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Prefetching Considered Harmful?
Yesterday I tried to access a page at Wolfram MathWorld and got this message instead of the material I was looking for:
This was puzzling since as far as I know, Firefox should only prefetch pages that the site specifically gives hints for. Apparently not.
What’s more curious, however, is why Wolfram blocks the entire session rather than just using a rewrite rule that’s triggered on the prefetch header to deny the prefetching itself. This would solve Wolfram’s problem and not be so obnoxious for their users. Like so:
RewriteEngine On
SetEnvIf X-moz prefetch HAS_X-moz
RewriteCond %{ENV:HAS_X-moz} prefetch
RewriteRule .* /prefetch-attempt [L]
Today, it’s not doing it. Maybe I just saw a transient problem.
Posted by windley on May 5, 2007 7:25 PM
Comment from Jesse Harris at May 5, 2007 11:37 PM
I've never understood why they don't serve you a non-prefetched version of the page with a note to disable prefetching to save their bandwidth and CPU time. DNSStuff.com is also pretty obnoxious about it.
Comment from BillyG at May 6, 2007 6:54 AM
Although I found it on one of their other sites, you have the correct action to take on the page you referred to. Just go to your about:config and change this to false: network.prefetch-next
By default, FF is prefetching on every page you go to. It's a bandwidth thing, I'm sure you understand. Why they didn't is beyond me.
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