VOLT: Template Engine

Volt provides Phalcon fast execution as it is very fast and designer friendly templating language written in C for PHP. It has many helpers defined to write views. Volt is inspired by Jinja and written by Armin Ronacher.

Implementation

Volt views are compiled in php which saves time to write php code manually.

{# app/views/products/show.volt #}
{% block last_products %}
{% for product in products %}
    * Name: {{ product.name|e }}
    {% if product.status === 'Active' %}
       Price: {{ product.price + product.taxes/100 }}
    {% endif  %}
{% endfor  %}
{% endblock %}

Activating Volt

In this we register Volt in view component having extension .phtml.

<?php
use Phalcon\Mvc\View;
use Phalcon\Mvc\View\Engine\Volt;
// Register Volt as a service
$di->set(
    'voltService',
    function ($view, $di) {
        $volt = new Volt($view, $di);
        $volt->setOptions(
            [
                'compiledPath'      =>'../app/compiled-templates/',
                'compiledExtension' => '.compiled',
            ]
        );
        return $volt;
    }
);
// Register Volt as template engine
$di->set(
    'view',
    function () {
        $view = new View();
        $view->setViewsDir('../app/views/');
        $view->registerEngines(
            [
'.volt' => 'voltService',
            ]
        );
        return $view;    });

Options available in volt

Option	Description	Default
compiledPath	A writable path where the compiled PHP templates will be placed	./
compiledExtension	An additional extension appended to the compiled PHP file	.php
compiledSeparator	Volt replaces the directory separators / and \ by this separator in order to create a single file in the compiled directory	%%
Stat	Whether Phalcon must check if exists differences between the template file and its compiled path	True
compileAlways	Tell Volt if the templates must be compiled in each request or only when they change	False
Prefix	Allows to prepend a prefix to the templates in the compilation path	Null
autoescape	Enables globally autoescape of HTML	False

Variables

Object variables may have attributes which can be accessed using the syntax: foo.bar. If you are passing arrays, you have to use the square bracket syntax: foo['bar']

{{ post.title }} {# for $post->title #}
{{ post['title'] }} {# for $post['title'] #}

Filters

Variables can be formatted or modified using filters. The pipe operator (|) is used to apply filters to variables:

{{ post.title|e }}
{{ post.content|striptags }}
{{ name|capitalize|trim }}

Following is the list of filters that can be used:

Filter	Description
abs	Applies the abs PHP function to a value.
Capitalize	Capitalizes a string by applying the ucwords PHP function to the value
convert_encoding	Converts a string from one charset to another
Default	Sets a default value in case that the evaluated expression is empty (is not set or evaluates to a falsy value)
escape	Applies Phalcon\Escaper->escapeHtml() to the value
escape_attr	Applies Phalcon\Escaper->escapeHtmlAttr() to the value
json_encode	Converts a value into its JSON representation
json_decode	Converts a value from its JSON representation to a PHP representation