#!/usr/bin/perl -w # # Copyright 2009 Google Inc. All Rights Reserved.

use CGI; use Digest::MD5 qw(md5_hex); use LWP::UserAgent; use URI::Escape; use strict;

# Tracker version. use constant VERSION => ‘4.4sp’;

use constant COOKIE_NAME => ‘__utmmobile’;

# The path the cookie will be available to, edit this to use a different # cookie path. use constant COOKIE_PATH => ‘/’;

# Two years. use constant COOKIE_USER_PERSISTENCE => ‘+2y’;

# 1x1 transparent GIF my @GIF_DATA = (

0x47, 0x49, 0x46, 0x38, 0x39, 0x61,
0x01, 0x00, 0x01, 0x00, 0x80, 0xff,
0x00, 0xff, 0xff, 0xff, 0x00, 0x00,
0x00, 0x2c, 0x00, 0x00, 0x00, 0x00,
0x01, 0x00, 0x01, 0x00, 0x00, 0x02,
0x02, 0x44, 0x01, 0x00, 0x3b);

my $query = new CGI;

# The last octect of the IP address is removed to anonymize the user. sub get_ip {

 my ($remote_address) = @_;
 if ($remote_address eq "") {
   return "";
 }

# Capture the first three octects of the IP address and replace the forth
# with 0, e.g. 124.455.3.123 becomes 124.455.3.0
 if ($remote_address =~ /^((\d{1,3}\.){3})\d{1,3}$/) {
   return $1 . "0";
 } else {
   return "";
 }

}

# Generate a visitor id for this hit. # If there is a visitor id in the cookie, use that, otherwise # use the guid if we have one, otherwise use a random number. sub get_visitor_id {

my ($guid, $account, $user_agent, $cookie) = @_;

# If there is a value in the cookie, don't change it.
if ($cookie ne "") {
  return $cookie;
}

my $message = "";
if ($guid ne "") {
# Create the visitor id using the guid.
  $message = $guid . $account;
} else {
# otherwise this is a new user, create a new random id.
  $message = $user_agent . get_random_number();
}

my $md5_string = md5_hex($message);

return "0x" . substr($md5_string, 0, 16);

}

# Get a random number string. sub get_random_number {

return int(rand(0x7fffffff));

}

# Writes the bytes of a 1x1 transparent gif into the response. sub write_gif_data {

my ($cookie, $utm_url) = @_;

my @header_args = (
    -type => 'image/gif',
    -Cache_Control =>
        'private, no-cache, no-cache=Set-Cookie, proxy-revalidate',
    -Pragma => 'no-cache',
    -cookie => $cookie,
    -expires => '-1d');

# If the debug parameter is on, add a header to the response that contains
# the url that was used to contact Google Analytics.
if (defined($query->param('utmdebug'))) {
  push(@header_args, -X_GA_MOBILE_URL => $utm_url);
}
print $query->header(@header_args);
print pack("C35", @GIF_DATA);

}

# Make a tracking request to Google Analytics from this server. # Copies the headers from the original request to the new one. # If request containg utmdebug parameter, exceptions encountered # communicating with Google Analytics are thown. sub send_request_to_google_analytics {

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

if (exists($ENV{'HTTP_ACCEPT_LANGUAGE'})) {
  $ua->default_header('Accepts-Language' => $ENV{'HTTP_ACCEPT_LANGUAGE'});
}
if (exists($ENV{'HTTP_USER_AGENT'})) {
  $ua->agent($ENV{'HTTP_USER_AGENT'});
}

my $ga_output = $ua->get($utm_url);

if (defined($query->param('utmdebug')) && !$ga_output->is_success) {
  print $ga_output->status_line;
}

}

# Track a page view, updates all the cookies and campaign tracker, # makes a server side request to Google Analytics and writes the transparent # gif byte data to the response. sub track_page_view {

my $domain_name = "";
if (exists($ENV{'SERVER_NAME'})) {
  $domain_name = $ENV{'SERVER_NAME'};
}

# Get the referrer from the utmr parameter, this is the referrer to the
# page that contains the tracking pixel, not the referrer for tracking
# pixel.
my $document_referer = "-";
if (defined($query->param('utmr'))) {
  $document_referer = uri_unescape($query->param('utmr'));
}
my $document_path = "";
if (defined($query->param('utmp'))) {
  $document_path = uri_unescape($query->param('utmp'));
}

my $account = $query->param('utmac');
my $user_agent = "";
if (exists($ENV{'HTTP_USER_AGENT'})) {
  $user_agent = $ENV{'HTTP_USER_AGENT'};
}

# Try and get visitor cookie from the request.
my $cookie = "";
if (defined($query->cookie(COOKIE_NAME))) {
  $cookie = $query->cookie(COOKIE_NAME);
}

my $guid = "";
if (exists($ENV{'HTTP_X_DCMGUID'})) {
  $guid = $ENV{'HTTP_X_DCMGUID'};
}

my $visitor_id = get_visitor_id($guid, $account, $user_agent, $cookie);

# Always try and add the cookie to the response.
my $new_cookie = $query->cookie(
    -name => COOKIE_NAME,
    -value => $visitor_id,
    -path => COOKIE_PATH,
    -expires => COOKIE_USER_PERSISTENCE);

my $utm_gif_location = "http://www.google-analytics.com/__utm.gif";

my $remote_address = "";
if (exists($ENV{'REMOTE_ADDR'})) {
  $remote_address = $ENV{'REMOTE_ADDR'};
}

# Construct the gif hit url.
my $utm_url = $utm_gif_location . '?' .
    'utmwv=' . VERSION .
    '&utmn=' . get_random_number() .
    '&utmhn=' . uri_escape($domain_name) .
    '&utmr=' . uri_escape($document_referer) .
    '&utmp=' . uri_escape($document_path) .
    '&utmac=' . $account .
    '&utmcc=__utma%3D999.999.999.999.999.1%3B' .
    '&utmvid=' . $visitor_id .
    '&utmip=' . get_ip($remote_address);

send_request_to_google_analytics($utm_url);

# Finally write the gif data to the response.
write_gif_data($new_cookie, $utm_url);

}

track_page_view();