Installs into .claude/skills of the current project.
Are you the author of File Uploads?
Add the live security badge to your README. It updates with every re-scan.
[](https://www.skillsdirectory.com/skills/ngxtm-file-uploads-devkit)
---
name: NestJS File Uploads
description: Secure file handling, Validation, and S3 streaming.
metadata:
labels: [nestjs, upload, multer, s3]
triggers:
files: ['**/*.controller.ts']
keywords: [FileInterceptor, Multer, S3, UploadedFile]
---
# File Upload Patterns
## Security (Input Validation)
- **Magic Bytes**: NEVER trust `content-type` header or file extension.
- **Tool**: Use `file-type` or `mmmagic` to verify the actual buffer signature.
- **Limits**: Set strict `limits: { fileSize: 5000000 }` (5MB) in Multer config to prevent DoS.
## Streaming (Scalability)
- **Memory Warning**: Default Multer `MemoryStorage` crashes servers with large files.
- **Pattern**: Use **Streaming** for any file > 10MB.
- **Library**: `multer-s3` (direct upload to bucket) or `busboy` (raw stream processing).
- **Architecture**:
1. Client requests Signed URL from API.
2. Client uploads directly to S3/GCS (Bypassing API server completely).
3. **Pro Tip**: This is the only way to scale file uploads infinitely.
## Processing
- **Async**: Don't process images/videos in the HTTP Request.
- **Flow**:
1. Upload file.
2. Push `FileUploadedEvent` to Queue (BullMQ).
3. Worker downloads, resizes/converts, and re-uploads.
