Question

The XML Structure is as below:

<Entities>
    <Entity>
        <EntityName>.... </EntityName>
        <EntityType>.... </EntityType>
        <Tables>
            <DataTables>
                <DataTable>1</DataTable>
                <DataTable>2</DataTable>
                <DataTable>3</DataTable>
                <DataTable>4</DataTable>
            </DataTables>
            <OtherTables>
                <OtherTable>5</OtherTable>
                <OtherTable>6</OtherTable>
            </OtherTables>
        </Tables>
    </Entity>
.
.
.
</Entities>

I need to parse the file based on the Entity name selected and retrieve all the tables specifically in the order mentioned. How do I do this in Perl and which module should be used?

Answer 1

My favourite module to parse XML in Perl is XML::Twig (tutorial).

Code Sample:

use XML::Twig;

my $twig = XML::Twig->new(
    twig_handlers => {
        #calls the get_tables method for each Entity element
        Entity    => sub {get_tables($_);},
    },
    pretty_print  => 'indented',                # output will be nicely formatted
    empty_tags    => 'html',                    # outputs <empty_tag />
    keep_encoding => 1,
);

$twig->parsefile(xml-file);
$twig->flush;

sub get_tables {
    my $entity = shift;

    #Retrieves the sub-elements of DataTables
    my @data_tables = $entity->first_child("Tables")->children("DataTables");
    #Do stuff with the DataTables

    #Retrieves the sub-elements of OtherTables
    my @other_tables = $entity->first_child("Tables")->children("OtherTables");
    #Do stuff with the OtherTables

    #Flushes the XML element from memory
    $entity->purge;
}