NAME
Template::Flute - Modern designer-friendly HTML templating Engine
VERSION
Version 0.021
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,
autodetect => {
disable => [qw/Foo::Bar/],
}
);
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:
Mr A Test
someone@example.com
and the following 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:
Bob McTest
bob@example.com
In other words, rather than including a templating language within your
templates which your designers must master and which could interfere
with previews in WYSIWYG 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{});
2. Parse template
Parse template with Template::Flute::HTML object.
$template = new Template::Flute::HTML;
$template->parse(q{
Cart Example
Name
Quantity
Price
Sample Book
$1
Total
$10
},
$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.
filters
Hash reference of filter functions.
i18n
Template::Flute::I18N object.
translate_attributes
An arrayref of attribute names to translate. If the name has a dot,
it is interpreted as tagname + attribute, so placeholder" will
unconditionally translate all the placeholders, while
input.placeholder only the placeholder found on the input tag.
Additional dotted values compose conditions for attributes. E.g.
input.value.type.submit means all the value attributes with attribute
type set to submit.
Defaults to ['input.value.type.submit', 'placeholder']
iterators
Hash references of iterators.
values
Hash reference of values to be used by the process method.
auto_iterators
Builds iterators automatically from values.
autodetect
A configuration option. It should be an hashref with a key disable
and a value with an arrayref with a list of classes for objects which
should be considered plain hashrefs instead. Example:
my $flute = Template::Flute->new(....
autodetect => { disable => [qw/My::Object/] },
....
);
Doing so, if you pass a value holding a My::Object object, and you
have a specification with something like this:
The value will be $object-{method}>, not $object-$method>.
The object is checked with isa.
Classical example: Dancer::Session::Abstract.
uri
Base URI for your template. This adjusts the links in the HTML tags
a, base, img, link and script.
email_cids
This is meant to be used on HTML emails. When this is set to an hash
reference (which should be empty), the hash will be populated with
the following values:
cid1 => { filename => 'foo.png' },
cid2 => { filename => 'foo2.gif' },
and in the body the images src attribute will be replaced with
cid:cid1.
The cid names are arbitrary and assigned by the template. The code
should look at the reference values which were modified.
cids
Optional hashref with options for the CID replacement behaviour.
By default, if the source looks like an HTTP/HTTPS URI, the image
source is not altered and no CID is assigned.
If you pass a base_url value in this hashref, the URI matching it
will be converted to cids and the rest of the path will be added to
the email_cids hashref.
Example:
my $cids = {};
$flute = Template::Flute->new(template => $template,
specification => $spec,
email_cids => $cids,
cids => {
base_url => 'http://example.com/'
});
Say the template contains images with source
http://example.com/image.png, the email_cids hashref will contain a
cid with filename "image.png".
METHODS
BUILD
Force creation of template class as soon as object is instantiated.
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.
patterns
Returns all patterns found in the specification.
scopes
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.
COMMON ATTRIBUTES
Common attributes for specification elements are:
name
Name of element.
class
Class of corresponding elements in the HTML template.
If this attribute is omitted, the value of the name attribute is used
to relate to the class in the HTML template.
id
Id of corresponding element in the HTML template. Overrides the class
attribute for the specification element.
target
HTML attribute to fill the value instead of replacing the body of the
HTML element.
joiner
String placed between the text and the appended value. The joiner
isn't added if the value is empty.
ELEMENTS
Possible elements in the specification are:
container
The first container is only shown in the output if the value
billing_address is set:
The second container is shown if the value warnings or the value
errors is set:
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:
KEY
|
FOO
|
BAR
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.
prepend
Prepends the param value to the text found in the HTML template.
target
The attribute to operate on. See below target for value for
details.
toggle
When the args attribute is set to tree, it doesn't interpolate
anything and just shows corresponding HTML element if param value
is set.
With target attribute, it simply toggles the target attribute.
Otherwise, if value is true, shows the HTML element and set its
content to the value. If value is false, removes the HTML element.
So, if your element has children elements, you probably want to use
the args="tree" attribute (see below for an example).
Other attributes for param elements are:
filter
Applies filter to param value.
increment
Uses value from increment instead of a value from the iterator.
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.
prepend
Prepends 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:
target
Specify the attribute to operate on instead of the tag content. It
can be a named attribute (e.g., href), the wildcard character(*,
meaning all the attributes found in the HTML template), or a comma
separated list (e.g., alt,title).
filter
Applies filter to value.
include
Processes the template file named in this attribute. This implies
the hook operation. See "INCLUDE FILES" for more information.
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
skip
This attribute (which can be provided to param or value specification
elements) supports the following values:
empty
Do not replace the template string if the value or parameter is
undefined, empty or just whitespace.
E.g.
pattern
You can define patterns in your specification to interpolate the
strings instead of replacing them.
A pattern is defined by the attributes name and type and its content.
type can be only string or regexp.
The interpolation happens if the value and param elements of the
specification have an attribute pattern set with the pattern's name.
Given this HTML:
There are 123 items in your shopping cart.
1in category 123
And this specification:
123
In this example, in the cartline and category classes' text, only the
template text "123" will be replaced by the value, not the whole
element content, yielding such output:
There are 42 items in your shopping cart.
1in category tofu
2in category pizza
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:
XML:
CONTAINERS
Conditional processing like IF or ELSE is done with the help of
containers.
Display image only if present
In this example we want to show an image only on a certain condition:
HTML:
XML:
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:
XML:
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