@vitaly-yosef/node-smart-logger/src/validation.ts

Universal logger for Node.js applications with support for both ESM and CommonJS. It provides advanced features, such as structured logging in JSON format, integration with AWS CloudWatch Logs, and contextual logging.

// Types (interface) for logger context
interface LoggerContext {
  traceId?: string;
  requestId?: string;
  operationId?: string;
  deviceId?: string;
  userId?: string;
  [key: string]: any;
}

/**
 * Validates and sanitizes a string to prevent log injection
 * @param input - String to sanitize
 * @returns Sanitized string
 */
export function sanitizeForLogging(input: string): string {
  if (typeof input !== 'string') {
    return String(input);
  }

  // Remove or replace characters that could be used for log injection
  return input
    .replace(/\n/g, '\\n')
    .replace(/\r/g, '\\r')
    .replace(/\t/g, '\\t')
    .replace(/\0/g, '\\0');
}

/**
 * Validates logger context data
 * @param context - Context data to validate
 * @returns Validated context data
 */
export function validateLoggerContext(context: Partial<LoggerContext>): LoggerContext {
  const validatedContext: LoggerContext = {};

  if (context.traceId) {
    // Validate UUID format
    if (typeof context.traceId === 'string' && /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(context.traceId)) {
      validatedContext.traceId = sanitizeForLogging(context.traceId);
    }
  }

  if (context.requestId) {
    // requestId can be any string, but we should sanitize it
    if (typeof context.requestId === 'string') {
      validatedContext.requestId = sanitizeForLogging(context.requestId);
    }
  }

  if (context.operationId) {
    // Validate UUID format
    if (typeof context.operationId === 'string' && /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i.test(context.operationId)) {
      validatedContext.operationId = sanitizeForLogging(context.operationId);
    }
  }

  if (context.deviceId) {
    // deviceId can be any string, but we should sanitize it
    if (typeof context.deviceId === 'string') {
      validatedContext.deviceId = sanitizeForLogging(context.deviceId);
    }
  }

  if (context.userId) {
    // userId can be any string, but we should sanitize it
    if (typeof context.userId === 'string') {
      validatedContext.userId = sanitizeForLogging(context.userId);
    }
  }

  return validatedContext;
}

/**
 * Validates service name
 * @param service - Service name to validate
 * @returns Validated service name
 */
export function validateServiceName(service: string): string {
  if (typeof service !== 'string' || service.trim() === '') {
    return 'default';
  }

  // Limit service name length and sanitize
  const trimmedService = service.trim();
  return sanitizeForLogging(trimmedService.substring(0, 100));
}

/**
 * Validates log level
 * @param level - Log level to validate
 * @returns Validated log level
 */
export function validateLogLevel(level: string): string {
  const validLevels = ['error', 'warn', 'info', 'http', 'verbose', 'debug', 'silly'];

  if (typeof level !== 'string') {
    return 'info';
  }

  const lowerLevel = level.toLowerCase();
  return validLevels.includes(lowerLevel) ? lowerLevel : 'info';
}