content.js

/*
  A content script that flags tracking requests.

  Copyright 2012 Disconnect, Inc.

  This program is free software: you can redistribute it and/or modify it under
  the terms of the GNU General Public License as published by the Free Software
  Foundation, either version 3 of the License, or (at your option) any later
  version.

  This program is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License along with
  this program. If not, see <http://www.gnu.org/licenses/>.

  Authors (one per line):

    Brian Kennish <byoogle@gmail.com>
    Jeffrey Lim <jfs.world@gmail.com>
*/

/* Parses a URL into a domain name and hostname, regex free. */
function getDomain(url) {
  anchor.href = url;
  var host = anchor.hostname;
  var labels = host.split('.');
  var labelCount = labels.length - 1;
  var name = labels.slice(-2).join('.');

  // IP addresses shouldn't be munged.
  if (isNaN(parseFloat(labels[labelCount]))) {
    for (var i = labelCount; i > 1; i--)
        if (tlds[labels.slice(-i).join('.')])
            name = labels.slice(-i - 1).join('.');
  } else name = host;

  return {name: name, host: host};
}

/* Constants. */
var extension = chrome.extension;
var sendRequest = extension.sendRequest;
var tlds = {};
var anchor = document.createElement('a');
var animate = true;

/*
  Raises tracking requests. We define a tracking request broadly because there
  are many ways to track besides cookies (IP addresses, LSOs, browser
  fingerprinting, to name a few) and we don't bug the user with sound effects.
*/
sendRequest({initialized: true}, function(response) {
  tlds = response.tlds;
  var extensionId = getDomain(extension.getURL('')).name;
  var referrerDomain = getDomain(response.referrerUrl);
  var referrerName = referrerDomain.name;
  var referrerHost = referrerDomain.host;
  var trackingBlocked = response.trackingBlocked;
  var services = response.services;
  var whitelist = response.whitelist;
  var blacklist = response.blacklist;

  document.addEventListener('beforeload', function(event) {
    var domain = getDomain(event.url);
    var name = domain.name;

    if (name && name != extensionId && name != referrerName) {
      if (
        trackingBlocked && services[name] && !whitelist[name] || blacklist[name]
      ) {
        event.preventDefault();
        $(event.target).hide();
      }

      sendRequest({
        domain: {name: name, host: domain.host},
        referrerDomain: {name: referrerName, host: referrerHost},
        type: event.target.nodeName.toLowerCase(),
        animate: animate && !(animate = false)
      });
    }
  }, true);
});