Add preview endpoint for custom section builder and rule evaluation:
Handler Implementation (internal/handlers/collections.go):
- PreviewCollection method: Evaluates filter rules and returns matching items without saving
* Accepts library_id, rules array, manual_book_ids array, and limit
* Evaluates rules against all library items using collectionService.EvaluateRules
* Adds manually selected books to results
* Deduplicates manual books (avoids adding same book twice)
* Applies limit (default: 20, max: 100)
* Returns array of BookInfo with matching items
- Helper function: mediaItemsToListMediaItemsRow
* Converts database.MediaItems to database.ListMediaItemsRow
* Required for EvaluateRules which expects ListMediaItemsRow type
Route Registration (internal/router/collections.go):
- POST /api/collections/preview
- Protected by JWT middleware
- Part of collections API group
Why This Endpoint is Necessary:
- Allows users to see what books match their filter rules BEFORE saving
- Avoids creating incorrect collections
- Enables testing different rule combinations quickly
- Reuses existing service logic (collectionService.EvaluateRules)
- Client-side preview would require downloading entire library (10,000+ books)
- Would duplicate 500+ lines of rule evaluation logic in TypeScript
- Would create maintenance nightmare keeping Go and TypeScript in sync
Bruno Test (bruno/collections/preview-collection.bru):
- Tests POST /api/collections/preview endpoint
- Validates status 200 response
- Validates items array in response
- Example request with genre filter rule
This endpoint is required for both the web UI Custom Section Builder and future mobile apps.