We maybe should mention that in a changelog

Suggested steps:

• Mention in developer changelog the change
• When DNT is activated, in the browser report footer, show a message explaining that Did you know? Internet Explorer 11 and newer are mostly not tracked because they have DoNotTrack activated by default and Matomo <a href=privacy-settings>is configured to respect DoNotTrack</a>
• Update the DNT inline help in the Privacy page and explain that some browsers will mostly not be tracked as they enable DoNotTrack by default and list them eg. "IE11 and newer"

FYI It shouldn't be mentioned in the developer changelog I would say. It's not related to the platform.

Also IE usage is nowadays at around 3% and maybe doesn't need to be mentioned in the browser report? And maybe only in the help text instead of footer to keep UI nice and clean and not clutter it with too unimportant things? Probably way more users are excluded with ad blockers etc

Also IE usage is nowadays at around 3%

That strongly depends on the website. Company intranets for example might have almost 100% IE in some cases. And especially those customers might need to change the Matomo config, as before the DNT setting didn't have any effect

Maybe we could show that when people are using the type IntranetWebsite? Not many would use that type just yet but eventually will. Or maybe could look at whether 2018 yearly archive had eg at least 5% IE users and then could show it. It'd be just annoying to show it to everyone all the time when it's not really that valuable for 98% of the users. You can't show messages for every edge cases otherwise it ends up quite funny :)

That strongly depends on the website. Company intranets for example might have almost 100% IE in some cases. And especially those customers might need to change the Matomo config, as before the DNT setting didn't have any effect

We provide business software for hospitals and have >66% IE11 users.

I suppose best be to disable DNT then. For sure we shouldn't show the footer message to all users, only when IE 11 used to make a significant amount of traffic. Maybe someone could also develop a simple plugin to keep ignoring DNT for IE11 but not others

@tsteur I think adding a plugin is the best way to handle the cases where the feature is needed (this way it is expected and users know the implications)

Would it work to post an event like

Piwik::postEvent('PrivacyManager.handleDNT', array($???));

here where plugins would get the user agent and detected DNT and then could return a boolean if the user should be tracked or not. (not sure if that is a bit too specific and if there is a more general way to make a plugin possible)
https://github.com/matomo-org/matomo/pull/13686/files#diff-698d1d7fe9c92e8a27eda0e8c4a88dedR75

Yes such an event would work. Eg postEvent('PrivacyManager.shouldIgnoreDnt', array(&$shouldIgnore = false));

refs #3531

I'm afraid, we might have a problem:
https://developer.apple.com/documentation/safari_release_notes/safari_12_1_release_notes

Removed support for the expired Do Not Track standard to prevent potential use as a fingerprinting variable.

Can someone on iOS 12.2 or the next Mac OS beta please test, if this means that Apple stops sending the header at all (which would make their reason useless as they are now more identifiable than before) or if they just always send DNT:1 without a setting to change it.

The latter would mean quite some issues as we couldn't merge this PR.

Quickly checked browser stack but there iOS 12.1 is running

btw here a bit more on the background: https://www.gizmodo.com.au/2019/02/apple-is-removing-do-not-track-from-safari/

I have now installed the 12.2 beta and indeed the option is gone.
But unlike I feared they are not sending the header by default, but just removed the header and the possibility to change it.
So this doesn't really have an influence on this PR.

In theory this PR is ready, but I totally fail to get the plugin event to work.

No matter what I change the handleDNTHeader() function is never executed. It seems like getPluginsLoadedAndActivated() doesn't include the plugin even though it is enabled.

Is there anything special a plugin has to do to work during tracking?

<?php
/**
 * Piwik - free/libre analytics platform
 *
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 */

namespace Piwik\Plugins\IgnoreDNTByDefault;

use Piwik\Common;
use Piwik\Tracker\Request;

class IgnoreDNTByDefault extends \Piwik\Plugin
{
    public function registerEvents() {
        return array(
            'PrivacyManager.shouldIgnoreDnt' => 'handleDNTHeader'
        );
    }

    public function handleDNTHeader(&$shouldIgnore) {
        Common::printDebug($shouldIgnore);
        $shouldIgnore = $this->isUserAgentWithDoNotTrackAlwaysEnabled();
    }

    public function isUserAgentWithDoNotTrackAlwaysEnabled() {
        $request = new Request($_REQUEST);
        $userAgent = $request->getUserAgent();
        $browsersWithDnt = $this->getBrowsersWithDNTAlwaysEnabled();
        foreach ($browsersWithDnt as $userAgentBrowserFragment) {
            if (stripos($userAgent, $userAgentBrowserFragment) !== false) {
                return true;
            }
        }
        return false;
    }

    /**
     * Some browsers have DNT enabled by default. For those we will ignore DNT and always track those users.
     *
     * @return array
     */
    protected function getBrowsersWithDNTAlwaysEnabled() {
        return array(
            // IE
            'MSIE',
            'Trident',
            // Maxthon
            'Maxthon',

            // Epiphany - https://github.com/matomo-org/matomo/issues/8682
            'Epiphany',
        );
    }
}

You need to add a method

public function isTrackerPlugin(){
return true;
}

It can't detect it is a tracker plugin cause the event it is listening to doesn't start with Tracker or Tracking. During tracking for performance and security reasons etc we only load needed plugins.

@tsteur Many thanks for the info, it works perfectly now.

The plugin can be found here: https://github.com/Findus23/plugin-IgnoreDNTEnabledByDefault

Totally missed this was merged.

Did someone have time to test the plugin (https://github.com/Findus23/plugin-IgnoreDNTEnabledByDefault)? @fdellwing ?

If so, I'd like to publish it before the release.