Symfony2

Web application framework

DC PHP, Aug 27th 2014
© David Buchmann, Liip AG

About David Buchmann

Twitter: @dbu

Senior backend developper at Liip
Symfony2 expert
Maintainer of Symfony2 Content Management Framework (CMF)
Other topics: Varnish, Elasticsearch, Vagrant
Liip is a web agency in Switzerland.

Outline

Philosophy
Dependency Injection
Core Components
- HttpFoundation
- Routing
- Twig
Using Symfony2 Framework
- Start a project
- Create your first bundle
- Model, View, Controller
Some more background on Symfony2

Symfony2

HTTP framework
Components: Over 20 high quality, cleanly separated libraries
Each suitable for standalone use
Full stack framework
- All components sensibly wired together
- Conventions for folder structure
- Bundles: Plugins that integrate into full stack

Composer

Dependency management reloaded

Define dependencies of your application
Libraries declare their dependencies
Composer resolves dependencies and downloads all needed libraries
Per project, not global in your system
Integrates autoloading
Simple to use, simple to publish libraries

You should too!

Think separation of concern over this or that framework
Write standalone libraries
Write separate integration layer for frameworks
RAD: Tied to framework

Dependeny Injection

1class MyClass
2{
3    public function do()
4    {
5        global $variable;
6        echo $variable;
7    }
8}

NO!

Dependeny Injection

1class MyClass
2{
3  public function do()
4  {
5    echo Registry::instance()->get('variable');
6  }
7}

Meh. A bit better but not good.

Dependeny Injection

01class MyClass
02{
03    private $variable;
04     
05    public function __construct($variable)
06    {
07        $this->variable = $variable;
08    }
09    public function do()
10    {
11        echo $this->variable;
12    }
13}

This is dependency injection!

Dependeny Injection

Independant of any "service container"
Push instead of pull
Dependencies are explicit
Reusable code
Testable code

Symfony2 Dependeny Injection

"service": lazy loaded class instance
Define what other services need to be injected
Service container only instantiates when actually needed

Core Components:

HttpFoundation

HTTP object oriented

Request
Response
Headers, Content negotiation
File upload and download, streaming
Session

The Request object

1// /test-path?name=test
2$request = Request::createFromGlobals();
3$request->query->get('name'); // test
4$request->getLanguages(); // ordered by priority
5$request->getContent(); // body of request
6Request::create('/test-path', 'GET', array('name' => 'test'));

Creating a response

1$response = new Response('Success', Response::HTTP_OK, 
2    array('content-type' => 'text/plain'));
3$response->headers->setCookie('foo' => 'bar');
4$response->setMaxAge(3600); // let client cache for 1 hour
5$response->send();

Special types of responses

01$response = new RedirectResponse('http://php.net');
02$response = new Response('Not Found', Response::HTTP_NOT_FOUND);
03 
04$path = '/path/to/file.txt';
05$response = new BinaryFileResponse($file);
06// overwrite the filename
07$response->setContentDisposition(
08    ResponseHeaderBag::DISPOSITION_ATTACHMENT,
09    'filename.txt'
10);

Core Components:

Routing

URL to PHP method

Route
RouteCollection
RequestContext
UrlMatcher
UrlGenerator

Routes

Path, with placeholders: /article/{slug}
Requirements: Regular expressions for placeholders, HTTP method and scheme
Array of default values

Request Matching

01$route = new Route('/articles/{slug}', 
02    array('controller' => 'MyClass'));
03$routes = new RouteCollection();
04$routes->add('article', $route);
05// convenient when using HttpFoundation:
06$context = RequestContext::fromRequest(
07    Request::createFromGlobals());
08 
09$matcher = new UrlMatcher($routes, $context);
10$parameters = $matcher->match('/articles/my');
11// array('slug'=>'my', 'controller'=>'MyClass', 
12//       '_route'=>'article')
13//
14// Your application knows how to call MyClass

Generate URL

1$generator = new UrlGenerator($routes, $context);
2$generator->generate('article', array(
3    'slug' => 'my',
4));
5// /article/my
6 
7$generator->generate('article', array(
8    'slug' => 'my'), true);
9// http://example.com/article/my

Load routes from file

1article:
2    path: /article/{slug}
3    defaults: { _controller: 'MyClass' }
4    requirements:
5        slug: [a-zA-Z\-]

