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ts/mail/delivery/smtpserver/utils/helpers.ts

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+/**
+ * SMTP Helper Functions
+ * Provides utility functions for SMTP server implementation
+ */
+
+import * as plugins from '../../../../plugins.ts';
+import { SMTP_DEFAULTS } from '../constants.ts';
+import type { ISmtpSession, ISmtpServerOptions } from '../interfaces.ts';
+
+/**
+ * Formats a multi-line SMTP response according to RFC 5321
+ * @param code - Response code
+ * @param lines - Response lines
+ * @returns Formatted SMTP response
+ */
+export function formatMultilineResponse(code: number, lines: string[]): string {
+  if (!lines || lines.length === 0) {
+    return `${code} `;
+  }
+  
+  if (lines.length === 1) {
+    return `${code} ${lines[0]}`;
+  }
+  
+  let response = '';
+  for (let i = 0; i < lines.length - 1; i++) {
+    response += `${code}-${lines[i]}${SMTP_DEFAULTS.CRLF}`;
+  }
+  response += `${code} ${lines[lines.length - 1]}`;
+  
+  return response;
+}
+
+/**
+ * Generates a unique session ID
+ * @returns Unique session ID
+ */
+export function generateSessionId(): string {
+  return `${Date.now()}-${Math.floor(Math.random() * 10000)}`;
+}
+
+/**
+ * Safely parses an integer from string with a default value
+ * @param value - String value to parse
+ * @param defaultValue - Default value if parsing fails
+ * @returns Parsed integer or default value
+ */
+export function safeParseInt(value: string | undefined, defaultValue: number): number {
+  if (!value) {
+    return defaultValue;
+  }
+  
+  const parsed = parseInt(value, 10);
+  return isNaN(parsed) ? defaultValue : parsed;
+}
+
+/**
+ * Safely gets the socket details
+ * @param socket - Socket to get details from
+ * @returns Socket details object
+ */
+export function getSocketDetails(socket: plugins.net.Socket | plugins.tls.TLSSocket): {
+  remoteAddress: string;
+  remotePort: number;
+  remoteFamily: string;
+  localAddress: string;
+  localPort: number;
+  encrypted: boolean;
+} {
+  return {
+    remoteAddress: socket.remoteAddress || 'unknown',
+    remotePort: socket.remotePort || 0,
+    remoteFamily: socket.remoteFamily || 'unknown',
+    localAddress: socket.localAddress || 'unknown',
+    localPort: socket.localPort || 0,
+    encrypted: socket instanceof plugins.tls.TLSSocket
+  };
+}
+
+/**
+ * Gets TLS details if socket is TLS
+ * @param socket - Socket to get TLS details from
+ * @returns TLS details or undefined if not TLS
+ */
+export function getTlsDetails(socket: plugins.net.Socket | plugins.tls.TLSSocket): {
+  protocol?: string;
+  cipher?: string;
+  authorized?: boolean;
+} | undefined {
+  if (!(socket instanceof plugins.tls.TLSSocket)) {
+    return undefined;
+  }
+  
+  return {
+    protocol: socket.getProtocol(),
+    cipher: socket.getCipher()?.name,
+    authorized: socket.authorized
+  };
+}
+
+/**
+ * Merges default options with provided options
+ * @param options - User provided options
+ * @returns Merged options with defaults
+ */
+export function mergeWithDefaults(options: Partial<ISmtpServerOptions>): ISmtpServerOptions {
+  return {
+    port: options.port || SMTP_DEFAULTS.SMTP_PORT,
+    key: options.key || '',
+    cert: options.cert || '',
+    hostname: options.hostname || SMTP_DEFAULTS.HOSTNAME,
+    host: options.host,
+    securePort: options.securePort,
+    ca: options.ca,
+    maxSize: options.size || SMTP_DEFAULTS.MAX_MESSAGE_SIZE,
+    maxConnections: options.maxConnections || SMTP_DEFAULTS.MAX_CONNECTIONS,
+    socketTimeout: options.socketTimeout || SMTP_DEFAULTS.SOCKET_TIMEOUT,
