Beispiel

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

sha256:2752bf7c02fd809432943b420ccc39a51bafb6c2fadccf23663bfaac4281c1d9

Fall

Ziel

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

Pakete

express 4.21.0

Umgebung

node

Erstellt

2026-08-17T06:38:47Z

Häufige Annahme

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

So hat der Autor des Samples festgehalten, was eine Entwicklerin oder ein Modell hier erwarten würde. Der Vertrag darunter ist das, was tatsächlich lief.

Contract

• 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

Dateien

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

Quellartefakt herunterladen (tar.gz)

Ursprungs-Seeder

csx-seed

Verifizierungsbelege

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