dcrouter/test/suite/smtpclient_email-composition/test.cep-08.custom-headers.ts

import { tap, expect } from '@git.zone/tstest/tapbundle';
import { startTestSmtpServer } from '../../helpers/server.loader.js';
import { createSmtpClient } from '../../helpers/smtp.client.js';
import { Email } from '../../../ts/mail/core/classes.email.js';

let testServer: any;

tap.test('setup test SMTP server', async () => {
  testServer = await startTestSmtpServer();
  expect(testServer).toBeTruthy();
  expect(testServer.port).toBeGreaterThan(0);
});

tap.test('CEP-08: Basic custom headers', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Create email with custom headers
  const email = new Email({
    from: 'sender@example.com',
    to: ['recipient@example.com'],
    subject: 'Custom Headers Test',
    text: 'Testing custom headers',
    headers: {
      'X-Custom-Header': 'Custom Value',
      'X-Campaign-ID': 'CAMP-2024-03',
      'X-Priority': 'High',
      'X-Mailer': 'Custom SMTP Client v1.0'
    }
  });

  // Capture sent headers
  const sentHeaders: { [key: string]: string } = {};
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.includes(':') && !command.startsWith('MAIL') && !command.startsWith('RCPT')) {
      const [key, ...valueParts] = command.split(':');
      if (key && key.toLowerCase().startsWith('x-')) {
        sentHeaders[key.trim()] = valueParts.join(':').trim();
      }
    }
    return originalSendCommand(command);
  };

  const result = await smtpClient.sendMail(email);
  expect(result).toBeTruthy();
  
  console.log('Custom headers sent:');
  Object.entries(sentHeaders).forEach(([key, value]) => {
    console.log(`  ${key}: ${value}`);
  });
  
  // Verify custom headers were sent
  expect(Object.keys(sentHeaders).length).toBeGreaterThanOrEqual(4);
  expect(sentHeaders['X-Custom-Header']).toEqual('Custom Value');
  expect(sentHeaders['X-Campaign-ID']).toEqual('CAMP-2024-03');

  await smtpClient.close();
});

tap.test('CEP-08: Standard headers override protection', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Try to override standard headers via custom headers
  const email = new Email({
    from: 'real-sender@example.com',
    to: ['real-recipient@example.com'],
    subject: 'Real Subject',
    text: 'Testing header override protection',
    headers: {
      'From': 'fake-sender@example.com', // Should not override
      'To': 'fake-recipient@example.com', // Should not override
      'Subject': 'Fake Subject', // Should not override
      'Date': 'Mon, 1 Jan 2000 00:00:00 +0000', // Might be allowed
      'Message-ID': '<fake@example.com>', // Might be allowed
      'X-Original-From': 'tracking@example.com' // Custom header, should work
    }
  });

  // Capture actual headers
  const actualHeaders: { [key: string]: string } = {};
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.includes(':') && !command.startsWith('MAIL') && !command.startsWith('RCPT')) {
      const [key, ...valueParts] = command.split(':');
      const headerKey = key.trim();
      if (['From', 'To', 'Subject', 'Date', 'Message-ID'].includes(headerKey)) {
        actualHeaders[headerKey] = valueParts.join(':').trim();
      }
    }
    return originalSendCommand(command);
  };

  await smtpClient.sendMail(email);
  
  console.log('\nHeader override protection test:');
  console.log('From:', actualHeaders['From']);
  console.log('To:', actualHeaders['To']);
  console.log('Subject:', actualHeaders['Subject']);
  
  // Standard headers should not be overridden
  expect(actualHeaders['From']).toInclude('real-sender@example.com');
  expect(actualHeaders['To']).toInclude('real-recipient@example.com');
  expect(actualHeaders['Subject']).toInclude('Real Subject');

  await smtpClient.close();
});

tap.test('CEP-08: Tracking and analytics headers', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Common tracking headers
  const email = new Email({
    from: 'marketing@example.com',
    to: ['customer@example.com'],
    subject: 'Special Offer Inside!',
    text: 'Check out our special offers',
    headers: {
      'X-Campaign-ID': 'SPRING-2024-SALE',
      'X-Customer-ID': 'CUST-12345',
      'X-Segment': 'high-value-customers',
      'X-AB-Test': 'variant-b',
      'X-Send-Time': new Date().toISOString(),
      'X-Template-Version': '2.1.0',
      'List-Unsubscribe': '<https://example.com/unsubscribe?id=12345>',
      'List-Unsubscribe-Post': 'List-Unsubscribe=One-Click',
      'Precedence': 'bulk'
    }
  });

