@reldens/server-utils/README.md

Reldens - Server Utils

# Reldens - Server Utils

A Node.js server toolkit providing secure application server creation, HTTP/2 CDN support, file handling, encryption, and file upload capabilities for production-ready applications with modular security configurations.

[![Reldens - GitHub - Release](https://www.dwdeveloper.com/media/reldens/reldens-mmorpg-platform.png)](https://github.com/damian-pastorini/reldens)

## Features

### AppServerFactory
- Complete Express.js server configuration with modular security
- HTTPS/HTTP server creation with SSL certificate management
- HTTP/2 CDN server with optimized static asset delivery
- Optimized static asset caching for CSS, JS, fonts, and images
- SNI (Server Name Indication) support for multi-domain hosting
- Virtual host management with domain mapping
- Development mode detection with appropriate configurations
- CORS configuration with flexible origin management
- Rate limiting with customizable thresholds
- Reverse proxy support for routing multiple domains to backend servers
- Security headers and XSS protection
- Helmet integration for enhanced security
- Protocol enforcement (HTTP to HTTPS redirection)
- Trusted proxy configuration
- Request parsing with size limits and validation
- Static file serving with security headers
- Compression middleware with smart filtering
- Input validation utilities

### Http2CdnServer
- Dedicated HTTP/2 server for static asset delivery
- Optimized for serving CSS, JavaScript, images, and fonts
- Dynamic CORS origin validation with regex pattern support
- Configurable cache headers per file extension
- Comprehensive MIME type detection
- HTTP/1.1 fallback support
- Security headers (X-Content-Type-Options, X-Frame-Options, Vary)
- Standalone or integrated with AppServerFactory
- Multiple static path support
- Separate SSL certificate support from main server

#### Modular Security Components
The AppServerFactory now uses specialized security configurers:

- **CorsConfigurer** - Dynamic CORS origin validation with development domain support
- **DevelopmentModeDetector** - Automatic development environment detection
- **ProtocolEnforcer** - Protocol redirection with development mode awareness
- **RateLimitConfigurer** - Global and endpoint-specific rate limiting
- **ReverseProxyConfigurer** - Domain-based reverse proxy with WebSocket support
- **SecurityConfigurer** - Helmet integration with CSP management and XSS protection

### FileHandler
- Secure file system operations with path validation
- File and folder creation, copying, and removal
- JSON file parsing and validation
- File type detection based on magic numbers
- Secure filename generation
- Path sanitization and traversal protection
- File permissions checking
- Folder content listing and filtering
- Temporary file creation
- File quarantine functionality for security threats
- Binary file head reading for type detection
- Directory walking with callback processing
- File comparison and relative path calculations
- Comprehensive error handling with detailed context

### Encryptor
- Password hashing using PBKDF2 with configurable iterations
- Password validation against stored hashes
- AES-256-GCM data encryption and decryption
- Secure token generation with a customizable length
- TOTP (Time-based One-Time Password) generation
- Data hashing with multiple algorithms (SHA-256, SHA-512, MD5)
- HMAC generation and verification
- Constant-time string comparison for security
- Cryptographically secure random value generation

### UploaderFactory
- Multer-based file upload handling with security validation
- Multiple file upload support with field mapping
- File type validation using MIME types and extensions
- Filename security validation and sanitization
- File size limits and upload count restrictions
- Secure filename generation option
- File content validation based on magic numbers
- Dangerous file extension filtering
- Automatic file cleanup on validation failure
- Custom error response handling
- Upload destination mapping per field

## Installation

```bash
npm install @reldens/server-utils
```

## Quick Start

### Basic Server Setup

```javascript
const { AppServerFactory } = require('@reldens/server-utils');

let appServerFactory = new AppServerFactory();
let serverResult = appServerFactory.createAppServer({
    port: 3000,
    useHttps: false,
    autoListen: true,
    useCompression: true
});

if(serverResult){
    let { app, appServer } = serverResult;
    console.log('Server running on port 3000');
}
```

