Question

I’m not too familiar with Perl, but I am using it for a simple script I am going to write. This script will interface with Qualys so while looking up information about the Qualys API I found this statement while looking through their sample code. I have put it on Pastebin.com (here) so you don’t have to download it to view it. If for some reason you do want to download it yourself, here is a link to the page where I got it for those that want to be able to download the source (it’s the “Get Map” one).

Anyways, here is the statement (line 261) that has me a little confused:

$request = new HTTP::Request GET => $url;

I’m confused about the new and GET => $url parts of the statement.

1. I think I mostly understand what’s going on with the new part of the statement, but if someone could explain how the HTTP::Request works with creating a new LWP::UserAgent that would help clarify this line (I looked at LWP::UserAgent on CPAN, but the “KEY/DEFAULT” table they have under the new subroutine explanation made little sense to me).
2. I really have no idea what is happening in the GET => $url part of the statement. My guess is that it is assigning a value in either HTTP::Request or LWP::UserAgent but I can’t find any information to back up that idea.

Answer 1

The given line is equivalent to

$request = HTTP::Request->new(GET => $url);

which could also be written as

$request = HTTP::Request->new('GET', $url);

The example used the indirect method syntax.

The connection between HTTP::Request and LWP::UserAgent is sketched in the CPAN documentation as followes:

require HTTP::Request;
$request = HTTP::Request->new(GET => 'http://www.example.com/');

$ua = LWP::UserAgent->new;
$response = $ua->request($request);

So The HTTP:.Request->new(...) creates a new request which can be executed by a user agent