Hello all.

I have an XML file as follows:

<messages> </messages>
inside it - <message> with attribute ID.
For each <message>
- one <message_id>,
- one <message_desc>,
- and ... many elements / parameters - each one inside <row>...</row> tags.

What I want is:
- Show the user all message ID's and Desc,
- Ask the user to choose an ID,
- and then: show the user and ask him / her about each of the elements / parameters (from the <row></row> tags) - of the *chosen message*.

I managed - with XML::Twig - to do the first two: show the message ID's and Desc, and get the message ID from the user.

But how do I handle each of the elements / parameters from the <row></row> tags? I want to show it...

Thanks.

Here is my code: 

#!/usr/bin/env perl
use strict;
use warnings;
use XML::Twig;
#################################################
#################################################

my $twig_show_messages = new XML::Twig( 
    twig_handlers =>                  # message will be called 
    { message => \&print_all_messages_id_desc }   # when each message 
+element
    );                                # has been parsed 
    $twig_show_messages->parsefile("sip2_params_client_small.xml"); # 
+build the twig
#### $twig_show_messages->flush;

########################################
########################################
print "Your SIP2 message ID?>_\t";

my $match_msg='';
chomp ($match_msg=<> );

## Check the input 
if ($match_msg !~ /^(-)*\d{2}$/){ ##  Input must be 2 digits! If not..
+. exit!
       print "***===>>>input $match_msg. \n"; 
       print "\tIt is not numeric, or does *not* contain two digit\n";
       exit;
       }
########################################
########################################

my $twig_for_a_message= new XML::Twig(); 

########################################
########################################

my $twig_the_selected_message= new XML::Twig( 
    twig_handlers => 
    { doc => \&doc,    
    section => \&section, 
    } 
);

########################################
########################################

&print_chosen_msg;

#################################################
#################################################
#################################################
#################################################
#################################################
#################################################
sub print_all_messages_id_desc
  { my( $twig, $message)= @_;                     # handlers params ar
+e always
                                                  # the twig and the e
+lement
    my $message_id = $message->first_child('message_id')->text;    # g
+et the text of message_id
    my $message_desc = $message->first_child('message_desc')->text; # 
+get the text of message_desc
    print "$message_id\t$message_desc\n";       # print message id and
+ desc 
 }

#################################################
#################################################

 sub print_chosen_msg {
     my  $sw_msg_flag= ' '; 
     print "You chose:\t"; 
     ### START XML::Twig 
     XML::Twig->new(
         twig_handlers => { 
             ## START message_id
             message_id => sub {
                 if ($_->text eq $match_msg) {
                     print $_->text ;
                     print "\t";
                     $sw_msg_flag='Y';
                 }  ## END IF
             }, ## END message_id 
             message_desc => sub {
                 if ($sw_msg_flag eq 'Y') { 
                     print "\n";
                     print $_->text ;
                     print "\n";
                     $sw_msg_flag='N';
                     # exit;
                 } ## END IF
             } ## END message_desc
         } ## END twig_handlers 
         
     )->parsefile('sip2_params_client.xml');
     ### END XML::Twig
     print "\t==============================\n";
 }

[download]

Example of the XML: 

<?xml version="1.0" encoding="UTF-8"?>
<messages>
 <message id ="23">
   <!-- <row> -->
     <message_id>23</message_id>
     <message_desc>Patron Status Request</message_desc>
     <ver/>
     <!--  <field_desc></field_desc> -->
     <field_id/>
     <format/>
   <!-- </row> -->
   <row>
     <ver/>
     <field_desc>language        </field_desc>
     <field_id/>
     <format>3-char, fixed-length required field</format>
   </row>
   <row>
     <ver/>
     <field_desc>transaction date</field_desc>
     <field_id/>
     <format>18-char, fixed-length required field: YYYYMMDDZZZZHHMMSS<
+/format>
   </row>
   <row>
     <ver/>
     <field_desc>institution id   </field_desc>
     <field_id>AO</field_id>
     <format>variable-length required field</format>
   </row>
   <row>
     <ver/>
     <field_desc>patron identifier</field_desc>
     <field_id>AA</field_id>
     <format>variable-length required field</format>
   </row>
   <row>
     <ver/>
     <field_desc>terminal password</field_desc>
     <field_id>AC</field_id>
     <format>variable-length required field</format>
   </row>
   <row>
     <ver/>
     <field_desc>patron password  </field_desc>
     <field_id>AD</field_id>
     <format>variable-length required field</format>
   </row>
   <!-- message end -->
 </message>
 <message id="09">
   <!-- <row> -->
     <message_id>09</message_id>
     <message_desc>Checkin</message_desc>
     <ver/>
     <!--  <field_desc></field_desc> -->
     <field_id/>
     <format/>
   <!-- </row> -->
   <row>
     <ver/>
     <field_desc>no block</field_desc>
     <field_id/>
     <format>1-char, fixed-length required field: Y or N.</format>
   </row>
   <row>
     <ver/>
     <field_desc>transaction date</field_desc>
     <field_id/>
     <format>18-char, fixed-length required field: YYYYMMDDZZZZHHMMSS<
+/format>
   </row>
   <row>
     <ver/>
     <field_desc>return date</field_desc>
     <field_id/>
     <format>18-char, fixed-length required field: YYYYMMDDZZZZHHMMSS<
+/format>
   </row>
   <row>
     <ver/>
     <field_desc>current location</field_desc>
     <field_id>AP</field_id>
     <format>variable-length required field</format>
   </row>
  <!-- message end -->
 </message>
 <!-- </sip2_client_send> -->
</messages>

[download]

In reply to XML::Twig - how to get and display only selected elements? by meorero

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