Timestamp for Apache::Upload uploads.

[Matthew Hodgson]

Hi,

I could have sworn that at some point under Apache/1.3.27 and mod_perl/1.27
I had the ability to find a timestamp of some kind for uploaded files using
Apache::Upload.  To be precise, I thought that:

$upload = $apr->upload;
$filehandle = $upload->fh;
$timestamp = (stat($filehandle))[9];

yielded some kind of intelligent timestamp for an uploaded file (last
modification time of the original file on the client computer, istr) when
upped using IE6 or Mozilla 1.2 from Windoze.

However, on trying to recreate this I'm having no joy whatsoever.  On
looking through the $upload->info tied hash, the only mime headers that IE6
provides appear to be

Content-Disposition: form-data; name="sa_spec_upload";
filename="G:\download\filename.jpg"
Content-Type: application/octet-stream

...which is notably lacking any time-related information at all.

Am I completely imagining this ever having worked?  Does anyone know of any
special circumstances where typical browsers such as Mozilla or IE would
submit timestamps for the source file somewhere in the multipart/form-data
MIME encoding?

thanks in advance,

Matthew.

Re: mod_perl 2.0 and print/send_http_header method SEGFAULT

[Stas Bekman]

Stas Bekman wrote:

Jérôme Augé wrote:

[...]

After making your example work, I don't see any segfaults. Please try 
again with modperl-1.99_08 which was released a few days ago.
[...]

1. You can't push_handlers when you are inside a response handler.
Use PerlHeaderParserHandler instead


I've played some more with your original code and did find the segfault 
you were talking about. Though it happens when you use push_handlers in 
the same phase to which you push to. Hence I didn't see it in the code 
that I've fixed.

So most likely your _05 version will work just fine with the version that 
I've posted in my original reply.

Meanwhile I'm looking at how it's the best to prevent from the segfault to 
happen and push_handlers() be used in a wrong place.

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Re: mod_perl 2.0 and print/send_http_header method SEGFAULT

[Stas Bekman]

Jérôme Augé wrote:

Hi,

I'm beginning with mod_perl (mod_perl-1.99_05 + Apache 2.0.40 from
RedHat 8.0) and I want to write a module for rewriting the documents
that passes through the Apache proxy. So, I looked at the
Apache::AdBlocker
(http://perl.apache.org/docs/tutorials/tips/mod_perl_tricks/mod_perl_tricks.html#A_Banner_Ad_Blocker)
module and I'm facing some problems for writing the content of the
documents back to the client.

My main problem is that I get a SEGFAULT when calling the "$r->print()"
or "$r->send_http_header()" method.
I get the request, copy the headers from "headers_in", make my own
request with LWP, copy the headers to "headers_out", then it SEGFAULT
when writing the document ... Are this methods deprecated/not fully
implemented ? what is the correct way to write data to the client ?

The other problem is that if I use the "$r->push_handlers(PerlHandler =>
\&proxy_handler)" mechanism, my "proxy_handler()" function is never
called, so I do the work directly into the handler sub, is this ok ?

I attached my test module below (I register it with a "PerlTransHandler
Apache::Plop" statement in httpd.conf)


After making your example work, I don't see any segfaults. Please try 
again with modperl-1.99_08 which was released a few days ago.

I've attached Plop.pm that apparently works. Hope that this is what you 
wanted to accomplish. I've used the following config:


SetHandler perl-script
PerlHeaderParserHandler Apache::Plop


Now to your code:

1. You can't push_handlers when you are inside a response handler.
Use PerlHeaderParserHandler instead

2. $r->headers_in->do() expects a return value and will abort on 0; see 
the attached code

also it should be:
$request->header( $_[0] => $_[1] );
instead of:
$request->header( {$_[0]} => $_[1] );

have you looked at error_log? You'd have seen that error reported.

3. This is not good:
my $request = HTTP::Request->new( $r->method, $r->uri);
since you don't the whole url. Use this instead:
my $request = HTTP::Request->new( $r->method, $r->construct_url);
this requires 'use Apache::URI'

4.  Finally I've used a special header: (which can be anything)
  $request->header( GetReal => 1 );
to know that now I'm inside the real request.

Hope that this helps.

Also you might want to use a sub-request rather than a heavy weighted LWP 
to accomplish what you do.

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package Apache::Plop;

use strict;
use Apache::RequestRec;
use Apache::RequestIO;
use Apache::RequestUtil;
use Apache::Const;
use Apache::ServerUtil;
use Apache::Response;
use Apache::URI;
use APR::Table;
use LWP::UserAgent;

my $ua = LWP::UserAgent->new();

sub handler {
my $r = shift;

if( $r->proxyreq ) {
return Apache::DECLINED;
}
print STDERR "Good, this is a proxyreq ...\n";

$r->handler("perl-script"); #ok, let's do it   
$r->push_handlers(PerlResponseHandler => \&proxy_handler);
return Apache::OK;
}


sub proxy_handler {
my $r = shift;

if( $r->method ne "GET" ) {
return Apache::DECLINED;
}
print STDERR "Good, this is a GET method ...\n";

if ( ($r->headers_in->get('GetReal')||0) == 1) {
$r->content_type('text/plain');
print "hey";
return Apache::OK;
}

# prepare the "real" request
my $request = HTTP::Request->new( $r->method, $r->construct_url);

# copy headers from client request
my %headers_in;
print STDERR "-- client headers --\n";
$r->headers_in()->do(
sub {
warn "$_[0]: $_[1]\n";
$headers_in{ $_[0] } = $_[1];
$request->header( $_[0] => $_[1] );
return 1;
}
   );
print STDERR "-- end --\n";

# make the "real" request myself
$ua->agent( $headers_in{ 'User-Agent' } );

$request->header( GetReal => 1 );

warn $request->as_string;

my $response = $ua->request( $request );

if ( ! $response->is_success() ) {
print STDERR "== ERROR ==\n";
return Apache::DECLINED;
}

print STDERR "-- server headers --\n";
my %headers_out;
$response->headers()->scan(
sub {
print STDERR "$_[0]: $_[1]\n";
$headers_out{$_[0]} = $_[1];
}
   );
print STDERR "-- end --\n";

# simply override the content
my $content = $response->content;
$content = "plop";

# adjust the headers for the new content
$headers_out{ 'Content-length' } = length( $content );
$headers_out{ 'Content-type' } = 'text/html';

# copy the modified response headers back to Apache
foreach (keys %headers_out) {
   

Re: 1.3.27 DSO hassles

[John D Groenveld]

In message <[EMAIL PROTECTED]>, Stas Bekman writes:
>There were some suggestions offered in this thread (large files CFLAGS?)
>http://marc.theaimsgroup.com/?t=10168427183&r=1&w=2
>Though I didn't see a success report.
>
>If somebody on Solaris 2.6 were able to get it to work, please chime in.

Apache/modperl works fine for me as DSO under Solaris 7,8,9.
2.6 is EOL, but I suspect it will work with latest recommended patches.

