4.8. Aura.Html
Provides HTML escapers and helpers, including form input helpers, that can be used in any template, view, or presentation system.
4.8.1. Foreword
4.8.1.1. Installation
This library requires PHP 5.3 or later with mbstring and/or iconv installed; we recommend using the latest available version of PHP as a matter of principle. It has no userland dependencies.
It is installable and autoloadable via Composer as aura/html.
Alternatively, download a release or clone this repository, then require or include its autoload.php file.
4.8.1.2. Quality
To run the unit tests at the command line, issue composer install and then vendor/bin/phpunit at the package root. This requires Composer to be available as composer.
This library attempts to comply with PSR-1, PSR-2, and PSR-4. If you notice compliance oversights, please send a patch via pull request.
4.8.1.3. Community
To ask questions, provide feedback, or otherwise communicate with the Aura community, please join our Google Group, follow @auraphp on Twitter, or chat with us on #auraphp on Freenode.
4.8.2. Getting Started
The easiest way to instantiate a HelperLocator with all the available helpers is to use the HelperLocatorFactory:
<?php
$factory = new \Aura\Html\HelperLocatorFactory;
$helper = $factory->newInstance();
?>
4.8.2.1. Built-In Helpers
Once you have a HelperLocator, you can then use the helpers by calling them as methods on the HelperLocator instance. See the tag helpers and form helpers pages for more information.
N.b.: All built-in helpers escape values appropriately; see the various helper class internals for more information.
4.8.2.2. Custom Helpers
There are two steps to adding your own custom helpers:
-
Write a helper class
-
Set a factory for that class into the HelperLocator under a service name
A helper class needs only to implement the __invoke() method. We suggest extending from AbstractHelper to get access to indenting, escaping, etc., but it's not required.
The following example helper class applies ROT-13 to a string.
<?php
namespace Vendor\Package;
use Aura\Html\Helper\AbstractHelper;
class Obfuscate extends AbstractHelper
{
public function __invoke($string)
{
return $this->escaper->html(str_rot13($input));
}
}
?>
Now that we have a helper class, we set a factory for it into the HelperLocator under a service name. Therein, we create and return the helper class.
<?php
$helper->set('obfuscate', function () {
return new \Vendor\Package\Obfuscate;
});
?>
The service name in the HelperLocator doubles as a method name. This means we can call the helper via $this->obfuscate():
<?= $helper->obfuscate('plain text') ?>
Note that we can use any service name for the helper, although it is generally useful to name the service for the helper class, and for a word that can be called as a method.
Please examine the classes in Aura\Html\Helper for more complex and powerful
examples.
4.8.2.3. Escaping
One of the important but menial tasks with PHP-based template systems is that of escaping output properly. Escaping output is absolutely necessary from a security perspective. This package comes with an escape() helper that has four escaping methods:
-
$this->escape()->html('foo')to escape HTML values -
$this->escape()->attr('foo')to escape unquoted HTML attributes -
$this->escape()->css('foo')to escape CSS values -
$this->escape()->js('foo')to escape JavaScript values
Here is a contrived example of the various escape() helper methods:
<head>
<style>
body {
color: <?= $this->escape()->css($theme->color) ?>;
font-size: <?= $this->escape()->css($theme->font_size) ?>;
}
</style>
<script language="javascript">
var foo = "<?= $this->escape()->js($js->foo); ?>";
</script>
</head>
<body>
<h1><?= $this->escape()->html($blog->title) ?></h1>
<p class="byline">
by <?= $this->escape()->html($blog->author) ?>
on <?= $this->escape()->html($blog->date) ?>
</p>
<div id="<?php $this->escape()->attr($blog->div_id) ?>">
<?= $blog->raw_html ?>
</div>
</body>
Unfortunately, escaper functionality is verbose, and can make the template code look cluttered. There are two ways to mitigate this.
The first is to assign the escape() helper to a variable, and then invoke it as a callable. Here is a contrived example of the various escaping methods as callables:
<?php
// assign the escaper helper properties to callable variables
$h = $this->escape()->html;
$a = $this->escape()->attr;
$c = $this->escape()->css;
$j = $this->escape()->js;
?>
<head>
<style>
body {
color: <?= $c($theme->color) ?>;
font-size: <?= $c($theme->font_size) ?>;
}
</style>
<script language="javascript">
var foo = "<?= $j($js->foo); ?>";
</script>
</head>
<body>
<h1><?= $h($blog->title) ?></h1>
<p class="byline">
by <?= $h($blog->author) ?>
on <?= $h($blog->date) ?>
</p>
<div id="<?php $a($blog->div_id) ?>">
<?= $blog->raw_html ?>
</div>
</body>
Alternatively, the Escaper class used by the escape() helper comes with four static methods to reduce verbosity and clutter: h(), a(), c(), j(), and. These escape values for HTML content values, unquoted HTML attribute values, CSS values, and JavaScript values, respectively.
N.b.: In Aura, we generally avoid static methods. However, we feel the tradeoff of less-cluttered templates can be worth using static methods in this one case.
To call the static Escaper methods in a PHP-based template, use the Escaper as a short alias name, then call the static methods on the alias. (If you did not instantiate a HelperLocatorFactory, you will need to prepare the static escaper methods by calling Escaper::setStatic(new Escaper).)
Here is a contrived example of the various static methods:
<?php use Aura\Html\Escaper as e; ?>
<head>
<style>
body {
color: <?= e::c($theme->color) ?>;
font-size: <?= e::c($theme->font_size) ?>;
}
</style>
<script language="javascript">
var foo = "<?= e::j($js->foo); ?>";
</script>
</head>
<body>
<h1><?= e::h($blog->title) ?></h1>
<p class="byline">
by <?= e::h($blog->author) ?>
on <?= e::h($blog->date) ?>
</p>
<div id="<?php e::a($blog->div_id) ?>">
<?= $blog->raw_html ?>
</div>
</body>