Summary

Next.js keys its response cache by pathname, so every host an app serves shares one entry. Cloudflare Workers Cache keys an entry by its path and query, entrypoint, ctx.props and Worker version, not by host. But vinext put the request's full URL, host included, into its __vinext_cache_key digest and into the ctx.props it passed the cached entrypoint. So every host filled and stored its own copy of each page.

The Workers Cache adapter now declares responseStageCacheIdentity: "host-free". Core gives it the same host-free identity the Response Store gets (the canonical cache identity origin, or a Pages page's configured i18n domain), but keeps every dispatch's query. Workers Cache keys the dispatched query itself, and the render needs it, so the App page query-free identity stays Response Store only. The manifest-based query-free dispatch for static-candidate App pages is unchanged.

On a shared dispatch with an identity:

• The gateway puts the identity's props and URL into the ctx.props and the digest it keys by.
• The host-bearing props (requestOrigin, requestUrl, requestHost) and the real request URL go in an internal header that Workers Cache doesn't key. The gateway strips that header from public requests.
• The cached entrypoint restores those fields before rendering, so a cold render or the edge's background refresh sees the real host.
• An identity invocation without a valid restore, or one whose restore names another path or query, fails closed with a 400 no-store.
• If an identity differs from its dispatch in anything but those host fields, the dispatch keys itself as before.

Cloudflare also keys a few headers that name another host, such as X-Forwarded-Host. A proxy in front of the Worker that sets one still gets an entry per forwarded host; the docs say so.

Workers Cache warms what its cacheability probe finds cacheable. A probe dispatch bypasses the shared transport, so it never marked a Pages page as shared across hosts, and the render-time check that refuses a shared entry for a page whose getInitialProps an imported wrapper attaches only ran during admission. Warming then waited forever for an entry that page's shared dispatch never stores. A probe now marks the page shared across hosts, as its shared dispatch is, and that check marks the render dynamic (Next.js doesn't treat a getInitialProps page as static), in probes and admission alike.

The same admission rules as the Response Store apply. A render that reads the host is dynamic and isn't stored. Per-request Pages responses (getServerSideProps, API routes, pages whose getInitialProps runs) keep the host in their keys under an explicit CDN policy, as a CDN in front of Next.js would. docs/caching.mdx now describes Workers Cache together with the Response Store.

Tests

• Unit (tests/cloudflare-cdn-worker.test.ts):
  • An App and a Pages host-free identity get one ctx.props, digest and path for two hosts, and each render sees its own host and URL.
  • An identity that names another path or query, or drops a prop other than the host, isn't used.
  • The entrypoint refuses a missing, malformed, other-page or non-host restore.
  • The gateway strips a forged restore header.
  • These fail on the pre-fix worker.
• Request stages:
  • tests/app-rsc-handler.test.ts: a host-free App page identity keeps the query and selector headers.
  • tests/pages-request-worker-stage.test.ts: the static Pages identity test now runs for both identity kinds.
  • Probes of a page shared across hosts, Pages-only and hybrid, carry sharedAcrossHosts without a cache identity. The hybrid bridge marks such a getInitialProps render dynamic in admit and probe modes.
• Deployed e2e (tests/e2e/cloudflare-workers/cache-prewarm.spec.ts, workers-cache job):
  • The PR's preview alias (pr-<n>-workers-cache) and its Version URL are two hosts of one uploaded version. A new demo route, /api/worker-version, reports the version id.
  • An App page, a getStaticProps page and an ISR route handler filled on the alias host are a HIT, with the same render, on the Version URL host.
  • The test doesn't compare a Version URL with production traffic. On the deployed prewarm Worker, a Version URL never reached the entries that production requests filled. Cloudflare's docs don't say whether those share a cache.
  • A getInitialProps page that echoes the host always shows each host its own.
• Local Response Store e2e still passes (55/55). Local wrangler dev doesn't emulate Workers Cache, so the deployed job is the e2e proof.