GraphQL 备忘清单

这份快速参考备忘单提供了 GraphQL 的简要概述

入门概述Schema内置标量类型类型定义类型修饰符输入参数基本输入输入默认值具有多个参数的输入具有多个参数和默认值的输入输入类型自定义标量接口联合枚举查询和变更(Mutations)字段查询可以有注释参数 Arguments不同类型的参数别名(Aliases)片段(Fragments)在片段内使用变量操作名称(Operation name)变量(Variables)默认变量(Default variables)指令(Directives)变更(Mutations)内联片段(Inline Fragments)元字段(Meta fields)另见

入门

概述

  • RESTful API 的另一种方法
  • GraphQL 是一种 API 查询语言
  • 使用清晰的共享术语轻松描述 GraphQL API 的形状。
  • 客户端发出查询/突变以读取和更新数据
  • GraphQL 语法可以表达复杂的实体关系
  • 用 不同语言 实现 GraphQL 的库

GraphQL

Schema

:--
schemaGraphQL 架构定义
query读取和遍历数据
mutation修改数据或触发动作
subscription发生事件时运行查询

内置标量类型

:--
Int有符号 32 位整数
Float有符号双精度浮点值
StringUTF-8 字符序列
Boolean对或错布尔值类型
ID唯一标识符

类型定义

:--
scalar标量类型
type对象类型
interface接口类型
union联合类型
enum枚举类型
input输入对象类型

类型修饰符

:--
String可空字符串
String!非空字符串
[String]可空字符串列表
[String]!可空字符串的非空列表
[String!]!非空字符串的非空列表

输入参数

基本输入

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

输入默认值

type Query {
  users(limit: Int = 10): [User]
}

具有多个参数的输入

type Query {
  users(limit: Int, sort: String): [User]
}

具有多个参数和默认值的输入

type Query {
  users(limit: Int = 10, sort: String): [User]
}
type Query {
  users(limit: Int, sort: String = "asc"): [User]
}
type Query {
  users(limit: Int = 10, sort: String = "asc"): [User]
}

输入类型

input ListUsersInput {
  limit: Int
  since_id: ID
}

type Mutation {
  users(params: ListUsersInput): [User]!
}

自定义标量

scalar Url
type User {
  name: String
  homepage: Url
}

接口

interface Foo {
  is_foo: Boolean
}
interface Goo {
  is_goo: Boolean
}
type Bar implements Foo {
  is_foo: Boolean
  is_bar: Boolean
}
type Baz implements Foo, Goo {
  is_foo: Boolean
  is_goo: Boolean
  is_baz: Boolean
}

实现一个或多个接口的对象

联合

type Foo {
  name: String
}
type Bar {
  is_bar: String
}
union SingleUnion = Foo
union MultipleUnion = Foo | Bar
type Root {
  single: SingleUnion
  multiple: MultipleUnion
}

一个或多个对象的联合

枚举

enum USER_STATE {
  NOT_FOUND
  ACTIVE
  INACTIVE
  SUSPENDED
}
type Root {
  stateForUser(userID: ID!): USER_STATE!
  users(state: USER_STATE, limit: Int = 10): [User]
}

查询和变更(Mutations)

字段

{
  hero {
    name
  }
}

结果:

{
  "data": {
    "hero": {
      "name": "R2-D2"
    }
  }
}

查询可以有注释

{
  hero {
    name
    # 查询可以有注释！
    friends {
      name
    }
  }
}

结果:

{
  "data": {
    "hero": {
      "name": "R2-D2",
      "friends": [
        { "name": "Luke Skywalker" },
        { "name": "Han Solo" }
      ]
    }
  }
}

参数 Arguments

{
  human(id: "1000") {
    name
    height
  }
}

结果:

{
  "data": {
    "human": {
      "name": "Luke Skywalker",
      "height": 1.72
    }
  }
}

不同类型的参数

{
  human(id: "1000") {
    name
    height(unit: FOOT)
  }
}

结果:

{
  "data": {
    "human": {
      "name": "Luke Skywalker",
      "height": 5.6430448
    }
  }
}

别名(Aliases)

{
  empireHero: hero(episode: EMPIRE) {
    name
  }
  jediHero: hero(episode: JEDI) {
    name
  }
}

结果:

{
  "data": {
    "empireHero": {
      "name": "Luke Skywalker"
    },
    "jediHero": {
      "name": "R2-D2"
    }
  }
}

片段(Fragments)