Using gcc2.95.3
Using perl5.8, but also worked under 5.6.1 and 5.00503
Build openssl
 ./config --prefix=/opt/openssl \
 --openssldir=/opt/openssl shared
 env LD_RUN_PATH=/opt/openssl/lib make

Build Apache/mod_ssl
 ./configure --with-apache=../apache_1.3.27
 cd ../apache_1.3.27
 env SSL_BASE=/opt/openssl ./configure --prefix=/opt/apache \
 --enable-module=most --enable-shared=max
 # Add the var CFLAGS="-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64" to the env command 
if you want largefiles or built your perl that way
 # Edit src/modules/ssl/Makefile and add -R$(SSL_LIBDIR) to SSL_LDFLAGS
 # If using gcc2, edit src/modules/proxy/Makefile and add 
"-L/path/to/gcc-lib/$host_info/$gcc_version/ -lgcc" to LIBS_SHLIB

Build modperl
 perl Makefile.PL USE_APXS=1 WITH_APXS=/opt/apache/bin/apxs \
 EVERYTHING=1 PERL_TRACE=1 

John
[EMAIL PROTECTED]

Re: 1.3.27 DSO hassles

[Stas Bekman]

Sinclair, Alan (CORP, GEAccess) wrote:

All,
Having been successfully using modperl for the last 2 years statically
linked with Apache, I have been trying again to make modperl work with
1.3.27 when the Apache core modules are loaded as DSOs. There has been some
traffic in the past on this subject and I checked the archives  and followed
through on some of the suggestions
- Recompiled perl 5.6 with the --Ubincompat5005 option for specific use with
modperl
- Setup modperl using the perl compiled with --Ubincompat5005 
- I use the following configure options for the APACI for Apache 1.3.27
./configure --prefix=/opt/apache-so \
--enable-rule=SHARED_CORE \
--enable-module=most \
--enable-shared=max \
--activate-module=src/modules/perl/libperl.a \
--disable-shared=perl 
 
Apache is compiled and statically links modperl without any problems
(Solaris 2.6). When Apache is executed, I receive this error:
fatal: relocation error: file /opt/apache-so/libexec/mod_negotiation.so:
symbol __floatdisf: referenced symbol not found 
I have tried the recommendations, specifically the issue with perl's malloc
on Solaris which can be corrected with the --Ubincompat5005  option.

There were some suggestions offered in this thread (large files CFLAGS?)
http://marc.theaimsgroup.com/?t=10168427183&r=1&w=2
Though I didn't see a success report.

If somebody on Solaris 2.6 were able to get it to work, please chime in.

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Re: Writing to stdin of subprocess under modperl 1.0 fails :/

[Stas Bekman]

Antti Haapala wrote:

Hello all,

	I'm having trouble with following script under mod_perl
1.26 (perl 5.6.1).

use strict ();
use IO::Handle ();
use IPC::Open2 ();


[...]

Use IPC::Run instead of the IPC::Open* family, it surely works and a much 
more flexible tool!

Probably need to add an item to the guide's troubleshooting.


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Re: Inserting a handler in "stack of handlers".

[Stas Bekman]

Geoffrey Young wrote:



Ruslan U. Zakirov wrote:


Hello All!
Short synopsis:
  How to push handler just after handler that working now?
More about the problem.
 I've got main handler, that forms stack of handlers from query 
string
by calling push_handlers(). Then each module doing his job. Some handlers
needs to put another hook just after they end thier job. I do it with
direct call to SomeModule::handler($r), it works for me, but it's rude
back(as i think). I've tried to do the same with push_handlers, but this
function push handlers only at the end of handler's list and content 
appears at
the bottom of page :(
Any suggestion?
Best regards, Ruslan.


you can't really do this now I don't think.  generally, the way would be 
to use get_handlers() to get the current chain, then use set_handlers() 
to set it to what you want it to be (inserting logic to splice the added 
handler where you want it).  unfortunately, you can't call 
set_handlers() for the current phase, so adding another handler right 
after the current one runs probably isn't possible.

That should probably be possible in 2.0, but it's not implemented yet. 
Patches are welcome.


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Re: Load balancers

[Stas Bekman]

John Siracusa wrote:

(This may seem off topic for this list, but I'll try to bring it around
before the end of the message :)

We've been struggling with load balancers for a while now.


It seems that most experts hang at [EMAIL PROTECTED] It's also 
preferrable that the hw solutions will be discussed there.

[...]
This brings me to the mod_perl angle.  Has anyone ever tried using a slimmed
down mod_perl server as a load balancer?  Is this feasible?  Making routing
decisions is obviously the easy part when using mod_perl, but would those
mod_perl apache process just be too big and too slow to proxy requests
efficiently?  And how would they deal with detecting back-end servers that
have failed?


As someone has mentioned, squid is doing that (See the guide). The good 
thing is that it spawns the process and never quits it, so you don't have 
an overhead of perl startup for each request. Indeed it'll use a lot of 
memory. But may be toying with mod_perl 2.0 / threaded mpm will prove to 
be more memory efficient. Also PPerl comes to a mind.

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Re: pre-spawning database connections[newbie]

[Stas Bekman]

Sven Geisler wrote:

Hi Ben,

Do you use Apache::DBI?
I mean yes because you're using connect_on_init.

Apache::DBI do not really close your DBI connection. You will get the
same connection with the same connection parameters, when you call
DBI->connect. All connections are cached by Apache::DBI.

Yes, you should call DBI->connect.

Each sub process will get it's own connections.


What Sven said, plus it helps to RTFM before asking the list. Please read:
http://perl.apache.org/docs/1.0/guide/databases.html#Apache__DBI___Initiate_a_persistent_database_connection


Am Mon, 2003-01-13 um 13.08 schrieb Ben Wrigley:


Hi All,

I'm a mod_perl newbie and just trying to understand a little more about the startup.pl files and prespawning databases. 

I am using the connect_on_init routine in the startup.pl which is fine.

What I'm not sure is then how to use this most economically in my scripts. 

It seems that in the scripts you should call the DBI->connect again, but that seems to be bypassing the connection I made at startup or am I misunderstanding completely.

Thanks for your help

Ben





--


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Re: unsubscribe modperl

[Stas Bekman]

[EMAIL PROTECTED] wrote:

unsubscribe modperl 

The information to unsubscribe is in the header of the email:

list-help: 
list-unsubscribe: 
list-post: 

You have to unsubscribe yourself, I can't help you, so please don't email 
me. ;)

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Re: mod_perl & mod_jk

[Stas Bekman]

MATHIHALLI,MADHUSUDAN (HP-Cupertino,ex1) wrote:

I think I found the problem - it was because of a LoadModule directive that
was defined in 1.99-07, but renamed to PerlLoadModule in 1.99-08. The reason
why I ran into the problem of unable to load mod_jk, was because I was
trying to load mod_jk after the mod_perl is loaded.

