Sendfile messages should not be cached

[GoogleCodeExporter]

From lmaroncelli:

<link rel="stylesheet" type="text/css" 
href="www.info-alberghi.com/css/style.css">

is replaced with:

<style></style>

on:

http://www.info-alberghi.com/

which is on version: 1.9.32.2-4321



Here's the context for the missing <link>:

<script type="text/javascript">

var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-2007570-1']);
_gaq.push(['_setDomainName', 'info-alberghi.com']);
_gaq.push(['_setAllowLinker', true]);
_gaq.push(['_trackPageview']);

(function() {
var ga = document.createElement('script'); ga.type = 'text/javascript'; 
ga.async = true;
ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 
'http://www') + '.google-analytics.com/ga.js';
var s = document.getElementsByTagName('script')[0]; 
s.parentNode.insertBefore(ga, s);
})();

</script>
<style></style>
<script type="text/javascript" 
src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>

Original issue reported on code.google.com by sligocki@google.com on 24 Feb 2015 at 4:45

[sligocki]

From lmaroncelli@gmail.com:

[Tue Apr 14 10:11:38 2015] [error] [mod_pagespeed 1.9.32.3-4448 @3747] [0414/101138:ERROR:in_place_resource_recorder.cc(225)] Empty resource in IPRO for URL http://www.info-alberghi.com/js/jquery.countdown.js Response headers: HTTP/1.0 200 (null)\r\nX-Accel-Version: 0.01\r\nX-Accel-Redirect: /internal-nginx-static-location/js/jquery.countdown.js\r\nCache-Control: public, max-age=31536000\r\nExpires: Wed, 13 Apr 2016 08:11:38 GMT\r\nVary: Accept-Encoding\r\nContent-Encoding: gzip\r\nX-Powered-By: PleskLin\r\nContent-Length: 20\r\nConnection: close\r\nContent-Type: text/javascript\r\nDate: Tue, 14 Apr 2015 08:11:38 GMT\r\n\r\n Request headers: GET HTTP/1.0\r\nHost:www.info-alberghi.com\r\nX-Real-IP: 151.47.123.28\r\nX-Forwarded-For: 151.47.123.28\r\nX-Accel-Internal: /internal-nginx-static-location\r\nConnection: close\r\nAccept: /\r\nUser-Agent: Mozilla/5.0 (Linux; Android 4.4.2; it-it; SAMSUNG GT-I9505 Build/KOT49H) AppleWebKit/537.36 (KHTML, like Gecko) Version/1.5 Chrom
e/28.0.1500.94 Mobile Safari/537.36\r\nReferer: http://www.info-alberghi.com/mail_scheda_inviata_new.php\r\nAccept-Encoding: gzip,deflate,sdch

[sligocki]

From @jeffkaufman:

Thanks for sending this! It looks like the key thing in this error is:

X-Accel-Redirect: /internal-nginx-static-location/js/jquery.countdown.js

Your site is set up like this, right?

[user] -> [nginx] -> [apache+mod_pagespeed]

What's happening is that apache is issuing a response like this:

HTTP/1.0 200 (null)
...
X-Accel-Redirect: /internal-nginx-static-location/js/jquery.countdown.js
Cache-Control: public, max-age=31536000
...

[empty response body]

Then nginx sees the X-Accel-Redirect header, and reads the relevant file off of disk to send out as the response body.

We can think of PageSpeed as sitting between nginx and apache, which means it sees this response before the response body is filled in. The problem is, PageSpeed doesn't know it's seeing an incomplete response, so it saves a copy of the response body (empty) as it goes by and then later when it sees references to that file in the html it inlines it as an empty resource.

Thanks for helping us debug this! For your site, and any other sites having this issue with 1.9.32.3 the best fix is to turn off IPRO:

ModPagespeedInPlaceResourceOptimization off

In our next release we'll make sure to handle this case. I think what we need to do is:

• Recognize that X-Accel-Redirect means a response is incomplete, and don't cache it.
• Look for other headers that mean this and blacklist them as well.
• In case there are any other headers used for this, don't cache any responses that have an empty body.

Relevant doc:

• http://download1.parallels.com/Plesk/Doc/en-US/online/plesk-administrator-guide/index.htm?fileName=70837.htm
• http://wiki.nginx.org/XSendfile

[sligocki]

A fix is in progress.

[sachinjsk]

Hi guys,

I'm running into the same issue.

I've setup enjoy-swimming.com with pretty much all the default settings. Rewrite level is set to CoreFilters. With Pagespeed on

<link rel="stylesheet" href="http://www.enjoy-swimming.com/support-files/master.css" type="text/css" />

was getting replaced with:

<style></style>

I could see that there are some css errors in that page, so I tried disabling inline_css filter, but that didn't fix it. It was generating a pagespeed specific cache file, but that was empty.

After reading comments here I tried turning off ModPagespeedInPlaceResourceOptimization, but that didn't help either.

What I find odd is that the page loads fine in Chrome but not in Firefox or Safari. You can see it in action by visiting - http://www.enjoy-swimming.com/?ModPagespeed=on

Please note that the rewritten master.css file looks good in chrome, but is empty in Safari/Firefox.

Domain: http://www.enjoy-swimming.com
Pagespeed version: 1.9.32.3-stable

Thanks for any help.

Sachin

[sligocki]

Hi @sachinjsk,

Can you try flushing the mod_pagespeed cache and see if that fixes things? You can do this by simply changing the filename of master.css to something like master.css?1 or by following these instructions: https://developers.google.com/speed/pagespeed/module/system#purge_cache (Leave ModPagespeedInPlaceResourceOptimization off as well)

This bug is polluting the mod_pagespeed cache and we have separate cache values for different sets of browsers. It looks like your cache has broken values for Firefox, but good values for Chrome, flushing should harmonize them.

[sachinjsk]

Hi @sligocki,

I purged the entire cache via Pagespeed admin page. Still broken in Firefox/Safari.

ModPagespeedInPlaceResourceOptimization is turned off.

[sachinjsk]

Please let me know if there's anything else I can help with to narrow down this bug.

[jeffkaufman]

Checking enjoyswimming.com, in FF I see:

http://www.enjoy-swimming.com/support-files/A.master.css.pagespeed.cf.7KqI9_oL9h.css

which is empty, while in Chrome I see:

http://www.enjoy-swimming.com/support-files/A.master.css.pagespeed.cf.i2p-4h4bmP.css

which consists of a single @import:

@import url(rwd-v2.css)

Loading http://www.enjoy-swimming.com/support-files/rwd-v2.css , that's not empty and has lots of css directives.

[jeffkaufman]

@sachinjsk Could you post your Apache config, or send it to jefftk@google.com ?

Is there anything in your Apache error log marked "error" or "warn"?

[sachinjsk]

@jeffkaufman I'm trying to setup a machine with simpler out of the box apache config. Will send you the config as soon as I have them ready.