File Upload Handling Node.js (Multer — recommended) Memory storage (for cloud forwarding) Python (FastAPI) Java (Spring Boot) Spring config: File Validation Beyond MIME Anti-Patterns | Anti-Pattern | Fix | |--------------|-----| | Trust client MIME type only | Validate magic bytes with | | Original filename as storage key | Use UUID to prevent path traversal and collisions | | No file size limit | Always set | | Sync disk writes on upload | Use streams or async writes | | Storing uploads in app directory | Use separate or cloud storage | | No cleanup of temp files | Implement lifecycle/cron c…