Same code different URL not working? - perl

Question

OK, this is driving me mad. I currently run a background script on our server that logs in to our SagePay account every 5 minutes and updates currently logged in users on our local database.
SagePay rolled out a new admin system some time ago but due to many complaints kept the old version running alongside so I never bothered to update my script. SagePay have now decided to decommission the old version so I have no choice.
The following code is just the first part of script that logs in to SagePay:
use LWP::UserAgent;
use HTTP::Cookies;
use HTTP::Request;
use HTTP::Headers;
use HTTP::Request::Common qw(POST);
my $request = "";
my $content = "";
my $req = "";
my $cookie_jar = HTTP::Cookies->new();
my $ua = LWP::UserAgent->new();
$ua->cookie_jar($cookie_jar);
$ua->agent('Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)');
# LOGIN TO SAGEPAGY
$req = (POST 'https://portal.sagepay.com/myoldskool/loginpage.asp',
["vendorname" => "MYVENDORNAME",
"username" => "MYUSERNAME",
"password" => "MYPASSWORD",
"clickedButton" => "login"]);
$request = $ua->request($req);
$content = $request->content;
print $content;
This code works perfectly every time and prints the HTML of the SagePay dashboard as it would if you logged in.
The new POST url is https://portal.sagepay.com/mysagepay/j_spring_security_check and the parameters that need to be passed are pretty much the same, so technically I should just need to make the following alterations to the code and it should work:
$req = (POST 'https://portal.sagepay.com/mysagepay/j_spring_security_check',
["inp_vspvendorname" => "MYVENDORNAME",
"inp_username" => "MYUSERNAME",
"inp_password" => "MYPASSWORD",
"CSRFToken" => ""]);
When I change this code in my script $content prints nothing and I cannot for the life of me figure out why. I've even tried using HttpRequester Firefox addon and sent the same params to the same URL and that returns the dashboard HTML as expected.
$request->status_line is '302 Found'.
Obviously I can't give you my login details for SagePay but even just getting it to return the HTML for an invalid login, at least I'm making progress. I've been stuck on this for a few days now, I'm hoping someone can help.

Answer 1

You're receiving an HTTP 302 response, which is a redirect. By default, LWP::UserAgent doesn't follow redirects with POST requests. To change this, alter the user agent's requests_redirectable array before sending the request:
push #{ $ua->requests_redirectable }, 'POST';
my $response = $ua->request($req);