[squid-users] squid seems to be altering Content-Type response headers

Hi list,

I'm a squid newbie, and I'm baffled by this. I see urls that come in
as 'text/xml', but after a while, squid starts declaring them as
'textl/html'. This seems to happen after I get a TCP_REFRESH_HIT/304
or TCP_REFRESH_HIT/200. E.g.:

1257062345.706 0 127.0.0.1 TCP_HIT/200 43811 GET http://wordpress.org/development/feed/ - NONE/- text/xml
1257062349.093 0 127.0.0.1 TCP_HIT/200 43811 GET http://wordpress.org/development/feed/ - NONE/- text/xml
1257062369.819 0 127.0.0.1 TCP_HIT/200 43811 GET http://wordpress.org/development/feed/ - NONE/- text/xml
1257062411.195 0 127.0.0.1 TCP_HIT/200 43811 GET http://wordpress.org/development/feed/ - NONE/- text/xml
1257062417.219 0 127.0.0.1 TCP_HIT/200 43846 GET http://wordpress.org/development/feed/ - NONE/- text/xml
1257062417.768 125 127.0.0.1 TCP_MISS/200 1591 GET http://wordpress.org/favicon.ico - DIRECT/72.233.56.139 application/octet-stream 1257062446.025 129 127.0.0.1 TCP_REFRESH_HIT/304 461 GET http://wordpress.org/development/feed/ - DIRECT/72.233.56.138 text/html

...

1257062489.765 0 127.0.0.1 TCP_HIT/200 43795 GET http://wordpress.org/development/feed/ - NONE/- text/html
1257062561.439 0 127.0.0.1 TCP_HIT/200 43796 GET http://wordpress.org/development/feed/ - NONE/- text/html
1257062568.249 0 127.0.0.1 TCP_HIT/200 43796 GET http://wordpress.org/development/feed/ - NONE/- text/html

When I do:

~# squidclient -m PURGE http://wordpress.org/development/feed/
HTTP/1.0 200 OK
Server: squid/2.7.STABLE7
Date: Sun, 01 Nov 2009 08:12:53 GMT
Content-Length: 0
Expires: Sun, 01 Nov 2009 08:12:53 GMT
X-Cache: MISS from localhost.localdomain
X-Cache-Lookup: NONE from localhost.localdomain:3128
Via: 1.0 localhost.localdomain:3128 (squid/2.7.STABLE7)
Connection: close

Then all's right with the world again:

1257063219.237 395 127.0.0.1 TCP_MISS/200 43779 GET http://wordpress.org/development/feed/ - DIRECT/72.233.56.138 text/xml

...

1257063263.068 0 127.0.0.1 TCP_HIT/200 43809 GET http://wordpress.org/development/feed/ - NONE/- text/xml
1257063265.805 0 127.0.0.1 TCP_HIT/200 43809 GET http://wordpress.org/development/feed/ - NONE/- text/xml

But the pattern seems to be that soon it will begin to return the
incorrect 'text/html' again.

These posts claim that squid shouldn't ever be altering the
Content-Type headers:

http://www.mail-archive.com/squid-users@squid-cache.org/msg67818.html
http://www.squid-cache.org/mail-archive/squid-users/200111/1119.html

Am I missing something obvious? Is this a misconfiguration on my part
(I have a stock Debian Sid installation), or is there something wrong
with the Wordpress site (so far I've only seen the problem with
wordpress.com and wordpress.org, but I haven't tested extensively)?

Celejar

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