Mysterious 404s reported in access.log from Serf of the right file at the wrong path.

[GoogleCodeExporter]

From wojtek.kosinski@gmail.com:

access.log from http://mapvivo.com has:

91.121.9.21 - - [17/Nov/2010:04:22:07 +0000] "GET /_screen.css HTTP/
1.1" 404 10498 "-" "Serf/0.3.1"

But _screen.css is referenced from the front page HTML as:

<link rel="stylesheet" href="/style/_screen.css" type="text/css" media="screen, 
projection">

So we in the path to getting that CSS file loaded for rewrite, we are querying 
it from the wrong source, but not all of the time.  We are evidently finding it 
correctly because mod_pagespeed correctly applies the combine_css filter 
yielding:

<link rel="stylesheet" type="text/css" media="screen, projection" 
href="http://mapvivo.com/style/cc.f110f647eac9bd9bc90cc240c303ef3a._screen,s+_ge
neral,s+colorbox,_colorbox,s.css">


This is the correct rewrite, and the site looks correctly skinned so I believe 
that we are reading _screen.css correctly, at least in that particular filter.


I put this as a high priority because this could be the root cause of a number 
of issues, but appears to be a very manageable testcase.

One potential confusion is that the above fragments are from the front page of 
mapvivo.com but there is other evidence in the query log that some failing 
requests are coming from deeper in the site.

Original issue reported on code.google.com by jmara...@google.com on 17 Nov 2010 at 3:51