  const result = await smtpClient.sendMail(email);
  expect(result).toBeTruthy();
  
  console.log('Sent email with tracking headers for analytics');

  await smtpClient.close();
});

tap.test('CEP-08: MIME extension headers', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // MIME-related custom headers
  const email = new Email({
    from: 'sender@example.com',
    to: ['recipient@example.com'],
    subject: 'MIME Extensions Test',
    html: '<p>HTML content</p>',
    text: 'Plain text content',
    headers: {
      'MIME-Version': '1.0', // Usually auto-added
      'X-Accept-Language': 'en-US, en;q=0.9, fr;q=0.8',
      'X-Auto-Response-Suppress': 'DR, RN, NRN, OOF',
      'Importance': 'high',
      'X-Priority': '1',
      'X-MSMail-Priority': 'High',
      'Sensitivity': 'Company-Confidential'
    }
  });

  // Monitor headers
  const mimeHeaders: string[] = [];
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.includes(':') && 
        (command.includes('MIME') || 
         command.includes('Importance') || 
         command.includes('Priority') ||
         command.includes('Sensitivity'))) {
      mimeHeaders.push(command.trim());
    }
    return originalSendCommand(command);
  };

  await smtpClient.sendMail(email);
  
  console.log('\nMIME extension headers:');
  mimeHeaders.forEach(header => console.log(`  ${header}`));

  await smtpClient.close();
});

tap.test('CEP-08: Email threading headers', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Simulate email thread
  const messageId = `<${Date.now()}.${Math.random()}@example.com>`;
  const inReplyTo = '<original-message@example.com>';
  const references = '<thread-start@example.com> <second-message@example.com>';

  const email = new Email({
    from: 'sender@example.com',
    to: ['recipient@example.com'],
    subject: 'Re: Email Threading Test',
    text: 'This is a reply in the thread',
    headers: {
      'Message-ID': messageId,
      'In-Reply-To': inReplyTo,
      'References': references,
      'Thread-Topic': 'Email Threading Test',
      'Thread-Index': Buffer.from('thread-data').toString('base64')
    }
  });

  // Capture threading headers
  const threadingHeaders: { [key: string]: string } = {};
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    const threadHeaders = ['Message-ID', 'In-Reply-To', 'References', 'Thread-Topic', 'Thread-Index'];
    const [key, ...valueParts] = command.split(':');
    if (threadHeaders.includes(key.trim())) {
      threadingHeaders[key.trim()] = valueParts.join(':').trim();
    }
    return originalSendCommand(command);
  };

  await smtpClient.sendMail(email);
  
  console.log('\nThreading headers:');
  Object.entries(threadingHeaders).forEach(([key, value]) => {
    console.log(`  ${key}: ${value}`);
  });
  
  // Verify threading headers
  expect(threadingHeaders['In-Reply-To']).toEqual(inReplyTo);
  expect(threadingHeaders['References']).toInclude(references);

  await smtpClient.close();
});

tap.test('CEP-08: Security and authentication headers', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Security-related headers
  const email = new Email({
    from: 'secure@example.com',
    to: ['recipient@example.com'],
    subject: 'Security Headers Test',
    text: 'Testing security headers',
    headers: {
      'X-Originating-IP': '[192.168.1.100]',
      'X-Auth-Result': 'PASS',
      'X-Spam-Score': '0.1',
      'X-Spam-Status': 'No, score=0.1',
      'X-Virus-Scanned': 'ClamAV using ClamSMTP',
      'Authentication-Results': 'example.com; spf=pass smtp.mailfrom=sender@example.com',
      'ARC-Seal': 'i=1; cv=none; d=example.com; s=arc-20240315; t=1710500000;',
      'ARC-Message-Signature': 'i=1; a=rsa-sha256; c=relaxed/relaxed;',
      'ARC-Authentication-Results': 'i=1; example.com; spf=pass'
    }
  });

  const result = await smtpClient.sendMail(email);
  expect(result).toBeTruthy();
  
  console.log('Sent email with security and authentication headers');

  await smtpClient.close();
});

tap.test('CEP-08: Header folding for long values', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Create headers with long values that need folding
  const longValue = 'This is a very long header value that exceeds the recommended 78 character limit per line and should be folded according to RFC 5322 specifications for proper email transmission';
  
  const email = new Email({
    from: 'sender@example.com',
    to: ['recipient@example.com'],
    subject: 'Header Folding Test with a very long subject line that should be properly folded',
    text: 'Testing header folding',
    headers: {
      'X-Long-Header': longValue,
      'X-Multiple-Values': 'value1@example.com, value2@example.com, value3@example.com, value4@example.com, value5@example.com, value6@example.com',
      'References': '<msg1@example.com> <msg2@example.com> <msg3@example.com> <msg4@example.com> <msg5@example.com> <msg6@example.com> <msg7@example.com>'
    }
  });

