content-hash-cache-pattern

File processing results are cached by computing a SHA-256 content hash to generate stable, path-independent cache keys. This approach auto-invalidates cache entries when the underlying file content changes, ensuring only fresh results are served.

File caches break on renames because path-based keys change when the location changes. Content-hash caching solves this by using SHA-256 hashes of the file content itself, making cache keys completely path-independent and resilient to renames.

Auto-invalidation is achieved by using a SHA-256 content hash as the cache key. When the file content changes, the hash changes, naturally producing a new key and bypassing stale cache entries without manual cleanup or explicit expiration logic.

Caching logic is wrapped in a separate service layer while core processing logic remains pure. This single responsibility principle separation keeps business logic clean and allows an optional cache toggle to disable caching without affecting the core functionality.

Yes, the service layer wrapper includes an optional cache toggle allowing you to disable caching without modifying core logic. This keeps processing functions pure while controlling cache behavior externally during development or debugging.

Content-hash caching is less effective when processing extremely large files where computing SHA-256 hashes becomes a bottleneck, or when files change so frequently that cache hit rates remain low and the hashing overhead outweighs the processing savings.