Home > XML::Simple

XML::Simple Quick Start

Say you have a script called foo.pl:

  use XML::Simple;
  
  my $opt = XMLin();

and a config file called foo.xml:

  <opt>
    <host name="romulus">
      <addr>10.0.0.101</addr>
      <addr>10.0.1.101</addr>
    </host>
    <host name="remus">
      <addr>10.0.0.102</addr>
    </host>
  </opt>

The second line of the script will populate $opt with the following hashref:

  {
    'host' => {
      'romulus' => {
	'addr' => [
	  '10.0.0.101',
	  '10.0.1.101'
	]
      },
      'remus' => {
	'addr' => '10.0.0.102'
      }
    }
  };

Allowing you to refer to the second address on host romulus as follows:

  $opt->{host}->{romulus}
    ->{addr}->[1]

Strict Mode

The example above shows how much can be achieved with a small amount of code, but it glosses over some very important details.

In your production code, you should be certain to set the KeyAttr and ForceArray options. To understand why this important and to see how to ensure you don't forget, read this article on the Perl Monks web site.

XML::Simpler

On April 1st 2002, the XML::Simpler module was released.

You can download it from here (if you must).

XML::Simple

Description

XML::Simple is a Perl module that makes it really easy to read and write XML files. You can get a full rundown of the module's capabilities and limitations in the manual page and the Frequently Asked Questions.

XML::Simple was originally developed for the purpose of reading and writing config files in XML format (which offers various advantages over say .INI format). Having said that, many people find it useful for other purposes.

Warning: XML::Simple is not very useful for handling XML containing 'mixed content'. eg:

   <p>This is <b>mixed</b> content</p>

You'll find there are plenty of other modules that work well with mixed content. They're just not 'simple' :-).

You may also be interested in the Perl-XML-FAQ I've been working on recently (CVS source here).

Downloading XML::Simple

The latest release of XML::Simple is available from CPAN.

There is no 'unstable' or developer release at this time.

Installation

If you're running a recent release of ActiveState Perl, you'll find that XML::Simple version 2.14 (and the HTML documentation) is already installed on your system – so you don't need to do anything!

Before you install XML::Simple, you must have an XML parser module installed. You can use either XML::Parser or XML::SAX. If you've installed XML::SAX, you should probably also install XML::SAX::Expat for a performance boost.

The easiest way to install is using the CPAN shell. To download, unpack, test and install the latest stable version:

  perl -MCPAN -e shell
  cpan> install XML::Simple

You can of course download the package and install it manually:

  perl Makefile.PL
  make
  make test
  make install

If all else fails, just extract Simple.pm from the download and drop it into the directory called 'XML' under your Perl 'lib'.

Recent Changes

The change log is included in the distribution.

For a trip back in time, you can also read the announcement of version 1.00.