68 lines
1.9 KiB
Markdown
68 lines
1.9 KiB
Markdown
# sntp
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An SNTP v4 client (RFC4330) for node. Simpy connects to the NTP or SNTP server requested and returns the server time
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along with the roundtrip duration and clock offset. To adjust the local time to the NTP time, add the returned `t` offset
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to the local time.
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[](http://travis-ci.org/hueniverse/sntp)
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# Usage
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```javascript
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var Sntp = require('sntp');
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// All options are optional
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var options = {
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host: 'nist1-sj.ustiming.org', // Defaults to pool.ntp.org
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port: 123, // Defaults to 123 (NTP)
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resolveReference: true, // Default to false (not resolving)
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timeout: 1000 // Defaults to zero (no timeout)
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};
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// Request server time
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Sntp.time(options, function (err, time) {
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if (err) {
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console.log('Failed: ' + err.message);
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process.exit(1);
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}
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console.log('Local clock is off by: ' + time.t + ' milliseconds');
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process.exit(0);
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});
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```
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If an application needs to maintain continuous time synchronization, the module provides a stateful method for
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querying the current offset only when the last one is too old (defaults to daily).
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```javascript
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// Request offset once
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Sntp.offset(function (err, offset) {
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console.log(offset); // New (served fresh)
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// Request offset again
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Sntp.offset(function (err, offset) {
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console.log(offset); // Identical (served from cache)
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});
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});
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```
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To set a background offset refresh, start the interval and use the provided now() method. If for any reason the
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client fails to obtain an up-to-date offset, the current system clock is used.
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```javascript
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var before = Sntp.now(); // System time without offset
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Sntp.start(function () {
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var now = Sntp.now(); // With offset
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Sntp.stop();
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});
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```
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