Defining routes

A full route definition can contain up to four parts:

1. The URL pattern route. This is matched against the URL passed to the `RequestContext`, and can contain named wildcard placeholders (e.g. {placeholders}) to match dynamic parts in the URL.

2. An array of default values. This contains an array of arbitrary values that will be returned when the request matches the route.

3. An array of requirements. These define constraints for the values of the placeholders as regular expressions.

4. An array of options. These contain internal settings for the route and are the least commonly needed.

Take the following route, which combines several of these ideas:

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$route = new Route(
    '/archive/{month}', // path
    array('controller' => 'showArchive'), // default values
    array('month' => '[0-9]{4}-[0-9]{2}'), // requirements
    array() // options
);

// ...

$parameters = $matcher->match('/archive/2012-01');
// array(
//     'controller' => 'showArchive',
//     'month'      => '2012-01',
//     '_route'     => ...
//  )

$parameters = $matcher->match('/archive/foo');
// throws ResourceNotFoundException

In this case, the route is matched by /archive/2012-01, because the {month} wildcard matches the regular expression wildcard given. However, /archive/foo does not match, because "foo" fails the month wildcard.

Besides the regular expression constraints there are two special requirements you can define:

• _method enforces a certain HTTP request method (HEAD, GET, POST, ...)
• _scheme enforces a certain HTTP scheme (http, https)

For example, the following route would only accept requests to /foo with the POST method and a secure connection:

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$route = new Route(
    '/foo',
    array(),
    array('_method' => 'post', '_scheme' => 'https' )
);

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$route = new Route(
    '/start/{suffix}',
    array('suffix' => ''),
    array('suffix' => '.*')
);

Using Prefixes

You can add routes or other instances of RouteCollection to another collection. This way you can build a tree of routes. Additionally you can define a prefix, default requirements and default options to all routes of a subtree:

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$rootCollection = new RouteCollection();

$subCollection = new RouteCollection();
$subCollection->add(...);
$subCollection->add(...);

$rootCollection->addCollection(
    $subCollection,
    '/prefix',
    array('_scheme' => 'https')
);

Set the Request Parameters

The RequestContext provides information about the current request. You can define all parameters of an HTTP request with this class via its constructor:

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public function __construct(
    $baseUrl = '',
    $method = 'GET',
    $host = 'localhost',
    $scheme = 'http',
    $httpPort = 80,
    $httpsPort = 443
)

Normally you can pass the values from the $_SERVER variable to populate the RequestContext. But If you use the HttpFoundation component, you can use its Request class to feed the RequestContext in a shortcut:

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use Symfony\Component\HttpFoundation\Request;

$context = new RequestContext();
$context->fromRequest(Request::createFromGlobals());

Generate a URL

While the UrlMatcher tries to find a route that fits the given request you can also build a URL from a certain route:

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use Symfony\Component\Routing\Generator\UrlGenerator;

$routes = new RouteCollection();
$routes->add('show_post', new Route('/show/{slug}'));

$context = new RequestContext($_SERVER['REQUEST_URI']);

$generator = new UrlGenerator($routes, $context);

$url = $generator->generate('show_post', array(
    'slug' => 'my-blog-post',
));
// /show/my-blog-post

Load Routes from a File

You've already seen how you can easily add routes to a collection right inside PHP. But you can also load routes from a number of different files.

The Routing component comes with a number of loader classes, each giving you the ability to load a collection of route definitions from an external file of some format. Each loader expects a FileLocator instance as the constructor argument. You can use the FileLocator to define an array of paths in which the loader will look for the requested files. If the file is found, the loader returns a RouteCollection.

If you're using the YamlFileLoader, then route definitions look like this:

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# routes.yml
route1:
    pattern: /foo
    defaults: { _controller: 'MyController::fooAction' }

route2:
    pattern: /foo/bar
    defaults: { _controller: 'MyController::foobarAction' }

To load this file, you can use the following code. This assumes that your routes.yml file is in the same directory as the below code:

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use Symfony\Component\Config\FileLocator;
use Symfony\Component\Routing\Loader\YamlFileLoader;

// look inside *this* directory
$locator = new FileLocator(array(__DIR__));
$loader = new YamlFileLoader($locator);
$collection = $loader->load('routes.yml');

Besides YamlFileLoader there are two other loaders that work the same way:

• XmlFileLoader
• PhpFileLoader

If you use the PhpFileLoader you have to provide the name of a php file which returns a RouteCollection:

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// RouteProvider.php
use Symfony\Component\Routing\RouteCollection;
use Symfony\Component\Routing\Route;

$collection = new RouteCollection();
$collection->add(
    'route_name',
    new Route('/foo', array('controller' => 'ExampleController'))
);
// ...

return $collection;

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use Symfony\Component\Routing\Loader\ClosureLoader;

$closure = function() {
    return new RouteCollection();
};

$loader = new ClosureLoader();
$collection = $loader->load($closure);

The all-in-one Router

The Router class is a all-in-one package to quickly use the Routing component. The constructor expects a loader instance, a path to the main route definition and some other settings:

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public function __construct(
    LoaderInterface $loader,
    $resource,
    array $options = array(),
    RequestContext $context = null,
    array $defaults = array()
);

With the cache_dir option you can enable route caching (if you provide a path) or disable caching (if it's set to null). The caching is done automatically in the background if you want to use it. A basic example of the Router class would look like:

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$locator = new FileLocator(array(__DIR__));
$requestContext = new RequestContext($_SERVER['REQUEST_URI']);

$router = new Router(
    new YamlFileLoader($locator),
    'routes.yml',
    array('cache_dir' => __DIR__.'/cache'),
    $requestContext
);
$router->match('/foo/bar');