### HTTP/2 CDN Server with Express

Serve your main application through Express on port 443, and static assets through HTTP/2 CDN on port 8443:

```javascript
let appServerFactory = new AppServerFactory();
let serverResult = appServerFactory.createAppServer({
    port: 443,
    useHttps: true,
    keyPath: '/ssl/main-server.key',
    certPath: '/ssl/main-server.crt',
    http2CdnEnabled: true,
    http2CdnPort: 8443,
    http2CdnKeyPath: '/ssl/cdn-server.key',
    http2CdnCertPath: '/ssl/cdn-server.crt',
    http2CdnStaticPaths: ['/var/www/public'],
    http2CdnCorsOrigins: [
        'https://example.com',
        /^https:\/\/(www\.)?example\.(com|net)$/
    ],
    autoListen: true
});

if(serverResult){
    let { app, appServer, http2CdnServer } = serverResult;
    console.log('Express server on port 443');
    console.log('HTTP/2 CDN server on port 8443');
}
```

**Note:** If `http2CdnKeyPath` and `http2CdnCertPath` are not specified, the CDN server will use the same certificates as the main server (`keyPath` and `certPath`).

Browser usage:
```html
<link rel="stylesheet" href="https://cdn.example.com:8443/css/style.css">
<script src="https://cdn.example.com:8443/js/app.js"></script>
```

### Standalone HTTP/2 CDN Server

```javascript
const { Http2CdnServer } = require('@reldens/server-utils');

let cdnServer = new Http2CdnServer();
cdnServer.port = 8443;
cdnServer.keyPath = '/ssl/cdn.key';
cdnServer.certPath = '/ssl/cdn.crt';
cdnServer.staticPaths = ['/var/www/public', '/var/www/assets'];
cdnServer.corsOrigins = [
    'https://main-site.com',
    /^https:\/\/(new\.)?((site1|site2)\.(com|net))$/
];

if(cdnServer.create()){
    cdnServer.listen();
    console.log('HTTP/2 CDN running on port 8443');
}
```

### HTTPS Server with Optimized Caching

```javascript
let appServerFactory = new AppServerFactory();
let serverResult = appServerFactory.createAppServer({
    port: 443,
    useHttps: true,
    keyPath: '/ssl/server.key',
    certPath: '/ssl/server.crt',
    autoListen: true
});
```

Cache configuration is automatic with defaults:
- CSS/JS: 1 year
- Fonts: 1 year
- Images: 30 days

Override cache settings if needed:

```javascript
let appServerFactory = new AppServerFactory();
appServerFactory.cacheConfig = {
    '.css': 86400,
    '.js': 86400,
    '.png': 604800
};
let serverResult = appServerFactory.createAppServer({
    useHttps: true,
});
```

### File Operations

```javascript
const { FileHandler } = require('@reldens/server-utils');

// Read a JSON configuration file
let config = FileHandler.fetchFileJson('/path/to/config.json');
if(config){
    console.log('Configuration loaded:', config);
}

// Create a folder securely
if(FileHandler.createFolder('/path/to/new/folder')){
    console.log('Folder created successfully');
}

// Generate a secure filename
let secureFilename = FileHandler.generateSecureFilename('user-upload.jpg');
console.log('Secure filename:', secureFilename);
```

### Password Encryption

```javascript
const { Encryptor } = require('@reldens/server-utils');

// Hash a password
let hashedPassword = Encryptor.encryptPassword('userPassword123');
if(hashedPassword){
    console.log('Password hashed:', hashedPassword);
}

// Validate password
let isValid = Encryptor.validatePassword('userPassword123', hashedPassword);
console.log('Password valid:', isValid);

// Generate secure token
let secureToken = Encryptor.generateSecureToken(32);
console.log('Secure token:', secureToken);
```

