graphql

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GraphQL — Apollo Federation, Schema Design

GraphQL — Apollo Federation、Schema设计

API GraphQL moderne avec federation, DataLoader, optimisations.

现代化GraphQL API（含联邦架构、DataLoader、优化方案）

GraphQL vs REST

GraphQL — 1 query sur-mesure, no versioning, introspection auto
REST — Multiple endpoints, over-fetching, v1/v2/v3

GraphQL — 按需查询，无版本控制，支持自动自省
REST — 多端点，过度获取数据，存在v1/v2/v3版本迭代

Apollo Federation

graphql

undefined

graphql

undefined

Users service

type User @key(fields: "id") { id: ID!, name: String! }

Orders service

extend type User @key(fields: "id") { id: ID! @external orders: [Order!]! }


Gateway compose automatiquement les services.

extend type User @key(fields: "id") { id: ID! @external orders: [Order!]! }


网关会自动组合各服务。

N+1 Problem — DataLoader

N+1问题 — DataLoader

javascript

// ❌ N+1 queries
User: { orders: (u) => db.orders.findByUserId(u.id) }

// ✅ DataLoader batch
const loader = new DataLoader(async (ids) => {
  const orders = await db.orders.findByUserIds(ids);
  return ids.map(id => orders.filter(o => o.userId === id));
});
User: { orders: (u) => loader.load(u.id) }

javascript

// ❌ N+1查询
User: { orders: (u) => db.orders.findByUserId(u.id) }

// ✅ DataLoader批量处理
const loader = new DataLoader(async (ids) => {
  const orders = await db.orders.findByUserIds(ids);
  return ids.map(id => orders.filter(o => o.userId === id));
});
User: { orders: (u) => loader.load(u.id) }

Patterns

设计模式

Pagination (Relay)

分页（Relay规范）

graphql

type UserConnection {
  edges: [{ node: User!, cursor: String! }]!
  pageInfo: { hasNextPage: Boolean!, endCursor: String }!
}

graphql

type UserConnection {
  edges: [{ node: User!, cursor: String! }]!
  pageInfo: { hasNextPage: Boolean!, endCursor: String }!
}

Error Handling

错误处理

graphql

type CreateUserPayload {
  user: User
  errors: [{ field: String, message: String! }]
}

graphql

type CreateUserPayload {
  user: User
  errors: [{ field: String, message: String! }]
}

Optimizations

优化方案

DataLoader — Batch + cache
Persisted Queries — Hash lookup
Depth Limiting — Anti-DoS
Cost Analysis — Query budget

Voir

@api-designer

pour design

DataLoader — 批量处理 + 缓存
持久化查询（Persisted Queries） — 哈希查找
深度限制（Depth Limiting） — 防DoS攻击
成本分析（Cost Analysis） — 查询预算

详见

@api-designer

进行设计