NestJS File Uploads

Secure file handling, Validation, and S3 streaming.

majiayu000 7bb4e53 2 files · 1.5 KB Updated 567 repo stars

File contents

File Upload Patterns

Priority: P0 (FOUNDATIONAL)

Secure file upload handling with validation and storage patterns.

  • 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.

majiayu000/claude-skill-registry-data/tree/main/development/file-uploads commit 7bb4e53058

Frequently asked questions

npx skillmds add majiayu000/nestjs-file-uploads