Thoughts and Patterns of a Developer

Slim PHP 101 - How to use multiple view parsers

April 10, 2014

In this post we will go through setting up Slim to work with multiple view parsers, for this example we will look at using Slim’s PHP view library and the Twig view library. In order to use Slim with Twig we need a view parser, luckily enough there is already one created in the Slim Views repository.

We will be using composer to install all our dependencies.

Composer setup

Our composer.json file will look like below.

{
    "require": {
        "slim/slim": "2.4.*",
        "slim/views": "0.1.*",
        "twig/twig": "1.15.*",
    }
}

Once you have installed all your dependencies we can start setting up our Slim project. We will do all of our setup in our index.php file for this project. Here is what my index.php look like.

<?php
require 'vendor/autoload.php';

$app = new \Slim\Slim();

// GET routes
$app->get('/', function () use ($app) {
    $app->render('home.php');
})->name('home');

$app->get('/about', function () use ($app) {
    $app->render('about.php');
})->name('about');

$app->run();

Now we have a basic web project setup and rendering two templates with the Slim’s PHP view library.

Note: your templates should be in your designated templates directory, in this case that would be the default ./templates

Lets start adding in our extra code now to configure our twig renderer while keeping our current setup.

<?php
require 'vendor/autoload.php';

$app = new \Slim\Slim();

$app->container->singleton('twig', function ($c) {
    $twig = new \Slim\Views\Twig();

    /* Option */
    $twig->parserOptions = array(
        'debug' => true,
        'cache' => dirname(__FILE__) . '/cache'
    );

    /* Extensions */
    $twig->parserExtensions = array(
        new \Slim\Views\TwigExtension(),
    );

    $templatesPath = $c['settings']['templates.path'];
    $twig->setTemplatesDirectory($templatesPath);

    return $twig;
});

Step through index.php code above

Now we are injecting a dependency into the Slim DI container, which we will use as a resource locator later on. If you have a look into the Slim.php source code you will see this being used for quite a few dependencies inside of Slim itself. We are setting this as a singleton because we want the resource definition to remain each time it is requested.

In the singleton method we define our resource as twig and pass it a closure with our settings and extensions we want to load. The first piece of code inside of our closure is just instantiating the Twig view.

<?php
$twig = new \Slim\Views\Twig();

Now we have our Twig view initialised, we might want to setup our options and extensions we want Twig to use. This is what the lines below are doing:

<?php
/* Option */
$twig->parserOptions = array(
    'debug' => true,
    'cache' => dirname(__FILE__) . '/cache'
);

/* Extensions */
$twig->parserExtensions = array(
    new \Slim\Views\TwigExtension(),
);

Once we have this done we need to tell out Twig view parser where out template directory is located, we can get this through the resource locator from our Slim settings.

<?php
$templatesPath = $c['settings']['templates.path'];
$twig->setTemplatesDirectory($templatesPath);

Once we are done with our settings and setting the template path we return our instance.

<?php
return $twig;

Note: our instance will be lazy loaded, meaning the Twig view won’t be instantiated unless we request the resource from the resource locator.

Now we can start making changes to our code to make use of our newly setup Twig view. If we wanted to change our about route we would rewrite as:

<?php
$app->get('/about', function () use ($app) {
    $app->twig->display('about.php');
})->name('about');

We are now using our Twig view to render our template instead of the PHP view, while in our home route we are still using our PHP view. Here is the full code below:

<?php
require 'vendor/autoload.php';

$app = new \Slim\Slim();

$app->container->singleton('twig', function ($c) {
    $twig = new \Slim\Views\Twig();

    /* Option */
    $twig->parserOptions = array(
        'debug' => true,
        'cache' => dirname(__FILE__) . '/cache'
    );

    /* Extensions */
    $twig->parserExtensions = array(
        new \Slim\Views\TwigExtension(),
    );

    $templatesPath = $c['settings']['templates.path'];
    $twig->setTemplatesDirectory($templatesPath);

    return $twig;
});

// GET routes
$app->get('/', function () use ($app) {
    $app->render('home.php');
})->name('home');

$app->get('/about', function () use ($app) {
    $app->twig->display('about.php');
})->name('about');

Here are some use cases for doing this.

I am a freelance web developer who works under the name Silent Works. I work on various open source project and try to evolve with new technologies as they arrive.

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