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Posted to users@tomcat.apache.org by André Warnier <aw...@ice-sa.com> on 2011/07/14 12:29:38 UTC
response headers missing ?
Hi.
This is a bit of a side question, or let's say a question-by-proxy.
I happen to be also subscribed to a support list for mod_perl, and someone there made the
following comment as part of a post :
quote
We have 100+ web servers where apache fronts a separate tomcat server using mod_proxy.
Sadly, the tomcat dev's forgot to set any caching headers in the HTTP response (either
Expires, Last-Modified or Cache-control) so the sites are largely uncacheable by browsers
and the various tomcats are becoming overloaded.
unquote
Do any of the dev's here have a comment to make ?
(sadly, the mod_perl OP failed to provide any version information so far).
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Re: response headers missing ?
Posted by André Warnier <aw...@ice-sa.com>.
Rainer Jung wrote:
> On 14.07.2011 12:29, André Warnier wrote:
>> Hi.
>>
>> This is a bit of a side question, or let's say a question-by-proxy.
>>
>> I happen to be also subscribed to a support list for mod_perl, and
>> someone there made the following comment as part of a post :
>>
>> quote
>>
>> We have 100+ web servers where apache fronts a separate tomcat server
>> using mod_proxy.
>>
>> Sadly, the tomcat dev's forgot to set any caching headers in the HTTP
>> response (either Expires, Last-Modified or Cache-control) so the sites
>> are largely uncacheable by browsers and the various tomcats are becoming
>> overloaded.
>>
>> unquote
>>
>> Do any of the dev's here have a comment to make ?
>
> Yes, go for TC 7:
>
> http://tomcat.apache.org/tomcat-7.0-doc/config/filter.html#Expires_Filter
>
Genial, Rainer.
That looks exactly like what the mod_perl OP was looking for.
Even the reference to the Apache mod_expires will help him, I think.
Thanks.
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Re: response headers missing ?
Posted by Rainer Jung <ra...@kippdata.de>.
On 14.07.2011 12:29, André Warnier wrote:
> Hi.
>
> This is a bit of a side question, or let's say a question-by-proxy.
>
> I happen to be also subscribed to a support list for mod_perl, and
> someone there made the following comment as part of a post :
>
> quote
>
> We have 100+ web servers where apache fronts a separate tomcat server
> using mod_proxy.
>
> Sadly, the tomcat dev's forgot to set any caching headers in the HTTP
> response (either Expires, Last-Modified or Cache-control) so the sites
> are largely uncacheable by browsers and the various tomcats are becoming
> overloaded.
>
> unquote
>
> Do any of the dev's here have a comment to make ?
Yes, go for TC 7:
http://tomcat.apache.org/tomcat-7.0-doc/config/filter.html#Expires_Filter
Regards,
Rainer
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Re: response headers missing ?
Posted by Konstantin Kolinko <kn...@gmail.com>.
2011/7/14 André Warnier <aw...@ice-sa.com>:
> Hi.
>
> This is a bit of a side question, or let's say a question-by-proxy.
>
> I happen to be also subscribed to a support list for mod_perl, and someone
> there made the following comment as part of a post :
>
> quote
>
> We have 100+ web servers where apache fronts a separate tomcat server using
> mod_proxy.
>
> Sadly, the tomcat dev's forgot to set any caching headers in the HTTP
> response (either Expires, Last-Modified or Cache-control) so the sites are
> largely uncacheable by browsers and the various tomcats are becoming
> overloaded.
>
> unquote
>
> (sadly, the mod_perl OP failed to provide any version information so far).
>
AFAIK, DefaultServlet sets those headers, as well as ETag.
For JSP files or Servlets adding the headers is responsibility of their authors.
Well, usually JSPs and servlets have varying info and thus do not need
caching (or may have some time-limited caching, like 1 minute, or 10
seconds).
I think there was a filter somewhere, that can add those headers. I
think UrlRewriteFilter can be set up to add them as well.
Best regards,
Konstantin Kolinko
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Re: response headers missing ?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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Pid,
On 7/14/2011 6:37 AM, Pid wrote:
> I'd ask the OP to back that up with an explanation and some proof,
> contrary to the below:
Can you clarify this? It looks like request and response headers jumbled
together.
> Request URL:http://localhost:8081/tomcat.png Request Method:GET
> Status Code:304 Not Modified
^^^ Looks like start of response.
> Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
>
>
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
> Accept-Encoding:gzip,deflate,sdch Accept-Language:en-US,en;q=0.8
> Cache-Control:max-age=0 Connection:keep-alive Host:localhost:8081
> If-Modified-Since:Sat, 02 Jul 2011 21:38:58 GMT
> If-None-Match:W/"5103-1309642738000" User-Agent:Mozilla/5.0
> (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/535.1 (KHTML, like
> Gecko) Chrome/14.0.803.0 Safari/535.1
^^^ Definitely client headers.
> Date:Thu, 14 Jul 2011 10:35:31 GMT ETag:W/"5103-1309642738000"
> Server:Apache-Coyote/1.1
^^^ Definitely response headers.
Neither Expires nor Last-Modified nor Cache-Control appear in the
response headers, which was the original complaint.
One could argue that Etag is a proxy/replacement for Expires and
Last-Modified.
- -chris
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Re: response headers missing ?
Posted by Pid <pi...@pidster.com>.
On 14/07/2011 11:29, André Warnier wrote:
> Hi.
>
> This is a bit of a side question, or let's say a question-by-proxy.
>
> I happen to be also subscribed to a support list for mod_perl, and
> someone there made the following comment as part of a post :
>
> quote
>
> We have 100+ web servers where apache fronts a separate tomcat server
> using mod_proxy.
>
> Sadly, the tomcat dev's forgot to set any caching headers in the HTTP
> response (either Expires, Last-Modified or Cache-control) so the sites
> are largely uncacheable by browsers and the various tomcats are becoming
> overloaded.
>
> unquote
I'd ask the OP to back that up with an explanation and some proof,
contrary to the below:
Request URL:http://localhost:8081/tomcat.png
Request Method:GET
Status Code:304 Not Modified
Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Cache-Control:max-age=0
Connection:keep-alive
Host:localhost:8081
If-Modified-Since:Sat, 02 Jul 2011 21:38:58 GMT
If-None-Match:W/"5103-1309642738000"
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8)
AppleWebKit/535.1 (KHTML, like Gecko) Chrome/14.0.803.0 Safari/535.1
Date:Thu, 14 Jul 2011 10:35:31 GMT
ETag:W/"5103-1309642738000"
Server:Apache-Coyote/1.1
p
> Do any of the dev's here have a comment to make ?
>
> (sadly, the mod_perl OP failed to provide any version information so far).
Re: response headers missing ?
Posted by Christopher Schultz <ch...@christopherschultz.net>.
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André,
On 7/14/2011 7:25 AM, André Warnier wrote:
> quote [...] I would also add that most of the sites are "dynamically"
> driven pages, even involving MySQL querying, but once launched, the
> data remains fairly static - eg GET X will always resolve to reponse
> Y.
>
> [...]
>
> I think for this problem, I have to treat tomcat as a little, rather
> inefficient, black box and try to fixup on the apache front ends,
> hence the direction of my original idea...
>
> unquote
>
> One interesting suggestion here was to use the URLRewriteFilter. I
> will pass that on to the mod_perl OP.
If the OP is willing to get into the Java world, it might be easier to
write a simpler filter, since I think URLRewriteFilter expects to, you
know, re-write the request and not just add headers.
If "GET X" always returns "response Y", then a simple use of mod_headers
ought to do the trick with no mucking-around in Java.
- -chris
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Re: response headers missing ?
Posted by Stefan Mayr <st...@mayr-stefan.de>.
Am 14.07.2011 13:25, schrieb André Warnier:
> Mark Thomas wrote:
>> On 14/07/2011 11:29, André Warnier wrote:
>>> Hi.
>>>
>>> This is a bit of a side question, or let's say a question-by-proxy.
...
> I think for this problem, I have to treat tomcat as a little, rather
> inefficient, black box and try to fixup on the apache front ends, hence
> the direction of my original idea...
If you have no chance to get these applications fixed - keep it this
way. Treat the tomcat as black box and add cache-control headers on the
apache-frontend where possible.
Use Location(Match) and mod_headers to append whatever is needed to the
server response to make it browser-cachable
Stefan
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Re: response headers missing ?
Posted by André Warnier <aw...@ice-sa.com>.
Mark Thomas wrote:
> On 14/07/2011 11:29, André Warnier wrote:
>> Hi.
>>
>> This is a bit of a side question, or let's say a question-by-proxy.
>>
>> I happen to be also subscribed to a support list for mod_perl, and
>> someone there made the following comment as part of a post :
>>
>> quote
>>
>> We have 100+ web servers where apache fronts a separate tomcat server
>> using mod_proxy.
