sntp

What is sntp?

The sntp npm package is a simple Network Time Protocol (NTP) client for Node.js. It allows you to synchronize your system time with NTP servers, ensuring accurate timekeeping for your applications.

What are sntp's main functionalities?

Time Synchronization

This feature allows you to request the current time from an NTP server. The code sample demonstrates how to use the sntp package to get the current time from 'pool.ntp.org' and log it to the console.

const Sntp = require('sntp');

// Request the current time from an NTP server
Sntp.time({ host: 'pool.ntp.org', port: 123 }, (err, time) => {
  if (err) {
    console.error('Failed to get time:', err);
    return;
  }
  console.log('Current time:', new Date(time.now));
});

Custom NTP Server

This feature allows you to specify a custom NTP server to synchronize time with. The code sample shows how to get the current time from 'time.google.com' and log it to the console.

const Sntp = require('sntp');

// Request the current time from a custom NTP server
Sntp.time({ host: 'time.google.com', port: 123 }, (err, time) => {
  if (err) {
    console.error('Failed to get time:', err);
    return;
  }
  console.log('Current time from custom server:', new Date(time.now));
});

Time Offset

This feature allows you to calculate the time offset between your system time and the NTP server time. The code sample demonstrates how to get the time offset from 'pool.ntp.org' and log it to the console.

const Sntp = require('sntp');

// Request the current time and calculate the offset
Sntp.time({ host: 'pool.ntp.org', port: 123 }, (err, time) => {
  if (err) {
    console.error('Failed to get time:', err);
    return;
  }
  console.log('Time offset:', time.t);
});

Other packages similar to sntp

ntp-client

The ntp-client package is another NTP client for Node.js. It provides similar functionality to sntp, allowing you to synchronize your system time with NTP servers. However, ntp-client offers a simpler API and is easier to use for basic time synchronization tasks.

ntp-time

The ntp-time package is a Node.js module for retrieving the current time from NTP servers. It offers similar functionality to sntp, with a focus on providing accurate timekeeping for applications. It is a good choice if you need a reliable NTP client with minimal configuration.

README

sntp

An SNTP v4 client (RFC4330) for node. Simpy connects to the NTP or SNTP server requested and returns the server time along with the roundtrip duration and clock offset. To adjust the local time to the NTP time, add the returned t offset to the local time.

Usage

var Sntp = require('sntp');

// All options are optional

var options = {
    host: 'nist1-sj.ustiming.org',  // Defaults to pool.ntp.org
    port: 123,                      // Defaults to 123 (NTP)
    resolveReference: true,         // Default to false (not resolving)
    timeout: 1000                   // Defaults to zero (no timeout)
};

// Request server time

Sntp.time(options, function (err, time) {

    if (err) {
        console.log('Failed: ' + err.message);
        process.exit(1);
    }

    console.log('Local clock is off by: ' + time.t + ' milliseconds');
    process.exit(0);
});

If an application needs to maintain continuous time synchronization, the module provides a stateful method for querying the current offset only when the last one is too old (defaults to daily).

// Request offset once

Sntp.offset(function (err, offset) {

    console.log(offset);                    // New (served fresh)

    // Request offset again

    Sntp.offset(function (err, offset) {

        console.log(offset);                // Identical (served from cache)
    });
});

To set a background offset refresh, start the interval and use the provided now() method. If for any reason the client fails to obtain an up-to-date offset, the current system clock is used.

var before = Sntp.now();                    // System time without offset

Sntp.start(function () {

    var now = Sntp.now();                   // With offset
    Sntp.stop();
});