What was happening is that the mod_perl directives' gets registered with
Apache as soon as mod_perl is loaded. With the LoadModule defined by
mod_perl also, apache's ap_find_command_in_modules command returns a pointer
to mod_perl's loadmodule function (modperl_cmd_load_module), instead of
apache's load_module function (because mod_perl is the first in the modp
list). And then, to complicate the matters, the cmd->req_override is not set
to EXEC_ON_READ - thus mod_jk is never loaded..

Question: Is it okay if I rename LoadModule to PerlLoadModule in 1.99-07,
and continue with it ?. Does it need more modifications than just renaming
it ?..


Should be just that (though some tests will fail, but ignore that)

Index: src/modules/perl/mod_perl.c
===
RCS file: /home/cvs/modperl-2.0/src/modules/perl/mod_perl.c,v
retrieving revision 1.141
retrieving revision 1.142
diff -u -r1.141 -r1.142
--- src/modules/perl/mod_perl.c 17 Sep 2002 02:05:21 -  1.141
+++ src/modules/perl/mod_perl.c 7 Oct 2002 02:05:43 -   1.142
@@ -636,7 +636,7 @@
 MP_CMD_DIR_RAW_ARGS_ON_READ("=cut", pod_cut, "End of POD"),
 MP_CMD_DIR_RAW_ARGS_ON_READ("__END__", END, "Stop reading config"),

-MP_CMD_SRV_RAW_ARGS("LoadModule", load_module, "A Perl module"),
+MP_CMD_SRV_RAW_ARGS("PerlLoadModule", load_module, "A Perl module"),
 #ifdef MP_TRACE
 MP_CMD_SRV_TAKE1("PerlTrace", trace, "Trace level"),
 #endif



Thanks for the debugging pointers,


You are welcome ;)

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Re: Unregister streamed output filters

[Stas Bekman]

Esteban Fernandez Stafford wrote:

On Sat, 11 Jan 2003, Stas Bekman wrote:



Esteban Fernandez Stafford wrote:


Hello all,

is there a way to unregister a streamed filter? I have seen this in
many (all?) apache (C programmed) filters; they are able of declining
the filtering of a certain stream, for example, when they do not know
how to handle a certain content type. In the apache api this is done
with ap_remove_output_filter(f). Is there something similar in mp2?


Not at this moment, but hopefully it'll be supported soon.

Since you need this feature, telling us in what situation you'd like to
remove a filter will help us to build a better test case and provide a
good real-world example for documentation.



The easiest example that comes to mind is a filter for text/html that
performs some sort of transformation. This filter should unregister for
any content type that is not text/html. Browsing through some apache
code I have found two ways of doing this. One involves the
ap_remove_output_filter function (modules/filters/mod_deflate.c) and
the other returns a DECLINED at a cetrtain point
(modules/filters/mod_include.c). I am not sure about the internals of
each approach but I thought it might help.


Yup, I was reading mod_deflate just yesterday and saw it too. Thanks!


It occurs to me just now that it maybe also be possible to do this
staticaly in httpd.conf. Something like:

PerlOutputFilterHandler  MyApache::MyHtmlFilter text/html


Good idea, eventually there should be TIMTOWTDI ;)


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Re: Load balancers

[Nick Tonkin]

On Mon, 13 Jan 2003, Perrin Harkins wrote:

> John Siracusa wrote:
> > But in a full-fledged mod_perl solution, I could back out gracefully and
> > retry another server if I happened to initially choose a dead server before
> > my dead server detection code caught it.
> 
> That sounds cool, but how important is it really?  I'm not sure any of 
> these solutions (including the commercial ones) do that level of 
> seamless failover effectively.

True, I think. They just keep a table of live and dead servers, but a
request can often get assigned to a dead server before the table is
updated.

In practise this wasn't a problem for us. far more imprtant is that the
'sticky' feature work consistently, so that -- barring a server dying --
clicks-through go to where the impression data are stored (or whatever :)

- nick

   
Nick Tonkin   {|8^)>

1.3.27 DSO hassles

[Sinclair, Alan (CORP, GEAccess)]

All,
Having been successfully using modperl for the last 2 years statically
linked with Apache, I have been trying again to make modperl work with
1.3.27 when the Apache core modules are loaded as DSOs. There has been some
traffic in the past on this subject and I checked the archives  and followed
through on some of the suggestions
- Recompiled perl 5.6 with the --Ubincompat5005 option for specific use with
modperl
- Setup modperl using the perl compiled with --Ubincompat5005 
- I use the following configure options for the APACI for Apache 1.3.27
./configure --prefix=/opt/apache-so \
--enable-rule=SHARED_CORE \
--enable-module=most \
--enable-shared=max \
--activate-module=src/modules/perl/libperl.a \
--disable-shared=perl 
 
Apache is compiled and statically links modperl without any problems
(Solaris 2.6). When Apache is executed, I receive this error:
fatal: relocation error: file /opt/apache-so/libexec/mod_negotiation.so:
symbol __floatdisf: referenced symbol not found 
I have tried the recommendations, specifically the issue with perl's malloc
on Solaris which can be corrected with the --Ubincompat5005  option.

Any ideas
Thanks
Alan

RE: Load balancers

[Nick Tonkin]

On Mon, 13 Jan 2003, Jesse Erlbaum wrote:

> Hi John --
> 
> > That's for all the info so far.  To answer some questions, 
> > hardware is a cost issue right now.  It's somewhat scary that 
> > $3,200 was a "reasonable" price several years ago, but I 
> > suppose it could be worse.  We will investigate further.
> 
> Actually, $3200 was a STEAL!  Cisco's "Local Director" was in the mid
> five-figures at the time, IIRC.  :-)

So it was that range, not $15K as I thought. Yep, I remember that we got
both of them for far far less than a Cisco, and much better support. We
had the chief developer's cell phone number, and he would help us out all
the time. At the time we were growing so fast we were almost a test case
for them ... we took them up to at least 70 million dynamic requests a
day, with stickiness required, using the adaptive balancing, with no real
problems, before moving to the Foundry Systems hardware.

- nick

   
Nick Tonkin   {|8^)>

RE: Load balancers

[Jesse Erlbaum]

Hi Perrin --

> That sounds cool, but how important is it really?  I'm not 
> sure any of 
> these solutions (including the commercial ones) do that level of 
> seamless failover effectively.

I know the CPE will pull faulty servers our of the pool, but it does so
as a separate process (not by backing out of a bad request).  One
process constantly monitors servers, which informs the load-balancing
process as to server availability.

Constant monitoring was done by way of a request made to each server in
the cluster every few seconds.  There were two options.  The first was a
TCP request/response which was customizable.  The second was by way of a
request to a daemon process which was expected to return a server
performance metric.

This latter method was an open architecture -- the user was expected to
write the daemon and implement the metric to work on a scale of 0 to
100, IIRC: 0 == server down, 1 == lightly loaded, 100 == heavily loaded.

