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Stefan Hornburg (Racke)


Template::Flute - Modern designer-friendly HTML templating Engine


Version 0.0024


    use Template::Flute;

    my ($cart, $flute, %values);

    $cart = [{...},{...}];
    $values{cost} = ...

    $flute = new Template::Flute(specification_file => 'cart.xml',
                           template_file => 'cart.html',
                           iterators => {cart => $cart},
                           values => \%values,

    print $flute->process();


Template::Flute enables you to completely separate web design and programming tasks for dynamic web applications.

Templates are designed to be designer-friendly; there's no inline code or mini templating language for your designers to learn - instead, standard HTML and CSS classes are used, leading to HTML that can easily be understood and edited by WYSIWYG editors and hand-coding designers alike.

An example is easier than a wordy description:

Given the following template snippet:

    <div class="customer_name">Mr A Test</div>
    <div class="customer_email">someone@example.com</div>

and the following specification:

   <specification name="example" description="Example">
        <value name="customer_name" />
        <value name="email" field="customer_email" />

Processing the above as follows:

    $flute = Template::Flute->new(
        template_file      => 'template.html',
        specification_file => 'spec.xml',
        customer_name => 'Bob McTest',
        email => 'bob@example.com',
    print $flute->process;

The resulting output would be:

    <div class="customer_name">Bob McTest</div>
    <div class="email">bob@example.com</div>

In other words, rather than including a templating language within your templates which your designers must master and which could interfere with previews in WYSWYG tools, CSS selectors in the template are tied to your data structures or objects by a specification provided by the programmer.


The easiest way to use Template::Flute is to pass all necessary parameters to the constructor and call the process method to generate the HTML.

You can also break it down in separate steps:

1. Parse specification

Parse specification based on your specification format (e.g with Template::Flute::Specification::XML or Template::Flute::Specification::Scoped.).

    $xml_spec = new Template::Flute::Specification::XML;
    $spec = $xml_spec->parse(q{<specification name="cart" description="Cart">
         <list name="cart" class="cartitem" iterator="cart">
         <param name="name" field="title"/>
         <param name="quantity"/>
         <param name="price"/>
         <value name="cost"/>
2. Parse template

Parse template with Template::Flute::HTML object.

    $template = new Template::Flute::HTML;
        <title>Cart Example</title>
        <table class="cart">
        <tr class="cartheader">
        <tr class="cartitem">
        <td class="name">Sample Book</td>
        <td><input class="quantity" name="quantity" size="3" value="10"></td>
        <td class="price">$1</td>
        <tr class="cartheader"><th colspan="2"></th><th>Total</th>
        <td colspan="2"></td><td class="cost">$10</td>
3. Produce HTML output
    $flute = new Template::Flute(template => $template,
                               iterators => {cart => $cart},
                               values => {cost => '84.94'});



Create a Template::Flute object with the following parameters:


Specification file name.


Select specification parser. This can be either the full class name like MyApp::Specification::Parser or the last part for classes residing in the Template::Flute::Specification namespace.


Specification object or specification as string.


HTML template file.


Template::Flute::HTML object or template as string.


Template::Flute::Database::Rose object.


Hash reference of filter functions.


Template::Flute::I18N object.


Hash references of iterators.


Hash reference of values to be used by the process method.


Builds iterators automatically from values.


process [HASHREF]

Processes HTML template, manipulates the HTML tree based on the specification, values and iterators.

Returns HTML output.


Processes HTML template and returns Template::Flute::HTML object.


Runs the filter used by ELEMENT on VALUE and returns the result.

value NAME

Returns the value for NAME.

set_values HASHREF

Sets hash reference of values to be used by the process method. Same as passing the hash reference as values argument to the constructor.


Returns HTML template object, see Template::Flute::HTML for details.


Returns specification object, see Template::Flute::Specification for details.


The specification ties the elements in the HTML template to the data (variables, lists, forms) which is added to the template.

The default format for the specification is XML implemented by the Template::Flute::Specification::XML module. You can use the Config::Scoped format implemented by Template::Flute::Specification::Scoped module or write your own specification parser class.

Possible elements in the specification are:


The first container is only shown in the output if the value billing_address is set:

  <container name="billing" value="billing_address" class="billingWrapper">

The second container is shown if the value warnings or the value errors is set:

  <container name="account_errors" value="warnings|errors" class="infobox">
  <value name="warnings"/>
  <value name="errors"/>

Separator elements for list are added after any list item in the output with the exception of the last one.

Example specification, HTML template and output:

  <list name="list" iterator="tokens">
  <param name="key"/>
  <separator name="sep"/>

  <div class="list"><span class="key">KEY</span></div><span class="sep"> | </span>

  <div class="list"><span class="key">FOO</span></div><span class="sep"> | </span>
  <div class="list"><span class="key">BAR</span></div>

Value elements are replaced with a single value present in the values hash passed to the constructor of this class or later set with the set_values method.

The following operations are supported for value elements:


Insert HTML residing in value as subtree of the corresponding HTML element. HTML will be parsed with XML::Twig.


Only shows corresponding HTML element if value is set.

Other attributes for value elements are:


Processes the template file named in this attribute. This implies the hook operation.


Form elements are tied through specification to HTML forms. Attributes for form elements in addition to class and id are:

The link attribute can only have the value name and allows to base the relationship between form specification elements and HTML form tags on the name HTML attribute instead of class, which is usually more convenient.



Template::Flute uses iterators to retrieve list elements and insert them into the document tree. This abstraction relieves us from worrying about where the data actually comes from. We basically just need an array of hash references and an iterator class with a next and a count method. For your convenience you can create an iterator from Template::Flute::Iterator class very easily.


Lists can be accessed after parsing the specification and the HTML template through the HTML template object:



Only lists present in the specification and the HTML template can be addressed in this way.

See Template::Flute::List for details about lists.


Forms can be accessed after parsing the specification and the HTML template through the HTML template object:



Only forms present in the specification and the HTML template can be addressed in this way.

See Template::Flute::Form for details about lists.


Filters are used to change the display of value and param elements in the resulting HTML output:

    <value name="billing_address" filter="eol"/>

    <param name="price" filter="currency"/>

The following filters are included:


Uppercase filter, see Template::Flute::Filter::Upper.


Filter preserving line breaks, see Template::Flute::Filter::Eol.


Filter replacing missing text with no-break space, see Template::Flute::Filter::NobreakSingle.


Currency filter, see Template::Flute::Filter::Currency. Requires Number::Format module.


Date filter, see Template::Flute::Filter::Date. Requires DateTime and DateTime::Format::ISO8601 modules.

Filter classes are loaded at runtime for efficiency and to keep the number of dependencies for Template::Flute as small as possible.

See above for prerequisites needed by the included filter classes.


Files, especially components for web pages can be processed and included through value elements with the include attribute:

    <value name="sidebar" include="component.html"/>

The result replaces the inner HTML of the following div tag:

    <div class="sidebar">
        Sample content


Stefan Hornburg (Racke), <racke@linuxia.de>


Please report any bugs or feature requests to bug-template-flute at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Template-Flute.


You can find documentation for this module with the perldoc command.

    perldoc Template::Flute

You can also look for information at:


Thanks to David Previous (bigpresh) for writing a much clearer introduction for Template::Flute.

Thanks to Ton Verhagen for being a big supporter of my projects in all aspects.

Thanks to Terrence Brannon for spotting a documentation mix-up.


Template::Flute was initially named Template::Zoom. I renamed the module because of a request from Matt S. Trout, author of the HTML::Zoom module.


Copyright 2010-2011 Stefan Hornburg (Racke) <racke@linuxia.de>.

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.