This chapter describes how to use Silex.
If you want to get started fast, download Silex as an archive and extract it, you should have the following directory structure:
├── composer.json
├── composer.lock
├── vendor
│ └── ...
└── web
└── index.php
If you want more flexibility, use Composer instead. Create a composer.json:
{
"require": {
"silex/silex": "1.0.*@dev"
}
}
And run Composer to install Silex and all its dependencies:
$ curl -s http://getcomposer.org/installer | php
$ php composer.phar install
Tip
By default, Silex relies on the stable Symfony components. If you want to use their master version instead, add "minimum-stability": "dev" in your composer.json file.
Upgrading Silex to the latest version is as easy as running the update command:
$ php composer.phar update
To bootstrap Silex, all you need to do is require the vendor/autoload.php file and create an instance of Silex\Application. After your controller definitions, call the run method on your application:
// web/index.php
require_once __DIR__.'/../vendor/autoload.php';
$app = new Silex\Application();
// definitions
$app->run();
Then, you have to configure your web server (read the dedicated chapter for more information).
Tip
When developing a website, you might want to turn on the debug mode to ease debugging:
$app['debug'] = true;
Tip
If your application is hosted behind a reverse proxy and you want Silex to trust the X-Forwarded-For* headers, you will need to run your application like this:
use Symfony\Component\HttpFoundation\Request;
Request::trustProxyData();
$app->run();
In Silex you define a route and the controller that is called when that route is matched.
A route pattern consists of:
The controller is defined using a closure like this:
function () {
// do something
}
Closures are anonymous functions that may import state from outside of their definition. This is different from globals, because the outer state does not have to be global. For instance, you could define a closure in a function and import local variables of that function.
Note
Closures that do not import scope are referred to as lambdas. Because in PHP all anonymous functions are instances of the Closure class, we will not make a distinction here.
The return value of the closure becomes the content of the page.
Here is an example definition of a GET route:
$blogPosts = array(
1 => array(
'date' => '2011-03-29',
'author' => 'igorw',
'title' => 'Using Silex',
'body' => '...',
),
);
$app->get('/blog', function () use ($blogPosts) {
$output = '';
foreach ($blogPosts as $post) {
$output .= $post['title'];
$output .= '<br />';
}
return $output;
});
Visiting /blog will return a list of blog post titles. The use statement means something different in this context. It tells the closure to import the $blogPosts variable from the outer scope. This allows you to use it from within the closure.
Now, you can create another controller for viewing individual blog posts:
$app->get('/blog/show/{id}', function (Silex\Application $app, $id) use ($blogPosts) {
if (!isset($blogPosts[$id])) {
$app->abort(404, "Post $id does not exist.");
}
$post = $blogPosts[$id];
return "<h1>{$post['title']}</h1>".
"<p>{$post['body']}</p>";
});
This route definition has a variable {id} part which is passed to the closure.
When the post does not exist, we are using abort() to stop the request early. It actually throws an exception, which we will see how to handle later on.
POST routes signify the creation of a resource. An example for this is a feedback form. We will use the mail function to send an e-mail:
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
$app->post('/feedback', function (Request $request) {
$message = $request->get('message');
mail('feedback@yoursite.com', '[YourSite] Feedback', $message);
return new Response('Thank you for your feedback!', 201);
});
It is pretty straightforward.
Note
There is a SwiftmailerServiceProvider included that you can use instead of mail().
The current request is automatically injected by Silex to the Closure thanks to the type hinting. It is an instance of Request, so you can fetch variables using the request get method.
Instead of returning a string we are returning an instance of Response. This allows setting an HTTP status code, in this case it is set to 201 Created.
Note
Silex always uses a Response internally, it converts strings to responses with status code 200 Ok.
You can create controllers for most HTTP methods. Just call one of these methods on your application: get, post, put, delete. You can also call match, which will match all methods:
$app->match('/blog', function () {
...
});
You can then restrict the allowed methods via the method method:
$app->match('/blog', function () {
...
})
->method('PATCH');
You can match multiple methods with one controller using regex syntax:
$app->match('/blog', function () {
...
})
->method('PUT|POST');
Note
The order in which the routes are defined is significant. The first matching route will be used, so place more generic routes at the bottom.
As it has been shown before you can define variable parts in a route like this:
$app->get('/blog/show/{id}', function ($id) {
...
});
It is also possible to have more than one variable part, just make sure the closure arguments match the names of the variable parts:
$app->get('/blog/show/{postId}/{commentId}', function ($postId, $commentId) {
...
