🌐 NPM Storage Package

A powerful TypeScript-based NPM package for seamless file uploads to AWS S3, Google Cloud Storage (GCS), and Azure Blob Storage with Express.js/Multer integration. One unified API for all your cloud storage needs!

🚀 Features

✅ Unified API – One consistent interface for S3, GCS, and Azure
✅ Express.js + Multer Integration – Drop-in replacement for standard multer
✅ Multiple Upload Patterns – Single file, multiple files, multiple fields
✅ TypeScript Support – Full type safety and IntelliSense
✅ Flexible Configuration – Field-specific settings and validation
✅ Production Ready – Error handling, file filtering, size limits

📦 Installation

npm install npm-storage-package multer express

yarn add npm-storage-package multer express

🔧 Quick Start

1️⃣ Basic Setup

import express from 'express';
import { StorageFactory } from 'npm-storage-package';

const app = express();

// Configure once, use everywhere
const storage = new StorageFactory({
  azure: {
    bucket: 'my-container',
    credentials: { connectionString: process.env.AZURE_CONNECTION_STRING }
  },
  s3: {
    bucket: 'my-bucket',
    region: 'us-east-1',
    credentials: {
      accessKeyId: process.env.AWS_ACCESS_KEY_ID,
      secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY
    }
  },
  gcs: {
    bucket: 'my-gcs-bucket',
    projectId: 'my-project-id',
    keyFilename: './serviceaccountkey.json'
  }
});

2️⃣ Single File Upload

app.post('/upload/single', 
  storage.azureMulter({
    destination: 'uploads/',
    generateFileName: (req, file) => `${Date.now()}-${file.originalname}`
  }).single('file'), 
  (req, res) => {
    res.json({
      success: true,
      file: {
        originalName: req.file.originalname,
        cloudUrl: req.file.path,
        cloudKey: req.file.cloudKey,
        size: req.file.size
      }
    });
  }
);

3️⃣ Multiple Files Upload

app.post('/upload/multiple', 
  storage.s3Multer({
    destination: 'gallery/',
    fileFilter: (req, file) => file.mimetype.startsWith('image/'),
    limits: { fileSize: 5 * 1024 * 1024 } // 5MB
  }).array('photos', 10), 
  (req, res) => {
    const uploadedFiles = req.files.map(file => ({
      originalName: file.originalname,
      cloudUrl: file.path,
      size: file.size
    }));
    
    res.json({
      success: true,
      totalFiles: req.files.length,
      files: uploadedFiles
    });
  }
);

4️⃣ Multiple Fields Upload

app.post('/upload/profile', 
  storage.gcsMulter({
    fieldConfigs: {
      avatar: {
        destination: 'avatars/',
        allowedExtensions: ['.jpg', '.jpeg', '.png'],
        fileSizeLimit: 2 * 1024 * 1024, // 2MB
        generateFileName: (req, file) => `avatar-${req.user.id}-${Date.now()}.jpg`
      },
      document: {
        destination: 'documents/',
        allowedExtensions: ['.pdf', '.doc', '.docx'],
        fileSizeLimit: 10 * 1024 * 1024 // 10MB
      }
    }
  }).fields([
    { name: 'avatar', maxCount: 1 },
    { name: 'document', maxCount: 3 }
  ]), 
  (req, res) => {
    res.json({
      success: true,
      files: {
        avatar: req.files.avatar?.[0]?.path,
        documents: req.files.document?.map(f => f.path)
      }
    });
  }
);

📚 API Reference

StorageFactory Class

The main class for creating configured storage instances.

const storage = new StorageFactory({
  azure?: AzureConfig,
  s3?: S3Config,
  gcs?: GCSConfig
});

Provider Methods

Each provider has a unified method that returns a configured multer instance:

storage.azureMulter(options)

storage.s3Multer(options)

storage.gcsMulter(options)

Upload Options

| Option | Type | Description | |--------|------|-------------| | destination | string | Upload destination path | | generateFileName | Function | Custom filename generator | | fileFilter | Function | File validation function | | limits | Object | File size/count limits | | fieldConfigs | Object | Field-specific configurations |

Field Configuration

For multiple fields upload, each field can have:

| Option | Type | Description | |--------|------|-------------| | destination | string | Field-specific upload path | | allowedExtensions | string[] | Allowed file extensions | | fileSizeLimit | number | Maximum file size in bytes | | generateFileName | Function | Custom filename for this field |

🔧 Configuration

Azure Blob Storage

azure: {
  bucket: 'container-name',
  credentials: {
    connectionString: 'DefaultEndpointsProtocol=https;AccountName=...'
  }
}

AWS S3

s3: {
  bucket: 'bucket-name',
  region: 'us-east-1',
  credentials: {
    accessKeyId: 'AKIA...',
    secretAccessKey: 'your-secret-key'
  }
}

