content-hash-cache-pattern

Content-hash caching prevents re-processing unchanged files by using SHA-256 file hashes as cache keys instead of file paths. This ensures cache hits work even after files are moved or renamed, automatically invalidating only when content changes.

File-based caches typically break when files are renamed because they rely on file paths as cache keys. Using SHA-256 content hashes as cache keys instead ensures your cache survives file renaming, moving, and directory changes while invalidating correctly on content updates.

You can add caching to pure processing functions without modifying their logic by implementing a separate service layer. This architectural pattern wraps your existing PDF text extraction or image analysis functions with content-hash cache lookups, preserving the original processing core.

The best way to cache expensive file operations like PDF parsing is using a file-based O(1) cache storage system keyed by SHA-256 content hashes. This eliminates the need for an external index file, preventing corruption risks while optimizing lookup speeds.

You do not need an external index file to manage cache invalidation. By storing cache entries as individual files named with their SHA-256 content hash, the system achieves O(1) lookup and automatic invalidation without the risk of index corruption.

Yes, you can use content-hash caching for CLI tools with a cache toggle option. This pattern applies to workflows where identical files are processed repeatedly across separate runs, ensuring only updated content triggers expensive text extraction or analysis operations.