workers-best-practices

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Your knowledge of Cloudflare Workers APIs, types, and configuration may be outdated. Prefer retrieval over pre-training for any Workers code task — writing or reviewing.
你对Cloudflare Workers API、类型和配置的认知可能已过时。在任何Workers代码任务(编写或审查)中,优先通过检索获取最新信息,而非依赖预训练知识

Retrieval Sources

检索来源

Fetch the latest versions before writing or reviewing Workers code. Do not rely on baked-in knowledge for API signatures, config fields, or binding shapes.
SourceHow to retrieveUse for
Workers best practicesFetch
https://developers.cloudflare.com/workers/best-practices/workers-best-practices/
Canonical rules, patterns, anti-patterns
Workers typesSee
references/review.md
for retrieval steps
API signatures, handler types, binding types
Wrangler config schema
node_modules/wrangler/config-schema.json
Config fields, binding shapes, allowed values
Cloudflare docsSearch tool or
https://developers.cloudflare.com/workers/
API reference, compatibility dates/flags
在编写或审查Workers代码前,获取最新版本内容。不要依赖内置知识来处理API签名、配置字段或绑定结构。
来源检索方式适用场景
Workers最佳实践获取
https://developers.cloudflare.com/workers/best-practices/workers-best-practices/
标准规则、模式、反模式
Workers类型查看
references/review.md
获取检索步骤
API签名、处理器类型、绑定类型
Wrangler配置 schema
node_modules/wrangler/config-schema.json
配置字段、绑定结构、允许值
Cloudflare文档使用搜索工具或访问
https://developers.cloudflare.com/workers/
API参考、兼容性日期/标识

FIRST: Fetch Latest References

第一步:获取最新参考资料

Before reviewing or writing Workers code, retrieve the current best practices page and relevant type definitions. If the project's
node_modules
has an older version, prefer the latest published version.
bash
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在审查或编写Workers代码前,先获取当前的最佳实践页面和相关类型定义。如果项目的
node_modules
中是旧版本,优先使用最新发布的版本
bash
undefined

Fetch latest workers types

获取最新workers types

mkdir -p /tmp/workers-types-latest &&
npm pack @cloudflare/workers-types --pack-destination /tmp/workers-types-latest &&
tar -xzf /tmp/workers-types-latest/cloudflare-workers-types-*.tgz -C /tmp/workers-types-latest
mkdir -p /tmp/workers-types-latest &&
npm pack @cloudflare/workers-types --pack-destination /tmp/workers-types-latest &&
tar -xzf /tmp/workers-types-latest/cloudflare-workers-types-*.tgz -C /tmp/workers-types-latest

Types at /tmp/workers-types-latest/package/index.d.ts

类型文件路径:/tmp/workers-types-latest/package/index.d.ts

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Reference Documentation

参考文档

  • references/rules.md
    — all best practice rules with code examples and anti-patterns
  • references/review.md
    — type validation, config validation, binding access patterns, review process
  • references/rules.md
    — 包含所有最佳实践规则及代码示例和反模式
  • references/review.md
    — 类型验证、配置验证、绑定访问模式、审查流程

Rules Quick Reference

规则速查

Configuration

配置

RuleSummary
Compatibility dateSet
compatibility_date
to today on new projects; update periodically on existing ones
nodejs_compatEnable the
nodejs_compat
flag — many libraries depend on Node.js built-ins
wrangler typesRun
wrangler types
to generate
Env
— never hand-write binding interfaces
SecretsUse
wrangler secret put
, never hardcode secrets in config or source
wrangler.jsoncUse JSONC config for non-secret settings — newer features are JSON-only
规则概述
Compatibility date新项目将
compatibility_date
设置为当前日期;现有项目定期更新该字段
nodejs_compat启用
nodejs_compat
标识——许多库依赖Node.js内置功能
wrangler types运行
wrangler types
生成
Env
——切勿手动编写绑定接口
密钥使用
wrangler secret put
,切勿在配置或源码中硬编码密钥
wrangler.jsonc对非敏感设置使用JSONC格式配置——新特性仅支持JSON格式