### File Upload Configuration

```javascript
const { UploaderFactory } = require('@reldens/server-utils');

let uploaderFactory = new UploaderFactory({
    maxFileSize: 10 * 1024 * 1024, // 10MB
    mimeTypes: {
        image: ['image/jpeg', 'image/png', 'image/gif'],
        document: ['application/pdf', 'text/plain']
    },
    allowedExtensions: {
        image: ['.jpg', '.jpeg', '.png', '.gif'],
        document: ['.pdf', '.txt']
    },
    applySecureFileNames: true
});

let uploader = uploaderFactory.createUploader(
    [{ name: 'avatar' }, { name: 'document' }],
    { avatar: '/uploads/avatars', document: '/uploads/docs' },
    { avatar: 'image', document: 'document' }
);

// Use with Express
app.post('/upload', uploader, (req, res) => {
    console.log('Files uploaded:', req.files);
    res.json({ success: true });
});
```

## Advanced Configuration

### HTTP/2 CDN with Separate Certificates

Configure separate SSL certificates for your CDN server:

```javascript
let appServerFactory = new AppServerFactory();
let serverResult = appServerFactory.createAppServer({
    useHttps: true,
    port: 443,
    keyPath: '/ssl/app-server.key',
    certPath: '/ssl/app-server.crt',
    http2CdnEnabled: true,
    http2CdnPort: 8443,
    http2CdnKeyPath: '/ssl/cdn-server.key',
    http2CdnCertPath: '/ssl/cdn-server.crt',
    http2CdnHttpsChain: '/ssl/cdn-chain.pem',
    http2CdnStaticPaths: ['/var/www/public'],
    http2CdnCorsOrigins: [
        'https://main-site.com',
        'https://app.main-site.com',
        /^https:\/\/(new\.)?main-site\.(com|net)$/
    ],
    http2CdnCacheConfig: {
        '.css': 31536000,
        '.js': 31536000,
        '.woff2': 31536000,
        '.png': 2592000
    }
});
```

### HTTP/2 CDN with Multiple Origins

The HTTP/2 CDN server supports multiple origin validation methods:

```javascript
let appServerFactory = new AppServerFactory();
let serverResult = appServerFactory.createAppServer({
    http2CdnEnabled: true,
    http2CdnPort: 8443,
    http2CdnStaticPaths: ['/var/www/public'],
    http2CdnCorsOrigins: [
        'https://main-site.com',
        'https://app.main-site.com',
        /^https:\/\/(new\.)?main-site\.(com|net)$/,
        /^https:\/\/(app|admin)\.secondary-site\.com$/
    ]
});
```

### HTTPS Server with Multiple Domains

```javascript
let appServerFactory = new AppServerFactory();

appServerFactory.addDomain({
    hostname: 'example.com',
    keyPath: '/ssl/example.com.key',
    certPath: '/ssl/example.com.crt',
    aliases: ['www.example.com']
});

appServerFactory.addDomain({
    hostname: 'api.example.com',
    keyPath: '/ssl/api.example.com.key',
    certPath: '/ssl/api.example.com.crt'
});

let serverResult = appServerFactory.createAppServer({
    useHttps: true,
    useVirtualHosts: true,
    keyPath: '/ssl/default.key',
    certPath: '/ssl/default.crt',
    port: 443,
    enforceProtocol: true,
    developmentMultiplier: 10
});
```

### Development Mode Configuration

```javascript
let appServerFactory = new AppServerFactory();

// Add development domains (automatically detected)
appServerFactory.addDevelopmentDomain('localhost');
appServerFactory.addDevelopmentDomain('dev.myapp.local');

let serverResult = appServerFactory.createAppServer({
    port: 3000,
    corsOrigin: ['http://localhost:3000', 'http://dev.myapp.local:3000'],
    developmentMultiplier: 5, // More lenient rate limiting in dev
    developmentPorts: [3000, 3001, 8080],
    developmentExternalDomains: {
        'script-src': ['https://cdn.example.com'],
        'style-src': ['https://fonts.googleapis.com']
    }
});
```

