CODEWITHSUNDEEP
javascriptphp
Ivan
Ivan

Reputation: 1304

Redirect IF referrer matches destination

I would like to redirect to a different page if the referrer matches the loaded website. I want to do this because I run a php rotator script running simultaneously on several websites. But IF I have site A being advertised on sites A B C D, I would like site A to show only if the referrer matches site B C or D or not to show if referrer matches site A. This is to prevent showing the same website on itself.

The script is a php script loaded in an iframe. It doesn't have referrer cloaking or anything like that. I can include any javascript or php in the rotator script.

Any ideas or pointers would be appreciated. Thank you!

Upvotes: 0

Views: 781

Answers (1)

Metagrapher
Metagrapher

Reputation: 8912

sorry, this is a little long, but I want to make sure this is well answered.

Let's be clear and use consistent terminology to make sure we're on the same page here:

redirect means to capture the request for the current page and point it at a different page.

For example:
typing "http://gooogle.com" into your address bar will perform a redirect to "http://google.com"

There are multiple kinds of redirects, we'll not got into them here.

referer indicates the URI that linked to the page being requested, as pulled from the HTTP headers

For example:
You're on the page "http://slate.com"
You click a link that leads you to "http://newsweek.com"
your referer is "http://slate.com" in this case.

A redirect may modify the value of the referer, depending on the type of redirect.

In order to accomplish what you wish: to not display an ad in an iframe for the page you are currently on, you are not actually concerned about either of these. You don't need any redirection, and you don't need to be concerned about who linked to the current page.

Consider how your page works:

There is a javascript that executes on page load that inserts an iframe into your document.
That iframe, in turn, loads the PHP file on the server, which displays the ad.

So you have an HTML page that looks something like this:
index.html

<!doctype HTML>
<html>
  <head><title>Server A Index</title></head>
  <body>
    <header>
      <section id="top_banner_ad">
        <script src="./js/adrotator.js"></script>
      </section>
    </header>
    <!-- Some content... -->
  </body>
</html>

Which calls a JavaScript that looks something like this:
/js/adrotator.js 

var holder = document.getElementById("top_banner_ad");
var iframe = document.createElement("iframe");
iframe.src = "http://example.com/inc/adrotators.php";
holder.appendChild(iframe);

Which calls, finally, a PHP script that looks something like this:
/inc/adrotators.php

<!doctype HTML>
<html>
  <head><title></title></head>
  <body>
    <?php $advert = get_advert(); ?>
    <a href="<?php echo $advert['url']; ?>">
      <img src="<?php echo $advert['imgsrc']; ?>">
    </a>
  </body>
</html>

I'm not sure what you have access to in this scenario, but I'm going to assume you have access to all of these: the page hosting the script (index.html), the javascript that creates the iframe (/js/adrotator.js), and the php script that is called by the iframe (/inc/adrotator.php).

You have at least 2 solutions:

You can either have /js/adrotator.js find out from index.html and tell the /inc/adrotator.php who it is, or you can have /inc/adrotator.php find out who it's parent frame is.

  • So, the iframe has knowledge of its parent frame (though they can only actually communicate under certain circumstances)
    If your iframe loads a page that is on the same domain (subdomains matter), one solution would be to have a javascript in the iframe (in the HTML generated by the PHP) check its parent, like so:

    parent.document.location.href

    And then request a new ad if the target domain matches the parent.

  • (preferred) If you can modify the javascript that creates the iframe in your page, then you could have the javascript check the url and add it as a url parameter to the src attribute of the iframe it calls.
    For example: 

    var host_url = window.location.href;  
var iframe = document.createElement("iframe");  
iframe.src = "http://example.com/ad_rotator.php?host="+ host_url;
document.body.appendChild(iframe);

    And then your PHP script would not serve an ad whose target matches $_GET["host"]

    <?php 
  $advert = get_advert();
  while ($advert['url'] == $_GET['host']) {
    $advert = get_advert();
  }
?>
<a href="<?php echo $advert['url']; ?>">
  <img src="<?php echo $advert['imgsrc']; ?>">
</a>

all the code here is untested pseudo-code, you will definitely need to modify this, it's just a starter

If you can't modify the PHP that loads the ad, nor can you modify the script that injects the iframe, you're pretty much hosed.

Upvotes: 2

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