});
While it’s not suggested, you could also do this (note the switched arguments):
$app->get('/blog/show/{postId}/{commentId}', function ($commentId, $postId) {
...
});
You can also ask for the current Request and Application objects:
$app->get('/blog/show/{id}', function (Application $app, Request $request, $id) {
...
});
Note
Note for the Application and Request objects, Silex does the injection based on the type hinting and not on the variable name:
$app->get('/blog/show/{id}', function (Application $foo, Request $bar, $id) {
...
});
Before injecting the route variables into the controller, you can apply some converters:
$app->get('/user/{id}', function ($id) {
// ...
})->convert('id', function ($id) { return (int) $id; });
This is useful when you want to convert route variables to objects as it allows to reuse the conversion code across different controllers:
$userProvider = function ($id) {
return new User($id);
};
$app->get('/user/{user}', function (User $user) {
// ...
})->convert('user', $userProvider);
$app->get('/user/{user}/edit', function (User $user) {
// ...
})->convert('user', $userProvider);
The converter callback also receives the Request as its second argument:
$callback = function ($post, Request $request) {
return new Post($request->attributes->get('slug'));
};
$app->get('/blog/{id}/{slug}', function (Post $post) {
// ...
})->convert('post', $callback);
In some cases you may want to only match certain expressions. You can define requirements using regular expressions by calling assert on the Controller object, which is returned by the routing methods.
The following will make sure the id argument is numeric, since \d+ matches any amount of digits:
$app->get('/blog/show/{id}', function ($id) {
...
})
->assert('id', '\d+');
You can also chain these calls:
$app->get('/blog/show/{postId}/{commentId}', function ($postId, $commentId) {
...
})
->assert('postId', '\d+')
->assert('commentId', '\d+');
You can define a default value for any route variable by calling value on the Controller object:
$app->get('/{pageName}', function ($pageName) {
...
})
->value('pageName', 'index');
This will allow matching /, in which case the pageName variable will have the value index.
Some providers (such as UrlGeneratorProvider) can make use of named routes. By default Silex will generate a route name for you, that cannot really be used. You can give a route a name by calling bind on the Controller object that is returned by the routing methods:
$app->get('/', function () {
...
})
->bind('homepage');
$app->get('/blog/show/{id}', function ($id) {
...
})
->bind('blog_post');
Note
It only makes sense to name routes if you use providers that make use of the RouteCollection.
If you don’t want to use anonymous functions, you can also define your controllers as methods. By using the ControllerClass::methodName syntax, you can tell Silex to lazily create that controller class for you:
$app->get('/', 'Igorw\Foo::bar');
use Silex\Application;
use Symfony\Component\HttpFoundation\Request;
namespace Igorw
{
class Foo
{
public function bar(Request $request, Application $app)
{
...
}
}
}
This will load the Igorw\Foo class on demand, create an instance and call the bar method to get the response. You can use Request and Silex\Application type hints to get $request and $app injected.
For an even stronger separation between Silex and your controllers, you can define your controllers as services.
If a controller setting must be applied to all controllers (a converter, a middleware, a requirement, or a default value), you can configure it on $app['controllers'], which holds all application controllers:
$app['controllers']
->value('id', '1')
->assert('id', '\d+')
->requireHttps()
->method('get')
->convert('id', function () { /* ... */ })
->before(function () { /* ... */ })
;
These settings are applied to already registered controllers and they become the defaults for new controllers.
Note
The global configuration does not apply to controller providers you might mount as they have their own global configuration (see the Modularity paragraph below).
If some part of your code throws an exception you will want to display some kind of error page to the user. This is what error handlers do. You can also use them to do additional things, such as logging.
To register an error handler, pass a closure to the error method which takes an Exception argument and returns a response:
use Symfony\Component\HttpFoundation\Response;
$app->error(function (\Exception $e, $code) {
return new Response('We are sorry, but something went terribly wrong.');
});
You can also check for specific errors by using the $code argument, and handle them differently:
use Symfony\Component\HttpFoundation\Response;
$app->error(function (\Exception $e, $code) {
switch ($code) {
case 404:
$message = 'The requested page could not be found.';
break;
default:
$message = 'We are sorry, but something went terribly wrong.';
}
return new Response($message);
});
Note
As Silex ensures that the Response status code is set to the most appropriate one depending on the exception, setting the status on the response won’t work. If you want to overwrite the status code (which you should not without a good reason), set the X-Status-Code header:
return new Response('Error', 404 /* ignored */, array('X-Status-Code' => 200));
You can restrict an error handler to only handle some Exception classes by setting a more specific type hint for the Closure argument:
$app->error(function (\LogicException $e, $code) {
// this handler will only \LogicException exceptions
// and exceptions that extends \LogicException
});
If you want to set up logging you can use a separate error handler for that. Just make sure you register it before the response error handlers, because once a response is returned, the following handlers are ignored.
