Yii2 Template Engine

Simple, fast and flexible HTML templating engine for Yii2 PHP framework with zero configuration. Supports basic control structures (IF, FOR, SET), dynamic directives and active record relations. It is similar to Twig or Blade, though much simpler.

It can be used to render e.g. an invoice or a contract from HTML markup edited in a WYSIWYG editor and turn it optionally into a PDF or MS Word file. Generic version without framework dependency can be found at lubosdz/html-templating-engine.

Installation

$ composer require "lubosdz/yii2-template-engine"

or via composer.json:

"require": {
	...
	"lubosdz/yii2-template-engine": "^1.0",
	...
},

Basic usage

Initiate template engine inside Yii application:

use lubosdz\yii2\TemplateEngine;
$engine = new TemplateEngine();

or register as a component in app/config/main.php:

...
'components' => [
	'engine' => [
		'class' => 'lubosdz\yii2\TemplateEngine',
	]
]
...

$engine = Yii::$app->template;

Use method $engine->render($html [, $values]) to generate HTML output:

$html = source HTML markup with placeholders like <h1>{{ processMe }}</h1>. This argument can be also path alias starting with @ to load existing HTML file, such as @app/templates/invoice.html
$values = array of values like pairs [placeholderName => value] to be injected into or evaluated inside placeholders

Once output generated, it can be e.g. supplied to PDF or MS Word renderer to produce a PDF or MS Word file respectively.

Simple placeholders

Templating engine collects all placeholders within supplied HTML markup and attempts to replace them with matching $values or evaluate as control structure. Placeholders that have not been processed are left untouched by default. This behaviour is suitable for development. In production, setting $engine->setForceReplace(true) can be set to replace unprocessed placeholders with empty string.

$html = 'Hello <b>{{ who }}</b>!';
$values = ['who' => 'world'];
echo $engine->render($html, $values);
// output: "Hello <b>world</b>!"

Built-in directives

Template engine comes with couple of generally usable methods for basic date, time and string manipulation - directives. These can be referenced directly inside supplied HTML markup. Directives use the pipe operator | to chain operations within the placeholder.

$html = $engine->render('Generated on {{ today }} at {{ time }}.');
// output - respecting EN locale: "Generated on Dec 31, 2021 at 11:59pm."
// output - respecting SK/CS locale: "Generated on 31. 12. 2021 at 23:59."

echo $engine->render('Meet me at {{ now(7200) | time }}.');
// output example, if now is 8:30am: "Meet me at 10:30am." (shift +2 hours = 7200 secs)

echo $engine->render('My name is {{ user.name | escape }}.', ['user' => [
	'name' => '<John>',
]]);
// filtered output: "My name is &lt;John&gt;."

echo $engine->render('Hello {{ user.name | truncate(5) | e }}.', ['user' => [
	'name' => '<John>',
]]);
// truncated and filtered output: "Hello &lt;John...."

Specific for the Yii 2 framework, object properties as well as related models are automatically collected, if referenced inside placeholders.

$html = $engine->render('Hello {{ customer.name }}.', [
	'customer' => Customer::findOne($id), // find active record
]);
// output e.g.: "Hello John Doe."

$html = $engine->render('Address is {{ customer.address.city }} {{ customer.address.zip }}.', [
	'customer' => Customer::findOne($id), // Customer has defined relation to object `Address`
]);
// output e.g.: "Address is Prague 10000."

Dynamic directives

Dynamic directives allows extending functionality for chaining operations inside parsed placeholders. They can be added at a runtime as callable anonymous functions accepting arguments.

