HTTP ::守护进程和线程

Question

I have the following code on Windows XP and ActiveState ActivePerl 5.8.

What could be the problem with it? Why does it not work?

I tried to set it as a proxy to my IE but when I connect to some URLs from my IE nothing happens. The code enters the thread function and nothing happens.

use HTTP::Daemon;
use threads;
use HTTP::Status;
use LWP::UserAgent;

my $webServer;
my $d = HTTP::Daemon->new(
    LocalAddr => '127.0.0.1',
    LocalPort => 80,
    Listen    => 20
) || die;

print "Web Server started!\n";
print "Server Address: ", $d->sockhost(), "\n";
print "Server Port: ",    $d->sockport(), "\n";

while (my $c = $d->accept) {
    threads->create(\&process_one_req, $c)->detach();
}

sub process_one_req {
    STDOUT->autoflush(1);
    my $c = shift;
    while (my $r = $c->get_request) {
        if ($r->method eq "GET") {
            print "Session info\n", $r->header('Host');
            my $ua       = LWP::UserAgent->new;
            my $response = $ua->request($r);
            $c->send_response($response);

        } else {
            $c->send_error(RC_FORBIDDEN);
        }

    }
    $c->close;
    undef($c);
}

Answer 1

I added the following line to the code before LWP::UserAgent->new and it seems to be working for me (in linux).

$r->uri("http://" . $r->header('Host') . "/" . $r->uri());

The uri that you got from the HTTP::Request object from the original request does not have the hostname. So added it to make it a absolute uri. Tested as follows:

$ curl -D - -o /dev/null -s -H 'Host: www.yahoo.com' http://localhost:8080/
HTTP/1.1 200 OK
Date: Thu, 27 Jan 2011 12:59:56 GMT
Server: libwww-perl-daemon/5.827
Cache-Control: private
Connection: close
Date: Thu, 27 Jan 2011 12:57:15 GMT
Age: 0
---snip--

UPDATE: Looks like I was completely wrong. I didnt need to make the change to URI object. Your original code worked for me as it is in Linux

Answer 2

If I recall correctly, this is because of the threading model in Windows where file handles are not passed between processes unless specifically asked for. This PerlMonks post seems to shed some light on the underlying problem, and may lead to an approach that works for you (I imagine you may be able to call the windows API on the file descriptor of of the client connection to allow access to it within the spawned thread).

Perl threads on Windows generally make my head hurt, while on UNIX-list systems I find them very easy to deal with. Then again, I imagine figuring out how to correctly use forked processes to emulate threads on a system that ONLY supports threads and not forking would make most people's head hurt.