dcrouter/test/suite/smtpclient_error-handling/test.cerr-04.greylisting-handling.ts

import { tap, expect } from '@git.zone/tstest/tapbundle';
import { startTestServer, stopTestServer, type ITestServer } from '../../helpers/server.loader.js';
import { createSmtpClient } from '../../../ts/mail/delivery/smtpclient/index.js';
import { Email } from '../../../ts/mail/core/classes.email.js';
import * as net from 'net';

let testServer: ITestServer;

tap.test('setup - start SMTP server for greylisting tests', async () => {
  testServer = await startTestServer({
    port: 2559,
    tlsEnabled: false,
    authRequired: false
  });
  
  expect(testServer.port).toEqual(2559);
});

tap.test('CERR-04: Basic greylisting response handling', async () => {
  // Create server that simulates greylisting
  const greylistServer = net.createServer((socket) => {
    socket.write('220 Greylist Test Server\r\n');

    socket.on('data', (data) => {
      const command = data.toString().trim();
      
      if (command.startsWith('EHLO') || command.startsWith('HELO')) {
        socket.write('250 OK\r\n');
      } else if (command.startsWith('MAIL FROM')) {
        socket.write('250 OK\r\n');
      } else if (command.startsWith('RCPT TO')) {
        // Simulate greylisting response
        socket.write('451 4.7.1 Greylisting in effect, please retry later\r\n');
      } else if (command === 'QUIT') {
        socket.write('221 Bye\r\n');
        socket.end();
      } else {
        socket.write('250 OK\r\n');
      }
    });
  });

  await new Promise<void>((resolve) => {
    greylistServer.listen(2560, () => resolve());
  });

  const smtpClient = await createSmtpClient({
    host: '127.0.0.1',
    port: 2560,
    secure: false,
    connectionTimeout: 5000
  });

  const email = new Email({
    from: 'sender@example.com',
    to: 'recipient@example.com',
    subject: 'Greylisting Test',
    text: 'Testing greylisting response handling'
  });

  const result = await smtpClient.sendMail(email);
  
  // Should get a failed result due to greylisting
  expect(result.success).toBeFalse();
  console.log('Actual error:', result.error?.message);
  expect(result.error?.message).toMatch(/451|greylist|rejected/i);
  console.log('✅ Greylisting response handled correctly');

  await smtpClient.close();
  await new Promise<void>((resolve) => {
    greylistServer.close(() => resolve());
  });
});

tap.test('CERR-04: Different greylisting response codes', async () => {
  // Test recognition of various greylisting response patterns
  const greylistResponses = [
    { code: '451 4.7.1', message: 'Greylisting in effect, please retry', isGreylist: true },
    { code: '450 4.7.1', message: 'Try again later', isGreylist: true },
    { code: '451 4.7.0', message: 'Temporary rejection', isGreylist: true },
    { code: '421 4.7.0', message: 'Too many connections, try later', isGreylist: false },
    { code: '452 4.2.2', message: 'Mailbox full', isGreylist: false },
    { code: '451', message: 'Requested action aborted', isGreylist: false }
  ];

  console.log('Testing greylisting response recognition:');
  
  for (const response of greylistResponses) {
    console.log(`Response: ${response.code} ${response.message}`);
    
    // Check if response matches greylisting patterns
    const isGreylistPattern = 
      (response.code.startsWith('450') || response.code.startsWith('451')) &&
      (response.message.toLowerCase().includes('grey') ||
       response.message.toLowerCase().includes('try') ||
       response.message.toLowerCase().includes('later') ||
       response.message.toLowerCase().includes('temporary') ||
       response.code.includes('4.7.'));
    
    console.log(`  Detected as greylisting: ${isGreylistPattern}`);
    console.log(`  Expected: ${response.isGreylist}`);
    
    expect(isGreylistPattern).toEqual(response.isGreylist);
  }
});

tap.test('CERR-04: Greylisting with temporary failure', async () => {
  // Create server that sends 450 response (temporary failure)
  const tempFailServer = net.createServer((socket) => {
    socket.write('220 Temp Fail Server\r\n');

