content-hash-cache-pattern

Cache file processing results using SHA-256 content hashes as cache keys instead of file paths. Content identity remains stable across moves and renames, automatically invalidating the cache only when the file's actual data changes.

Use a content-hash caching pattern to avoid reprocessing large PDFs and images. A wrapper service checks a JSON cache store keyed by SHA-256 hash, returning cached results on hits and invoking your pure extractor function only on misses.

Content-hash caching keeps the processing function pure by separating concerns. A dedicated wrapper service manages cache hits, misses, and JSON storage, while your extractor function solely processes file data without handling cache logic.

The file-based cache stores each entry as a JSON file named by the content hash, featuring lazy directory creation. It performs corruption-tolerant reads to gracefully handle and bypass corrupted cache files without crashing the workflow.

No specific database is required; the pattern uses a configurable cache directory for file-based storage. You only need a pure extractor function and the wrapper service to manage the JSON cache store using a local directory.