TTYL,

-Jesse-


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  [EMAIL PROTECTED]
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  Fax: 212-684-6226

Writing to stdin of subprocess under modperl 1.0 fails :/

[Antti Haapala]

Hello all,

I'm having trouble with following script under mod_perl
1.26 (perl 5.6.1).

use strict ();
use IO::Handle ();
use IPC::Open2 ();

###
#
# Check $username & $password against YP database
sub check_password {
my ($username, $passwd) = @_;

my($rh, $wh);

# open bi-dir pipe
my $pid = IPC::Open2::open2($rh, $wh,
"/usr/local/bin/ypmatch_by_ilmo", $username);

$write->printflush("$passwd\n");

my $ret = <$read>;

close($write);
close($read);

waitpid $pid, 0;

return $ret;
}

This snippet works as expected when run from command line. When run under
mod_perl the program spawned by open2 receives nothing but EOF from its
stdin, but is still able to provide its output to caller process.

What I'm doing wrong? Is there something similar to
Apache::SubProcess::spawn_proc_prog in MP1.x?

-- 
Antti Haapala

Re: Load balancers

[Dzuy Nguyen]

I've developed an embedded (Linux) load balancer solution.  It's small form
factor, runs on 8MB flash minimum, no hard drive, no fan so no wories about
hard drive failure.  It is LVS NAT (L4) based with configurable monitoring
service.  It load balances any port you want.  I've deployed it to load balance
web servers, mail server, etc.  One of the busier sites is using it to load
balance 6 web servers with 5M average hits a day.  They've had twice that
traffic and the load balancer seems to be fine.  LVS says it can balance up
to 24 servers.  Cost $500.

John Siracusa wrote:

That's for all the info so far.  To answer some questions, hardware is a
cost issue right now.  It's somewhat scary that $3,200 was a "reasonable"
price several years ago, but I suppose it could be worse.  We will
investigate further.

The mod_rewrite solutions lack dead server detection, and that's something
I'd rather not try to roll on my own, especially after seeing how well (or
not, actually) existing software solutions do.  But I've added it to the
list.

We're investigating LVS right now.

It's kind of disappointing to hear that the mod_perl solution it probably
not feasible.  Perl solutions are always more fun to implement ;)

We chose pound over pen, but we may revisit pen again.  I suspect we will
have similar problems with our expected load, however.

Whackamole, fun name aside, does not seem to be what we need.

We don't need the caching part of Squid, and I wasn't aware it did load
balancing too.  I'll check it out.

Thanks for all the info, and please feel free to send me more, especially if
there's some gem of a software load balancer out there somewhere... :)

-John

RE: Load balancers

[Stephen Reppucci]

On Mon, 13 Jan 2003, Jesse Erlbaum wrote:

> > That's for all the info so far.  To answer some questions,
> > hardware is a cost issue right now.  It's somewhat scary that
> > $3,200 was a "reasonable" price several years ago, but I
> > suppose it could be worse.  We will investigate further.
>
> Actually, $3200 was a STEAL!  Cisco's "Local Director" was in the mid
> five-figures at the time, IIRC.  :-)

No, the local directors were that never that much, maybe "low
five-figures", like $12-15K or so. Boston.com was running on a pair of
(saturated) low end LD's up until around Y2K, when we revamped the load
balancing architecture and switched over to ArrowPoint (which then got
gobbled up by Cisco) load distributing switches.

At that time, a past-its-prime LD could be had for $3K or so, and a
state-of-the-art Arrowpoint CS-150 ran around $12K (but we installed the
higher capacity CS-800, which ran around $30K each -- just don't ask
them to support HTTP 100% correctly... ;^)

I've been out of touch with hardware load balancing equipment over the
last couple of years, but if the decline in hardware costs of these
things has continued, I'd guess a reasonably chunky solution can be had
in the $5-7K range at this point. (Of course, you'd need to multiply
that cost by two for complete redundancy...)

[ Love to hear from someone with current knowledge if this is the case
  though...]

-- 
Steve Reppucci   [EMAIL PROTECTED] |
Logical Choice Software  http://logsoft.com/ |
=-=-=-=-=-=-=-=-=-=-  My God!  What have I done?  -=-=-=-=-=-=-=-=-=-=

Re: Load balancers

[John Siracusa]

On 1/13/03 1:28 PM, Perrin Harkins wrote:
> John Siracusa wrote:
>> But in a full-fledged mod_perl solution, I could back out gracefully and
>> retry another server if I happened to initially choose a dead server before
>> my dead server detection code caught it.
> 
> That sounds cool, but how important is it really?  I'm not sure any of
> these solutions (including the commercial ones) do that level of
> seamless failover effectively.

The five-figure ones better! ;)

(they should also make me lunch)
-John

Re: Load balancers

[Perrin Harkins]

John Siracusa wrote:

But in a full-fledged mod_perl solution, I could back out gracefully and
retry another server if I happened to initially choose a dead server before
my dead server detection code caught it.


That sounds cool, but how important is it really?  I'm not sure any of 
these solutions (including the commercial ones) do that level of 
seamless failover effectively.

- Perrin

RE: Load balancers

[Jesse Erlbaum]

Hi John --

> That's for all the info so far.  To answer some questions, 
> hardware is a cost issue right now.  It's somewhat scary that 
> $3,200 was a "reasonable" price several years ago, but I 
> suppose it could be worse.  We will investigate further.

Actually, $3200 was a STEAL!  Cisco's "Local Director" was in the mid
five-figures at the time, IIRC.  :-)


> It's kind of disappointing to hear that the mod_perl solution 
> it probably not feasible.  Perl solutions are always more fun 
> to implement ;)

Ah yes...  Fun, for sure.  I would have loved to make one, but that was
just not the correct thing to do at the time.


TTYL,

-Jesse-


--

  Jesse Erlbaum
  The Erlbaum Group
  [EMAIL PROTECTED]
  Phone: 212-684-6161
  Fax: 212-684-6226

Re: Inserting a handler in "stack of handlers".

[Geoffrey Young]

Ruslan U. Zakirov wrote:

Hello All!
Short synopsis:
  How to push handler just after handler that working now?
More about the problem.
 I've got main handler, that forms stack of handlers from query string
by calling push_handlers(). Then each module doing his job. Some handlers
needs to put another hook just after they end thier job. I do it with
direct call to SomeModule::handler($r), it works for me, but it's rude
back(as i think). I've tried to do the same with push_handlers, but this
function push handlers only at the end of handler's list and content appears at
the bottom of page :(
Any suggestion?
Best regards, Ruslan.


you can't really do this now I don't think.  generally, the way would be to 
use get_handlers() to get the current chain, then use set_handlers() to set 
it to what you want it to be (inserting logic to splice the added handler 
where you want it).  unfortunately, you can't call set_handlers() for the 
current phase, so adding another handler right after the current one runs 
probably isn't possible.