Google Cloud Storage

// Option 1: Service Account Key File
gcs: {
  bucket: 'bucket-name',
  projectId: 'your-project-id',  // or auto-extracted from key file
  keyFilename: './path/to/serviceaccountkey.json'
}

// Option 2: JSON Credentials
gcs: {
  bucket: 'bucket-name',
  credentials: {
    // Service account JSON object
    type: 'service_account',
    project_id: 'your-project-id',
    private_key: '-----BEGIN PRIVATE KEY-----\n...',
    client_email: '[email protected]'
    // ... other fields
  }
}

💡 Advanced Examples

Custom File Validation

const imageUpload = storage.s3Multer({
  destination: 'images/',
  fileFilter: (req, file) => {
    // Only allow images
    if (!file.mimetype.startsWith('image/')) {
      throw new Error('Only image files are allowed');
    }
    
    // Custom validation logic
    if (file.originalname.length > 100) {
      throw new Error('Filename too long');
    }
    
    return true;
  },
  generateFileName: (req, file) => {
    const userId = req.user?.id || 'anonymous';
    const timestamp = Date.now();
    const extension = file.originalname.split('.').pop();
    return `${userId}-${timestamp}.${extension}`;
  }
});

app.post('/upload/image', imageUpload.single('image'), handler);

Dynamic Configuration

function createDynamicUpload(provider) {
  const configs = {
    azure: storage.azureMulter({ destination: 'azure-uploads/' }),
    s3: storage.s3Multer({ destination: 's3-uploads/' }),
    gcs: storage.gcsMulter({ destination: 'gcs-uploads/' })
  };
  
  return configs[provider];
}

app.post('/upload/:provider', (req, res, next) => {
  const upload = createDynamicUpload(req.params.provider);
  upload.single('file')(req, res, next);
}, handler);

Error Handling

app.use((error, req, res, next) => {
  if (error.code === 'LIMIT_FILE_SIZE') {
    return res.status(400).json({
      success: false,
      error: 'File too large'
    });
  }
  
  if (error.code === 'LIMIT_FILE_COUNT') {
    return res.status(400).json({
      success: false,
      error: 'Too many files'
    });
  }
  
  // Handle cloud storage errors
  if (error.message.includes('bucket')) {
    return res.status(500).json({
      success: false,
      error: 'Storage configuration error'
    });
  }
  
  res.status(500).json({
    success: false,
    error: error.message
  });
});

🛠️ File Object Properties

After successful upload, files are available in req.file (single) or req.files (multiple):

{
  fieldname: 'avatar',
  originalname: 'profile.jpg',
  encoding: '7bit',
  mimetype: 'image/jpeg',
  size: 15234,
  destination: 'avatars/',
  filename: 'avatar-123456789.jpg',
  path: 'https://storage.googleapis.com/bucket/avatars/avatar-123456789.jpg',
  cloudKey: 'avatars/avatar-123456789.jpg'
}

🧪 Testing Your Setup

Check out the complete test project in the /test-project directory:

cd test-project
npm install
cp .env.example .env
# Edit .env with your credentials
npm start
# Visit http://localhost:3000

The test project includes:

• ✅ Single file upload example
• ✅ Multiple files upload example
• ✅ Multiple fields upload example
• ✅ HTML form for easy testing
• ✅ Error handling demonstrations

🔒 Security Best Practices

✅ Environment Variables – Never hardcode credentials
✅ File Validation – Always validate file types and sizes
✅ Rate Limiting – Implement upload rate limits
✅ Authentication – Protect upload endpoints
✅ CORS Configuration – Set proper CORS for web uploads
✅ Virus Scanning – Consider adding virus scanning

Example Environment Setup

# .env file
AZURE_CONNECTION_STRING=DefaultEndpointsProtocol=https;AccountName=...
AZURE_CONTAINER_NAME=uploads

AWS_ACCESS_KEY_ID=AKIA...
AWS_SECRET_ACCESS_KEY=...
AWS_REGION=us-east-1
AWS_S3_BUCKET=my-bucket

GCS_PROJECT_ID=my-project
GCS_BUCKET_NAME=my-bucket
GCS_KEY_FILE=./serviceaccountkey.json

📖 More Examples

For detailed examples and advanced usage patterns, see:

• 📄 EXAMPLES.md - Complete usage examples
• 🧪 test-project/ - Working test implementation
• 📚 TypeScript Definitions - Full type definitions

🤝 Contributing

We welcome contributions! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

🆘 Support

• 📧 Issues: GitHub Issues
• 📖 Documentation: Examples & Guides
• 💬 Discussions: GitHub Discussions

⭐ Show Your Support

If this package helped you, please consider:

• ⭐ Starring the repository
• 🐛 Reporting issues
• 💡 Suggesting improvements
• 🤝 Contributing code

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