asset-fingerprint-cache

name	asset-fingerprint-cache
description	Track generated media assets with stable file fingerprints so caches, previews, and downstream consumers can tell when storyboards, videos, thumbnails, or design assets actually changed.

Asset Fingerprint Cache

Use When

• Generated media files are reused across preview, render, or review flows.
• You need a lightweight way to detect whether assets changed.
• Cache busting or downstream invalidation depends on file updates.

Core Rule

• Cache identity should come from the asset file state, not guesswork.

Inputs

• project path
• asset directories to scan: storyboards, videos, thumbnails, characters, scenes, props
• optional root-level media files

Outputs

• mapping of relative asset paths to fingerprints
• change detection signal for cache busting or selective reruns

Workflow

1. Scan the known media directories.
2. Collect a stable lightweight fingerprint per file: mtime-based is acceptable when content hashing is unnecessary.
3. Exclude version-history directories from the live fingerprint map.
4. Expose the fingerprint map to preview, cache, or invalidation logic.
5. Recompute cheaply after writes rather than doing expensive deep hashes by default.

Good Uses

• bust preview URLs when a storyboard changes
• detect that a generated clip or thumbnail was updated
• know whether downstream compose or publish surfaces should refresh

Bad Uses

• treating temp files as permanent cache keys
• scanning archived version directories as if they were live assets
• using heavyweight hashing where mtime-level invalidation is enough

Pair With

• Use with generated-asset-versioning for tracked asset history.
• Use with partial-regeneration to decide what truly changed in a rerun.

Aggregated From

• ArcReel/ArcReel asset_fingerprints.py
• generated-media project cache-busting patterns

Validation Checklist

• Fingerprints cover the live media directories.
• Version-history folders are excluded from the live cache map.
• Changed assets get new fingerprints promptly.
• Fingerprints are cheap enough to recompute frequently.