I've been experimenting trying to get the time down for some HTTP code which was using LWP. HTTP::Lite was faster then HTTP::GHTTP was faster again and WWW::Curl seemed to be the fastest. However when posting I seem to get a mysterious persistent header string even though I've cleared it. Here is example code:

use strict;
use warnings;
use WWW::Curl::Easy;
use WWW::Curl::Form;
use Encode;

my $hdr;
my $curl = WWW::Curl::Easy->new();
$curl->setopt(CURLOPT_NOPROGRESS, 1); # shut off the built-in progress
+ meter
$curl->setopt(CURLOPT_HEADER, 0); # don't include hdr in body
$curl->setopt(CURLOPT_ENCODING, 'gzip');
$curl->setopt(CURLOPT_PROXY, ''); # no proxy
open my $fh, ">", \$hdr;
$curl->setopt(CURLOPT_WRITEHEADER, $fh);

$curl->setopt(CURLOPT_URL, 'http://xxx.yyy.zzz:82/vx');

post();
print "FIRST HEADER $hdr\n\n";
$hdr = '';
sleep 2;
post();
print "SECOND HEADER $hdr\n";

sub post {
    my $form = WWW::Curl::Form->new;

    $curl->setopt(CURLOPT_HTTPHEADER, ['Expect:','']);
    $form->formadd('method', 'login');
    $form->formadd('username', 'xxx');
    $form->formadd('password', 'xxx');
    $curl->setopt(CURLOPT_HTTPPOST, $form);

    my $response_body;
    $curl->setopt(CURLOPT_WRITEDATA,\$response_body);

    my $retcode = $curl->perform;
    if ($retcode != 0) {
        die "post_request failed (", $retcode,
            " - ", $curl->errbuf, ")";
    }
    my $decoded_content = decode ('utf-8', $response_body);
}
[download]

which outputs

FIRST HEADER HTTP/1.1 200 OK
Server: nginx/1.0.4
Date: Tue, 28 Jun 2011 17:57:39 GMT
Content-Type: application/json; charset=UTF-8
Connection: keep-alive
Set-Cookie: XXX=A6C8DD1FCAEFF6A4E040007F010036E6%3Abcffbfc621258ed7c1f
+4b8fba
d5e515230912a769433656c984bad7a0ceb73ec; path=/; expires=Wed, 29-Jun-2
+011 17:57:
39 GMT
Content-Length: 68



SECOND HEADER HTTP/1.1 200 OK
Server: nginx/1.0.4
Date: Tue, 28 Jun 2011 17:57:39 GMT
Content-Type: application/json; charset=UTF-8
Connection: keep-alive
Set-Cookie: XXX=A6C8DD1FCAEFF6A4E040007F010036E6%3Abcffbfc621258ed7c1f
+4b8fba
d5e515230912a769433656c984bad7a0ceb73ec; path=/; expires=Wed, 29-Jun-2
+011 17:57:
39 GMT
Content-Length: 68

HTTP/1.1 200 OK
Server: nginx/1.0.4
Date: Tue, 28 Jun 2011 17:57:41 GMT
Content-Type: application/json; charset=UTF-8
Connection: keep-alive
Set-Cookie: XXX=A6C8AF9C5885B010E040007F010033A2%3A88dd9574a4b678c1e55
+e0fd63
ec1c2fbebc77c7cfd456473df25dc22db26ab90; path=/; expires=Wed, 29-Jun-2
+011 17:57:
41 GMT
Content-Length: 68
[download]

even though $hdr is cleared between post calls. Notice the data in $hdr in the second case contains the identical data from the first post - see the times. The more times you post the longer $hdr gets like it has stored every header result ever made. I'm quite prepared to find I've done something wrong but I find this strange. Any ideas?

Sorry I cannot provide a URL for the exact service but it is not visible on the net. It is basically a starman service which allows you to login to an API.