phantomas/modules/blockDomains/blockDomains.js

Headless Chromium-based web performance metrics collector and monitoring tool

/**
 * Aborts requests to external resources or given domains
 *
 * Does not emit any metrics
 */
"use strict";

module.exports = function (phantomas) {
  var ourDomain,
    // --no-externals
    noExternalsMode = phantomas.getParam("no-externals") === true,
    // --allow-domain .fastly.net,.googleapis.com
    allowedDomains = phantomas.getParam("allow-domain"),
    allowedDomainsRegExp,
    // --block-domain google-analytics.com
    blockedDomains = phantomas.getParam("block-domain"),
    blockedDomainsRegExp;

  ourDomain = new URL(phantomas.getParam("url")).hostname;

  phantomas.setMetric("blockedRequests"); // @desc number of requests blocked due to domain filtering @optional

  function checkBlock(domain) {
    var blocked = false;

    // --no-externals
    if (noExternalsMode && ourDomain !== false && domain !== ourDomain) {
      blocked = true;
    }

    // match blacklist (--block-domain)
    if (blockedDomainsRegExp && blockedDomainsRegExp.test(domain)) {
      blocked = true;
    }

    // match whitelist (--allow-domain)
    if (allowedDomainsRegExp) {
      if (allowedDomainsRegExp.test(domain) || domain === ourDomain) {
        blocked = false;
      } else {
        blocked = true;
      }
    }

    return blocked;
  }

  // parse settings
  function parseParameter(value) {
    return value.split(",").map(function (item) {
      return item.trim();
    });
  }

  allowedDomains =
    typeof allowedDomains === "string" ? parseParameter(allowedDomains) : false;
  blockedDomains =
    typeof blockedDomains === "string" ? parseParameter(blockedDomains) : false;

  if (noExternalsMode) {
    phantomas.log(
      'Block domains: working in --no-externals mode ("%s" is our domain)',
      ourDomain
    );
  }

  if (allowedDomains !== false) {
    phantomas.log("Block domains: whitelist - " + allowedDomains.join(", "));
    allowedDomainsRegExp = new RegExp("(" + allowedDomains.join("|") + ")$");
  }

  if (blockedDomains !== false) {
    phantomas.log("Block domains: blacklist - " + blockedDomains.join(", "));
    blockedDomainsRegExp = new RegExp("(" + blockedDomains.join("|") + ")$");
  }

  if (noExternalsMode || allowedDomains !== false || blockedDomains !== false) {
    // https://github.com/GoogleChrome/puppeteer/blob/v1.11.0/docs/api.md#pagesetrequestinterceptionvalue
    phantomas.on("init", async (page) => {
      await page.setRequestInterception(true);

      page.on("request", (interceptedRequest) => {
        const url = interceptedRequest.url(),
          domain = new URL(url).hostname;

        if (checkBlock(domain)) {
          interceptedRequest.abort();

          phantomas.log("Request has been blocked: <%s>", url);

          // stats
          phantomas.incrMetric("blockedRequests");
          phantomas.addOffender("blockedRequests", url);
        } else {
          interceptedRequest.continue();
        }
      });

      phantomas.log("Requests intercepting enabled");
    });
  }
};