### Custom Security Configuration

```javascript
let appServerFactory = new AppServerFactory();

let serverResult = appServerFactory.createAppServer({
    useHelmet: true,
    helmetConfig: {
        contentSecurityPolicy: {
            directives: {
                defaultSrc: ["'self'"],
                styleSrc: ["'self'", "'unsafe-inline'"],
                scriptSrc: ["'self'"]
            }
        }
    },
    globalRateLimit: 100, // requests per window
    windowMs: 60000, // 1 minute
    maxRequests: 30,
    trustedProxy: '127.0.0.1',
    useXssProtection: true,
    sanitizeOptions: {allowedTags: [], allowedAttributes: {}}
});
```

### External Domains Configuration

When using `developmentExternalDomains` to configure CSP policies, keys can be specified in either kebab-case or camelCase format. The system automatically converts kebab-case keys to the appropriate camelCase format:

```javascript
let serverResult = appServerFactory.createAppServer({
    developmentExternalDomains: {
        // Both formats work - choose whichever you prefer
        'scriptSrc': ['https://cdn.example.com'],           // camelCase
        'script-src': ['https://platform-api.example.com'], // kebab-case (auto-converted)
        'styleSrc': ['https://fonts.googleapis.com'],       // camelCase
        'font-src': ['https://fonts.gstatic.com']           // kebab-case (auto-converted)
    }
});
```

The system automatically adds these domains to both the base directive and the corresponding `-elem` variant (e.g., `scriptSrc` and `scriptSrcElem`).

### Helmet CSP Configuration Options

The security configurer provides flexible CSP directive handling with merge or override behavior:

#### Merging Directives (Default)

By default, custom CSP directives are merged with the security defaults, allowing you to add additional sources without redefining all directives:

```javascript
let serverResult = appServerFactory.createAppServer({
    useHelmet: true,
    helmetConfig: {
        contentSecurityPolicy: {
            directives: {
                // These will be ADDED to the default directives
                scriptSrc: ['https://analytics.example.com'],
                styleSrc: ['https://cdn.example.com']
            }
        }
    }
});

// Result: default directives + your additional sources
```

#### Overriding Directives

Set `overrideDirectives: true` to completely replace the default directives with your custom configuration:

```javascript
let serverResult = appServerFactory.createAppServer({
    useHelmet: true,
    helmetConfig: {
        contentSecurityPolicy: {
            overrideDirectives: true,  // Replace defaults entirely
            directives: {
                defaultSrc: ["'self'"],
                scriptSrc: ["'self'", "https://trusted-cdn.com"],
                styleSrc: ["'self'", "'unsafe-inline'"],
                imgSrc: ["'self'", "data:", "https:"],
                fontSrc: ["'self'"],
                connectSrc: ["'self'"],
                frameAncestors: ["'none'"],
                baseUri: ["'self'"],
                formAction: ["'self'"]
            }
        }
    }
});
```

### Reverse Proxy Configuration

Route multiple domains to different backend servers through a single SSL-enabled entry point:

```javascript
let appServerFactory = new AppServerFactory();

let serverResult = appServerFactory.createAppServer({
    port: 443,
    useHttps: true,
    useVirtualHosts: true,
    keyPath: '/ssl/server.key',
    certPath: '/ssl/server.crt',
    reverseProxyEnabled: true,
    reverseProxyRules: [
        {
            hostname: 'demo.reldens.com',
            target: 'https://localhost:8444',
            pathPrefix: '/',
            websocket: true,
            secure: false
        },
        {
            hostname: 'api.example.com',
            target: 'https://localhost:8445',
            pathPrefix: '/',
            websocket: false
        }
    ],
    autoListen: true
});
```

#### Reverse Proxy Features

- Multiple backend routing with independent configuration per domain
- WebSocket support for real-time applications
- SSL termination at entry point
- Header preservation (X-Forwarded-For, X-Forwarded-Proto, X-Forwarded-Host)
- Virtual host integration
- Path-based routing
- Graceful error handling

