Express.js Integration

# Install Express.js and dependencies
npm init -y
npm install express
npm install -g @relay/sms-dev

# Start sms-dev in the background
sms-dev

// server.js
const express = require('express');
const app = express();
const port = 3000;

// Middleware
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// SMS API client pointing to sms-dev
const SMS_API_URL = 'http://localhost:4001';

// Helper function to send SMS
async function sendSMS(to, from, body) {
  try {
    const response = await fetch(`${SMS_API_URL}/v1/messages`, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ to, from, body })
    });
    
    if (!response.ok) {
      throw new Error(`HTTP error! status: ${response.status}`);
    }
    
    return await response.json();
  } catch (error) {
    console.error('Failed to send SMS:', error);
    throw error;
  }
}

// Routes
app.get('/', (req, res) => {
  res.json({ 
    message: 'SMS Express Server',
    status: 'running',
    smsDevUrl: 'http://localhost:4000'
  });
});

// Send SMS endpoint
app.post('/send-sms', async (req, res) => {
  try {
    const { to, from, body } = req.body;
    
    if (!to || !from || !body) {
      return res.status(400).json({
        error: 'Missing required fields: to, from, body'
      });
    }
    
    const result = await sendSMS(to, from, body);
    res.json({
      success: true,
      messageId: result.id,
      message: 'SMS sent successfully'
    });
  } catch (error) {
    res.status(500).json({
      error: 'Failed to send SMS',
      details: error.message
    });
  }
});

// Webhook endpoint for receiving SMS replies
app.post('/webhook', (req, res) => {
  const { from, to, body, messageId } = req.body;
  
  console.log(`📱 Received SMS from ${from} to ${to}: ${body}`);
  
  // Process the incoming message
  handleIncomingSMS(from, to, body, messageId);
  
  // Respond with 200 OK
  res.status(200).send('OK');
});

// Handle incoming SMS logic
async function handleIncomingSMS(from, to, body, messageId) {
  const message = body.toLowerCase().trim();
  
  try {
    if (message === 'help') {
      await sendSMS(to, from, 
        'Available commands:\n' +
        '• HELP - Show this menu\n' +
        '• TIME - Get current time\n' +
        '• JOKE - Get a random joke\n' +
        '• STOP - Unsubscribe'
      );
    } else if (message === 'time') {
      const now = new Date().toLocaleString();
      await sendSMS(to, from, `Current time: ${now}`);
    } else if (message === 'joke') {
      const jokes = [
        'Why do programmers prefer dark mode? Because light attracts bugs! 🐛',
        'How many programmers does it take to change a light bulb? None, that\'s a hardware problem! 💡',
        'Why do Java developers wear glasses? Because they can\'t C# 👓'
      ];
      const randomJoke = jokes[Math.floor(Math.random() * jokes.length)];
      await sendSMS(to, from, randomJoke);
    } else if (message === 'stop') {
      await sendSMS(to, from, 'You have been unsubscribed. Reply START to resubscribe.');
    } else {
      await sendSMS(to, from, 
        `Thanks for your message: "${body}"\n\n` +
        'Reply HELP for available commands.'
      );
    }
  } catch (error) {
    console.error('Error handling incoming SMS:', error);
  }
}

app.listen(port, () => {
  console.log(`🚀 Server running at http://localhost:${port}`);
  console.log(`📱 Virtual Phone: http://localhost:4000`);
  console.log(`🔗 Webhook URL: http://localhost:${port}/webhook`);
});

# Send an SMS message
curl -X POST http://localhost:3000/send-sms \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+1234567890",
    "from": "+1987654321", 
    "body": "Hello from Express! Reply HELP for commands."
  }'

# Response:
{
  "success": true,
  "messageId": "msg_abc123",
  "message": "SMS sent successfully"
}