How to use Perl to download a file which need a code confirm?

Question

I just begin to learn some Perl based web application, however, I encounter an problem, I try to write a Perl script to download a file, which need input a code before download it. as an example, please see this url: http://epaper.dfdaily.com/dfzb/page/1/2013-08/17/A01/20130817A01_pdf.pdf.

I tried to google somehow i choose to use WWW::Mechanize, as below code, but I can't get the file. Anyone can help me on this? much thanks!!

my code here: (I suppose already get the correct code and store it to $code):

my $mech = WWW::Mechanize -> new();
$mech -> get($url);
$mech -> submit_form(
         form_number => 0,
         fields => {checkCode => $code}
     );

print $mech -> content;

Sorry for the chinese url... But it quite simple to understand. :) — Coeus Wang, Aug 17 '13 at 13:27
It's a CAPTCHA. You need either to cheat, or to be a human being to download it. I suspect StackOverflow users won't help you cheat a CAPTCHA. — David-SkyMesh, Aug 17 '13 at 13:28
If you get permission from the website administrator/owner to download the PDF's in an automated manner, perhaps they'll also provide URLS that only use HTTP Auth (rather than CAPTCHA). — David-SkyMesh, Aug 17 '13 at 13:34
I can not get the permisson... :( So i try to download by input correct CAPTCHA, but I don't know how to submit the request. — Coeus Wang, Aug 17 '13 at 13:37
Can or Cannot (get permission)? (It's unclear from your wording). If you cannot get permission, then stop trying. Just because you want something doesn't mean you should be able to have it. — David-SkyMesh, Aug 17 '13 at 13:37

score 0 · Accepted Answer · answered Aug 17 '13 at 14:39

This is sample code to demonstrate how you can do it. The code will create captcha.jpg file in the programs directory so you can check it and input CAPTCHA after that:

use strict;
use warnings;
use FindBin qw($Bin);
#use HTML::TreeBuilder::XPath;
use WWW::Mechanize;

my $mech = WWW::Mechanize->new();
$mech->agent_alias("Windows IE 6");
$mech->get(
    "http://epaper.dfdaily.com/dfzb/page/1/2013-08/17/A01/20130817A01_pdf.pdf");

#you don't need commented code
#because CAPTCHA URL is always the same for this site
#my $tree = HTML::TreeBuilder->new_from_content( $mech->content() );
#my ($src) = $tree->findvalues('//img[@id="checkcode"]');
$mech->get("http://203.156.244.168:9000/validatecodegen");
open my $fh, ">:raw", "$Bin/captcha.jpg" or die $!;
print {$fh} $mech->content();
close $fh;
$mech->back();

print "Input CAPTCHA: ";
my $code = <>;
chomp $code;
$mech->submit_form(

    with_fields => {
        checkCode => $code,

    },
    button => "Submit",
);

$mech->save_content("$Bin/result.pdf");

How to use Perl to download a file which need a code confirm?

1 Answers1