FAQ: How to find out what mechanize is really sending

Hi Andy,

Sent this as a response to the wrong email. So here it is with the right
subject line and sent to the list.

Andy Lester wrote:
> Whatever you find out, please write up something that I can put into 
> the FAQ.

In an earlier post, I talked about using Tamper Data to find out what
Firefox is really sending to the server. Here is a way to find out what
$mech is sending.

The underlying function is from HTTP::Request: $r->as_string, where $r
is an HTTP::Request object. HTML::Form has a method $form->click which
returns the HTTP::Request object (which would normally be passed to
LWP::UserAgent). So

    $f = $mech->current_form();  # or one of its cousins - gives an
                                 # HTML::Forms object
    $r = $f->click( [args] );    # returns HTTP::Request object
    $t = $r->as_string();        # text of the request to compare with
                                 # Tamper Data results.

This is not quite the same as what $mech sends, because $mech processes
the request with _modify_request, which (I believe) adds headers,
cookies and other goodies, so for this to work properly, we have
to add a step:

    $f = $mech->current_form();  # or one of its cousins - gives an
                                 # HTML::Forms object
    $r = $f->click( [args] );    # returns HTTP::Request object
    $r = $mech->_modify_request( $r );  # v1.12 internal routine.
                                 #  Compatibility in future releases?
    $t = $r->as_string();        # text of the request to compare with
                                 # Tamper Data results.

Given that this needs to use an internal function to get the right answer,
it would be nice if there were a method:

     $mech->Pretend_to_click_and_give_me_the_message()

Cheers,

Peter

P.S. Just bought your perl debugging book today. It looks really good. :-)