Request & Response Handling

请求与响应处理

RuleSummary
StreamingStream large/unknown payloads — never
await response.text()
on unbounded data
waitUntilUse
ctx.waitUntil()
for post-response work; do not destructure
ctx
规则概述
流处理对大体积/未知大小的负载使用流处理——切勿在无限制数据上执行
await response.text()
waitUntil使用
ctx.waitUntil()
处理响应后的任务;不要解构
ctx

Architecture

架构

RuleSummary
Bindings over RESTUse in-process bindings (KV, R2, D1, Queues) — not the Cloudflare REST API
Queues & WorkflowsMove async/background work off the critical path
Service bindingsUse service bindings for Worker-to-Worker calls — not public HTTP
HyperdriveAlways use Hyperdrive for external PostgreSQL/MySQL connections
规则概述
优先使用绑定而非REST使用进程内绑定(KV、R2、D1、Queues)——而非Cloudflare REST API
队列与工作流将异步/后台工作移出关键路径
服务绑定Worker间调用使用服务绑定——而非公开HTTP调用
Hyperdrive外部PostgreSQL/MySQL连接始终使用Hyperdrive

Observability

可观测性

RuleSummary
Logs & TracesEnable
observability
in config with
head_sampling_rate
; use structured JSON logging
规则概述
日志与追踪在配置中启用
observability
并设置
head_sampling_rate
;使用结构化JSON日志

Code Patterns

代码模式

RuleSummary
No global request stateNever store request-scoped data in module-level variables
Floating promisesEvery Promise must be
await
ed,
return
ed,
void
ed, or passed to
ctx.waitUntil()
规则概述
无全局请求状态切勿在模块级变量中存储请求作用域的数据
浮动Promise每个Promise必须被
await
return
void
,或传递给
ctx.waitUntil()

Security

安全

RuleSummary
Web CryptoUse
crypto.randomUUID()
/
crypto.getRandomValues()
— never
Math.random()
for security
No passThroughOnExceptionUse explicit try/catch with structured error responses
规则概述
Web Crypto使用
crypto.randomUUID()
/
crypto.getRandomValues()
——切勿用
Math.random()
处理安全相关场景
禁止passThroughOnException使用显式try/catch并返回结构化错误响应

Anti-Patterns to Flag

需要标记的反模式

Anti-patternWhy it matters
await response.text()
on unbounded data
Memory exhaustion — 128 MB limit
Hardcoded secrets in source or configCredential leak via version control
Math.random()
for tokens/IDs
Predictable, not cryptographically secure
Bare
fetch()
without
await
or
waitUntil
Floating promise — dropped result, swallowed error
Module-level mutable variables for request stateCross-request data leaks, stale state, I/O errors
Cloudflare REST API from inside a WorkerUnnecessary network hop, auth overhead, added latency
ctx.passThroughOnException()
as error handling
Hides bugs, makes debugging impossible
Hand-written
Env
interface
Drifts from actual wrangler config bindings
Direct string comparison for secret valuesTiming side-channel — use
crypto.subtle.timingSafeEqual
Destructuring
ctx
(
const { waitUntil } = ctx
)
Loses
this
binding — throws "Illegal invocation" at runtime
any
on
Env
or handler params
Defeats type safety for all binding access
as unknown as T
double-cast
Hides real type incompatibilities — fix the design
implements
on platform base classes (instead of
extends
)
Legacy — loses
this.ctx
,
this.env
. Applies to DurableObject, WorkerEntrypoint, Workflow
env.X
inside platform base class
Should be
this.env.X
in classes extending DurableObject, WorkerEntrypoint, etc.
反模式影响
在无限制数据上执行
await response.text()
内存耗尽——Workers内存限制为128MB
源码或配置中硬编码密钥凭证通过版本控制泄露
使用
Math.random()
生成令牌/ID
可预测,不具备密码学安全性
未加
await
waitUntil
的裸
fetch()
浮动Promise——结果丢失,错误被吞掉
使用模块级可变变量存储请求状态请求间数据泄露、状态过期、I/O错误
在Worker内部调用Cloudflare REST API不必要的网络跳转、认证开销、延迟增加
ctx.passThroughOnException()
作为错误处理方式
隐藏bug,无法调试
手动编写
Env
接口
与实际Wrangler配置绑定产生偏差
直接字符串比较密钥值计时侧信道风险——使用
crypto.subtle.timingSafeEqual
解构
ctx
const { waitUntil } = ctx
丢失
this
绑定——运行时抛出"Illegal invocation"错误
Env
或处理器参数上使用
any
破坏所有绑定访问的类型安全
使用
as unknown as T
双重类型转换
隐藏真实的类型不兼容问题——应修复设计
对平台基类使用
implements
(而非
extends
遗留用法——丢失
this.ctx
this.env
。适用于DurableObject、WorkerEntrypoint、Workflow
在平台基类内部使用
env.X
对于继承自DurableObject、WorkerEntrypoint等的类,应使用
this.env.X