HTH

--Geoff

Re: Load balancers

[John Siracusa]

On 1/13/03 1:04 PM, Perrin Harkins wrote:
> John Siracusa wrote:
>> The mod_rewrite solutions lack dead server detection, and that's something
>> I'd rather not try to roll on my own, especially after seeing how well (or
>> not, actually) existing software solutions do.  But I've added it to the
>> list.
> ...
>> It's kind of disappointing to hear that the mod_perl solution it probably
>> not feasible.  Perl solutions are always more fun to implement ;)
> 
> The mod_rewrite option is a Perl solution.  You would write some Perl
> code to manage the availability checks and optionally to provide a new
> load-balancing algorithm.  It's very similar to using mod_perl for it,
> except you get to skip writing lots of annoying proxy code.

But in a full-fledged mod_perl solution, I could back out gracefully and
retry another server if I happened to initially choose a dead server before
my dead server detection code caught it.  With the rewrite solution, I can't
think of a reasonable way to keep users from ever getting passed to dead
server.  (Obviously I can't check the server I plan to send to on every
request :)

-John

Re: Load balancers

[Perrin Harkins]

John Siracusa wrote:

The mod_rewrite solutions lack dead server detection, and that's something
I'd rather not try to roll on my own, especially after seeing how well (or
not, actually) existing software solutions do.  But I've added it to the
list.

...

It's kind of disappointing to hear that the mod_perl solution it probably
not feasible.  Perl solutions are always more fun to implement ;)


The mod_rewrite option is a Perl solution.  You would write some Perl 
code to manage the availability checks and optionally to provide a new 
load-balancing algorithm.  It's very similar to using mod_perl for it, 
except you get to skip writing lots of annoying proxy code.

- Perrin

Re: Load balancers

[John Siracusa]

That's for all the info so far.  To answer some questions, hardware is a
cost issue right now.  It's somewhat scary that $3,200 was a "reasonable"
price several years ago, but I suppose it could be worse.  We will
investigate further.

The mod_rewrite solutions lack dead server detection, and that's something
I'd rather not try to roll on my own, especially after seeing how well (or
not, actually) existing software solutions do.  But I've added it to the
list.

We're investigating LVS right now.

It's kind of disappointing to hear that the mod_perl solution it probably
not feasible.  Perl solutions are always more fun to implement ;)

We chose pound over pen, but we may revisit pen again.  I suspect we will
have similar problems with our expected load, however.

Whackamole, fun name aside, does not seem to be what we need.

We don't need the caching part of Squid, and I wasn't aware it did load
balancing too.  I'll check it out.

Thanks for all the info, and please feel free to send me more, especially if
there's some gem of a software load balancer out there somewhere... :)

-John

RE: OSCON ideas - missing proceedings

[Nathan Torkington]

Mark Schoonover writes:
> Are there plans to do the University again??

Every year or two I try again to revive it.  Your message started me
again this year.  No promises, but we're looking into it.

> Thanks Nat for the work you did down here!! 

Thanks for your kind words.  I love every minute of being at a
conference, so it's hard to describe it as work.[*]

Nat
[*] Just don't ask me about the minutes organizing the conference before
it all happens :-)

Inserting a handler in "stack of handlers".

[Ruslan U. Zakirov]

Hello All!
Short synopsis:
  How to push handler just after handler that working now?
More about the problem.
 I've got main handler, that forms stack of handlers from query string
by calling push_handlers(). Then each module doing his job. Some handlers
needs to put another hook just after they end thier job. I do it with
direct call to SomeModule::handler($r), it works for me, but it's rude
back(as i think). I've tried to do the same with push_handlers, but this
function push handlers only at the end of handler's list and content appears at
the bottom of page :(
Any suggestion?
Best regards, Ruslan.

Re: Load balancers

[Francesc Guasch Ortiz]

John Siracusa wrote:

We've been struggling with load balancers for a while now.  My requirements
are pretty simple. I have a handful of plain and mod_perl apache servers,
So...suggestions?  How are other people handling load balancing?



I have tested pen. It's easy to set up and works fine so far.

The server has only 70k hits/day. I don't know how
will it work under heavy load. The purpose was to keep
working if one server was down.

Pen is a load balancer for "simple" TCP-based protocols such as HTTP or 
SMTP. It allows several servers to appear as one to the outside. It 
automatically detects servers that are down and distributes clients 
among the available servers. This gives high availability and scalable 
performance.

http://siag.nu/pen/

Re: Load balancers

[James G Smith]

Perrin Harkins <[EMAIL PROTECTED]> wrote:
>John Siracusa wrote:
>> But meanwhile, we're still open to alternatives.  Surprisingly, there don't
>> seem to be many (software) options.  (A hardware load balancer is not an
>> option at his time, but I'll also take any suggestions in that area :)
>
>I've always used hardware ones.  I believe big/ip does everything you 
>need.  However, if I were going to use a software solution I would be 
>looking at Linux Virtual Server, probably starting with the Red Hat 
>offering based on it.

We're currently using a couple of big/ip switches, but don't have web
servers behind them yet (using them for smtp and such at the
moment).

We're looking at using them or one of the switches from NetScaler
(netscaler.com) which looked quite impressive.  NetScalar is really
built for web servers (or so it seems from our meetings with them)
while big/ip is a more generic solution.

Both big/ip and netscalar allow sessions to be bound to a backend
server, iirc, which can be a nice optimization (which we haven't had
to take advantage of yet).
-- 
James Smith <[EMAIL PROTECTED]>, 979-862-3725
Texas A&M CIS Operating Systems Group, Unix

Re: Load balancers

[Leo Lapworth]

Hi John,

I use wackamole (http://www.backhand.org/wackamole/) on my (2) front end
servers with 6 IP addresses doing Round Robin (RR) DNS.

This is suffichent for loadbalencing the light (HTML / IMAGE only)
front end. I had a issue with this once, it got the IP address allocation
confused, but otherwise it's been running fine for a year.

The front end machines proxy pass to a backend App (mod_perl) server,
they do this by name e.g. backend-server, we then have a script that
monitors the backend-server and alters the /etc/resolv.conf file if
server 1 goes down and alters the ip address to our second machine.

Our second machine is actually the DB machine so this is just an
emergency fall back until the apps server can be brought up again.

Thankfully I've never had to test this in anger!

Leo

more info:

front ends run debian on standard compaq rack mount servers
backend 2 Sun Solaris boxes, 1 with mod_perl other with MySQL
traffic: 4 / mill pages a month, 50 / 60 hits a second peak

Lots and lots of cacheing on the app and indexes on the DB.

RE: Load balancers

[Jesse Erlbaum]

Hi John --


> But meanwhile, we're still open to alternatives.  
> Surprisingly, there don't seem to be many (software) options. 
>  (A hardware load balancer is not an option at his time, but 
> I'll also take any suggestions in that area :)


Why is hardware not an option?  Cost?  If so, I'd take a look at the
system Nick recommended -- the Coyote Point Equalizer:

  http://www.coyotepoint.com/equalizer.htm

A few years ago I bought their "E-250".  It cost about $3,200, which was
nothing compared to the other solutions out there at the time.  This
load balancing system (LBS) was for a corporate intranet with a user
base of 50k to 60k users, with the expectation that it would be capable
of handling a third of the total user base at any time.

