Author Topic: Cache-busting LUBID bug  (Read 1221 times)

hpguru

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Cache-busting LUBID bug
« on: June 17, 2002, 01:09:24 AM »
Anyone familiar with this? I find it here and there. It is an obvious web bug but what is "Cache-busting" about it?


<script language="JavaScript">
<!--
// Cache-busting LUBID bug.
var ran = Math.round(Math.random() * 899999) + 100000;
var lubid_string = "<img src="http://lubid.lycos.com/one.asp?site=members.tripod.com&ord=" + ran + "" height="1" width="1">";
document.write(lubid_string);
//-->
</script>



Facing each other,
a thousand miles apart.
Facing each other,
a thousand miles apart.

Scott Lemmon

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Cache-busting LUBID bug
« Reply #1 on: June 17, 2002, 04:58:23 AM »
They probably mean the URL is rigged to change randomly so the browser calls the bug each time the page loads rather than caching it (like it would a normal image).

 
 

hpguru

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Cache-busting LUBID bug
« Reply #2 on: June 17, 2002, 06:45:39 AM »
Thanks Scott.

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pooms

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Cache-busting LUBID bug
« Reply #3 on: June 17, 2002, 06:47:26 PM »
I would guess that the image itself isn't what is important, but that
the browser does an HTTP GET. As Scott says, putting the random number
in the URL would avoid the browser serving a cached copy. The ASP
probably serves the same image no matter what random number is in the
URL. But by forcing an HTTP GET, the ASP gets access to the HTTP
headers, so it could use "Referer" to count page hits, or use cookies
to do other tracking.