#### Rule Properties

- `hostname` (string, required) - Domain to match
- `target` (string, required) - Backend URL
- `pathPrefix` (string, optional) - Path prefix, default: '/'
- `websocket` (boolean, optional) - Enable WebSocket, default: true
- `changeOrigin` (boolean, optional) - Change origin header, default: true
- `secure` (boolean, optional) - Verify SSL certificates, default: false
- `logLevel` (string, optional) - 'debug', 'info', 'warn', 'error', 'silent'

#### Example: Multiple Game Servers

```javascript
reverseProxyRules: [
    { hostname: 'demo.game.com', target: 'https://localhost:8444', websocket: true },
    { hostname: 'staging.game.com', target: 'https://localhost:8445', websocket: true }
]
```

## API Reference

### AppServerFactory Methods

- `createAppServer(config)` - Creates and configures Express server
- `addDomain(domainConfig)` - Adds domain configuration for virtual hosting
- `addDevelopmentDomain(domain)` - Adds development domain pattern
- `setDomainMapping(mapping)` - Sets domain to configuration mapping
- `enableServeHome(app, callback)` - Enables homepage serving
- `serveStatics(app, staticPath)` - Serves static files
- `serveStaticsPath(app, route, staticPath)` - Serves static files on specific route
- `enableCSP(cspOptions)` - Enables Content Security Policy
- `listen(port)` - Starts server listening
- `close()` - Gracefully closes server

### AppServerFactory HTTP/2 CDN Configuration

- `http2CdnEnabled` - Enable HTTP/2 CDN server (default: false)
- `http2CdnPort` - HTTP/2 CDN port (default: 8443)
- `http2CdnKeyPath` - CDN SSL private key path (falls back to `keyPath`)
- `http2CdnCertPath` - CDN SSL certificate path (falls back to `certPath`)
- `http2CdnHttpsChain` - CDN certificate chain path (falls back to `httpsChain`)
- `http2CdnStaticPaths` - Paths to serve from CDN (default: [])
- `http2CdnCorsOrigins` - Allowed CORS origins for CDN (default: [])
- `http2CdnCorsAllowAll` - Allow all origins (default: false)
- `http2CdnMimeTypes` - Override default MIME types (default: {})
- `http2CdnCacheConfig` - Override default cache config (default: {})

### AppServerFactory Reverse Proxy Configuration

- `reverseProxyEnabled` - Enable reverse proxy (default: false)
- `reverseProxyRules` - Array of proxy rules (default: [])

### Http2CdnServer Methods

- `create()` - Creates HTTP/2 secure server
- `listen()` - Starts listening on configured port
- `close()` - Gracefully closes HTTP/2 server

### Http2CdnServer Configuration

- `port` - Server port (default: 8443)
- `keyPath` - SSL private key path
- `certPath` - SSL certificate path
- `httpsChain` - Certificate chain path (optional)
- `staticPaths` - Array of static file directories
- `cacheConfig` - Cache max-age per extension
- `allowHTTP1` - Allow HTTP/1.1 fallback (default: true)
- `corsOrigins` - Array of allowed origins (strings or RegExp)
- `corsAllowAll` - Allow all origins (default: false)
- `corsMethods` - Allowed HTTP methods (default: 'GET, OPTIONS')
- `corsHeaders` - Allowed request headers (default: 'Content-Type')
- `securityHeaders` - Custom security headers
- `varyHeader` - Vary header value (default: 'Accept-Encoding, Origin')
- `mimeTypes` - MIME type mappings

