| name | lgs-1920-backend-video-conversion |
| description | Maintain LGS1920 FFmpeg video conversion jobs, multipart input parsing, progress polling and SSE, downloads, cancellation, temporary files, cleanup, and conversion error handling. Use when changing ConvertVideoController.js, conversions.js, or ConvertVideoResource.js. |
LGS1920 Backend Video Conversion
Use this skill for asynchronous conversion jobs exposed by the /convert API. Preserve the job lifecycle and make cleanup correct on success, failure, cancellation, disconnect, and restart.
Workflow
- Inspect
ConvertVideoController.js, src/controllers/conversions.js, ConvertVideoResource.js, and the Studio conversion client before editing.
- Define the accepted multipart fields, formats, codecs, limits, output naming, and response headers at the request boundary.
- Keep conversion state transitions explicit: accepted, running, completed, failed, cancelled, downloaded, and cleaned up.
- Spawn FFmpeg through the existing Bun integration. Do not interpolate unvalidated user input into shell commands or command strings.
- Keep progress polling and SSE consistent, heartbeat connections, handle disconnects, and do not leak internal process errors.
- Resolve input and output paths inside the controlled temporary directory. Clean up on every terminal path and avoid deleting active jobs.
- Make cancellation idempotent and ensure a late FFmpeg event cannot revive a cancelled or cleaned-up conversion.
- Add focused tests for validation, progress, cancellation, download headers, stale cleanup, process failure, and temporary-file cleanup.
Safety and reliability
- Enforce file size, duration, format, and resource limits before starting expensive work.
- Keep conversion IDs opaque and do not use user-provided names as identifiers.
- Do not include full local paths, command arguments, or raw FFmpeg stderr in public responses.
- Dispose of timers, streams, process listeners, and SSE controllers on every exit path.
- Preserve the existing CORS and progress headers expected by the Studio client.
- Never run the development server manually while validating a conversion change.
