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

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

I have logged into my adsl modem using the following code.

use strict;
use WWW::Mechanize;
use LWP::Simple;
use MIME::Base64;

my $pubIP = get("http://whatismyip.org/");
my $url = "http://$pubIP/resetrouter.html";

my $username = "foo";
my $password = "bar";
my $button = "Save/Reboot";

my @args = (
    Authorization => "Basic " .
        MIME::Base64::encode( $username . ':' . $password )
);

my $mech = WWW::Mechanize->new(autocheck => 1);

$mech->credentials( $url, "test", $username, $password );
$mech->get( $url, @args ) or die $mech->die;
print $mech->content;
$mech->click($button);
[download]

the return value of print $mech->content; is as follows which means i have successfully logged into my adsl modem:

<html>
   <head>
      <meta HTTP-EQUIV='Pragma' CONTENT='no-cache'>
      <link rel="stylesheet" href='stylemain.css' type='text/css'>
         <link rel="stylesheet" href='colors.css' type='text/css'>
            <script language="javascript">
<!-- hide

function btnReset() {
   var code = 'location="rebootinfo.cgi"';
   eval(code);
}

function frmLoad() {
   var sysReboot = '0';
   var lanRefresh = '0';

   if ( sysReboot == '1' )
      btnReset();
   else if ( lanRefresh == '1' ) {
      var code = 'location="resetrouter.cgi?lanRefresh=0"';
      eval(code);
   }
}

// done hiding -->
</script>
   </head>
   <body onLoad='frmLoad()'>
      <blockquote>
         <center>
            <br>
            <strong>Click the button below to save and reboot the rout
+er.</strong>
      </blockquote></center>
      <p align="center">
         <input type='button' onClick='btnReset()' value='Save/Reboot'
+>
         <br>
      </p>
   </body>
</html>
[download]

but immediately after print statement, as i pass through the $mech->click($button) statement i am getting the error Can't call method "click" on an undefined value at c:/Perl/site/lib/WWW/Mechanize.pm line 707.

did lot of googling and searching perl monk as well...got the results as saying the object is not initiated...in my case $mech....but i can't see how.

Please suggest me where am i doing it wrong.

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

Replies are listed 'Best First'.
Re: Can't call method "click" on an undefined value by ikegami (Patriarch) on Jun 01, 2008 at 03:41 UTC
Note that the error is origination from within WWW::Mechanize. It's not `$mech` that's undefined. `WWW::Mechanize::click` in turns calls the method `click` of another object. The problem is that WWW::Mechanize doesn't find the button you want it to find but proceeds to try to click it anyway. According to the docs, The first argument is the name of the button to be clicked The document doesn't contain any buttons named `Save/Reboot`. You'd be better off using a method that can locate a button by value, such as `click_button`. `$mech->click_button( value => $button );` [download]	[reply] [d/l] [select]
Re^2: Can't call method "click" on an undefined value by Anonymous Monk on Jun 01, 2008 at 04:08 UTC
Actually, its because he hasn't selected a form (form_name form_number), and since there are no forms on the page	[reply]
Re: Can't call method "click" on an undefined value by Anonymous Monk on Jun 01, 2008 at 03:42 UTC
`my $pubIP = get("http://whatismyip.org/"); my $url = "http://$pubIP/resetrouter.html";` [download] Thats a prefect way for someone to compromise your router. How do I get the local internet IP address? How do I find out my hostname/domainname/IP address?	[reply] [d/l]
Re: Can't call method "click" on an undefined value by ikegami (Patriarch) on Jun 01, 2008 at 21:07 UTC
In short, it sounds like you have three problems, one of which hasn't been mentioned yet. There's no FORM element, and it sounds like WWW::Mechanize needs one. That's not even valid HTML. `->click($bttn_val)` should probably be `->click_button(value => $bttn_val)` WWW::Mechanize can't process JavaScript.	[reply] [d/l] [select]
Re: Can't call method "click" on an undefined value by Anonymous Monk on Jun 01, 2008 at 04:13 UTC
Look at the javascript, to reset the router, just `->get('.../rebootinfo.cgi');`	[reply] [d/l]
Re^2: Can't call method "click" on an undefined value by neoanantha (Initiate) on Jun 01, 2008 at 10:20 UTC
appending the cgi to url did it for time being...i am now able to reboot my adsl modem... but still i would have wanted to achieve it by clicking the button...anyways will keep trying...am sure object instantiation is creating problem somewhere...but unable to trace it thanks for ur help monks...truly appreciated	[reply]
Re^3: Can't call method "click" on an undefined value by Anonymous Monk on Jun 01, 2008 at 11:42 UTC
That is impossible. 1. The html is broken (no form tags), which is why there is no default form, to be set as default, or for you to select (via `$mech->form_name or $mech->form_number`), and why `$mech->click` doesn't work. This is a bug in WWW::Mechanize, it should throw a useful error messages, example `use WWW::Mechanize; $ua=WWW::Mechanize->new; $ua->get('http://search.cpan.org');#got a form warn $ua->forms; warn $ua->submit; $ua->get('http://cpan.org');#no forms here warn $ua->forms; warn $ua->submit; #dies here __END__ HTML::Form=HASH(0x1d76ca0) at - line 6. HTTP::Response=HASH(0x1d77114) at - line 7. Warning: something's wrong at - line 9. Can't call method "make_request" on an undefined value at D:/Perl/site +/lib/WWW/Mechanize.pm line 1641.` [download] 2. Clicking the button calls javascript, which is not supported (see WWW::Mechanize::FAQ). Besides, the javascript only redirects to rebootinfo.cgi (and it does that with eval -- whoever wrote this should be shot).	[reply] [d/l] [select]
Re: Can't call method "click" on an undefined value by Anonymous Monk on Jun 01, 2008 at 03:36 UTC
Please suggest me where am i doing it wrong. Upgrade WWW::Mechanize	[reply]
Re^2: Can't call method "click" on an undefined value by neoanantha (Initiate) on Jun 01, 2008 at 04:19 UTC
upgraded to 1.34 still getting the same error: Can't call method "click" on an undefined value at c:/Perl/lib/WWW/Mechanize.pm line 1541. eventhough the click function exists in Mechanize.pm and changed...`$mech->click($buttton)` to `$mech->click_button(value => $button)` which resulted in the following error Can't call method "find_input" on an undefined value at c:/Perl/lib/WWW/Mechanize.pm line 1614.	[reply] [d/l] [select]


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