GraphQL & Absinthe

Comment utiliser Absinthe pour bâtir un API GraphQL performant, fiable et facile à maintenir. Voici comment Absinthe a réussi à abstraire les problèmes "classiques" d’un API standard.

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1. GraphQL & Absinthe GraphQL & Absinthe
3. * Agnostique
4. type Query { me: User } type User { id: ID name: String } Le serveur défini:
5. query { me { name } } Le client envoie une query:
6. { "me": { "name": “Simon Prévost” } } Le client recoit:
7. mutation { updateMe(name: “test”) { name } } Le client envoie une mutation:
8. { “updateMe": { "name": “Test” } } Le client recoit:
9. Interface Union type Custom Scalar types Mutation Enums Validation Documentation Fragments Arguments Subscription Directive Client-side integration
11. Absinthe GraphQL & Absinthe
13. Intégration avec Phoenix def deps do [ {:absinthe, "!~> 1.4"}, {:absinthe_plug, "!~> 1.4"} ] end plug Absinthe.Plug, schema: MyAppWeb.Schema Ajout des dépendances Ajout du module dans le Endpoint Phoenix
14. → defmodule MyAppWeb.Schema do use Absinthe.Schema object :user do field :name, :string end query do field :me, :user do resolve fn _, _, _ !-> {:ok, Repo.find(User, "me")} end end end end type Query { me: User } type User { id: ID name: String } → Définition de schemas
15. Resolve fn root, args, info !-> end
16. { me { name } } Root field :name, :string do resolve fn root, _, _ !-> {:ok, Map.get(root, :name)} end end
17. Resolve fn root, args, info !-> end
18. { me { name(uppercase: true) } } Arguments type User { id: ID name(uppercase Boolean): String }
19. Arguments field :name, :string do resolve fn (root, %{uppercase: true}, _) !-> {:ok, Map.get(root, :name) !|> String.upcase} (root, _args, _) !-> {:ok, Map.get(root, :name)} end end
20. Resolve fn root, args, info !-> end
21. { me { id name } } Infos field :user, :user do resolve fn _, _, info !-> child_fields = info !|> Absinthe.Resolution.project() !|> Enum.map(&(&1.name)) … end end
22. Resolve {:ok, _} {:error, _}
23. defmodule MyAppWeb.Schema do use Absinthe.Schema object :user do field :name, :string end query do field :me, :user do resolve fn _, _, _ !-> {:ok, Repo.find(User, "me")} end end end end Resolve
24. Solving classic API problems
25. Solving GraphQL { posts { author { name } } }
26. Solving GraphQL defmodule MyAppWeb.Schema do use Absinthe.Schema object :post do field :author, :author end query do field :posts, list_of(:posts) do resolve fn _, _, _ !-> {:ok, Repo.all(Post)} end end end end
27. Solving GraphQL object :post do field :author, :author do resolve fn root, _, _ !-> {:ok, Repo.get(Author, root.author_id) end end end
28. Introducing Batch Plugin {:batch, _}
29. Plugins object :post do field :author, :user do resolve fn post, _, _ !-> batch({!__MODULE!__, :users_by_id}, post.author_id, fn batch_results !-> {:ok, Map.get(batch_results, post.author_id)} end) end end end def users_by_id(_, user_ids) do users = Repo.all from u in User, where: u.id in ^user_ids Map.new(users, fn user !-> {user.id, user} end) end
30. Introducing Dataloader https://github.com/absinthe-graphql/dataloader
31. Plugins → Dataloader object :post do field :name, :string field :author, dataloader(User) end
32. Solving GraphQL { posts { author { name approved } } }
33. Introducing Middleware {:middleware, _}
34. Middleware field :answer, :string do middleware MyAppWeb.Authentication resolve &get_answer/3 middleware MyAppWeb.Helper.StripHTML end
35. Middleware field :time_consuming, :thing do resolve fn _, _, _ !-> async(fn !-> {:ok, long_time_consuming_function()} end) end end field :time_consuming, :thing do resolve fn _, _, _ !-> task = Task.async(fn !-> {:ok, long_time_consuming_function()} end {:middleware, Elixir.Absinthe.Middleware.Async, task} end end
36. Solving GraphQL mutation createUser { createUser(email: “foo”) { successful record { id } errors { message } } }
37. Introducing Kronky https://github.com/Ethelo/kronky
38. Introducing so much more
39. Custom Scalar defmodule MyApp.Type.IPAddress do use Absinthe.Schema.Notation scalar :ip_address, name: "IPAddress" do serialize(&serialize_ip_address/1) parse(&parse_ip_address/1) end defp parse_ip_address(%Absinthe.Blueprint.Input.String{value: ip_address}) do ip_address !|> to_charlist !|> :inet.parse_address() !|> case do {:ok, _address} !-> {:ok, ip_address} {:error, _reason} !-> :error end end defp parse_ip_address(%Absinthe.Blueprint.Input.Null{}), do: {:ok, nil} defp parse_ip_address(_), do: :error defp serialize_ip_address(value), do: value end
40. Subscription Intentionally left blank
41. Subscription subscription { newUsers { id account { name } } }
42. Subscription subscription do field :new_users, :user do arg :account_id, non_null(:id) config fn args, _info !-> {:ok, topic: args.account_id} end trigger :create_user, topic: fn user !-> user.account_id end end end
43. En bref
44. En bref
45. One more thing
46. Introducing Accent Open source
47. Questions?