GraphQL

主要让 consumer/client 方使用便捷
核心特性/卖点 - 推荐开启
- GlobalID - ID 包含类型消息，能实现 ID -> __typename
- Graph Cache - 以 __typename + id 来缓存 - 类似一个内存的 KV 数据库，可以直接查询
  - 配合自定义 resolver 将查询指向缓存能大量减少查询
  - 需要暴露 __typename, 但是一般影响不大
- Batch
- Subscription - EventSource, WebSocket
- 代码生成
推荐特性
- partial query - 只返回需要的字段
- Document Cache - 以查询维度来缓存
- persisted query - 通过 hash 来缓存查询, 避免暴露整个查询内容
- schema aware - 直接告诉查询引擎 schema 内容能让查询引擎更加智能
  - 例如判断 nullable 可以先返回缓存数据再发起查询
- federation - 多个 schema 合并
- schema stitching - 多个 schema 合并

特点
- 面向终端
- 接口数据格式由客户端定义
- 强类型
GraphQL 规范
- October2016
Wikipedia GraphQL
实现
- graphql/graphql-js
  - A reference implementation of GraphQL for JavaScript
- graphql-java/graphql-java
  - GraphQL Java implementation
- neelance/graphql-go
  - GraphQL server with a focus on ease of use
  - 强类型, 基于反射
  - 直接基于 schema 解析
- vektah/gqlgen
  - go generate based graphql server library
  - HN
- graphql-go/graphql
  - An implementation of GraphQL for Go / Golang
  - 弱类型, Resolver 返回 interface{}
  - 解析的 schema 不能转为代码中的对象
- graphql-python/graphene
  - GraphQL framework for Python
  - graphene-python.org
- graphql-js/graphene
  - graphene-js.org
工具
- postgraphql/postgraphql
  - A GraphQL API created by reflection over a PostgreSQL schema.
- 2fd/graphdoc
- apollographql/graphql-syntax
  - A catalog of different packages and syntaxes to generate a GraphQL-JS schema
- graphql/graphiql
  - An in-browser IDE for exploring GraphQL
- google/rejoiner
  - HN
接口参考
- Facebook Graph API
- GitHubGraphQL API v4
  - 接口地址 api.github.com/graphql
  - github 文档
- shopify 文档
  - explorer
- graphcms.com/docs/api_simple
参考
- Improve GraphQL Performance with Automatic Persisted Queries
  - 优化查询大小
  - 使用一个 Hash 值作为查询标识
- The future of state management
  - 使用 GraphQL 来管理应用状态
- GraphQL.g4
  - 语法参考
- Designing GraphQL Mutations
  - 设计修改操作
- GraphQL schema stitching
  - 合并多个 Schema
- A guide to authentication in GraphQL
  - 认证
  - 识别用户身份
- Authorization in GraphQL
  - 鉴权
  - 判断用户是否进行相关操作
- Reusable GraphQL schema directives
- Principled GraphQL
Relay
- facebook/relay
- Learn Relay
- What is a Query?
  - The node and viewer fields
Pagination
- 直接返回数组
- 返回数组接收翻页参数
- 返回链接
  - collections(first: Int!, after: String, reverse: Boolean): CollectionConnection!
  - followers(first: Int, after: String, last: Int, before: String): FollowerConnection!
客户端
- Apollo React
- prisma-labs/graphql-request
  - 非常简单的客户端 - 配合 react-query 使用
  - react-query vs apollo client

bash

# 获取 Schema
npm install -g graphqurl
gq https://my-graphql-engine.com/v1/graphql --introspect > schema.graphql
gq https://my-graphql-engine.com/v1/graphql -H 'X-Hasura-Admin-Secret: adminsecretkey' --introspect > schema.graphql
gq https://my-graphql-engine.com/v1/graphql --introspect --format json > schema.json

# https://github.com/apollographql/apollo-tooling
# schema.json
npm install -g apollo
apollo schema:download --endpoint https://my-graphql-engine.com/v1/graphql
apollo schema:download --endpoint https://my-graphql-engine.com/v1/graphql --header 'X-Hasura-Admin-Secret: adminsecretkey'

依赖包graphqurlapollo

FAQ

N + 1

Avoiding n+1 requests in GraphQL, including within subscriptions

TBD

graphql.org/code

skevy/graphiql-app Light, Electron-based Wrapper around GraphiQL

apollographql/apollo-server

graphcool/graphql-playground GraphQL IDE for better development workflows (GraphQL Subscriptions, interactive docs & collaboration)

docker run -p 5000

postgraphql/postgraphql --connection postgres://POSTGRES_USER

@POSTGRES_HOST

/POSTGRES_SCHEMA

chentsulin/awesome-graphql Awesome list of GraphQL & Relay

www.graphql.com graphql.org/learn/best-practices GraphQL Best Practices

www.apollographql.com Apollo provides a universal GraphQL API on top of your existing services, so you can build new application features fast without waiting on backend changes.

facebook/dataloader DataLoader is a generic utility to be used as part of your application's data fetching layer to provide a consistent API over various backends and reduce requests to those backends via batching and caching.

blog.datank.ai/graphql-grpc-part-1-54d92a109619 GraphQL & gRPC