Review Workflow

审查流程

  1. Retrieve — fetch latest best practices page, workers types, and wrangler schema
  2. Read full files — not just diffs; context matters for binding access patterns
  3. Check types — binding access, handler signatures, no
    any
    , no unsafe casts (see
    references/review.md
    )
  4. Check config — compatibility_date, nodejs_compat, observability, secrets, binding-code consistency
  5. Check patterns — streaming, floating promises, global state, serialization boundaries
  6. Check security — crypto usage, secret handling, timing-safe comparisons, error handling
  7. Validate with tools
    npx tsc --noEmit
    , lint for
    no-floating-promises
  8. Reference rules — see
    references/rules.md
    for each rule's correct pattern
  1. 检索 — 获取最新的最佳实践页面、Workers类型和Wrangler schema
  2. 阅读完整文件 — 不要只看差异;绑定访问模式需要上下文信息
  3. 检查类型 — 绑定访问、处理器签名、无
    any
    类型、无不安全类型转换(详见
    references/review.md
  4. 检查配置 — compatibility_date、nodejs_compat、可观测性、密钥、绑定与代码的一致性
  5. 检查模式 — 流处理、浮动Promise、全局状态、序列化边界
  6. 检查安全 — 加密使用、密钥处理、计时安全比较、错误处理
  7. 工具验证 — 运行
    npx tsc --noEmit
    ,使用lint检查
    no-floating-promises
  8. 参考规则 — 查看
    references/rules.md
    获取各规则的正确模式

Scope

适用范围

This skill covers Workers-specific best practices and code review. For related topics:
  • Durable Objects: load the
    durable-objects
    skill
  • Workflows: see Rules of Workflows
  • Wrangler CLI commands: load the
    wrangler
    skill
本技能涵盖Workers专属的最佳实践和代码审查。相关主题请参考:
  • Durable Objects:加载
    durable-objects
    技能
  • Workflows:查看Rules of Workflows
  • Wrangler CLI命令:加载
    wrangler
    技能

Principles

原则

  • Be certain. Retrieve before flagging. If unsure about an API, config field, or pattern, fetch the docs first.
  • Provide evidence. Reference line numbers, tool output, or docs links.
  • Focus on what developers will copy. Workers code in examples and docs gets pasted into production.
  • Correctness over completeness. A concise example that works beats a comprehensive one with errors.
  • 确保准确:标记问题前先检索信息。若对API、配置字段或模式不确定,先获取文档内容。
  • 提供依据:引用行号、工具输出或文档链接。
  • 聚焦开发者会复制的内容:示例和文档中的Workers代码会被直接复制到生产环境。
  • 正确性优先于完整性:一个简洁可运行的示例胜过包含错误的全面示例。