Module proxy_cache 

Response caching (proxy-cache), ported from APISIX’s apisix/plugins/proxy-cache.

Serving a cached response means looking up the cache before the upstream call and storing the fresh response after it — two moments a single featherbit node cannot span. The behavior is expressed as a pair of nodes sharing one cache, linked by a required id:

• a lookup node placed before upstream, which serves a cache hit straight to the client (short-circuiting the upstream call), and
• a store node placed after upstream, which caches a fresh response for later hits.

Both nodes derive the cache key identically from the same cache_key template and the request, and share one namespace via id, so they always agree. State lives in crate::traffic::CacheRegistry.

Wiring

           ┌──────────────────┐        ┌──────────┐        ┌──────────────────┐
 listener →│ proxy-cache      │success →│ upstream │success →│ proxy-cache      │→ client
           │  (phase=lookup)  │        │          │        │  (phase=store)   │
           └──────────────────┘        └──────────┘        └──────────────────┘
                   │ error                                    (caches responses
                   ▼                                        whose status is cacheable)
              client.in
        (cached response, HIT)

On a hit, the lookup node writes the cached response onto the context, adds featherbit-cache-status: HIT, and fails with PROXY_CACHE_HIT — its error port goes to client.in, delivering the cached response without touching the upstream. On a miss it passes through; the store node then caches the upstream response and marks it featherbit-cache-status: MISS.

Structs

ProxyCachePlugin

One node of a proxy-cache lookup/store pair.

Enums

Role 🔒

Which half of the pair this node is.

Constants

CACHE_STATUS_HEADER 🔒

Header written by both nodes to report the cache outcome.

HIDDEN_HEADERS 🔒

Response headers hidden from clients when hide_cache_headers is set.

Functions

parse_statuses 🔒

Reads a Vec<u16> of HTTP statuses from a JSON array, if present and valid.