You need an IP address (maybe a hostname) in the constructor, not a URL.

You'll need to read up on HTTP (as a protocol) to find out what kind of request you can make to retrieve a web page. It'll be something like this:

my $request = "GET /path/to/file.html HTTP/1.0\n\n";
print $socket $request;
my $result;
{ 
    local $/;
    $result = <$socket>;
}
[download]

That's highly untested.