingNumber street zipcode borough grade } } { "data": { "restaurant": { "name": "Cafe Ghia", "buildingNumber": "24", "street": "Irving Avenue", "zipcode": "11237", "borough": "BROOKLYN", "grade": "A" } } } https://nyc-restaurant-grades.com/graphql POST
52. class Restaurant < ActiveRecord::Base enum borough: ['BRONX', 'BROOKLYN', 'MANHATTAN', 'STATEN_ISLAND', 'QUEENS'] has_many :inspections def grade return unless last_inspection last_inspection.grade end private def last_inspection inspections.where.not(grade: nil).order(inspected_at: :desc).last end end app/models/restaurant.rb
53. Enter, Relay
54. but first
55. an introduction to Graph Theory
56. Graphs contain:
57. nodes
58. edges
59. { "name": "Cafe Ghia", "buildingNumber": "24", "street": "Irving Avenue", "zipcode": "11237", "borough": "BROOKLYN" }
60. { "name": "Cafe Ghia", "buildingNumber": "24", "street": "Irving Avenue", "zipcode": "11237", "borough": "BROOKLYN" } { "grade": "A", "score": 13, "type": "Cycle Inspection", "violationCode": "10B", "violationDescription": "Plumbing not properly installed.", "inspectedAt": "2016-02-18 00:00:00 UTC", "gradedAt": "2016-02-18 00:00:00 UTC" }
61. { "name": "Cafe Ghia", "buildingNumber": "24", "street": "Irving Avenue", "zipcode": "11237", "borough": "BROOKLYN" } { "grade": "A", "score": 13, "type": "Cycle Inspection", "violationCode": "02G", "violationDescription": "Cold food item held above 41ºF", "inspectedAt": "2016-02-18 00:00:00 UTC", "gradedAt": "2016-02-18 00:00:00 UTC" } { "grade": "A", "score": 13, "type": "Cycle Inspection", "violationCode": "10B", "violationDescription": "Plumbing not properly installed.", "inspectedAt": "2016-02-18 00:00:00 UTC", "gradedAt": "2016-02-18 00:00:00 UTC" }
62. { restaurant(name:"Cafe Ghia") { inspections(first:2) { edges { node { violationCode violationDescription } } } } } https://nyc-restaurant-grades.com/graphql POST
63. { restaurant(name:"Cafe Ghia") { inspections(first:2) { edges { node { violationCode violationDescription } } } } } { "data": { "restaurant": { "inspections": { "edges": [ { "node": { "violationCode": "10F", "violationDescription": "Non-food contact surface improperly constructed. Unacceptable material used." } }, { "node": { "violationCode": "04L", "violationDescription": "Evidence of mice or live mice present in facility's food and/or non-food areas." } } ] } } } } https://nyc-restaurant-grades.com/graphql POST
64. graphql-relay-ruby
65. app/graph/graph/types/restaurant.rb module Graph module Types Restaurant = GraphQL::ObjectType.define do name 'Restaurant' description 'A place of business serving food in New York City' connection :inspections, -> { Types::Inspection.connection_type } do description 'List the inspections.' resolve -> (object, arguments, context) do object.inspections end end end end end
66. Mutations
67. Versions
68. More information
69. https://facebook.github.io/graphql/
70. http://nyc-restaurant-grades.com
71. https://github.com/bswinnerton/nyc-restaurant-grades
72. Thanks Follow me on Twitter & GitHub: @bswinnerton