dd-trace/packages/dd-trace/src/exporters/common/url.js

Datadog APM tracing client for JavaScript

'use strict'

const net = require('node:net')

const { urlToHttpOptions } = require('./url-to-http-options-polyfill')

/**
 * @param {string} hostname
 * @returns {boolean}
 */
function isLoopbackHost (hostname) {
  // Gate the 127/8 prefix on an IPv4 literal so names such as 127.example.com cannot pass.
  return hostname === 'localhost' ||
    hostname === '::1' ||
    hostname === '[::1]' ||
    (hostname.startsWith('127.') && net.isIPv4(hostname))
}

/**
 * Convert an agent/intake URL into Node http(s) request options.
 *
 * A Windows named pipe (`unix://./pipe/<name>`) parses the `.` as the URL
 * authority, dropping it from the path. Fold it back so the socket path stays
 * `//./pipe/<name>`; otherwise it collapses to `/pipe/<name>` and misses the
 * pipe. Exporters receive `config.url` as a URL object, so this must run for
 * both string and object input.
 *
 * @param {string|URL|object} urlObjOrString
 * @returns {object}
 */
function parseUrl (urlObjOrString) {
  // `urlToHttpOptions` returns `pathname` at runtime, but @types/node narrows it
  // to `ClientRequestArgs`, which omits it; cast so the named-pipe fold below can
  // read and rewrite it.
  const url = /** @type {import('node:http').ClientRequestArgs & { pathname: string }} */ (
    urlObjOrString !== null && typeof urlObjOrString === 'object'
      ? urlToHttpOptions(urlObjOrString)
      : urlToHttpOptions(new URL(urlObjOrString))
  )

  if (url.protocol === 'unix:' && url.hostname === '.') {
    url.path = url.pathname = `//.${url.pathname}`
  }

  return url
}

module.exports = { isLoopbackHost, parseUrl }