>>
>> Sadly, the tomcat dev's forgot to set any caching headers in the HTTP
>> response (either Expires, Last-Modified or Cache-control) so the sites
>> are largely uncacheable by browsers and the various tomcats are becoming
>> overloaded.
>>
>> unquote
>>
>> Do any of the dev's here have a comment to make ?
>
> "Sadly, the mod_perl OP forget to do any research (such as requesting
> Tomcat's homepage and reading the headers) so my response is largely
> unprintable in polite society and the various Tomcat devs are becoming
> under impressed."
>
Wooaw.
It was not my intention to start an inter-Apache-list war here, so I have a couple of
things to add :
1) reading the next post of the original mod_perl poster, it has become clear to me that
what he meant by "the tomcat dev's" was not "The Tomcat Dev's". He obviously meant "the
dev's who developed the applications running under Tomcat".
And he was not talking about static pages, it is more complicated than that.
So you can all get back to being your usual serene and competent helpful selves again.
2) to further dispel the issue, here is the second post by the same OP.
(I also have to add that I am quoting all this without permission, and it was just by
curiosity).
quote
...
> Assuming that what you say about Tomcat is true (I don't know, and it
> may be worth asking this on the Tomcat list), I can think of another way
> to achieve what you seem to want :
> if you can distinguish, from the request URL (or any other request
> property), the requests that are for invariant things, then you could
> arrange to /not/ proxy these requests to Tomcat, and serve them directly
> from Apache httpd.
Indeed that is a good idea. We are doing that for new projects for css and js files
(apache does not proxy certain paths and picks these up from the local filesystem).
We can't do that for the 100 odd legacy servers as no-one has time o delve into the
java/JSP code. I need to do something "outside" of tomcat where possible. Just to explain,
each web server is a paid-for project - and when it's done, it sits there for 5+ years.
Only I have the time/inclination to fix this as it's killing my VMWare infrastructure.
Because the sites are all fronted by apache in a similar way, one solution is likely to
apply to most of the sites.
I would also add that most of the sites are "dynamically" driven pages, even involving
MySQL querying, but once launched, the data remains fairly static - eg GET X will always
resolve to reponse Y.
I'm planning a small seminar on the value of Cache-Control for my dev colleagues so they
can stop making this mistake ;-> But that still leaves a lot of "done" projects to fix.
> Which proxying method exactly are you using between Apache and Tomcat ?
> (if you are using mod_proxy, then you are either using mod_proxy_http or
> mod_proxy_ajp; you could also consider using mod_jk).
mod_proxy_http specifically.
mod_jk looks interesting for new projects (we have local tomcats for those now) - I think
it may be a non-starter for old stuff as trying to retro fit it may not be so simple (our
older tomcat servers are in a remote farm on their own machines hence the use of
mod_proxy_http).
> Also, what are the versions of Apache and Tomcat that you are using ?
>
Apache 2.2 (various sub versions) and both tomcat 5.5 and tomcat 6 (but all on remote
machines listening on TCP sockets).
I think for this problem, I have to treat tomcat as a little, rather inefficient, black
box and try to fixup on the apache front ends, hence the direction of my original idea...
unquote
.. and I am sure that he does not *really* mean it either, like he says in that last phrase.
One interesting suggestion here was to use the URLRewriteFilter. I will pass that on to
the mod_perl OP.
Thanks for your answers, and peace to all.
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Re: response headers missing ?
Posted by Mark Thomas <ma...@apache.org>.
On 14/07/2011 11:29, André Warnier wrote:
> Hi.
>
> This is a bit of a side question, or let's say a question-by-proxy.
>
> I happen to be also subscribed to a support list for mod_perl, and
> someone there made the following comment as part of a post :
>
> quote
>
> We have 100+ web servers where apache fronts a separate tomcat server
> using mod_proxy.
>
> Sadly, the tomcat dev's forgot to set any caching headers in the HTTP
> response (either Expires, Last-Modified or Cache-control) so the sites
> are largely uncacheable by browsers and the various tomcats are becoming
> overloaded.
>
> unquote
>
> Do any of the dev's here have a comment to make ?
"Sadly, the mod_perl OP forget to do any research (such as requesting
Tomcat's homepage and reading the headers) so my response is largely
unprintable in polite society and the various Tomcat devs are becoming
under impressed."
Mark
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