Netty - Node.js URL Monitoring Library

Description: Monitor uptime, response time, SSL certificates, DNS, and more. Supports multiple URLs, retries, intervals, slow response alerts, and event-driven notifications.

Installation: npm install monitor

Usage Example:

const Monitor = require('./monitor');

const monitor = new Monitor({ url: ['https://example.com', 'https://google.com'], interval: 30000, // check every 30 seconds timeout: 10000, // request timeout retries: 2, // retry failed requests twice retryDelay: 2000, // wait 2s between retries slowThreshold: 1500 // emit 'slow' if response > 1.5s });

monitor.on('check', (res) => console.log('Checked:', res)); monitor.on('up', (res) => console.log('UP:', res.url)); monitor.on('down', (res) => console.log('DOWN:', res.url)); monitor.on('slow', (res) => console.log('SLOW response:', res.url, res.responseTime)); monitor.on('error', (err) => console.log('Error:', err));

monitor.start();

// Access last result for a specific URL setTimeout(() => { console.log('Last result for example.com:', monitor.getLast('https://example.com')); }, 35000);

Features:

• Monitor multiple URLs
• Interval-based checks
• DNS lookup verification
• HTTP/HTTPS requests with retries
• SSL certificate validation
• SSL expiration warnings (7 days before expiry)
• Response time tracking
• Slow response alerts
• Event-driven (check, up, down, slow, error)
• Keeps last 100 checks per URL

Events: check - Emitted after every check up - Emitted if URL is up down - Emitted if URL is down slow - Emitted if response time exceeds threshold error - Emitted on network/DNS/SSL error

Result Object Structure: url: URL being monitored up: true/false statusCode: HTTP status code responseTime: response time in ms dns: DNS lookup info { address, family } ssl: SSL certificate info { subject, issuer, validFrom, validTo } sslExpired: true/false sslWarning: true if SSL expires within 7 days checkedAt: ISO timestamp

Methods: start() - Start monitoring all URLs stop() - Stop monitoring checkAll() - Perform a single check for all URLs getLast(url) - Get the last check result for a URL getHistory(url) - Get the last 100 results for a URL

License: MIT