### FileHandler Methods

- `exists(path)` - Checks if file or folder exists
- `createFolder(path)` - Creates folder with a recursive option
- `remove(path)` - Removes file or folder recursively
- `removeMultiple(filePaths)` - Removes multiple files from an array of paths
- `copyFile(source, destination)` - Copies file to destination
- `copyFolderSync(source, destination)` - Copies folder recursively
- `readFile(path)` - Reads file contents as string
- `writeFile(path, content)` - Writes content to file
- `fetchFileJson(path)` - Reads and parses JSON file
- `fetchFileContents(path)` - Reads file with validation
- `updateFileContents(path, content)` - Updates existing file
- `isFile(path)` - Checks if a path is a file
- `isFolder(path)` - Checks if a path is folder
- `getFilesInFolder(path, extensions)` - Lists files with optional filtering
- `validateFileType(path, type, allowedTypes, maxSize)` - Validates file type and size
- `detectFileType(path)` - Detects MIME type from file signature
- `generateSecureFilename(originalName)` - Generates cryptographically secure filename
- `quarantineFile(path, reason)` - Moves file to quarantine folder
- `createTempFile(prefix, extension)` - Creates a temporary file path
- `moveFile(from, to)` - Moves a file to new location
- `getFileSize(path)` - Gets file size in bytes
- `compareFiles(file1, file2)` - Compares file contents
- `getRelativePath(from, to)` - Calculates a relative path
- `walkDirectory(path, callback)` - Recursively processes a directory tree
- `getDirectorySize(path)` - Calculates total directory size
- `emptyDirectory(path)` - Removes all contents from directory

### Encryptor Methods

- `encryptPassword(password)` - Hashes password with salt
- `validatePassword(password, hash)` - Validates password against hash
- `generateSecretKey()` - Generates 256-bit secret key
- `encryptData(data, key)` - Encrypts data with AES-256-GCM
- `decryptData(encryptedData, key)` - Decrypts AES-256-GCM data
- `generateSecureToken(length)` - Generates base64url token
- `generateTOTP(secret, timeStep)` - Generates time-based OTP
- `hashData(data, algorithm)` - Hashes data with specified algorithm
- `generateHMAC(data, secret, algorithm)` - Generates HMAC signature
- `verifyHMAC(data, secret, signature, algorithm)` - Verifies HMAC signature
- `constantTimeCompare(a, b)` - Performs constant-time string comparison

### UploaderFactory Methods

- `createUploader(fields, buckets, allowedTypes)` - Creates multer upload middleware
- `validateFilenameSecurity(filename)` - Validates filename for security
- `validateFile(file, allowedType, callback)` - Validates a file during upload
- `validateFileContents(file, allowedType)` - Validates file content after upload
- `convertToRegex(key)` - Converts MIME type patterns to regex

## Security Features

### Path Traversal Protection
All file operations include comprehensive path validation to prevent directory traversal attacks and access to system files.

### Secure File Upload
File uploads are validated at multiple levels including filename, MIME type, file extension, file size, and content validation using magic number detection. Failed uploads are automatically cleaned up using efficient file removal.

### Rate Limiting
Configurable rate limiting with development mode detection for appropriate thresholds in different environments.

### HTTPS Support
Full SSL/TLS support with SNI for multi-domain hosting and automatic certificate management.

### HTTP/2 CDN Security
The HTTP/2 CDN server includes security headers, CORS validation with pattern matching, and query string stripping to prevent cache poisoning.

### Input Validation
Built-in validators for common input types including email, username, strong passwords, alphanumeric strings, and IP addresses.

### Cryptographic Security
Industry-standard encryption using PBKDF2 for passwords, AES-256-GCM for data encryption, and secure random generation for tokens.

## Error Handling

All methods include comprehensive error handling with detailed error objects containing context information. Errors are logged appropriately and never expose sensitive system information.

---

## Documentation

[https://www.reldens.com/documentation/utils/](https://www.reldens.com/documentation/utils/)

Need something specific?

[Request a feature here: https://www.reldens.com/features-request](https://www.reldens.com/features-request)

---

### [Reldens](https://github.com/damian-pastorini/reldens/ "Reldens")

##### [By DwDeveloper](https://www.dwdeveloper.com/ "DwDeveloper")