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Re: The Rubber meets the Road - DNT compliance code

From: イアンフェッティ <ifette@google.com>
Date: Wed, 13 Jun 2012 08:22:18 -0700
Message-ID: <CAF4kx8f6vqJB-ysV+9BuixSK6U42vX8csHjj_YUeMaifgpWThQ@mail.gmail.com>
To: Peter Cranstone <peter.cranstone@gmail.com>
Cc: W3 Tracking <public-tracking@w3.org>
Many websites already do this -- "serve this JS to this user agent". It is
neither complex nor hard.

On Wed, Jun 13, 2012 at 7:44 AM, Peter Cranstone

> All,
> There's a lot of questions around a non-compliant UA sending a DNT header.
> There's still no definition on the forum or the spec on what constitutes a
> non compliant UA, or even who is going to maintain a "blacklist" of those
> non-compliant UA's. Finally there's no description of a message that should
> be sent back to the consumer indicating that he's using a non-compliant UA.
> So I'm posting a link today of what something might look like running on a
> server. The reason this is in PHP is because there are lot of servers (in
> the 10's of millions) that cannot suddenly start adding server side modules
> that do the detection. So it will all have to be done via a script.
> Think about this for a moment. In the real world server side admins are
> going to have to add code to EVERY CGI script to do this. The performance
> hit is going to be HUGE.
> Here's the link: http://www.5o9mm.com/mod_dnt_test_1.php
> We've blacklisted the following browsers:
> HTTP_DNT_BLACKLISTED_USER_AGENT_1 = Mozilla/4.0 (compatible; MSIE 7.0;
> Windows NT 6.1; Trident/5.0)
> HTTP_DNT_BLACKLISTED_USER_AGENT_2 = Mozilla/5.0 (compatible; MSIE 9.0;
> Windows NT 6.1; Trident/5.0)
> HTTP_DNT_BLACKLISTED_USER_AGENT_3 = Mozilla/4.0 (compatible; MSIE 7.0;
> Windows NT 6.0; Trident/5.0)
> HTTP_DNT_BLACKLISTED_USER_AGENT_4 = Mozilla/5.0 (compatible; MSIE 9.0;
> Windows NT 6.0; Trident/5.0)
> HTTP_DNT_BLACKLISTED_USER_AGENT_5 = Mozilla/5.0 (Windows NT 6.0; rv:8.0.1)
> Gecko/20100101 Firefox/8.0.1
> So every time someone hits the Web site we have to run a check. The
> request time for this check on our server is:
> REQUEST_TIME = 1339597469
> For that single page. Now multiply that by every page on your Web site
> that is scripted. Ouch.
> Now here's where it gets really interesting. Let's say that I'm on the
> blacklist. What does the server do? By rights it should abort the entire
> request and send a 400 invalid request response back to the user.
> So what the heck does the user do now?
> If this spec is going to be Trusted and used it has to work in the real
> world which is NOT 100% technical. They turn it on (or have it turned on
> for them) and they expect magic. They don't expect to be told that there
> browser is non-compliant and they can either go get another one or get
> tracked.
> Peter
> ___________________________________
> Peter J. Cranstone
> 720.663.1752
Received on Wednesday, 13 June 2012 15:22:52 UTC

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