Module cache_page 

View-level caching middleware.

Wrap a [Router] subtree with cache_page and every eligible GET or HEAD response for that subtree is cached for the configured TTL. Subsequent requests for the same URI + query string get the cached response without hitting the handler.

use umbral_cache::cache_page;
use std::time::Duration;

let public = Router::new()
    .route("/", get(home))
    .route("/about", get(about))
    .layer(cache_page(Duration::from_secs(60)));

Cache key

cache:page:GET:<host>:/path?query — method + Host header + full URI including query string. Fragments are stripped by the browser and never reach the server. Including the Host header prevents multi-tenant cache-poisoning where tenant A’s cached page would otherwise be served to requests arriving on a different Host.

What gets cached

Only GET and HEAD responses with HTTP status 200 are stored. The following bypass caching:

• Any method other than GET / HEAD (POST, PUT, PATCH, DELETE).
• Status code other than 200.
• Response carries Cache-Control: no-store.
• Response carries a Set-Cookie header (the body may be personalised).
• Request carries an umbral_session cookie — personalised / logged-in requests are neither served from nor written to the page cache, keeping the cache to the safe anonymous-only subset.

Ambient cache dependency

cache_page reads the ambient super::Cache via super::ambient(). If the ambient cache has not been initialised (i.e. super::CachePlugin::init has not been called), cache misses and stores are silently skipped — the handler always fires normally. This is intentional: a misconfigured cache degrades gracefully rather than returning 500s.

Deferred

• ETag / 304 conditional caching — the current implementation always serves the full cached body. A future iteration will store and compare ETags to emit 304 Not Modified, saving bandwidth.
• Vary-header awareness (Vary: Accept-Language, etc.).
• Per-route cache key prefix customisation.

Structs

CachePageLayer

tower::Layer returned by cache_page. Wraps the inner service with CachePageService.

CachePageService

tower::Service produced by CachePageLayer.

Constants

DEFAULT_MAX_OBJECT_BYTES

Return a CachePageLayer that caches eligible GET/HEAD responses for ttl.

Functions

cache_page