The CPE-250 handled the job with ease.  We initially rolled out with
four separate "Web Application Server" machines ("LAMP" architecture),
and a procedure to allow us to add additional machines in four hours, if
need be.

The system has been in production for about two years.  In that time we
have had individual servers crash, but the intranet has had less than 15
minutes of downtime since we implemented the CPE.


Regarding software solutions, mod_perl or otherwise:  I initially looked
at this, and ultimately rejected it as an option.  No robust systems had
emerged at the time.  Based on a cost/performance comparison against the
CP product I calculated it would cost far more than $3,200 to roll our
own system which would provide the configurability, ease of use and
reliability of the available hardware solution. 


FWIW, the "Equalizer" is implemented as a rack-mountable BSD machine
running custom software.  The software implements load-balancing via
dynamic port-forwarding (*NOT* an HTTP proxy), so it is capable of
forwarding any TCP service (SMTP, database, etc.).  The GUI is
web-based, very easy to use, and includes graphical reporting of
activity.  Load balancing can be configured to be purely round-robin,
but the CPE features a very effective dynamic adaptive load balancing
system based on server response time which is very effective.

It has been a couple years since I talked to Coyote Point about their
product.  I would check to see if it is still cost-competitive.


HTH,

-Jesse-


--

  Jesse Erlbaum
  The Erlbaum Group
  [EMAIL PROTECTED]
  Phone: 212-684-6161
  Fax: 212-684-6226

Re: Load balancers

[Larry Leszczynski]

> The Load Balancing section of this doc might help:
> http://httpd.apache.org/docs/misc/rewriteguide.html
> 
> Just straight apache + mod_rewrite could be the simple solution you
> seek. The Proxy Throughput Round-Robin example shows how to add a
> script to do mapping as well - could work for your availability
> detection requirement.

We've also used mod_rewrite in a lightweight reverse proxy as a stopgap
when load balancing hardware was not available.  One option for detecting
live backend servers is to use the "prg" rewrite map like Paolo says,
where a script does some sort of availability check.  Another option which
we have used is the "rnd" map where a server is selected randomly from a
flat file, where that file can be kept updated by an external (non-Apache)
process like a cron job that checks backend server availability
(mod_rewrite notices on-the-fly when that file has changed).


Larry Leszczynski
[EMAIL PROTECTED]

Re: Redirect or Subprocess - Problems

[Nick Tonkin]

On Mon, 13 Jan 2003, Marc Ian Brewer wrote:

> Hi everybody,
> 
> I have a problem with Mod_Perl 1.27 on Apache 1.3.12. We have an Perl
> Transaction Handler which takes all requests. The Transaction Handler
> is only for redirecting to different pages. One of this pages is an
> embedded Perl page.
> 
> Our problem is, that one request will be proceed more then 3 times
> from the transaction handler. After that the results will be
> displayed. So we will have awful performance problems.
> 
> Our archivtecture is like this :
> 
> 
> --Request-> Perl Transaction Handler (4 or more
> times)---> Content Display By Embedded Perl
> --> Response
> 
> Has someone an idea to solve this problem ???

You do not make your problem very clear. What is "performance
problems?" If you mean that the httpd hangs around for a long time waiting
for the other processes to end, and thus your web server gets bogged down,
than you should look at setting up a thin front-end apache with the
mod_perl server behind. That's the subject of a good deal of info in the
mod_perl Guide and in the archives of this list.


- nick

   
Nick Tonkin   {|8^)>

Re: Load balancers

[Andy Osborne]

John Siracusa wrote:
[snip]
>

But meanwhile, we're still open to alternatives.  Surprisingly, there don't
seem to be many (software) options.  (A hardware load balancer is not an
option at his time, but I'll also take any suggestions in that area :)


[snip]


So...suggestions?  How are other people handling load balancing?


Squid in accelerator mode for ordinary http and the linux virtual
server stuff for https.  Works nicely for us (about a couple of
million requests a day, mostly http).

Andy

--
Andy Osborne    "Vertical B2B Communities"
Senior Internet Engineer
Sift Group100 Victoria Street, Bristol BS1 6HZ
tel:+44 117 915 9600  fax:+44 117 915 9630   http://www.sift.co.uk

Re: Load balancers

[Steven Adams]

On Monday 13 January 2003 08:03 am, John Siracusa wrote:
> (We're running various versions of Linux on our servers, if that makes any
> difference.)
>
> So...suggestions?  How are other people handling load balancing?
>
> -John

Hey John,
Take a look at the LVS project, www.foundrynetworks.com and 
www.f5networks.com. I've used Foundry and F5 gear for load-balancing with 
session persistence and had really good results - cost might be an issue with 
both of these units. I have been putting together an LVS (DR) solution for 
some work that's similar to what your doing but haven't finished it yet.

Steve

Re: Load balancers

[Nick Tonkin]

On Mon, 13 Jan 2003, John Siracusa wrote:

> But meanwhile, we're still open to alternatives.  Surprisingly, there don't
> seem to be many (software) options.  (A hardware load balancer is not an
> option at his time, but I'll also take any suggestions in that area :)

My experience in this area led quickly to the conclusion that there is no
viable software solution, at least when you get a bit of traffic.

We quickly moved to hardware load balancing and did very well with the
Coyote Point Equalizer, which was affordable and powerful. Also the
developers (Bill Kish is/was the lead developer) were very responsive and
worked with us to tweak as necessary.

After a while we got one of those loser "CFOs" who was golf pals with the
new "COO" or something, and he bought a bunch of Foundry Systems Server
Irons that worked alright but were orders of magnitude more expensive.

- nick

   
Nick Tonkin   {|8^)>

Re: Load balancers

[Perrin Harkins]

John Siracusa wrote:

But meanwhile, we're still open to alternatives.  Surprisingly, there don't
seem to be many (software) options.  (A hardware load balancer is not an
option at his time, but I'll also take any suggestions in that area :)


I've always used hardware ones.  I believe big/ip does everything you 
need.  However, if I were going to use a software solution I would be 
looking at Linux Virtual Server, probably starting with the Red Hat 
offering based on it.

This brings me to the mod_perl angle.  Has anyone ever tried using a slimmed
down mod_perl server as a load balancer?  Is this feasible?


Not a good idea.  It would eat all your memory.  You'd be much better 
off with the mod_rewrite solution mentioned in this thread.

- Perrin

Re: Load balancers

[John Siracusa]

On 1/13/03 11:12 AM, Ask Bjoern Hansen wrote:
> On Mon, 13 Jan 2003, John Siracusa wrote:
>> So...suggestions?  How are other people handling load balancing?
> 
> With hardware load balancers.  :-)

Sure, rub it in ;)

> You forgot to include the information about number of servers,
> requests per second at peak times, reponse sizes, etc etc.