  // Monitor line lengths
  let maxLineLength = 0;
  let foldedLines = 0;
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    const lines = command.split('\r\n');
    lines.forEach(line => {
      const length = line.length;
      maxLineLength = Math.max(maxLineLength, length);
      if (line.startsWith(' ') || line.startsWith('\t')) {
        foldedLines++;
      }
    });
    return originalSendCommand(command);
  };

  await smtpClient.sendMail(email);
  
  console.log(`\nHeader folding results:`);
  console.log(`  Maximum line length: ${maxLineLength}`);
  console.log(`  Folded continuation lines: ${foldedLines}`);
  
  // RFC 5322 recommends 78 chars, requires < 998
  if (maxLineLength > 998) {
    console.log('  WARNING: Line length exceeds RFC 5322 limit');
  }

  await smtpClient.close();
});

tap.test('CEP-08: Custom headers with special characters', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Headers with special characters
  const email = new Email({
    from: 'sender@example.com',
    to: ['recipient@example.com'],
    subject: 'Special Characters in Headers',
    text: 'Testing special characters',
    headers: {
      'X-Special-Chars': 'Value with special: !@#$%^&*()',
      'X-Quoted-String': '"This is a quoted string"',
      'X-Unicode': 'Unicode: café, naïve, 你好',
      'X-Control-Chars': 'No\ttabs\nor\rnewlines', // Should be sanitized
      'X-Empty': '',
      'X-Spaces': '   trimmed   ',
      'X-Semicolon': 'part1; part2; part3'
    }
  });

  // Capture how special characters are handled
  const specialHeaders: { [key: string]: string } = {};
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.toLowerCase().includes('x-') && command.includes(':')) {
      const [key, ...valueParts] = command.split(':');
      specialHeaders[key.trim()] = valueParts.join(':').trim();
    }
    return originalSendCommand(command);
  };

  await smtpClient.sendMail(email);
  
  console.log('\nSpecial character handling:');
  Object.entries(specialHeaders).forEach(([key, value]) => {
    console.log(`  ${key}: "${value}"`);
    // Check for proper encoding/escaping
    if (value.includes('=?') && value.includes('?=')) {
      console.log(`    -> Encoded as RFC 2047`);
    }
  });

  await smtpClient.close();
});

tap.test('CEP-08: Duplicate header handling', async () => {
  const smtpClient = createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000,
    debug: true
  });

  await smtpClient.connect();

  // Some headers can appear multiple times
  const email = new Email({
    from: 'sender@example.com',
    to: ['recipient@example.com'],
    subject: 'Duplicate Headers Test',
    text: 'Testing duplicate headers',
    headers: {
      'Received': 'from server1.example.com',
      'X-Received': 'from server2.example.com', // Workaround for multiple
      'Comments': 'First comment',
      'X-Comments': 'Second comment', // Workaround for multiple
      'X-Tag': ['tag1', 'tag2', 'tag3'] // Array might create multiple headers
    }
  });

  // Count occurrences of headers
  const headerCounts: { [key: string]: number } = {};
  const originalSendCommand = smtpClient.sendCommand.bind(smtpClient);
  
  smtpClient.sendCommand = async (command: string) => {
    if (command.includes(':') && !command.startsWith('MAIL') && !command.startsWith('RCPT')) {
      const [key] = command.split(':');
      const headerKey = key.trim();
      headerCounts[headerKey] = (headerCounts[headerKey] || 0) + 1;
    }
    return originalSendCommand(command);
  };

  await smtpClient.sendMail(email);
  
  console.log('\nHeader occurrence counts:');
  Object.entries(headerCounts)
    .filter(([key, count]) => count > 1 || key.includes('Received') || key.includes('Comments'))
    .forEach(([key, count]) => {
      console.log(`  ${key}: ${count} occurrence(s)`);
    });

  await smtpClient.close();
});

tap.test('cleanup test SMTP server', async () => {
  if (testServer) {
    await testServer.stop();
  }
});

export default tap.start();