WWW::Mechanize text field issue

Question

I'm trying to submit a form by post method using WWW::Mechanize perl module.

use WWW::Mechanize;

my $mech = WWW::Mechanize->new();
...
$mech->get($url);
...
my $response = $mech->submit_form(
        form_name => $name,
        fields    => {
                        $field_name => $field_value
                         },
        button    => 'Button'  
    );

$field_name is generally speaking a text field (though the type is not specified explicitly in the form), which has a preset value.

$field_name => $field_value in $mech->submit_form on whatever reason does not replace the value, instead $field_value is added into the form after the original value:

{submitted_field_value} = {original_value},{provided_value}

How to replace {original_value} with {provided_value} in the form to be submitted ?

score 1 · Answer 1 · answered Jan 01 '12 at 10:45

1

What happens if you add this single line to your code before calling $mech->submit_form():

$mech->field( $name, [$field_value], 1 );

This makes sure that the first value is added, or overwritten if it already exists. 1 is the number parameter (or position index)

See the documentation of WWW::Mechanize:

$mech->field( $name, \@values, $number )

Given the name of a field, set its value to the value specified. [...]

The optional $number parameter is used to distinguish between two fields with the same name. The fields are numbered from 1.

answered Jan 01 '12 at 10:45

knb

9,138
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knb, thanks for your reply. The issue is that the value is added not overwritten in spite of it already exists. I'd love to have a lib/function which works always as it's described in documentation, unfortunately, it's not so. The field name is unique and the value is added to the correct field. Just trying to figure out whether the issue is with the site of my interest or it is a common (known) bug. – cur4so Jan 02 '12 at 19:37
@cur4so: Can you run it through the perl debugger and then inspect the variables, and, if necessary, remove the existing member from Test:WWW::Mechanize's data structure that holds the form variables? Assuming it's a hash: if calling delete $fields{$name} does not solve your problem, I don't know what could. I know this would break encapsulation but sometimes this has to be done. Maybe the issue gets resolved later anyway by finding another lurking problem with your data. – knb Jan 03 '12 at 21:23

score 0 · Answer 2 · answered Jan 01 '12 at 01:38

0

It's important to remember WWW::Mechanize is better thought of as a 'headless browser' as opposed to say LWP or curl, which only handle all the fiddly bits of http requests for you. Mech keeps its state as you do things.

You'll need to get the form by using $mech->forms or something similar (its best to decide from the documentation. I mean there so many ways to do it.), and then set the input field you want to change, using the field methods.

I guess the basic way to do this comes out as so:

$mech->form_name($name);
$mech->field($field_name, $field_value);
my $response = $mech->click('Button');

Should work. I believe it will also work if you get the field and directly use that (ie my $field = $mech->form_name($name); then use $field methods instead of $mech.

answered Jan 01 '12 at 01:38

Jarrod Funnell

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yeh, there are too many ways to do so but I'm looking for just one (any) to have it done. For this reason I especially appreciate a hands on experience not a guess ... – cur4so Jan 02 '12 at 19:43
Well it is true that I took a punt but it's a bit unfair to say I have no experience either, I've used Mechanize many times, I've simply never had to remove a value from a form before. That said, I certainly tested my simple example on a page with a hidden value and successfully changed it instead of adding to it, so.. – Jarrod Funnell Jan 03 '12 at 01:36
I didn't meant that you don't have experience. I just see that you didn't had this issue (value addition instead of replacement) in your past and didn't reproduced it before your reply. So, you're making a blind guess and it not always works ;). Peace, I don't meant to offend you. Sorry, if it's so. – cur4so Jan 03 '12 at 23:28

cur4so · Accepted Answer · 2012-01-04T04:23:41.990

I managed to make it working at my will. Thanks Timbus and knb for your suggestions. Though my case may not be completely general (I know the preset value) but I'd share what I've found (by trails & errors).

my $mech = WWW::Mechanize->new();
$mech->get($url);  
$mech->form_name( $name );

my $fields = $mech->form_name($name);
foreach my $k ( @{$fields->{inputs}}){
 if ($k->{value} eq $default_value){
   $k->{value}=$field_value;
   }
}

my $response = $mech->click('Button_name');

WWW::Mechanize text field issue

3 Answers3