GraphQL Spiekbrief

GraphQL is een querytaal voor API's en een runtime voor het uitvoeren van query's met bestaande applicatiegegevens.

Query's

Basisquery en JSON-antwoord

{ status }

JSON Response:

{
  "data": {
    "status": "available"
  }
}

Geneste objecten

{
  hero {
    name
    height
  }
}

Lijsten

{
  friends {
    name
  }
}

Argumenten

{
  hero(id: "1000") {
    id
    name
  }
}

Aliassen

{
  luke: hero(id: "1000") {
    name
  }
  han: hero(id: "1001") {
    name
  }
}

Operatienamen en variabelen

Query Definition:

query FindHero($id: String!) {
  hero(id: $id) {
    name
  }
}

Variables Payload (JSON):

{
  "id": "1000"
}

Mutaties (Mutations)

mutation CreateReviewForEpisode($ep: Episode!, $review: ReviewInput!) {
  createReview(episode: $ep, review: $review) {
    stars
    commentary
  }
}

Inline-fragmenten

{
  search(q: "john") {
    id
    ... on User {
      name
    }
    ... on Comment {
      body
      author {
        name
      }
    }
  }
}

GraphQL via HTTP

GET-verzoek

fetch('https://api.example.com/graphql?query={me{name}}')

POST-verzoek

fetch('https://api.example.com/graphql', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    query: 'query GetHero($id: String!) { hero(id: $id) { name } }',
    variables: { id: '1000' }
  })
})

Schema Definition Language (SDL)

Basistypen

type Query {
  me: User
  users(limit: Int): [User]
}

type User {
  id: ID!
  name: String
}

Ingebouwde scalaire typen

Trefwoorden voor typedefinitie

Typemodifiers

Interfaces

interface Entity {
  id: ID!
}

type User implements Entity {
  id: ID!
  name: String
}

Enums (Opsommingen)

enum Direction {
  NORTH
  EAST
  SOUTH
  WEST
}

Unions

union SearchResult = Human | Droid | Starship

type Query {
  search(text: String): [SearchResult]
}

Referenties

• GraphQL Official Documentation
• GraphQL Queries and Mutations
• GraphQL Serving over HTTP