* four servers

* peak of 30 hits/sec (fluctuates though)

* response sizes vary: most are less than 20K, but a significant minority
are 500K-5MB (i.e. file downloads)

But really, stability is out #1 concern right now.  Slowdown under load is
much more desirable that "error under load" or "lock-up under load" :)

-John

Re: Memory Usage

[domm]

Hi!

On Mon, Jan 13, 2003 at 10:15:58AM -0500, Chris Faust wrote:

> Sometimes it will run for days without an issue and other times the machine
> will die, normally because of out of memory problems.
> ..
> Any help or direction would be appreciated.

There is quite a lot of documentation about memory issues at
  http://perl.apache.org/docs/1.0/guide/performance.html

or in the mod_perl Site in general.
  http://perl.apache.org
  
Did you RTFM?


-- 
#!/usr/bin/perl   http://domm.zsi.at
for(ref bless{},just'another'perl'hacker){s-:+-$"-g&&print$_.$/}

Re: Load balancers

[Paolo Campanella]

On Mon, 13 Jan 2003 11:03:28 -0500
John Siracusa <[EMAIL PROTECTED]> wrote:

> We've been struggling with load balancers for a while now.  My
> requirements are pretty simple. I have a handful of plain and mod_perl
> apache servers, some of which are identical and a few of which are the
> only ones that can perform unique functions.  We want a load balancer
> that:
>
> 
> * distributes requests to the server(s) that can handle them.  I need to
> route to specific servers based on requested URL and perhaps headers
> and/or protocol type (SSL).
> 
> * detects when a server is down and does not send request to that
> server. This process should be as transparent to the user as possible.
> 
> * doesn't crash or lock up.

The Load Balancing section of this doc might help:
http://httpd.apache.org/docs/misc/rewriteguide.html

Just straight apache + mod_rewrite could be the simple solution you
seek. The Proxy Throughput Round-Robin example shows how to add a
script to do mapping as well - could work for your availability
detection requirement.


Bye

Paolo

Re: Load balancers

[Ask Bjoern Hansen]

On Mon, 13 Jan 2003, John Siracusa wrote:

> So...suggestions?  How are other people handling load balancing?

With hardware load balancers.  :-)

You forgot to include the information about number of servers,
requests per second at peak times, reponse sizes, etc etc.


  - ask

-- 
ask bjoern hansen, http://www.askbjoernhansen.com/ !try; do();

Load balancers

[John Siracusa]

(This may seem off topic for this list, but I'll try to bring it around
before the end of the message :)

We've been struggling with load balancers for a while now.  My requirements
are pretty simple. I have a handful of plain and mod_perl apache servers,
some of which are identical and a few of which are the only ones that can
perform unique functions.  We want a load balancer that:

* distributes requests to the server(s) that can handle them.  I need to
route to specific servers based on requested URL and perhaps headers and/or
protocol type (SSL).

* detects when a server is down and does not send request to that server.
This process should be as transparent to the user as possible.

* doesn't crash or lock up.

We started with mod_backhand, but it frequently seemed to get "confused",
failing to send requests to some hosts that were perfectly able to service
requests, and then locking up entirely when a back-end server became
overloaded.  I also found the diagnostics to be inaccurate and misleading
(or at least poorly documented), and the documentation in general to be
lacking.

Next, we tried "pound", which looked promising due to its simplicity.
Unfortunately, it too seems to freak out at least once a day, filling its
log with errors like this:

@40003e1ef2461015ce34 warning: error read from 123.123.123.123: Success
@40003e1ef24621631c8c warning: cannot read headers. got []
@40003e1ef2462163d424 warning: error read from 123.123.123.123: Success
@40003e1ef2462902488c warning: cannot read headers. got []
@40003e1ef246290332ec warning: error read from 123.123.123.123: Success
@40003e1ef246312225dc warning: cannot read headers. got []
@40003e1ef2463122be34 warning: error read from 123.123.123.123: Success
@40003e1ef24706782a84 warning: cannot read headers. got []
@40003e1ef2470678bef4 warning: error read from 123.123.123.123: Success
@40003e1ef247176094bc warning: cannot read headers. got []

We've been in contact with the author and have tried digging around in
and/or patching the source code with no improvement so far.

But meanwhile, we're still open to alternatives.  Surprisingly, there don't
seem to be many (software) options.  (A hardware load balancer is not an
option at his time, but I'll also take any suggestions in that area :)

This brings me to the mod_perl angle.  Has anyone ever tried using a slimmed
down mod_perl server as a load balancer?  Is this feasible?  Making routing
decisions is obviously the easy part when using mod_perl, but would those
mod_perl apache process just be too big and too slow to proxy requests
efficiently?  And how would they deal with detecting back-end servers that
have failed?

(We're running various versions of Linux on our servers, if that makes any
difference.)

So...suggestions?  How are other people handling load balancing?

-John

Memory Usage

[Chris Faust]

Hi All,

I've converted my site to mod_perl and everything seems great..

Sometimes it will run for days without an issue and other times the machine
will die, normally because of out of memory problems.

My question is, should I be doing anything to worry about memory? I mean I
would think when there was only X amount of memory left then Apache would
know what to do and not use everything that is left (plus some).

Maybe I'm doing something else wrong, I'm not sure..

I don't have the machine local to me, but during normal traffic I've seen
the memory go down at little as 5 meg and then come back on my SSH
connection (normally it would flux between 5-10 meg free up to 100 meg free,
there is 1 gig on the box).

I know this isn't a lot of info, but I'm not positive what I should even be
looking for, I believe mod_perl is all setup correctly, I'm not getting any
strange errors from my scripts or in the error_log.

We currently have 2 machines setup, one is RH 8 with Apache and mod_perl 2.0
and the other is RH 7.3 with Apache and mod_perl 1.3, both seem to have the
same problem although the 2.0 machine seems to have the problem more often.
Both at P4's with 1 gig of ram.

Any help or direction would be appreciated.

Thanks
-Chris

Redirect or Subprocess - Problems

[Marc Ian Brewer]

Hi everybody,
 
I have a problem with Mod_Perl 1.27 on Apache 
1.3.12. We have an Perl Transaction Handler which takes all requests. The 
Transaction Handler is only for redirecting to different pages. One of this pages is an embedded Perl page. 
 
Our problem is, that one request will be proceed 
more then 3 times from the transaction handler. After that the results will be 
displayed. So we will have awful performance problems.
 
Our archivtecture is like this :
 
--Request-> Perl Transaction Handler (4 or more 
times)---> Content Display By Embedded 
Perl --> Response
 
Has someone an idea to solve this problem ???
 
 
Greentings from Germany
 
 
Marc Ian BrewerFraunhofer-Institut für Software- und 
SystemtechnikEmil-Figge-Str. 9144227 Dortmund
 
Tel. 0231/9 76 77 - 419eMail: [EMAIL PROTECTED]

Re: pre-spawning database connections[newbie]

[Sven Geisler]

Hi Ben,

Do you use Apache::DBI?
I mean yes because you're using connect_on_init.

