node/lib/internal/http.js

'use strict';

const {
  Symbol,
  Date,
  DatePrototypeGetMilliseconds,
  DatePrototypeToUTCString,
} = primordials;

const { setUnrefTimeout } = require('internal/timers');
const { PerformanceEntry, notify } = internalBinding('performance');

let utcCache;

function utcDate() {
  if (!utcCache) cache();
  return utcCache;
}

function cache() {
  const d = new Date();
  utcCache = DatePrototypeToUTCString(d);
  setUnrefTimeout(resetCache, 1000 - DatePrototypeGetMilliseconds(d));
}

function resetCache() {
  utcCache = undefined;
}

class HttpRequestTiming extends PerformanceEntry {
  constructor(statistics) {
    super();
    this.name = 'HttpRequest';
    this.entryType = 'http';
    const startTime = statistics.startTime;
    const diff = process.hrtime(startTime);
    this.duration = diff[0] * 1000 + diff[1] / 1e6;
    this.startTime = startTime[0] * 1000 + startTime[1] / 1e6;
  }
}

function emitStatistics(statistics) {
  notify('http', new HttpRequestTiming(statistics));
}

module.exports = {
  kOutHeaders: Symbol('kOutHeaders'),
  kNeedDrain: Symbol('kNeedDrain'),
  utcDate,
  emitStatistics
};