How to Define Route Requirements

How to Define Route Requirements

Route requirements can be used to make a specific route only match under specific conditions. The simplest example involves restricting a routing {wildcard} to only match some regular expression:

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    // src/AppBundle/Controller/BlogController.php
    namespace AppBundle\Controller;
    
    use Symfony\Bundle\FrameworkBundle\Controller\Controller;
    use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
    
    class BlogController extends Controller
    {
        /**
         * @Route("/blog/{page}", name="blog_list", requirements={"page": "\d+"})
         */
        public function listAction($page)
        {
            // ...
        }
    }
    
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    # app/config/routing.yml
    blog_list:
        path:      /blog/{page}
        defaults:  { _controller: AppBundle:Blog:list }
        requirements:
            page: '\d+'
    
  • XML
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    <!-- app/config/routing.xml -->
    <?xml version="1.0" encoding="UTF-8" ?>
    <routes xmlns="http://symfony.com/schema/routing"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://symfony.com/schema/routing
            http://symfony.com/schema/routing/routing-1.0.xsd">
    
        <route id="blog_list" path="/blog/{page}">
            <default key="_controller">AppBundle:Blog:list</default>
            <requirement key="page">\d+</requirement>
        </route>
    
        <!-- ... -->
    </routes>
    
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    // app/config/routing.php
    use Symfony\Component\Routing\RouteCollection;
    use Symfony\Component\Routing\Route;
    
    $collection = new RouteCollection();
    $collection->add('blog_list', new Route('/blog/{page}', array(
        '_controller' => 'AppBundle:Blog:list',
    ), array(
        'page' => '\d+'
    )));
    
    // ...
    
    return $collection;
    

Thanks to the \d+ requirement (i.e. a "digit" of any length), /blog/2 will match this route but /blog/some-string will not match.

Why would you ever care about requirements? If a request matches two routes, then the first route always wins. By adding requirements to the first route, you can make each route match in just the right situations. See Adding {wildcard} Requirements for an example.

Since the parameter requirements are regular expressions, the complexity and flexibility of each requirement is entirely up to you. Suppose the homepage of your application is available in two different languages, based on the URL:

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    // src/AppBundle/Controller/MainController.php
    
    // ...
    class MainController extends Controller
    {
        /**
         * @Route("/{_locale}", defaults={"_locale": "en"}, requirements={
         *     "_locale": "en|fr"
         * })
         */
        public function homepageAction($_locale)
        {
        }
    }
    
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    # app/config/routing.yml
    homepage:
        path:      /{_locale}
        defaults:  { _controller: AppBundle:Main:homepage, _locale: en }
        requirements:
            _locale:  en|fr
    
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    <!-- app/config/routing.xml -->
    <?xml version="1.0" encoding="UTF-8" ?>
    <routes xmlns="http://symfony.com/schema/routing"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://symfony.com/schema/routing
            http://symfony.com/schema/routing/routing-1.0.xsd">
    
        <route id="homepage" path="/{_locale}">
            <default key="_controller">AppBundle:Main:homepage</default>
            <default key="_locale">en</default>
            <requirement key="_locale">en|fr</requirement>
        </route>
    </routes>
    
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    // app/config/routing.php
    use Symfony\Component\Routing\RouteCollection;
    use Symfony\Component\Routing\Route;
    
    $collection = new RouteCollection();
    $collection->add('homepage', new Route('/{_locale}', array(
        '_controller' => 'AppBundle:Main:homepage',
        '_locale'     => 'en',
    ), array(
        '_locale' => 'en|fr',
    )));
    
    return $collection;
    

For incoming requests, the {_locale} portion of the URL is matched against the regular expression (en|fr).

Path Parameters
/ {_locale} = "en"
/en {_locale} = "en"
/fr {_locale} = "fr"
/es won't match this route

Note

Since Symfony 3.2, you can enable UTF-8 route matching by setting the utf8 option when declaring or importing routes. This will make e.g. a . in requirements match any UTF-8 characters instead of just a single byte. The option is automatically enabled whenever a route or a requirement uses any non-ASCII UTF-8 characters or a PCRE Unicode property (\p{xx}, \P{xx} or \X). Note that this behavior is deprecated and a LogicException will be thrown instead in 4.0 unless you explicitly turn on the utf8 option.

Tip

The route requirements can also include container parameters, as explained in this article. This comes in handy when the regular expression is very complex and used repeatedly in your application.

Adding HTTP Method Requirements

In addition to the URL, you can also match on the method of the incoming request (i.e. GET, HEAD, POST, PUT, DELETE). Suppose you create an API for your blog and you have 2 routes: One for displaying a post (on a GET or HEAD request) and one for updating a post (on a PUT request). This can be accomplished with the following route configuration:

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    // src/AppBundle/Controller/BlogApiController.php
    namespace AppBundle\Controller;
    
    use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
    // ...
    
    class BlogApiController extends Controller
    {
        /**
         * @Route("/api/posts/{id}")
         * @Method({"GET","HEAD"})
         */
        public function showAction($id)
        {
            // ... return a JSON response with the post
        }
    
        /**
         * @Route("/api/posts/{id}")
         * @Method("PUT")
         */
        public function editAction($id)
        {
            // ... edit a post
        }
    }
    
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    # app/config/routing.yml
    api_post_show:
        path:     /api/posts/{id}
        defaults: { _controller: AppBundle:BlogApi:show }
        methods:  [GET, HEAD]
    
    api_post_edit:
        path:     /api/posts/{id}
        defaults: { _controller: AppBundle:BlogApi:edit }
        methods:  [PUT]
    
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    <!-- app/config/routing.xml -->
    <?xml version="1.0" encoding="UTF-8" ?>
    <routes xmlns="http://symfony.com/schema/routing"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://symfony.com/schema/routing
            http://symfony.com/schema/routing/routing-1.0.xsd">
    
        <route id="api_post_show" path="/api/posts/{id}" methods="GET|HEAD">
            <default key="_controller">AppBundle:BlogApi:show</default>
        </route>
    
        <route id="api_post_edit" path="/api/posts/{id}" methods="PUT">
            <default key="_controller">AppBundle:BlogApi:edit</default>
        </route>
    </routes>
    
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    // app/config/routing.php
    use Symfony\Component\Routing\RouteCollection;
    use Symfony\Component\Routing\Route;
    
    $collection = new RouteCollection();
    $collection->add('api_post_show', new Route('/api/posts/{id}', array(
        '_controller' => 'AppBundle:BlogApi:show',
    ), array(), array(), '', array(), array('GET', 'HEAD')));
    
    $collection->add('api_post_edit', new Route('/api/posts/{id}', array(
        '_controller' => 'AppBundle:BlogApi:edit',
    ), array(), array(), '', array(), array('PUT')));
    
    return $collection;
    

Despite the fact that these two routes have identical paths (/api/posts/{id}), the first route will match only GET or HEAD requests and the second route will match only PUT requests. This means that you can display and edit the post with the same URL, while using distinct controllers for the two actions.

Note

If no methods are specified, the route will match on all methods.

Tip

If you're using HTML forms and HTTP methods other than GET and POST, you'll need to include a _method parameter to fake the HTTP method. See How to Change the Action and Method of a Form for more information.

Adding a Host Requirement

You can also match on the HTTP host of the incoming request. For more information, see How to Match a Route Based on the Host in the Routing component documentation.

Adding Dynamic Requirements with Expressions

For really complex requirements, you can use dynamic expressions to match any information on the request. See How to Restrict Route Matching through Conditions.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.