Cloudflare R2 Storage

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Overview

• File upload with automatic URL generation
• Public URL access via custom domain or presigned URLs
• Automatic bucket validation
• Support for various content types

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Configuration

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Creating R2 Bucket

1. Log in to Cloudflare Dashboard
2. Navigate to R2 in the sidebar
3. Click Create bucket
4. Choose a bucket name (e.g., pos-kasir-images)
5. Select a location hint closest to your users

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Getting API Credentials

1. In R2 dashboard, click Manage R2 API Tokens
2. Click Create API token
3. Choose Object Read & Write permissions
4. Note your:
   • Access Key ID
   • Secret Access Key
   • Account ID (from R2 overview page)

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Environment Variables

# Cloudflare R2 Configuration
CLOUDFLARE_R2_ACCOUNT_ID=your_account_id
CLOUDFLARE_R2_ACCESS_KEY=your_access_key_id
CLOUDFLARE_R2_SECRET_KEY=your_secret_access_key
CLOUDFLARE_R2_BUCKET=pos-kasir-images
CLOUDFLARE_R2_PUBLIC_DOMAIN=https://images.yourdomain.com
CLOUDFLARE_R2_EXPIRY_SEC=3600

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Public Domain Setup (Optional)

1. In R2 bucket settings, click Settings
2. Under Public access, click Connect Domain
3. Enter your domain (e.g., images.yourdomain.com)
4. Add the provided DNS records to your Cloudflare DNS
5. Update CLOUDFLARE_R2_PUBLIC_DOMAIN with your domain

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Implementation Details

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Initialization

endpoint := fmt.Sprintf("%s.r2.cloudflarestorage.com", accountID)

client, err := minio.New(endpoint, &minio.Options{
    Creds:  credentials.NewStaticV4(accessKey, secretKey, ""),
    Secure: true,
})

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Uploading Files

fileURL, err := r2Client.UploadFile(
    ctx,
    "products/image-123.jpg",  // object name
    imageData,                  // file bytes
    "image/jpeg"                // content type
)

• image/jpeg - JPEG images
• image/png - PNG images
• image/webp - WebP images
• application/pdf - PDF documents

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Getting File URLs

fileURL, err := r2Client.GetFileShareLink(ctx, "products/image-123.jpg")

https://images.yourdomain.com/products/image-123.jpg

https://account-id.r2.cloudflarestorage.com/bucket/products/image-123.jpg?X-Amz-Algorithm=...

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Checking Bucket Existence

exists, err := r2Client.BucketExists(ctx)

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Usage Example

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Uploading Product Image

// Read image file
imageData, err := ioutil.ReadFile("product.jpg")
if err != nil {
    return err
}

// Upload to R2
objectName := fmt.Sprintf("products/%s.jpg", productID)
imageURL, err := r2Client.UploadFile(
    context.Background(),
    objectName,
    imageData,
    "image/jpeg",
)
if err != nil {
    return err
}

// Save imageURL to database
product.ImageURL = imageURL

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Organizing Files

• products/ - Product images
• receipts/ - Receipt PDFs or images
• logos/ - Business logos
• temp/ - Temporary uploads

objectName := fmt.Sprintf("products/%s/%s.jpg", categoryID, productID)

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Best Practices

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File Naming

// Good: unique and descriptive
fmt.Sprintf("products/%s-%s.jpg", productID, timestamp)

// Avoid: generic names that may conflict
"image.jpg"

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Content Type

contentTypes := map[string]string{
    ".jpg":  "image/jpeg",
    ".jpeg": "image/jpeg",
    ".png":  "image/png",
    ".webp": "image/webp",
    ".pdf":  "application/pdf",
}

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Error Handling

fileURL, err := r2Client.UploadFile(ctx, objectName, data, contentType)
if err != nil {
    if strings.Contains(err.Error(), "bucket") {
        // Bucket not found or access denied
    }
    if strings.Contains(err.Error(), "credentials") {
        // Invalid credentials
    }
    return err
}

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Troubleshooting

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Bucket Not Found

1. Verify bucket name in .env matches exactly (case-sensitive)
2. Check API token has access to the bucket
3. Ensure bucket is in the same account as the credentials

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Upload Failures

• Invalid credentials: Verify CLOUDFLARE_R2_ACCESS_KEY and CLOUDFLARE_R2_SECRET_KEY
• Insufficient permissions: Token needs “Object Read & Write” permission
• Wrong account ID: Verify CLOUDFLARE_R2_ACCOUNT_ID matches your R2 account

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Presigned URL Expired

1. URLs are temporary unless using public domain
2. Set up CLOUDFLARE_R2_PUBLIC_DOMAIN for permanent URLs
3. Or increase CLOUDFLARE_R2_EXPIRY_SEC (default 3600 = 1 hour)

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CORS Issues

1. In R2 bucket settings, configure CORS:

[
  {
    "AllowedOrigins": ["*"],
    "AllowedMethods": ["GET", "HEAD"],
    "AllowedHeaders": ["*"],
    "MaxAgeSeconds": 3600
  }
]

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Cost Optimization

• No egress fees - Download bandwidth is free
• $0.015/GB/month - Storage cost
• Free tier - 10GB storage included

• Storage: ~500MB = ~$0.0075/month
• Bandwidth: Unlimited downloads at no cost

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API Reference

• UploadFile(ctx, objectName, data, contentType) - Upload file and get URL
• GetFileShareLink(ctx, objectName) - Get URL for existing file
• BucketExists(ctx) - Check if bucket is accessible