Note
Silex ships with a provider for Monolog which handles logging of errors. Check out the Providers chapter for details.
Tip
Silex comes with a default error handler that displays a detailed error message with the stack trace when debug is true, and a simple error message otherwise. Error handlers registered via the error() method always take precedence but you can keep the nice error messages when debug is turned on like this:
use Symfony\Component\HttpFoundation\Response;
$app->error(function (\Exception $e, $code) use ($app) {
if ($app['debug']) {
return;
}
// logic to handle the error and return a Response
});
The error handlers are also called when you use abort to abort a request early:
$app->get('/blog/show/{id}', function (Silex\Application $app, $id) use ($blogPosts) {
if (!isset($blogPosts[$id])) {
$app->abort(404, "Post $id does not exist.");
}
return new Response(...);
});
You can redirect to another page by returning a redirect response, which you can create by calling the redirect method:
$app->get('/', function () use ($app) {
return $app->redirect('/hello');
});
This will redirect from / to /hello.
When you want to delegate the rendering to another controller, without a round-trip to the browser (as for a redirect), use an internal sub-request:
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\HttpKernelInterface;
$app->get('/', function () use ($app) {
// redirect to /hello
$subRequest = Request::create('/hello', 'GET');
return $app->handle($subRequest, HttpKernelInterface::SUB_REQUEST);
});
Tip
If you are using UrlGeneratorProvider, you can also generate the URI:
$request = Request::create($app['url_generator']->generate('hello'), 'GET');
There’s some more things that you need to keep in mind though. In most cases you will want to forward some parts of the current master request to the sub-request. That includes: Cookies, server information, session. Read more on how to make sub-requests.
If you want to return JSON data, you can use the json helper method. Simply pass it your data, status code and headers, and it will create a JSON response for you:
$app->get('/users/{id}', function ($id) use ($app) {
$user = getUser($id);
if (!$user) {
$error = array('message' => 'The user was not found.');
return $app->json($error, 404);
}
return $app->json($user);
});
It’s possible to create a streaming response, which is important in cases when you cannot buffer the data being sent:
$app->get('/images/{file}', function ($file) use ($app) {
if (!file_exists(__DIR__.'/images/'.$file)) {
return $app->abort(404, 'The image was not found.');
}
$stream = function () use ($file) {
readfile($file);
};
return $app->stream($stream, 200, array('Content-Type' => 'image/png'));
});
If you need to send chunks, make sure you call ob_flush and flush after every chunk:
$stream = function () {
$fh = fopen('http://www.example.com/', 'rb');
while (!feof($fh)) {
echo fread($fh, 1024);
ob_flush();
flush();
}
fclose($fh);
};
Silex comes with PHP traits that define shortcut methods.
Caution
You need to use PHP 5.4 or later to benefit from this feature.
Almost all built-in service providers have some corresponding PHP traits. To use them, define your own Application class and include the traits you want:
use Silex\Application;
class MyApplication extends Application
{
use Application\TwigTrait;
use Application\SecurityTrait;
use Application\FormTrait;
use Application\UrlGeneratorTrait;
use Application\SwiftmailerTrait;
use Application\MonologTrait;
use Application\TranslationTrait;
}
You can also define your own Route class and use some traits:
use Silex\Route;
class MyRoute extends Route
{
use Route\SecurityTrait;
}
To use your newly defined route, override the $app['route_class'] setting:
$app['route_class'] = 'MyRoute';
Read each provider chapter to learn more about the added methods.
Make sure to protect your application against attacks.
When outputting any user input (either route variables GET/POST variables obtained from the request), you will have to make sure to escape it correctly, to prevent Cross-Site-Scripting attacks.
Escaping HTML: PHP provides the htmlspecialchars function for this. Silex provides a shortcut escape method:
$app->get('/name', function (Silex\Application $app) {
$name = $app['request']->get('name');
return "You provided the name {$app->escape($name)}.";
});
If you use the Twig template engine you should use its escaping or even auto-escaping mechanisms.
Escaping JSON: If you want to provide data in JSON format you should use the Silex json function:
$app->get('/name.json', function (Silex\Application $app) {
$name = $app['request']->get('name');
return $app->json(array('name' => $name));
});