Apache::DBI do not really close your DBI connection. You will get the
same connection with the same connection parameters, when you call
DBI->connect. All connections are cached by Apache::DBI.

Yes, you should call DBI->connect.

Each sub process will get it's own connections.

Regards
Sven.


Am Mon, 2003-01-13 um 13.08 schrieb Ben Wrigley:
> Hi All,
> 
> I'm a mod_perl newbie and just trying to understand a little more about the 
>startup.pl files and prespawning databases. 
> 
> I am using the connect_on_init routine in the startup.pl which is fine.
> 
> What I'm not sure is then how to use this most economically in my scripts. 
> 
> It seems that in the scripts you should call the DBI->connect again, but that seems 
>to be bypassing the connection I made at startup or am I misunderstanding completely.
> 
> Thanks for your help
> 
> Ben

pre-spawning database connections[newbie]

[Ben Wrigley]

Hi All,
 
I'm a mod_perl newbie and just trying to understand 
a little more about the startup.pl files and prespawning databases. 

 
I am using the connect_on_init routine in the 
startup.pl which is fine.
 
What I'm not sure is then how to use this most 
economically in my scripts. 
 
It seems that in the scripts you should call the 
DBI->connect again, but that seems to be bypassing the connection I made at 
startup or am I misunderstanding completely.
 
Thanks for your help
 
Ben

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Re: array through pages

[Sven Geisler]

Hi koudjo,

easy:

use Storable qw(freeze thaw);
use MIME::Base64 qw(encode_base64 decode_base64);


# to encode use:
$pass_throw_var = encode_base64(freeze(\@your_array));

...

# to decode use:
$your_array_ref = thaw(decode_base64($pass_throw_var));


Regards
Sven.

Am Mon, 2003-01-13 um 10.26 schrieb koudjo ametepe:
> hello everybody
> 
> thank you for al your request and suggests.
> 
> I have a problem with array in perl cgi .I want to pass an array trhough two 
> pages , just like we do with a simple varaiable ; but i can't find the way 
> to do it .
> 
> Please can you give me sme ideas about it
> 
> Thank you
> 
> koudjo
> 
> 
> 
> 
> _
> MSN Search, le moteur de recherche qui pense comme vous ! 
> http://search.msn.fr/worldwide.asp
> 
> 

array through pages

[koudjo ametepe]

hello everybody

thank you for al your request and suggests.

I have a problem with array in perl cgi .I want to pass an array trhough two 
pages , just like we do with a simple varaiable ; but i can't find the way 
to do it .

Please can you give me sme ideas about it

Thank you

koudjo




_
MSN Search, le moteur de recherche qui pense comme vous ! 
http://search.msn.fr/worldwide.asp

array through pages

[koudjo ametepe]

hello everybody
thank you for al your request and suggests.
I have a problem with array in perl cgi .I want to pass an array trhough two pages , just like we do with a simple varaiable ; but i can't find the way to do it .
Please can you give me sme ideas about it 
Thank you 
koudjo MSN Search, le moteur de recherche qui pense comme vous ! Cliquez-ici 

mod_perl 2.0 and print/send_http_header method SEGFAULT

[Jérôme Augé]

Hi,

I'm beginning with mod_perl (mod_perl-1.99_05 + Apache 2.0.40 from
RedHat 8.0) and I want to write a module for rewriting the documents
that passes through the Apache proxy. So, I looked at the
Apache::AdBlocker
(http://perl.apache.org/docs/tutorials/tips/mod_perl_tricks/mod_perl_tricks.html#A_Banner_Ad_Blocker)
module and I'm facing some problems for writing the content of the
documents back to the client.

My main problem is that I get a SEGFAULT when calling the "$r->print()"
or "$r->send_http_header()" method.
I get the request, copy the headers from "headers_in", make my own
request with LWP, copy the headers to "headers_out", then it SEGFAULT
when writing the document ... Are this methods deprecated/not fully
implemented ? what is the correct way to write data to the client ?

The other problem is that if I use the "$r->push_handlers(PerlHandler =>
\&proxy_handler)" mechanism, my "proxy_handler()" function is never
called, so I do the work directly into the handler sub, is this ok ?

I attached my test module below (I register it with a "PerlTransHandler
Apache::Plop" statement in httpd.conf)

Thanks for your help,
Jérôme

-- 


package Apache::Plop;

use strict;
use Apache::RequestRec;
use Apache::RequestIO;
use Apache::RequestUtil;
use Apache::Const;
use Apache::ServerUtil;
use Apache::Response;
use APR::Table;
use LWP::UserAgent;

my $ua = LWP::UserAgent->new();

sub handler {
my $r = shift;

if( ! $r->proxyreq ) {
return Apache::DECLINED;
}
print STDERR "Good, this is a proxyreq ...\n";

# -->
# if I use this push_handlers, I never reach the "proxy_handler" sub
# So I commented it out and tried to do the work directly in "handler"

#$r->handler("perl-script"); #ok, let's do it   
#$r->push_handlers(PerlHandler => \&proxy_handler); 
#}
#
#sub proxy_handler {
#my $r = shift;

# <--

if( $r->method ne "GET" ) {
return Apache::DECLINED;
}
print STDERR "Good, this is a GET method ...\n";

# prepare the "real" request
my $request = HTTP::Request->new( $r->method, $r->uri );

# copy headers from client request
my %headers_in;
print STDERR "-- client headers --\n";
$r->headers_in()->do(
sub {
print STDERR "$_[0]: $_[1]\n";
$headers_in{$_[0]} = $_[1];
$request->header( {$_[0]}, $_[0] );
}
);
print STDERR "-- end --\n";

# make the "real" request myself
$ua->agent( $headers_in{ 'User-Agent' } );
my $response = $ua->request( $request );

if( ! $response->is_success() ) {
print STDERR "== ERROR ==\n";
return Apache::DECLINED;
}

print STDERR "-- server headers --\n";
my %headers_out;
$response->headers()->scan(
sub {
print STDERR "$_[0]: $_[1]\n";
$headers_out{$_[0]} = $_[1];
}
);
print STDERR "-- end --\n";

# simply override the content
my $content = $response->content;
$content = "plop";

# adjust the headers for the new content
$headers_out{ 'Content-length' } = length( $content );
$headers_out{ 'Content-type' } = 'text/html';

# copy the modified response headers back to Apache
foreach (keys %headers_out) {
$r->headers_out->{$_} = $headers_out{$_};
}
$r->content_type( $headers_out{ 'Content-type' } );

print STDERR "-- send/print --\n";

# -->
# here is where the SEGFAULT occurs

$r->send_http_header();
$r->print( $content );

# I don't know how to write a content back to the client :(
# <--

print STDERR "-- end --\n";

return Apache::OK;
}

1;