In the following example we will attach dynamic directive named coloredText and render output with custom inline CSS:

// attach dynamic directive (function) accepting 2 arguments
$engine->setDirective('coloredText', function($text, $color){
	return "<span style='color: {$color}'>{$text}</span>";
});

// process template - we can set different color in each call
echo $engine->render("This is {{ output | coloredText(yellow) }}", [
	'output' => 'colored text',
]);
// output: "This is <span style='color: yellow'>colored text</span>"

IF .. ELSEIF .. ELSE .. ENDIF

Control structure IF .. ELSEIF .. ELSE .. ENDIF is supported:

$templateHtml = "
{{ if countOrders > 0 }}
	<h3>Thank you!</h3>
{{ else }}
	<h3>Sure you want to leave?</h3>
{{ endif }}
";

$values = [
	'countOrders' => count(Customer::findOne($id)->orders); // e.g. 3
];

echo $engine->render($templateHtml, $values);
// output e.g.: "<h3>Thank you!</h3>" - if some order found

FOR ... ELSEFOR .. ENDFOR

Structure FOR ... ELSEFOR .. ENDFOR will create loop:

$templateHtml = "
<table>
{{ for item in items }}
	{{ SET subtotal = item.qty * item.price * (100 + item.vat) / 100 }}
	<tr>
		<td>#{{ loop.index }}</td>
		<td>{{ item.description }}</td>
		<td>{{ item.qty }}</td>
		<td>{{ item.price | round(2) }}</td>
		<td>{{ item.vat | round(2) }}%</td>
		<td>{{ subtotal | round(2) }} &euro;</td>
	</tr>
	{{ SET total = total + subtotal }}
{{ endfor }}
</table>
<p>Amount due: <b> {{ total | round(2) }} Eur</b></p>
";

$values = [
	'items' => [
		['description' => 'Item one', 'qty' => 1, 'price' => 1, 'vat' => 10],
		['description' => 'Item two', 'qty' => 2, 'price' => 2, 'vat' => 20],
		['description' => 'Item three', 'qty' => 3, 'price' => 3, 'vat' => 30],
		['description' => 'Item four', 'qty' => 4, 'price' => 4, 'vat' => 40],
	]
];

$html = $engine->render($templateHtml, $values);
// outputs valid HTML table with items e.g.: "<table><tr><td>#1</td><td> ..."

Following auxiliary variables are accessible inside each loop:

index .. (int) 1-based iteration counter
index0 .. (int) 0-based iteration counter
length .. (int) total number of items/iterations
first .. (bool) true on first iteration
last .. (bool) true on last iteration

SET command

Allows manipulating local template variables, such as count totals:

{{ SET subtotal = item.qty * item.price * (100 + item.vat) / 100 }}
{{ SET total = total + subtotal }}

Rendering PDF or MS Word files

Rendering engine allows user to safely change output without any programming knowledge. To add an extra value, we can also turn rendered HTML output into professionally looking PDF or MS Word file:

// first process HTML template and input values
$htmlOutput = $engine->render($htmlMarkup, $values);

// then generate PDF file:
$pdf = new \TCPDF();
$pdf->writeHTML($htmlOutput);
$path = $pdf->Output('/save/path/my-invoice.pdf');

// or generate MS Word file:
$word = new \PhpOffice\PhpWord\PhpWord();
$section = $word->addSection();
\PhpOffice\PhpWord\Shared\Html::addHtml($section, $htmlOutput);
$writer = \PhpOffice\PhpWord\IOFactory::createWriter($word, 'Word2007');
$writer->save('/save/path/my-invoice.docx');

Tips & notes

see tests/TemplateEngineTest.php for more examples
Running tests via phpunit on NuSphere's PhpEd in debug mode:

use -d parameter to inject debugging arguments, e.g. > phpunit -d DBGSESSID=12655478@127.0.0.1:7869 %*

Adding functionality - simply extend TemplateEngine class:

class MyRenderer extends \lubosdz\yii2\TemplateEngine
{
	// your code, custom directives, override parent methods ..
}

the Yii-dependency can be easily dropped so the engine can be used as a standalone renderer.

Changelog

1.0.3, ... under development

added support for loading HTML via path alias, e.g. $engine->render('@app/templates/invoice.html', $data)

1.0.2, released 2022-02-01

fix compatability for PHP 8.1

1.0.1, released 2021-12-30

fix tests for PHP 7.0 - 8.0
improved documentation

1.0.0, released 2021-12-13

initial release

fighcell/yii2-template-engine