#!/usr/local/bin/perl -w
use strict;
use HTTP::Proxy qw/:log/;
use HTTP::Headers ;
use HTTP::Proxy::HeaderFilter::simple;

# Variable init
my $host = undef;
my $port = 80;
my $log_file = "/tmp/proxy.log";
my $localhost = "proxy_host";
my $remotehost = "forwarded_host";
my $agent_timeout = 10;

sub search_credentials {
    my($iv_user,$iv_group) = @_;
    my($ht_user,$ht_passwd);
    # test example
    $ht_user   = 'some_web_user';
    $ht_passwd = 'passwd';
    return ($ht_user,$ht_passwd);
}

open(LOG,">>", $log_file);
my $proxy = HTTP::Proxy->new;
$proxy->port($port);
$proxy->host($host);
$proxy->logfh(*LOG);
$proxy->logmask(STATUS | PROCESS | HEADERS | FILTER); # Debug logging
my $filter = HTTP::Proxy::HeaderFilter::simple->new(
    sub {
        my ( $self, $headers, $message ) = @_;

        my $get_uri = $message->uri() ? $message->uri() : "http://$remotehost/";
        if( $get_uri =~ m%^/%) {
            print "Unaltered URI: $get_uri\n";
            $get_uri =~ s?^/?http://$remotehost/?  ;
            print "Altered URI: $get_uri\n";          
        }

        my $iv_user = $message->header('iv-user');
        my $iv_group = $message->header('iv-group');
        my($ht_user,$ht_passwd) = search_credentials($iv_user,$iv_group);

        $message->authorization_basic($ht_user,$ht_passwd);
    }
);
$proxy->push_filter(request => $filter );
# this is the mainloop
$proxy->start;