Symfony All The Things (Web)

My Symfony Hello World post introduced the smallest possible example of a Symfony application. Using this in trainings helps the participants understand of just how few parts a Symfony application contains. Sure, there are lots of classes participating under the hood, but I don’t care about the internals only about the public API.

We use microservice architectures for the bepado and PHP Profiler projects that Qafoo is working on at the moment. For the different components a mix of Symfony Framework, Silex, Symfony Components and our own Rest-Microframework (RMF) are used. This zoo of different solutions sparked a recent discussion with my colleague Manuel about when we would want to use Symfony for a web application.

We quickly agreed on: Always. I can’t speak for Manuel, but these are my reasons for this decision:

I always want to use a technology that is based on Symfony HttpKernel, because of the built-in caching, ESI and the Stack-PHP project. I usually don’t need this at the beginning of a project, but at some point the simplicity of extending the Kernel through aggregation is incredible. This leaves three solutions: Silex, Symfony Framework and Plain Components.

I want a well documented and standardized solution. We are working with a big team on bepado, often rotating team members for just some weeks or months. We can count the hours lost for developers when they have to start learning a new stack again. Knowing where to put routes, controllers, templates, configuration et al is important to make time for the real tasks. This leaves Symfony Framework and Silex. Everything built with the components is always custom and therefore not documented well enough.

I want a stable and extendable solution. Even when you just use Symfony for a very small component you typically need to interface with the outside world: OAuth, REST-API, HTTP Clients, Databases (SQL and NoSQL). There is (always) a bundle for that in Symfony. Yes, Silex typically has a copy-cat Provider for their own DIC system, but it is usually missing some configuration option or advanced use-case. In some cases its just missing something as simple as a WebDebug Toolbar integration that the Symfony Bundle has. My experience with Silex has been that its always several steps behind Symfony in terms of reusable functionality. One other downside with Silex in my opinion is its missing support for DIC and Route caching. Once your Silex application grows beyond its initial scope it starts to slow down.

I want just one solution if its flexible enough. It is great to have so many options, but that is also a curse. Lukas points out he is picking between Laravel, Silex or Symfony depending on the application use-case. But the web technology stack is already complex enough in my opionion. I rather have my developers learn and use different storage/queue or frontend technologies than have them juggle between three frameworks. If my experience with Symfony in the last 4 years taught me anything: Hands-on exposure with a single framework for that long leads to impressive productivity. And Symfony is flexible. The Dependency Injection based approach combined with the very balanced decoupling through bundles allows you to cherry-pick only what you need for every application: APIs, RAD, Large Teams. Everything is possible.

The analysis is obviously biased because of my previous exposure to the framework. The productivity gains are possible with any framework as long as it has a flourishing ecosystem. For anyone else this reasoning can end up to choose Laravel, Silex or Zend Framework 2.

So what is the minimal Symfony distribution that would be a starting point. Extending on the Symfony Hello World post:

composer.json index.php file A minimal AppKernel A minimal config.yml file routing files A console script A minimal application bundle

You can find all the code on Github.

Start with the composer.json:

{ "require" : { "symfony/symfony" : "@stable" , "symfony/monolog-bundle" : "@stable" , "vlucas/phpdotenv" : "@stable" }, "autoload" : { "psr-0" : { "Acme" : "src/" } } }

The index.php:

<?php // web/index.php require_once __DIR__ . "/../vendor/autoload.php" ; require_once __DIR__ . "/../app/AppKernel.php" ; use Symfony\Component\HttpFoundation\Request ; Dotenv :: load ( __DIR__ . '/../' ); $request = Request :: createFromGlobals (); $kernel = new AppKernel ( $_SERVER [ 'SYMFONY_ENV' ], ( bool ) $_SERVER [ 'SYMFONY_DEBUG' ]); $response = $kernel -> handle ( $request ); $response -> send (); $kernel -> terminate ( $request , $response );

We are using the package vlucas/phpdotenv to add Twelve Factor app compatibility, simplyfing configuration. This allows us to get rid of the different front controller files based on environment. We need a file called .env in our application root containing key-value pairs of environment variables:

# .env SYMFONY_ENV = dev SYMFONY_DEBUG = 1

Add this file to .gitignore. Your deployment to production needs a mechanism to generate this file with production configuration.

Our minimal AppKernel looks like this:

<?php // app/AppKernel.php use Symfony\Component\HttpKernel\Kernel ; use Symfony\Component\Config\Loader\LoaderInterface ; class AppKernel extends Kernel { public function registerBundles () { $bundles = array ( new Symfony\Bundle\FrameworkBundle\FrameworkBundle (), new Symfony\Bundle\TwigBundle\TwigBundle (), new Symfony\Bundle\MonologBundle\MonologBundle (), new Acme\HelloBundle\AcmeHelloBundle () ); if ( in_array ( $this -> getEnvironment (), array ( 'dev' , 'test' ))) { $bundles [] = new Symfony\Bundle\WebProfilerBundle\WebProfilerBundle (); } return $bundles ; } public function registerContainerConfiguration ( LoaderInterface $loader ) { $loader -> load ( __DIR__ . '/config/config.yml' ); if ( in_array ( $this -> getEnvironment (), array ( 'dev' , 'test' ))) { $loader -> load ( function ( $container ) { $container -> loadFromExtension ( 'web_profiler' , array ( 'toolbar' => true , )); }); } } }

It points to a configuration file config.yml. We don’t use different configuration files per environment here because we don’t need it. Instead we use the closure loader to enable the web debug toolbar when we are in development environment.