1// uses the optional Config component
2$locator = new FileLocator(array(__DIR__));
3$loader = new YamlFileLoader($locator);
4$collection = $loader->load('routes.yml');

Core Components:

Twig

Templating language

Clean separation of application logic and templating
Secure: Escaping by default
Convenient for frontend devs
Much more readable than PHP templates
Compiled to PHP, no speed penalty
Write custom extensions in PHP

Twig in 3 bullet points

{{ ... }} echo a value
{% ... %} execute something
provide control logic, loops and blocks

Example

1<!DOCTYPE html>
2<html>
3  <head>
4    <title>Welcome to Washington DC PHP!</title>
5  </head>
6  <body>
7    <h1>Hello: {{ name }}</h1>
8  </body>
9</html>

Control and data access

1<ul>
2    {% for user in users if user.active %}
3        <li>{{ user.username }}</li>
4    {% else %}
5        <li>No users found</li>
6    {% endfor %}
7</ul>

When object, isActive(), getActive() or public property active
When array, index 'active'

Inheritance

1{# base.html.twig #}
2<html>
3    <head>
4        {% block title %}Liip AG{% endblock %}
5    </head>
6    <body>
7        {% block body %}{% endblock %}
8    </body>
9</html>

1{% extends 'base.html.twig' %}
2{% block title %}
3    {{ content.title }} - {{ parent() }}
4{% endblock %}
5{% block body %}{{ content.text }}{% endblock %}

Extension points

Filter: {{ name|upper }}, {{ body|raw }}
Function: {{ min(a, b, c) }}
Tag: {% for i in 1..5 %}{{ i }}{% endfor %}
Lots of useful built-in things
Build your own: Filters and functions are easy
Custom Tags: Render PHP code in your code

Symfony2 full stack framework

Setting up a project

`1`	`$ curl -s https://getcomposer.org/installer \| php`

`2`	`$ php composer.phar create-project symfony/framework-standard-edition my-project 2.5.*`

Configure your web server to point to web subfolder of my-project

Directory Layout

app/ application configuration, bootstrap and overwritten files
src/ code specific to this application, organized as bundles
vendor/ all third party code, managed by composer
web/ web root, application entry point and static files

Develop

Entry point is "hostname.lo/app.php"
If you have mod_rewrite, there is a .htaccess to use "hostname.lo/"
Debug entry point is /app_dev.php
- Templates and configuration checked for changes and automatically re-compiled
- Different configuration per environment
- Debug toolbar at the bottom

Create your first bundle

`1`	`$ php app/console generate:bundle --namespace=DC/HelloBundle --format=yml`

`2`	`# simply accept all defaults, they are fine`

1// app/AppKernel.php
2public function registerBundles()
3{
4    $bundles = array(
5        // ...
6        new DC\HelloBundle\DCHelloBundle(),
7    );
8    return $bundles;
9}

Also links routing file from app/config/routing.yml

Bundle Directory Layout

Controller/ code for handling requests
DependencyInjection/ for managing bundle configuration (advanced feature)
Resources/config/ configuration files for this bundle, e.g. routing
Resources/views/ template files
Resources/public/ static files to expose through the web/ directory (stylesheets, javascript, ...)
Tests/ phpunit tests of this bundle.

Controller

01namespace DC\HelloBundle\Controller;
02 
03use Symfony\Component\HttpFoundation\Response;
04 
05class HelloController
06{
07    public function greetAction($name)
08    {
09        return new Response("Hello $name");
10    }
11}

Routing: Map request to controller

As seen before, pattern /hello/{name}
Controller as DCHelloBundle:Hello:greet
Symfony2 instantiates DC\HelloBundle\Controller\HelloController and calls greetAction
Method parameters from request

View

Symfony2 twig integration

Controller can easily render a template

1$this->render(
2    'DCHelloBundle:Hello:greet.html.twig',
3    array('name' => $name)
4);

Convenience Twig functions, e.g. path() function to render a route
Render a controller action from twig

Model

01<?php
02namespace DC\HelloBundle\Entity;
03class Page
04{
05    private $mainText;
06    public function __construct($text)
07    {
08        $this->mainText = $text;
09    }
10    public function getMainText()
11    {
12        return $this->mainText;
13    }
14    public function setMainText($text)
15    {
16        $this->mainText = $text;
17    }
18}

