content-hash-cache-pattern

You can cache expensive file processing results by generating a SHA-256 content hash of your files and storing the processed output as a {hash}.json file in a cache directory. This ensures O(1) lookup and prevents redundant work across multiple pipeline runs.

File caches often miss on rename because they use file paths as keys. Content-hash caching generates a SHA-256 hash from the actual file bytes, ensuring cache hits even after a file is moved or renamed within your pipeline.

The best way to cache PDF and image text extraction is to use a content-hash key based on the file's SHA-256 hash. Results are serialized as JSON files, allowing subsequent batch runs to skip already processed documents instantly.

SHA-256 content hashing for JSON caching works by reading the file's bytes to compute a unique hash string. This hash becomes the filename for a JSON file containing the extracted data, providing a reliable and corruption-resistant cache key.

Yes, you can apply a service-layer wrapper around your pure extraction function. This wrapper transparently intercepts calls to check the content-hash cache before processing and updates it with new JSON entries only when needed.

A limitation of content-hash caching is that it requires reading the entire file to compute the SHA-256 hash before checking the cache. For extremely large files, this initial hashing step still incurs I/O costs even when a cache hit occurs.