+    connectionTimeout: options.connectionTimeout || SMTP_DEFAULTS.CONNECTION_TIMEOUT,
+    cleanupInterval: options.cleanupInterval || SMTP_DEFAULTS.CLEANUP_INTERVAL,
+    maxRecipients: options.maxRecipients || SMTP_DEFAULTS.MAX_RECIPIENTS,
+    size: options.size || SMTP_DEFAULTS.MAX_MESSAGE_SIZE,
+    dataTimeout: options.dataTimeout || SMTP_DEFAULTS.DATA_TIMEOUT,
+    auth: options.auth,
+  };
+}
+
+/**
+ * Creates a text response formatter for the SMTP server
+ * @param socket - Socket to send responses to
+ * @returns Function to send formatted response
+ */
+export function createResponseFormatter(socket: plugins.net.Socket | plugins.tls.TLSSocket): (response: string) => void {
+  return (response: string): void => {
+    try {
+      socket.write(`${response}${SMTP_DEFAULTS.CRLF}`);
+      console.log(`→ ${response}`);
+    } catch (error) {
+      console.error(`Error sending response: ${error instanceof Error ? error.message : String(error)}`);
+      socket.destroy();
+    }
+  };
+}
+
+/**
+ * Extracts SMTP command name from a command line
+ * @param commandLine - Full command line
+ * @returns Command name in uppercase
+ */
+export function extractCommandName(commandLine: string): string {
+  if (!commandLine || typeof commandLine !== 'string') {
+    return '';
+  }
+  
+  // Handle specific command patterns first
+  const ehloMatch = commandLine.match(/^(EHLO|HELO)\b/i);
+  if (ehloMatch) {
+    return ehloMatch[1].toUpperCase();
+  }
+  
+  const mailMatch = commandLine.match(/^MAIL\b/i);
+  if (mailMatch) {
+    return 'MAIL';
+  }
+  
+  const rcptMatch = commandLine.match(/^RCPT\b/i);
+  if (rcptMatch) {
+    return 'RCPT';
+  }
+  
+  // Default handling
+  const parts = commandLine.trim().split(/\s+/);
+  return (parts[0] || '').toUpperCase();
+}
+
+/**
+ * Extracts SMTP command arguments from a command line
+ * @param commandLine - Full command line
+ * @returns Arguments string
+ */
+export function extractCommandArgs(commandLine: string): string {
+  if (!commandLine || typeof commandLine !== 'string') {
+    return '';
+  }
+  
+  const command = extractCommandName(commandLine);
+  if (!command) {
+    return commandLine.trim();
+  }
+  
+  // Special handling for specific commands
+  if (command === 'EHLO' || command === 'HELO') {
+    const match = commandLine.match(/^(?:EHLO|HELO)\s+(.+)$/i);
+    return match ? match[1].trim() : '';
+  }
+  
+  if (command === 'MAIL') {
+    return commandLine.replace(/^MAIL\s+/i, '');
+  }
+  
+  if (command === 'RCPT') {
+    return commandLine.replace(/^RCPT\s+/i, '');
+  }
+  
+  // Default extraction
+  const firstSpace = commandLine.indexOf(' ');
+  if (firstSpace === -1) {
+    return '';
+  }
+  
+  return commandLine.substring(firstSpace + 1).trim();
+}
+
+/**
+ * Sanitizes data for logging (hides sensitive info)
+ * @param data - Data to sanitize
+ * @returns Sanitized data
+ */
+export function sanitizeForLogging(data: any): any {
+  if (!data) {
+    return data;
+  }
+  
+  if (typeof data !== 'object') {
+    return data;
+  }
+  
+  const result: any = Array.isArray(data) ? [] : {};
+  
+  for (const key in data) {
+    if (Object.prototype.hasOwnProperty.call(data, key)) {
+      // Sanitize sensitive fields
+      if (key.toLowerCase().includes('password') ||
+          key.toLowerCase().includes('token') ||
+          key.toLowerCase().includes('secret') ||
+          key.toLowerCase().includes('credential')) {
+        result[key] = '********';
+      } else if (typeof data[key] === 'object' && data[key] !== null) {
+        result[key] = sanitizeForLogging(data[key]);
+      } else {
+        result[key] = data[key];
+      }
+    }
+  }
+  
+  return result;
+}