示例

Negotiate response content types with res.format, automatic Vary and Content-Type header injection, wildcard fallback, and 406 Not Acceptable error delegation

sha256:2752bf7c02fd809432943b420ccc39a51bafb6c2fadccf23663bfaac4281c1d9

案例

目标

Negotiate response content types with res.format, automatic Vary and Content-Type header injection, wildcard fallback, and 406 Not Acceptable error delegation HOW

包

express 4.21.0

环境

node

创建时间

2026-08-17T06:38:47Z

常见的想当然

res.format requires handlers to set their own Content-Type header and falls back to a 200 response or uncaught exception when the Accept header is unmatched

这是本样本作者记下的、开发者或模型在此处通常会有的预期。下面的契约才是真正运行过的东西。

契约

• res.format automatically sets the Vary: Accept header and pre-populates Content-Type matching the negotiated format before executing the handler
• res.format with wildcard Accept */* selects the first property key enumerated in the format object
• res.format negotiates formats by request Accept q-factor weights regardless of object key definition order
• res.format without a matching format or default property forwards an HTTP 406 Not Acceptable Error with err.types to next()
• res.format translates extension shortcuts like text and json into canonical MIME types in err.types
• res.format executes the default callback property when no format matches the Accept header without triggering a 406 error

文件

• NOTES.md
• csx.json
• package-lock.json
• package.json
• test/contract.mjs

下载源代码构件 (tar.gz)

原始种子者

csx-seed

验证回执

• node 22 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17 · ed25519:d91480838ac982c9