Struct HttpCache 

pub struct HttpCache { /* private fields */ }

HTTP cache with ETag and Last-Modified validation.

Implements RFC 7232 conditional requests to minimize network traffic. All responses are cached with their validation headers, and subsequent requests use If-None-Match (ETag) or If-Modified-Since headers to check for updates.

The cache uses Bytes for response bodies, enabling efficient sharing of cached data across multiple consumers without copying. Bytes is an Arc-like type optimized for network I/O.

Examples

use deps_core::cache::HttpCache;

let cache = HttpCache::new();

// First request - fetches from network
let data1 = cache.get_cached("https://index.crates.io/se/rd/serde").await?;

// Second request - uses conditional GET (304 Not Modified if unchanged)
let data2 = cache.get_cached("https://index.crates.io/se/rd/serde").await?;

Implementations

impl HttpCache

pub fn new() -> HttpCache

Creates a new HTTP cache with default configuration.

The cache uses a configurable timeout for all requests and identifies itself with an auto-versioned user agent.

pub async fn get_cached(&self, url: &str) -> Result<Bytes, DepsError>

Retrieves data from URL with intelligent caching.

On first request, fetches data from the network and caches it. On subsequent requests, performs a conditional GET request using cached ETag or Last-Modified headers. If the server responds with 304 Not Modified, returns the cached data. Otherwise, fetches and caches the new data.

If the conditional request fails due to network errors, falls back to the cached data (stale-while-revalidate pattern).

Returns

Returns Bytes containing the response body. Multiple calls for the same URL return cheap clones (reference counting) without copying data.

Errors

Returns DepsError::RegistryError if the initial fetch fails or if no cached data exists and the network is unavailable.

Examples

let cache = HttpCache::new();
let data = cache.get_cached("https://example.com/api/data").await?;
println!("Fetched {} bytes", data.len());

pub fn clear(&self)

Clears all cached entries.

This removes all cached responses, forcing the next request for any URL to fetch fresh data from the network.

pub fn len(&self) -> usize

Returns the number of cached entries.

pub fn is_empty(&self) -> bool

Returns true if the cache contains no entries.

Trait Implementations

impl Default for HttpCache

fn default() -> HttpCache

Returns the “default value” for a type.