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Backdrift provides secure file storage for uploads like profile pictures, documents, and attachments.

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Defining Storage

Describe what files you need to store: 
"Users can upload profile pictures."

"Tasks can have file attachments (PDFs, images, documents)."

"Products have multiple gallery images."

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How It Works

  1. Client requests a signed upload URL
  2. Client uploads directly to storage (not through your API)
  3. Client saves the file reference to the entity
  4. Files are retrieved via signed URLs or CDN

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Upload Flow

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1. Request Upload URL

POST /v1/tasks/{taskId}/attachments/upload-url
{
  "filename": "report.pdf",
  "contentType": "application/pdf"
}
Response: 
{
  "uploadUrl": "https://s3.amazonaws.com/bucket/...",
  "fileKey": "attachments/task-123/report.pdf",
  "expiresIn": 3600
}

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2. Upload File

curl -X PUT "${uploadUrl}" \
  -H "Content-Type: application/pdf" \
  --data-binary @report.pdf

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3. Save Reference

PATCH /v1/tasks/{taskId}
{
  "attachment_key": "attachments/task-123/report.pdf"
}

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Download Flow

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Get Signed URL

GET /v1/tasks/{taskId}/attachments/{fileKey}/download-url
Response: 
{
  "downloadUrl": "https://s3.amazonaws.com/bucket/...",
  "expiresIn": 3600
}

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File Restrictions

Configure allowed file types and sizes: 
"Attachments can be PDFs, images, or documents up to 10MB."

"Profile pictures must be images under 2MB."
This generates:
  • Content-type validation
  • File size limits
  • Optional virus scanning

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Storage Configuration

Backdrift configures storage with security best practices:
SettingDefault
EncryptionServer-side (AES-256)
VersioningDisabled
Public accessBlocked
CORSConfigured for your domain
LifecycleNo automatic deletion

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Lifecycle Policies

Configure automatic cleanup: 
"Delete attachments 90 days after the task is completed."

"Move old files to cheaper storage after 30 days."

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CDN (Optional)

For public files (like product images), enable CDN: 
"Product images should be served from a CDN for fast loading."
This creates a CloudFront distribution with:
  • Global edge caching
  • HTTPS
  • Automatic compression
  • Custom domain support

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Image Processing

For images, you can request transformations: 
"Generate thumbnails for uploaded images."

"Resize profile pictures to 200x200."

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Multi-Tenant Storage

In multi-tenant mode, files are isolated by organization: 
files/
├── org-123/
│   ├── tasks/
│   └── users/
├── org-456/
│   ├── tasks/
│   └── users/
A user from Org-123 cannot access files from Org-456.

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Security

All uploads and downloads use time-limited signed URLs. Direct bucket access is blocked.
Files are encrypted at rest using AES-256 server-side encryption.
Optional: Scan uploads for malware before accepting.
File access follows the same authorization rules as your entities.

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Example: Document Management

"A document management system where:
- Documents belong to folders
- Users can upload files (PDFs, Word, Excel) up to 50MB
- Documents have version history
- Deleted documents are retained for 30 days before permanent deletion"
This generates:
  • S3 bucket with versioning enabled
  • 30-day lifecycle policy for deleted objects
  • Signed URLs for secure upload/download
  • Content-type validation

Lovable Integration

Learn how to build frontends with file uploads in Lovable.