GraphQL 💙 Kotlin, 2024 edition

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GraphQL 💙 Kotlin LAUG - Feb 2024

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apollographql/apollo-kotlin Hi 👋

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The beginnings of GraphQL 3 2012: Facebook

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GraphQL describes your product Graph 4 Feed Post Post Ad Title Text XL Thumbnail S Thumbnail

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5 Feed Post Post Ad Title Text XL Thumbnail S Thumbnail GraphQL

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6 Feed Post Post Ad Title Text XL Thumbnail S Thumbnail GraphQL

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7 Feed Post Post Ad Title Text XL Thumbnail S Thumbnail GraphQL

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Le client récupère uniquement les données nécessaires No overfetching

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Le schema décrit le type des données Strongly typed

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Type system 10 type User { login: String bio: String isBountyHunter: Boolean status: UserStatus issueComments: List }

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● Objects Type system 11 type User { login: String bio: String isBountyHunter: Boolean status: UserStatus issueComments: List }

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● Objects ● Scalars ○ Boolean Type system 12 type User { login: String bio: String isBountyHunter: Boolean status: UserStatus issueComments: List }

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● Objects ● Scalars ○ Boolean ○ Int ○ Float ○ String Type system 13 type User { login: String bio: String isBountyHunter: Boolean status: UserStatus issueComments: List }

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● Objects ● Scalars ○ Boolean ○ Int ○ Float ○ String Type system 14 type User { login: String bio: String isBountyHunter: Boolean status: UserStatus issueComments: List }

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● Objects ● Scalars ○ Boolean ○ Int ○ Float ○ String ● Lists Type system 15 type User { login: String bio: String isBountyHunter: Boolean status: UserStatus issueComments: List }

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● Interfaces ● Unions Polymorphisme 16 interface Node { id: String } type User implements Node { id: String login: String bio: String [...] }

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Nullability! 17 type User { login: String❗ bio: String isBountyHunter: Boolean❗ status: UserStatus issueComments: List❗ }

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❤

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Autres propriétés de GraphQL 19 ● No overfetching ● Strongly typed ● Introspection ● No versioning ● Transport agnostic

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Mise en pratique 1 https://confetti-app.dev/sandbox/

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apollographql/apollo-kotlin

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Automatic code generation 22 user.graphql schema.sdl Swift, Kotlin, Golang, JS, Rust, etc...

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Codegen 23 { sessions { nodes { language title startsAt speakers { name } } } } class Session(val nodes: List) class Node( val language: String, val title: String, val startsAt: DateTime, val speakers: List ) class Speaker(val name: String)

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Depreciation 24 class Node( @Deprecated("startsAt uses non ISO 8601 format, use startDateTime instead") val startsAt: String, ) type Conference { startsAt: String @deprecated(reason: "startsAt uses non ISO 8601 format, use startDateTime instead") startDateTime: DateTime }

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Le schema évolue progressivement et utilise les mêmes règles de depreciations que Kotlin No versioning

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❤

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No content

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Mise en pratique 2

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GraphQL vs REST REST GraphQL resources graph multiple routes single endpoint swagger/open API builtin tooling versioning continuous evolution static queries dynamic queries

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What if GraphQL is REST?

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Persisted queries { sessions { nodes { language title startsAt speakers { name } } } } 57e2978c855b25cf5de4ba4a0160cf7402b3f393 Enregistrement des queries pendant le build

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Persisted queries GET confetti-app.dev/graphql?operationId=57e2978c855b25cf5de4ba4a0160cf7402b3f393 { "data": { "sessions": { "nodes": [ { "language": "en-US", "title": "Android Graphics: the Path to [UI] Riches", "startsAt": "2023-04-27T09:15", "speakers": [ { "name": "Chet Haase" }, { "name": "Romain Guy" } ] }

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Le futur

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A brief history of 2012 Inception at meta 2015 Open source 2018 GraphQL Foundation SDL 2021 Last spec version You are here Nullability 2024 Draft Deprecated input values Full unicode

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Non-Null String String! Nullable String? String 🤔

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Merci 💙 apollographql/apollo-kotlin martinbonnin https://openfeedback.io/zezxF16ZYW2DQCjMZDoj