Use it

Controller

1$page = new \DC\HelloBundle\Entity\Page('test');
2return $this->render(
3    'DCHelloBundle:Default:index.html.twig',
4    array('name' => $name, 'page' => $page)
5);

Template

`1`	`<p>{{ page.mainText }}</p>`

Doctrine ORM

Object-Relational mapper
Any PHP objects, not active record
Map with annotations, XML or yaml files

01use Doctrine\ORM\Mapping as ORM;
02 
03/**
04 * @ORM\Entity
05 */
06class Page
07{
08    /**
09     * @ORM\Column(name="id", type="integer")
10     * @ORM\Id
11     * @ORM\GeneratedValue(strategy="AUTO")
12     */
13    private $id;
14 
15    /**
16     * @ORM\Column(name="main_text", type="string")
17     */
18    private $mainText;
19    ...

Console commands to manage database

1$ app/console doctrine:schema:update --dump-sql
2CREATE TABLE Page (id INTEGER NOT NULL, main_text VARCHAR(255) NOT NULL, PRIMARY KEY(id))
3 
4$ app/console doctrine:schema:update --force
5Updating database schema...
6Database schema updated successfully! "1" queries were executed

Insert Doctrine Objects

1$page = new Page('DCPHP in Washington');
2 
3$em = $this->getDoctrine()->getManager();
4$em->persist($page);
5$em->flush();

Read Doctrine Objects

1$em = $this->getDoctrine()->getManager();
2$repository = $em->getRepository('DCHelloBundle:Page')
3$page = $repository->find($id);
4if (! $page) {
5    throw new NotFoundHttpException("no page $id");
6}
7// render as before
8}

Doctrine shell commands

doctrine:mapping:info - informations about the entities you defined
doctrine:generate:entities - generate classes from xml/yml mapping information
doctrine:generate:entity - interactive shell to define entity
doctrine:mapping:import - generate entities by inspecting an existing database
doctrine:migrations:status|diff|migrate - manage database changes in change scripts

Reuse: There is a bundle for that!

Find existing code

PHP has lots of cool libraries
Bundles integrate them into Symfony2
Fight the NIH syndrome
Each bundle you can use is one less you need to write and maintain
knpbundles.com
packagist.org

Integrate KnpMarkdownBundle

`1`	`php composer.phar require` `"knplabs/knp-markdown-bundle:1.2.*"`

Add to app/AppKernel.php

1$bundles = array(
2    // ...
3    new Knp\Bundle\MarkdownBundle\KnpMarkdownBundle(),
4);

Use it in template

`1`	`{{ page.mainText\|markdown }}`

Using git

Ignore the vendor/ directory
But track the composer.lock file (and composer.json of course)
The standard edition provides a reasonable .gitignore file
Track the parameters.yml.dist file but have parameters.yml ignored

Lots of interesting components

Console: Run console commands
Form: Build and handle web form submission
DomCrawler and CssSelector: Web scraper and functional testing
EventDispatcher: Register to events and define your own event types
Process: Run commands in separate processes
Validator: Rule format and validate whether data follows the rules
Security: Handle security inside the application

Symfony2

Web application framework

About David Buchmann

Twitter: @dbu

Outline

Symfony2

Composer

Dependency management reloaded

You should too!

Dependeny Injection

Dependeny Injection

Dependeny Injection

Dependeny Injection

Dependeny Injection

Symfony2 Dependeny Injection

Core Components:

HttpFoundation

HttpFoundation

HTTP object oriented

The Request object

Creating a response

Special types of responses

Core Components:

Routing

Routing

URL to PHP method

Routes

Request Matching

Generate URL

Load routes from file

Core Components:

Twig

Twig

Templating language

Twig in 3 bullet points

Example

Control and data access

Inheritance

Extension points

Symfony2 full stack framework

Setting up a project

Directory Layout

Develop

Create your first bundle

Bundle Directory Layout

Controller

Controller

Routing: Map request to controller

View

Symfony2 twig integration

Model

Use it

Controller

Template

Doctrine ORM

Console commands to manage database

Insert Doctrine Objects

Read Doctrine Objects

Doctrine shell commands

Reuse: There is a bundle for that!

Find existing code

Integrate KnpMarkdownBundle

Add to app/AppKernel.php

Use it in template

Using git

Lots of interesting components

Thank you!

Questions / Input / Feedback ?

@dbu