eve.aio.dns_cache

DNS cache with TTL-based expiration.

Caches successful and negative DNS results with configurable TTL bounds. Designed to wrap DnsResolver — check the cache before calling resolve(), and store results on completion.

Thread safety: cache access must happen on the event loop thread only. For cross-thread access, wrap calls with external synchronization.

Example:

auto cache = DnsCache.create();
scope (exit) cache.dispose();

// Before resolving:
auto cached = cache.lookup("example.com");
if (cached.length > 0) {
    // use cached addresses
} else {
    resolver.resolve("example.com", (ref l, t, addrs, err) @safe nothrow {
        if (err == DnsError.OK) {
            cache.store("example.com", addrs, 300); // TTL 300s
        } else if (err == DnsError.NONAME) {
            cache.storeNegative("example.com", 60); // negative TTL 60s
        }
    });
}