Can't call method "extract_cookies" on an undefined value

Todd Chester has asked for the wisdom of the Perl Monks concerning the following question:

Hi All,

First, I am really, really new to Perl, so please don't address me like I know what I am doing. You need to directly correct me. I don't mind you calling me a Dumb A** as long as you answer the question.

I am trying to read and set my cookies. I get the following error:

Can't call method "extract_cookies" on an undefined value at ./GetJavaTest.pl line 53 (#1)

If I remove the comment from line 51, a whole web page prints out. I don't get why I am trying to work on an "undefined value". There is tons of stuff in it. This is so frustrating!

The exact cookie I am trying to use is:

http://www.oracle.com/technetwork/java/javase/downloads/jre7-downloads-1880261.html

Lines 1024 to 1029:

function acceptAgreement(windowRef, part){
var doc = windowRef.document;
disableDownloadAnchors(doc, false, part);
hideAgreementDiv(doc, part);
writeSessionCookie( 'oraclelicense', 'accept-securebackup-cookie' );
}
[download]

What the heck (not my actual word) am I doing wrong???

Is there any way I can just write the cookie in like I can with wget? (See the code below for how to use wget.)

Many thanks,

-T

#!/usr/bin/perl

# Test java wget style download of Java

# wget --header "Cookie:
# oraclelicense=accept-securebackup-cookie"
# http://download.oracle.com/otn-pub/java/jdk/7u80-b15/jre-7u80-window
+s-i586.exe

# Notes:
#   This is going in a sub.  Do not use "die"

#   The "echo" of this will be read by a Bash script.  All debug
#   statements need to use STDERR

#   Known mistakes: the multimeg download need to go to a file
#                    not a variable

#                   cookies are not being transfered correctly

# http://www.perlmonks.org/?node_id=456612
# http://lwp.interglacial.com/ch11_01.htm

use strict;
use warnings;
use diagnostics;
# use diagnostics "-verbose";
use Term::ANSIColor qw( BOLD RED RESET );
use LWP::UserAgent;
use HTTP::Cookies qw ( extract_cookies );
use LWP::Protocol qw ( https );
use HTTP::Request qw ( request );

use constant MaxTime3 => scalar 3300; # Seconds

# Indent here is so I don't have to put it back when it goes back into
+ a sub
 
   my $ua;
   my $response;
   my $content;
   my $request;
   my $cookie_jar;
   my $ClickHere = "http://download.oracle.com/otn-pub/java/jdk/7u80-b
+15/jre-7u80-windows-i586.exe";
   my $RevAddr   = "http://www.oracle.com/technetwork/java/javase/down
+loads/jre7-downloads-1880261.html";

   $ua = LWP::UserAgent->new;
   $ua->cookie_jar ( {} );
   $request = HTTP::Request->new('GET', "$RevAddr" );
   print "\$request = ", $request -> as_string, "\n";

   $response = $ua->simple_request($request);
   # print "\$response = ", $response -> as_string, "\n";

   $cookie_jar->extract_cookies($response);

   $ua->timeout ( MaxTime3 );
   $ua->show_progress ( 1 );
   $response = $ua->get ( $ClickHere, ':content_file' => './eraseme.bi
+n' );
   print "\$ClickHere response = ", $response -> as_string, "\n";
[download]

Comment on Can't call method "extract_cookies" on an undefined value Select or Download Code