Symfony configuration becomes much simpler if we don’t use the inheritance and load everything from just a single file:

# app/config/config.yml framework : secret : % secret % router : resource : "%kernel.root_dir%/config/routing_%kernel.environment%.yml" strict_requirements : % kernel . debug % templating : engines : [ 'twig' ] profiler : enabled : % kernel . debug % monolog : handlers : main : type : fingers_crossed action_level : % monolog_action_level % handler : nested nested : type : stream path : "%kernel.logs_dir%/%kernel.environment%.log" level : debug

We can set the parameter values for %secret% and %monolog_action_level% by adding new lines to .env file, making use of the excellent external configuration parameter support in Symfony.

# .env SYMFONY_ENV = dev SYMFONY_DEBUG = 1 SYMFONY__SECRET = abcdefg SYMFONY__MONOLOG_ACTION_LEVEL = debug

Now add a routing_prod.yml file with a hello world route:

# app/config/routing_prod.yml hello_world : pattern : / hello / { name } defaults : _controller : "AcmeHelloBundle:Default:hello"

And because our routes are dependent on the environment in config.yml also a routing_dev.yml containing the WebDebug toolbar and profiler routes:

# app/config/routing_dev.yml _wdt : resource : "@WebProfilerBundle/Resources/config/routing/wdt.xml" prefix : / _wdt _profiler : resource : "@WebProfilerBundle/Resources/config/routing/profiler.xml" prefix : / _profiler _main : resource : routing_prod . yml

We now need a bundle AcmeHelloBundle that is referenced in routing.yml and in the AppKernel. When we follow Fabiens best practice about adding services, routes and templates into the app/config and app/Resources/views folders adding a bundle just requires the bundle class:

<?php // src/Acme/HelloBundle/AcmeHelloBundle.php namespace Acme\HelloBundle ; use Symfony\Component\HttpKernel\Bundle\Bundle ; class AcmeHelloBundle extends Bundle { }

And the controller that renders our Hello World:

<?php // src/Acme/HelloBundle/Controller/DefaultController.php namespace Acme\HelloBundle\Controller ; use Symfony\Bundle\FrameworkBundle\Controller\Controller ; class DefaultController extends Controller { public function helloAction ( $name ) { return $this -> render ( 'AcmeHelloBundle:Default:hello.html.twig' , array ( 'name' => $name ) ); } }

Now we only put a template into app/Resources:

{# app/Resources/AcmeHelloBundle/views/Default/hello.html.twig #} Hello {{ name }} !

As a last requirement we need a console script to manage our Symfony application. We reuse the vlucas/phpdotenv integration here to load all the required environment variables:

#!/usr/bin/env php <?php // app/console set_time_limit ( 0 ); require_once __DIR__ . '/../vendor/autoload.php' ; require_once __DIR__ . '/AppKernel.php' ; use Symfony\Bundle\FrameworkBundle\Console\Application ; use Symfony\Component\Console\Input\ArgvInput ; Dotenv :: load ( __DIR__ . '/../' ); $input = new ArgvInput (); $kernel = new AppKernel ( $_SERVER [ 'SYMFONY_ENV' ], ( bool ) $_SERVER [ 'SYMFONY_DEBUG' ]); $application = new Application ( $kernel ); $application -> run ( $input );

Voila. The minimal Symfony distribution is done.

Start the php built in webserver to take a look

$ php -S localhost:8080 web/index.php

I personally like this simplicity of that, the only thing that annoys me are the two routing files that I need to conditionally load the web profiler routes and the closure loader for the web_profiler extension. I suppose the nicer approach would be a compiler pass that does all the magic behind the scenes.

From this minimal distribution you can:

Add new services to app/config/config.yml . Add new routes to app/config/routing_prod.yml . Add controllers into new bundles and templates into app/Resources . Add third party bundles or Stack-PHP implementations when you need existing, reusable functionality such as OAuth, Databases etc. Add configuration variables to .env file instead of using the app/config/parameters.yml approach.

This scales well, because at every point you can move towards abstracting bundles and configuration more using Symfony’s built in functionality. No matter what type of application you build, it is always based on Symfony and the building blocks are always the same.

I suggest to combine this minimal Symfony with the QafooLabsFrameworkExtraBundle that I blogged about two weeks ago. Not only will the Symfony be lightweight also your controllers. You can built anything on top this foundation from simple CRUD, APIs, hexagonal- or CQRS-architextures.