NAME
Template::Flute - Modern designer-friendly HTML templating Engine
VERSION
Version 0.0094
SYNOPSIS
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();
DESCRIPTION
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" class="customer_email" />
</specification>
Processing the above as follows:
$flute = Template::Flute->new(
template_file => 'template.html',
specification_file => 'spec.xml',
);
$flute->set_values({
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.
Workflow
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"/>
</list>
<value name="cost"/>
</specification>});
2. Parse template
Parse template with Template::Flute::HTML object.
$template = new Template::Flute::HTML;
$template->parse(q{<html>
<head>
<title>Cart Example</title>
</head>
<body>
<table class="cart">
<tr class="cartheader">
<th>Name</th>
<th>Quantity</th>
<th>Price</th>
</tr>
<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>
<tr class="cartheader"><th colspan="2"></th><th>Total</th>
</tr>
<tr>
<td colspan="2"></td><td class="cost">$10</td>
</tr>
</table>
</body></html>},
$spec);
3. Produce HTML output
$flute = new Template::Flute(template => $template,
iterators => {cart => $cart},
values => {cost => '84.94'});
$flute->process();
CONSTRUCTOR
new
Create a Template::Flute object with the following parameters:
specification_file
Specification file name.
specification_parser
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
Specification object or specification as string.
template_file
HTML template file.
template
Template::Flute::HTML object or template as string.
database
Template::Flute::Database::Rose object.
filters
Hash reference of filter functions.
i18n
Template::Flute::I18N object.
iterators
Hash references of iterators.
values
Hash reference of values to be used by the process method.
auto_iterators
Builds iterators automatically from values.
METHODS
process [HASHREF]
Processes HTML template, manipulates the HTML tree based on the
specification, values and iterators.
Returns HTML output.
process_template
Processes HTML template and returns Template::Flute::HTML object.
filter ELEMENT VALUE
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.
template
Returns HTML template object, see Template::Flute::HTML for details.
specification
Returns specification object, see Template::Flute::Specification for
details.
SPECIFICATION
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:
container
The first container is only shown in the output if the value
`billing_address' is set:
<container name="billing" value="billing_address" class="billingWrapper">
</container>
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"/>
</container>
list
separator
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:
<specification>
<list name="list" iterator="tokens">
<param name="key"/>
<separator name="sep"/>
</list>
</specification>
<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>
param
Param elements are replaced with the corresponding value from the
list iterator.
The following operations are supported for param elements:
append
Appends the param value to the text found in the HTML template.
toggle
Only shows corresponding HTML element if param value is set.
Other attributes for param elements are:
filter
Applies filter to param value.
increment
Uses value from increment instead of a value from the iterator.
<param name="pos" increment="1">
value
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:
append
Appends the value to the text found in the HTML template.
hook
Insert HTML residing in value as subtree of the corresponding
HTML element. HTML will be parsed with XML::Twig. See INSERT
HTML for an example.
toggle
Only shows corresponding HTML element if value is set.
Other attributes for value elements are:
filter
Applies filter to value.
include
Processes the template file named in this attribute. This
implies the hook operation.
form
Form elements are tied through specification to HTML forms.
Attributes for form elements in addition to `class' and `id' are:
link
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.
input
filter
sort
i18n
SIMPLE OPERATORS
append
Appends the value to the text inside a HTML element or to an attribute
if `target' has been specified. This can be used in `value' and `param'
specification elements.
The example shows how to add a HTML class to elements in a list:
HTML:
<ul class="nav-sub">
<li class="category"><a href="" class="catname">Medicine</a></li>
</ul>
XML:
<specification>
<list name="category" iterator="categories">
<param name="name" class="catname"/>
<param name="catname" field="uri" target="href"/>
<param name="css" class="catname" target="class" op="append" joiner=" "/>
</list>
</specification>
CONDITIONALS
Display image only if present
In this example we want to show an image only on a certain condition:
HTML:
<span class="banner-box">
<img class="banner" src=""/>
</span>
XML:
<container name="banner-box" value="banner">
<value name="banner" target="src"/>
</container>
Source code:
if ($organization eq 'Big One') {
$values{banner} = 'banners/big_one.png';
}
Display link in a list only if present
In this example we want so show a link only if an URL is available:
HTML:
<div class="linklist">
<span class="name">Name</span>
<div class="link">
<a href="#" class="url">Goto ...</a>
</div>
</div>
XML:
<specification name="link">
<list name="links" class="linklist" iterator="links">
<param name="name"/>
<param name="url" target="href"/>
<param name="link" field="url" op="toggle" args="tree"/>
</list>
</specification>
Source code:
@records = ({name => 'Link', url => 'http://localhost/'},
{name => 'No Link'},
{name => 'Another Link', url => 'http://localhost/'},
);
$flute = Template::Flute->new(specification => $spec_xml,
template => $template,
iterators => {links => \@records});
$output = $flute->process();
ITERATORS
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.