{
  leftComparison: hero(episode: EMPIRE) {
    ...comparisonFields
  }
  rightComparison: hero(episode: JEDI) {
    ...comparisonFields
  }
}
​
fragment comparisonFields on Character {
  name
  appearsIn
  friends {
    name
  }
}

结果:

{
  "data": {
    "leftComparison": {
      "name": "Luke Skywalker",
      "appearsIn": [
        "NEWHOPE",
        "EMPIRE",
        "JEDI"
      ],
      "friends": [
        { "name": "Han Solo" },
        { "name": "Leia Organa" },
        { "name": "C-3PO" },
        { "name": "R2-D2" }
      ]
    },
    "rightComparison": {
      "name": "R2-D2",
      "appearsIn": [
        "NEWHOPE",
        "EMPIRE",
        "JEDI"
      ],
      "friends": [
        { "name": "Luke Skywalker" },
        { "name": "Han Solo" },
        { "name": "Leia Organa" }
      ]
    }
  }
}

在片段内使用变量

query HeroComparison($first: Int = 3) {
  leftComparison: hero(episode: EMPIRE) {
    ...comparisonFields
  }
  rightComparison: hero(episode: JEDI) {
    ...comparisonFields
  }
}
​
fragment comparisonFields on Character {
  name
  friendsConnection(first: $first) {
    totalCount
    edges {
      node {
        name
      }
    }
  }
}

结果:

{
  "data": {
    "leftComparison": {
      "name": "Luke Skywalker",
      "friendsConnection": {
        "totalCount": 4,
        "edges": [
          {
            "node": {
              "name": "Han Solo"
            }
          },
          {
            "node": {
              "name": "Leia Organa"
            }
          }
        ]
      }
    },
    "rightComparison": {
      "name": "R2-D2",
      "friendsConnection": {
        "totalCount": 3,
        "edges": [
          {
            "node": {
              "name": "Luke Skywalker"
            }
          },
          {
            "node": {
              "name": "Han Solo"
            }
          }
        ]
      }
    }
  }
}

操作名称(Operation name)

query HeroNameAndFriends {
  hero {
    name
    friends {
      name
    }
  }
}

结果:

{
  "data": {
    "hero": {
      "name": "R2-D2",
      "friends": [
        { "name": "Luke Skywalker" },
        { "name": "Han Solo" },
        { "name": "Leia Organa" }
      ]
    }
  }
}

变量(Variables)

# { "graphiql": true, "variables": { "episode": JEDI } }
query HeroNameAndFriends($episode: Episode) {
  hero(episode: $episode) {
    name
    friends {
      name
    }
  }
}

变量前缀必须为 $，后跟其类型

默认变量(Default variables)

query HeroNameAndFriends($episode: Episode = "JEDI") {
  hero(episode: $episode) {
    name
    friends {
      name
    }
  }
}

指令(Directives)

query Hero($episode: Episode, $withFriends: Boolean!) {
  hero(episode: $episode) {
    name
    friends @include(if: $withFriends) {
      name
    }
  }
}

{ "episode": "JEDI", "withFriends": false }

结果:

{
  "data": { "hero": { "name": "R2-D2" } }
}
  • @include(if: Boolean) 仅在参数为 true 时，包含此字段
  • @skip(if: Boolean) 如果参数为 true，跳过此字段

变更(Mutations)

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

{
  "ep": "JEDI",
  "review": {
    "stars": 5,
    "commentary": "This is a great movie!"
  }
}

结果:

{
  "data": {
    "createReview": {
      "stars": 5,
      "commentary": "This is a great movie!"
    }
  }
}

内联片段(Inline Fragments)

query HeroForEpisode($ep: Episode!) {
  hero(episode: $ep) {
    name
    ... on Droid {
      primaryFunction
    }
    ... on Human {
      height
    }
  }
}

{ "ep": "JEDI" }

结果:

{
  "data": {
    "hero": {
      "name": "R2-D2",
      "primaryFunction": "Astromech"
    }
  }
}

元字段(Meta fields)

{
  search(text: "an") {
    __typename
    ... on Human {
      name
    }
    ... on Droid {
      name
    }
    ... on Starship {
      name
    }
  }
}

结果:

{
  "data": {
    "search": [
      {
        "__typename": "Human",
        "name": "Han Solo"
      },
      {
        "__typename": "Human",
        "name": "Leia Organa"
      },
      {
        "__typename": "Starship",
        "name": "TIE Advanced x1"
      }
    ]
  }
}

另见

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