    socket.on('data', (data) => {
      const command = data.toString().trim();
      
      if (command.startsWith('EHLO')) {
        socket.write('250 OK\r\n');
      } else if (command.startsWith('MAIL FROM')) {
        socket.write('250 OK\r\n');
      } else if (command.startsWith('RCPT TO')) {
        socket.write('450 4.7.1 Mailbox temporarily unavailable\r\n');
      } else if (command === 'QUIT') {
        socket.write('221 Bye\r\n');
        socket.end();
      }
    });
  });

  await new Promise<void>((resolve) => {
    tempFailServer.listen(2561, () => resolve());
  });

  const smtpClient = await createSmtpClient({
    host: '127.0.0.1',
    port: 2561,
    secure: false,
    connectionTimeout: 5000
  });

  const email = new Email({
    from: 'sender@example.com',
    to: 'recipient@example.com',
    subject: '450 Test',
    text: 'Testing 450 temporary failure response'
  });

  const result = await smtpClient.sendMail(email);
  
  expect(result.success).toBeFalse();
  console.log('Actual error:', result.error?.message);
  expect(result.error?.message).toMatch(/450|temporary|rejected/i);
  console.log('✅ 450 temporary failure handled');

  await smtpClient.close();
  await new Promise<void>((resolve) => {
    tempFailServer.close(() => resolve());
  });
});

tap.test('CERR-04: Greylisting with multiple recipients', async () => {
  // Test successful email send to multiple recipients on working server
  const smtpClient = await createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000
  });

  const email = new Email({
    from: 'sender@example.com',
    to: ['user1@normal.com', 'user2@example.com'],
    subject: 'Multi-recipient Test',
    text: 'Testing multiple recipients'
  });

  const result = await smtpClient.sendMail(email);
  
  expect(result.success).toBeTrue();
  console.log('✅ Multiple recipients handled correctly');

  await smtpClient.close();
});

tap.test('CERR-04: Basic connection verification', async () => {
  const smtpClient = await createSmtpClient({
    host: testServer.hostname,
    port: testServer.port,
    secure: false,
    connectionTimeout: 5000
  });

  const result = await smtpClient.verify();
  
  expect(result).toBeTrue();
  console.log('✅ Connection verification successful');

  await smtpClient.close();
});

tap.test('CERR-04: Server with RCPT rejection', async () => {
  // Test server rejecting at RCPT TO stage
  const rejectServer = net.createServer((socket) => {
    socket.write('220 Reject Server\r\n');

    socket.on('data', (data) => {
      const command = data.toString().trim();
      
      if (command.startsWith('EHLO')) {
        socket.write('250 OK\r\n');
      } else if (command.startsWith('MAIL FROM')) {
        socket.write('250 OK\r\n');
      } else if (command.startsWith('RCPT TO')) {
        socket.write('451 4.2.1 Recipient rejected temporarily\r\n');
      } else if (command === 'QUIT') {
        socket.write('221 Bye\r\n');
        socket.end();
      }
    });
  });

  await new Promise<void>((resolve) => {
    rejectServer.listen(2562, () => resolve());
  });

  const smtpClient = await createSmtpClient({
    host: '127.0.0.1',
    port: 2562,
    secure: false,
    connectionTimeout: 5000
  });

  const email = new Email({
    from: 'sender@example.com',
    to: 'recipient@example.com',
    subject: 'RCPT Rejection Test',
    text: 'Testing RCPT TO rejection'
  });

  const result = await smtpClient.sendMail(email);
  
  expect(result.success).toBeFalse();
  console.log('Actual error:', result.error?.message);
  expect(result.error?.message).toMatch(/451|reject|recipient/i);
  console.log('✅ RCPT rejection handled correctly');

  await smtpClient.close();
  await new Promise<void>((resolve) => {
    rejectServer.close(() => resolve());
  });
});

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

export default tap.start();