Replies are listed 'Best First'.
Re: Can't call method "extract_cookies" on an undefined value by NetWallah (Canon) on Oct 17, 2015 at 05:27 UTC
In your code, $cookie_jar is declared, but never assigned. So, it croaks when you try to call a method on it. I think you need: `$ua->cookie_jar ($cookie_jar={}); # instead of $ua->cookie_jar ( {} );` [download] (untested) The best defense against logic is ignorance.	[reply] [d/l]
Re^2: Can't call method "extract_cookies" on an undefined value by Todd Chester (Scribe) on Oct 17, 2015 at 05:39 UTC
That helped. Now I am getting an even sillier error: `Can't call method "extract_cookies" on unblessed reference at ./GetJavaTest.pl line 53 (#1)` changing line 53 to: `$cookie_jar->HTTP::Cookies::extract_cookies($response);` give the same error: `Can't call method "HTTP::Cookies::extract_cookies" on unblessed reference at ./GetJavaTest.pl line 53.` What is an "unblessed reference" anyway?	[reply] [d/l] [select]
Re^3: Can't call method "extract_cookies" on an undefined value by Todd Chester (Scribe) on Oct 17, 2015 at 05:47 UTC
When I look at the web page it downloads, I find `writeSessionCookie( 'oraclelicense', 'accept-securebackup-cookie' );` in it Be nice if I could just add the cookie directly, like I can do with wget.	[reply] [d/l]
Re^4: Can't call method "extract_cookies" on an undefined value by Todd Chester (Scribe) on Oct 17, 2015 at 06:23 UTC
Re^5: Can't call method "extract_cookies" on an undefined value by Anonymous Monk on Oct 17, 2015 at 09:53 UTC
Re: Can't call method "extract_cookies" on an undefined value by tangent (Parson) on Oct 17, 2015 at 11:57 UTC
Normally, you shouldn't need to worry about extracting or setting the cookie at all. If $RevAddr sends a cookie it will be in cookie jar, and it will be returned automatically: `my $ua = LWP::UserAgent->new; $ua->cookie_jar( {} ); # auto calls HTTP::Cookies->new my $response = $ua->get( $RevAddr ); $ua->timeout( 10 ); $ua->show_progress ( 1 ); $response = $ua->get( $ClickHere, ':content_file' => './eraseme.bin' ) +;` [download] However in this case the cookie is set by a javascript function, so the above will not work. But as you already know the cookie you can set it directly: `my $ua = LWP::UserAgent->new; $ua->timeout( 10 ); $ua->show_progress ( 1 ); my $response = $ua->get( $ClickHere, ':content_file' => './eraseme.bin', 'Cookie' => 'oraclelicense=accept-securebackup-cookie', );` [download]	[reply] [d/l] [select]
Re: Can't call method "extract_cookies" on an undefined value by stevieb (Canon) on Oct 17, 2015 at 05:07 UTC
Been many years since I've dealt with anything web-based, but can you show us the implementation (code) of `extract_cookies()`? I may be missing something here, but if not, knowing the details of that subroutine will allow us to know what it's expecting. It's apparent that your `$response` doesn't contain what `extract_cookies()` needs. You get expected output if you `print ">$response<";`?	[reply] [d/l] [select]
Re^2: Can't call method "extract_cookies" on an undefined value by Todd Chester (Scribe) on Oct 17, 2015 at 05:29 UTC
"extract_cookies" comes from: `http://search.cpan.org/~gaas/HTTP-Cookies-6.01/lib/HTTP/Cookies.pm` `$cookie_jar->extract_cookies( $response ) The extract_cookies() method will look for Set-Cookie: and Set-Coo +kie2: headers in the HTTP::Response object passed as argument. Any of + these headers that are found are used to update the state of the $co +okie_jar.` [download] If I uncomment the print line, I get tons of html code.	[reply] [d/l] [select]
Re^3: Can't call method "extract_cookies" on an undefined value by hippo (Archbishop) on Oct 17, 2015 at 09:12 UTC
"extract_cookies" comes from: http://search.cpan.org/~gaas/HTTP-Cookies-6.01/lib/HTTP/Cookies.pm You will see that the synopsis on that page says: `use HTTP::Cookies; $cookie_jar = HTTP::Cookies->new( file => "$ENV{'HOME'}/lwp_cookies.dat", autosave => 1, ); use LWP; my $browser = LWP::UserAgent->new; $browser->cookie_jar($cookie_jar);` [download] But you have not done that in your code. In fact nowhere have you assigned anything at all to the variable `$cookie_jar` as in the second line above. That is the cause of your error message. You should instantiate the jar as shown in the synopsis and then everything should be fine.	[reply] [d/l] [select]
Re^4: Can't call method "extract_cookies" on an undefined value by Todd Chester (Scribe) on Oct 17, 2015 at 21:29 UTC
Re: Can't call method "extract_cookies" on an undefined value by Anonymous Monk on Oct 17, 2015 at 09:31 UTC
You should use the WWW::Mechanize subclass of LWP::UserAgent, its most convenient, you don't have to write 80% of what you wrote See also Re^2: Cannot create a cookie using HTTP::Cookies for secrets	[reply]