DROPDOWNS
Iterators can be used for dropdowns (HTML <select> elements) as well.
Template:
<select class="color"></select>
Specification:
<value name="color" iterator="colors"/>
Code:
@colors = ({value => 'red', label => 'Red'},
{value => 'black', label => 'Black'});
$flute = Template::Flute->new(template => $html,
specification => $spec,
iterators => {colors => \@colors},
values => {color => 'black'},
);
HTML output:
<select class="color">
<option value="red">Red</option>
<option value="black" selected="selected">Black</option>
</select>
Custom iterators for dropdowns
By default, the iterator for a dropdown is an arrayref of hashrefs with
two hardcoded keys: `value' and (optionally) `label'. You can override
this behaviour in the specification with `iterator_value_key' and
`iterator_name_key' to use your own hashref's keys from the iterator,
instead of `value' and `label'.
Specification:
<specification>
<value name="color" iterator="colors"
iterator_value_key="code" iterator_name_key="name"/>
</specification>
Template:
<html>
<select class="color">
<option value="example">Example</option>
</select>
</html>
Code:
@colors = ({code => 'red', name => 'Red'},
{code => 'black', name => 'Black'},
);
$flute = Template::Flute->new(template => $html,
specification => $spec,
iterators => {colors => \@colors},
values => { color => 'black' },
);
$out = $flute->process();
Output:
<html>
<head></head>
<body>
<select class="color">
<option value="red">Red</option>
<option selected="selected" value="black">Black</option>
</select>
</body>
</html>
LISTS
Lists can be accessed after parsing the specification and the HTML
template through the HTML template object:
$flute->template->lists();
$flute->template->list('cart');
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
Forms can be accessed after parsing the specification and the HTML
template through the HTML template object:
$flute->template->forms();
$flute->template->form('edit_content');
Only forms present in the specification and the HTML template can be
addressed in this way.
See Template::Flute::Form for details about forms.
FILTERS
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:
upper
Uppercase filter, see Template::Flute::Filter::Upper.
strip
Strips whitespace at the beginning at the end, see
Template::Flute::Filter::Strip.
eol Filter preserving line breaks, see Template::Flute::Filter::Eol.
nobreak_single
Filter replacing missing text with no-break space, see
Template::Flute::Filter::NobreakSingle.
currency
Currency filter, see Template::Flute::Filter::Currency. Requires
Number::Format module.
date
Date filter, see Template::Flute::Filter::Date. Requires DateTime
and DateTime::Format::ISO8601 modules.
country_name
Country name filter, see Template::Flute::Filter::CountryName.
Requires Locales module.
language_name
Language name filter, see Template::Flute::Filter::LanguageName.
Requires Locales module.
json_var
JSON to Javascript variable filter, see
Template::Flute::Filter::JsonVar. Requires JSON module.
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.
Chained Filters
Filters can also be chained:
<value name="note" filter="upper eol"/>
Example template:
<div class="note">
This is a note.
</div>
With the following value:
Update now!
Avoid security hazards!
The HTML output would look like:
<div class="note">
UPDATE NOW!<br />
AVOID SECURITY HAZARDS!
</div>
INSERT HTML AND INCLUDE FILES
INSERT HTML
HTML can be generated in the code or retrieved from a database and
inserted into the template through the `hook' operation:
<value name="description" op="hook"/>
The result replaces the inner HTML of the following `div' tag:
<div class="description">
Sample content
</div>
INCLUDE FILES
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
</div>
AUTHOR
Stefan Hornburg (Racke), <racke@linuxia.de>
BUGS
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.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Template::Flute
You can also look for information at:
* RT: CPAN's request tracker
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Template-Flute
* AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/Template-Flute
* CPAN Ratings
http://cpanratings.perl.org/d/Template-Flute
* Search CPAN
http://search.cpan.org/dist/Template-Flute/
ACKNOWLEDGEMENTS
Thanks to David Previous (bigpresh) for writing a much clearer
introduction for Template::Flute.
Thanks to Grega Pompe for proper implementation of nested lists and a
documentation fix.
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.
HISTORY
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.
LICENSE AND COPYRIGHT
Copyright 2010-2013 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.