itsual File Uploads and Storage
Overview
File handling involves security, performance, cost, and user experience trade-offs. Prefer direct-to-storage patterns for larger files.
When to Use
- Implementing file or image uploads
- Integrating with S3/GCS/Azure Blob or similar
- Reviewing security of existing upload flows
Key Practices
- Validate file type, size, and content where appropriate
- Prefer pre-signed URLs / direct uploads for large files
- Store metadata in your database; store blobs in object storage
- Apply least-privilege access controls and short-lived credentials
- Plan for virus scanning, image processing, or async pipelines if needed
- Define retention and deletion policies (including GDPR-style erasure)
- Use CDNs for frequently accessed public assets
Security Checklist
- Content-type and size limits enforced
- Files are not executable in dangerous contexts
- Access is authorized on every download/view
- Secrets are not required in the browser for private files
Verification
- Upload and download paths are secure and performant
- Orphaned files and storage costs are manageable
- Deletion/retention works as specified