Hybrid Cache Server

A small Rust service that acts as a Chrome-aware cache indexing server:

• RocksDB for persistent storage
• DashMap as an in-memory cache
• Meilisearch for index lookups
• Deduped file bodies so shared assets (e.g. CDNs like jQuery) are stored once and reused across websites

You send it HTTP responses (with your own resource_key / website_key) and it:

• Stores the metadata + body
• Deduplicates the body via a content hash
• Indexes metadata in Meilisearch
• Lets you quickly retrieve:
  • a single resource by resource_key
  • all resources for a given website by website_key

Data Model

Keys

• website_key
  Represents a site-level identifier. Examples:

  • "example.com"
  • "https://example.com"

  This is used to group resources so you can ask: “give me everything for this website”.

• resource_key
  A unique cache key per resource (you generate this on the producer side, typically from your put_hybrid_cache logic).

  Examples:

  • GET::https://example.com/
  • GET::https://example.com/style.css
  • GET::https://cdn.example.com/jquery.js::Accept:text/javascript

  Whatever you use here must match the key you pass to put_hybrid_cache(cache_key, ...).

• file_id
  Internally computed as blake3(body_bytes) and hex-encoded.
  All bodies with the same content share the same file_id and are stored once in RocksDB.

RocksDB Key Layout

Internally we use these key prefixes:

• file:{file_id} → JSON-encoded FileEntry (the raw body bytes)
• res:{resource_key} → JSON-encoded ResourceEntry (metadata, including file_id)
• site:{website_key}::{resource_key} → empty value used as an index to quickly scan all resources for a site

This layout lets us:

• Deduplicate file content (file:{file_id} reused across many resources)
• Quickly find all resource_keys for a given website_key via prefix iteration

HTTP API

All endpoints are under /cache/*.

1. POST /cache/index

Index a single resource (one HTTP response).

Request

• Headers:

  • Optional: X-Cache-Site: example.com
    Overrides/sets website_key if present.

• Body: JSON CachedEntryPayload:

{
  "website_key": "example.com",          // optional; can come from header or derived from URL
  "resource_key": "GET::https://example.com/style.css",
  "url": "https://example.com/style.css",
  "method": "GET",
  "status": 200,
  "request_headers": {
    "Accept": "text/css"
  },
  "response_headers": {
    "Content-Type": "text/css; charset=utf-8"
  },
  "body_base64": "LyogY3NzIGJvZHkgKi8K"
}