The sample was made for use with [caddy](https://caddyserver.com/) I would start there. You can substitute your node server with the example code I’ve provided below. Hope this clarifies how this works.
HTTPS Sample - Caddy Web Server Setup
This guide explains how to set up a basic Caddy web server to receive JSON payloads from the nRF9160 HTTPS sample.
Understanding the Sample
The nRF9160 HTTPS sample sends a JSON payload to a configurable endpoint via HTTPS POST request:
- JSON Payload Format:
{"do_something":true}
- Request Method: HTTP POST
- Content-Type:
application/json
- TLS Version: TLS 1.2
- Certificate: Uses ISRG Root X1 (Let’s Encrypt root CA)
The sample is configured via Kconfig options in src/cloud/Kconfig:
CONFIG_CLOUD_HOSTNAME: Target server hostname (default: “www.circuitdojo.com”)CONFIG_CLOUD_PORT: Server port (default: 443)CONFIG_CLOUD_PUBLISH_PATH: Endpoint path (default: “/some/path”)
Prerequisites
- A server with a public IP address or domain name
- A valid domain name pointing to your server (required for Let’s Encrypt SSL)
- Caddy v2 installed on your server
- Node.js (v14 or later) and npm installed
Installing Caddy
Ubuntu/Debian
sudo apt install -y debian-keyring debian-archive-keyring apt-transport-https curl
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | sudo gpg --dearmor -o /usr/share/keyrings/caddy-stable-archive-keyring.gpg
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' | sudo tee /etc/apt/sources.list.d/caddy-stable.list
sudo apt update
sudo apt install caddy
Other Systems
See the official Caddy installation guide: https://caddyserver.com/docs/install
Caddy Configuration
Create a Caddyfile at /etc/caddy/Caddyfile:
# Replace with your actual domain name
your-domain.com {
# Enable automatic HTTPS with Let's Encrypt
# Caddy will automatically obtain and renew SSL certificates
# Log requests to a file
log {
output file /var/log/caddy/nrf9160.log
format json
}
# Endpoint to receive nRF9160 data
route /api/device/data {
# Log the request body
reverse_proxy localhost:8080
}
}
Backend Server Setup
Install Dependencies
First, install Node.js if not already installed:
# Ubuntu/Debian
curl -fsSL https://deb.nodesource.com/setup_lts.x | sudo -E bash -
sudo apt-get install -y nodejs
# Verify installation
node --version
npm --version
Create the Node.js Server
Create the project directory and initialize:
sudo mkdir -p /opt/nrf9160-receiver
cd /opt/nrf9160-receiver
sudo npm init -y
sudo npm install express winston
Create the server at /opt/nrf9160-receiver/server.js:
const express = require('express');
const winston = require('winston');
// Configure logger
const logger = winston.createLogger({
level: 'info',
format: winston.format.combine(
winston.format.timestamp(),
winston.format.json()
),
transports: [
new winston.transports.File({ filename: '/var/log/nrf9160-receiver.log' }),
new winston.transports.Console({
format: winston.format.combine(
winston.format.colorize(),
winston.format.simple()
)
})
]
});
const app = express();
const PORT = 8080;
// Middleware to parse JSON
app.use(express.json());
// Request logging middleware
app.use((req, res, next) => {
logger.info({
method: req.method,
path: req.path,
ip: req.ip
});
next();
});
// Health check endpoint
app.get('/health', (req, res) => {
res.json({ status: 'healthy', timestamp: new Date().toISOString() });
});
// Main endpoint to receive nRF9160 data
app.post('/api/device/data', (req, res) => {
try {
const data = req.body;
logger.info('Received data from nRF9160', { payload: data });
// Validate expected fields
if ('do_something' in data) {
logger.info(`do_something flag: ${data.do_something}`);
}
// Send success response
res.status(200).json({
status: 'success',
timestamp: new Date().toISOString()
});
} catch (error) {
logger.error('Error processing request', { error: error.message });
res.status(500).json({
status: 'error',
message: 'Internal server error'
});
}
});
// Error handling middleware
app.use((err, req, res, next) => {
logger.error('Unhandled error', { error: err.message, stack: err.stack });
res.status(500).json({
status: 'error',
message: 'Internal server error'
});
});
// Start server
app.listen(PORT, 'localhost', () => {
logger.info(`nRF9160 receiver listening on localhost:${PORT}`);
});
// Graceful shutdown
process.on('SIGTERM', () => {
logger.info('SIGTERM received, shutting down gracefully');
process.exit(0);
});
process.on('SIGINT', () => {
logger.info('SIGINT received, shutting down gracefully');
process.exit(0);
});
Setting Up the Backend as a Service
Create a systemd service file at /etc/systemd/system/nrf9160-receiver.service:
[Unit]
Description=nRF9160 Data Receiver
After=network.target
[Service]
Type=simple
User=caddy
Group=caddy
WorkingDirectory=/opt/nrf9160-receiver
ExecStart=/usr/bin/node /opt/nrf9160-receiver/server.js
Restart=always
RestartSec=10
Environment=NODE_ENV=production
[Install]
WantedBy=multi-user.target
Enable and start the service:
# Set proper ownership
sudo chown -R caddy:caddy /opt/nrf9160-receiver
# Create log directory and set permissions
sudo touch /var/log/nrf9160-receiver.log
sudo chown caddy:caddy /var/log/nrf9160-receiver.log
# Enable and start the service
sudo systemctl daemon-reload
sudo systemctl enable nrf9160-receiver
sudo systemctl start nrf9160-receiver
# Check service status
sudo systemctl status nrf9160-receiver
Starting Caddy
# Reload Caddy configuration
sudo systemctl reload caddy
# Check Caddy status
sudo systemctl status caddy
# View Caddy logs
sudo journalctl -u caddy -f
Configuring the nRF9160 Sample
Update the configuration in your project’s prj.conf or via menuconfig:
CONFIG_CLOUD_HOSTNAME="your-domain.com"
CONFIG_CLOUD_PORT=443
CONFIG_CLOUD_PUBLISH_PATH="/api/device/data"
Build and flash the sample to your nRF9160 device.
Testing the Setup
Test with curl
curl -X POST https://your-domain.com/api/device/data \
-H "Content-Type: application/json" \
-d '{"do_something":true}'
Monitor Logs
# Watch backend receiver logs
sudo tail -f /var/log/nrf9160-receiver.log
# Watch Caddy logs
sudo tail -f /var/log/caddy/nrf9160.log
# Watch systemd service logs
sudo journalctl -u nrf9160-receiver -f
Troubleshooting
Certificate Issues
The sample uses the ISRG Root X1 certificate (Let’s Encrypt). Ensure your domain has a valid Let’s Encrypt certificate. Caddy handles this automatically if your domain is properly configured.
Connection Failures
- Verify firewall allows HTTPS traffic on port 443
- Check DNS records point to your server
- Ensure Caddy and backend services are running
- Review logs for specific error messages
nRF9160 Not Connecting
- Verify
CONFIG_CLOUD_HOSTNAME matches your domain exactly
- Check modem has LTE connectivity
- Review device logs for TLS handshake errors
- Ensure security tag (default: 42) is properly provisioned
Security Considerations
- The backend server runs on localhost only and is proxied by Caddy
- Caddy automatically handles SSL/TLS termination
- Consider adding authentication if deploying to production
- Review and rotate certificates regularly (Caddy handles this automatically)
- Monitor logs for suspicious activity
