content-hash-cache-pattern

You can cache file processing results by using SHA-256 content hashes as cache keys. This makes caching path-independent and auto-invalidates when file content changes, allowing cache reuse across moves and renames.

The best way to auto-invalidate cached data is using a content-hash based cache key. By hashing file contents with SHA-256, the cache automatically invalidates when the content changes, without relying on file paths.

Implement a content-hash cache by computing a SHA-256 hash for input files, storing results in file-based {hash}.json entries for O(1) lookups. A service-layer wrapper keeps processing pure while delegating caching to a separate concern.

Yes, content-hash caching works without external dependencies by using file-based cache storage. It stores results as {hash}.json entries and uses a frozen dataclass for cache entries to guarantee immutability and consistent serialization.

You use a service layer wrapper to separate concerns, keeping the file processing logic pure while delegating caching to a separate component. This ensures the processing pipeline remains clean and the cache logic is independently managed.

You should not use a content-hash approach when the caching overhead of computing SHA-256 hashes outweighs the cost of the file processing itself, or when dealing with strictly path-dependent workflows where content stability is guaranteed.