[squid-users] caching js/css references with parameters, possible squid bug

Wed Mar 23 15:33:29 UTC 2016

On 2016-03-19 04:50, Waitman Gobble wrote:

> On 2016-03-18 01:00, Amos Jeffries wrote:
> 
> On 18/03/2016 3:46 a.m., Waitman Gobble wrote:
> 
> When a script reference on an HTML page includes a parameter, the 
> script
> does not appear to be cached when using squid in accel mode (https).
> 
> For example,
> <script type='text/javascript'
> src='/wp-includes/js/jquery/jquery.js?ver=1.1.13'></script>
> 
> jquery.js does not appear to be cached in that case, each page request
> hits the originserver with a request for jquery.js. (also seems browser
> does not cache, either).
> How are you determining that?
> 
> Dynamic content (as signalled by the '?query-string') is expected to
> revalidate on each use unless that origin has sent explicit 
> cacheability
> headers. In HTTP/1.1 contact with the origin server is not always a 
> full
> fetch.

I was watching HTTP logs on origin server, every page request was also 
creating request for css, js, etc.

waitman.net - [19/Mar/2016:03:47:04 -0700] "GET 
/wp-content/themes/mh-magazine-lite/style.css?ver=2.1.2 HTTP/1.1" 200 
38550 "-"

After removing ?ver from html page, there was initial request:

waitman.net - [19/Mar/2016:03:50:15 -0700] "GET 
/wp-content/themes/mh-magazine-lite/style.css HTTP/1.1" 200 38550 "-"

but after that it was served from cache and no more hits on origin.

Perhaps it was not doing a "full request", but I was looking at the 
content length in the logs, 38550

>> Removing parameters from html allows the scripts to be cached, but I'm
>> wondering if there is a configuration to cache the scripts even with
>> parameter spec? In this case it's only a couple of minor modifications
>> to wp source, but it would be more convenient to avoid mod altogether.
>> 
>> Also, I noticed that when requesting content through squid in proxy 
>> mode
>> (not accel), with SSL request - a newline (\r\n) is appearing in the
>> header *before* the status, ie HTTP/1.1 200 OK. This does not happen
>> with http/80 requests. I haven't tested this thoroughly to be certain
>> that it's a problem in squid, but maybe you have an idea if it's
>> happening in the code? Something to consider. (Note: It could also be 
>> a
>> problem with libcurl, if squid is not the culprit).
> 
> Thats odd. Can you grab a packet trace between the two to figure that 
> out?

Yes, I will check it out and see where the newline is coming from.
I'm in Boston for the LibrePlanet weekend but can check it out next 
week.

I made a little test program and now I see what's going on, maybe this 
isn't actually a squid problem.. It's returning
'HTTP/1.1 200 Connection established'
through proxy SSL , then a space, then the actual headers. The other day 
I did not realize that first header line in my program :)

test program: http://git.cloudqx.com/snippets/2

test results:

https://waitman.net through proxy

# ./testsquid
HTTP/1.1 200 Connection established

HTTP/1.1 200 OK
Strict-Transport-Security: max-age=63072000; includeSubdomains
X-Powered-By: PHP/7.0.4
Content-Type: text/html; charset=UTF-8
X-Pingback: https://waitman.net/xmlrpc.php
Link: <https://waitman.net/wp-json/>; rel="https://api.w.org/"
Link: <https://waitman.net/>; rel=shortlink
Transfer-Encoding: chunked
Date: Wed, 23 Mar 2016 15:10:49 GMT
Server: Syntax error on line 110

<!DOCTYPE html>

http://waitman.net through proxy

# ./testsquid
HTTP/1.1 200 OK
Strict-Transport-Security: max-age=63072000; includeSubdomains
X-Powered-By: PHP/7.0.4
Content-Type: text/html; charset=UTF-8
X-Pingback: https://waitman.net/xmlrpc.php
Link: <https://waitman.net/wp-json/>; rel="https://api.w.org/"
Link: <https://waitman.net/>; rel=shortlink
Date: Wed, 23 Mar 2016 15:11:45 GMT
Server: Syntax error on line 110
X-Cache: MISS from ob4.cloudqx.com
Transfer-Encoding: chunked
Via: 1.1 ob4.cloudqx.com (squid/3.5.15-20160302-r14000)
Connection: keep-alive

https://waitman.net/pagedoesnotexist through proxy

# ./testsquid
HTTP/1.1 200 Connection established

HTTP/1.1 404 Not Found
Strict-Transport-Security: max-age=63072000; includeSubdomains
X-Powered-By: PHP/7.0.4
Expires: Wed, 11 Jan 1984 05:00:00 GMT
Cache-Control: no-cache, must-revalidate, max-age=0
Pragma: no-cache
Content-Type: text/html; charset=UTF-8
Link: <https://waitman.net/wp-json/>; rel="https://api.w.org/"
Transfer-Encoding: chunked
Date: Wed, 23 Mar 2016 15:17:50 GMT
Server: Syntax error on line 110

<!DOCTYPE html>

change test to go through accel

struct curl_slist *host = NULL;
host = curl_slist_append(NULL, "waitman.net:443:127.0.0.1");
curl_easy_setopt(conn, CURLOPT_RESOLVE, host);

https://waitman.net through accel

# ./testsquid
HTTP/1.1 200 OK
Strict-Transport-Security: max-age=63072000; includeSubdomains
X-Powered-By: PHP/7.0.4
Content-Type: text/html; charset=UTF-8
X-Pingback: https://waitman.net/xmlrpc.php
Link: <https://waitman.net/wp-json/>; rel="https://api.w.org/"
Link: <https://waitman.net/>; rel=shortlink
Date: Wed, 23 Mar 2016 15:15:49 GMT
Server: Syntax error on line 110
X-Cache: MISS from ob4.cloudqx.com
Transfer-Encoding: chunked
Via: 1.1 ob4.cloudqx.com (squid/3.5.15-20160302-r14000)
Connection: keep-alive

<!DOCTYPE html>

>> version info:
>> 
>> Squid Cache: Version 3.5.15-20160302-r14000
>> Service Name: squid
>> configure options:  '--prefix=/usr/local/squid' '--with-openssl=/usr'
>> --enable-ltdl-convenience
>> 
>> FreeBSD 10.2-RELEASE-p9 FreeBSD 10.2-RELEASE-p9 #0:
>> 
>> Thanks,

--
Waitman Gobble
Los Altos CA USA
+1 650 900 8557

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