How to Create a custom Route Loader
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How to Create a custom Route Loader
Basic applications can define all their routes in a single configuration file -
usually config/routes.yaml
(see Routing).
However, in most applications it's common to import routes definitions from
different resources: PHP attributes in controller files, YAML, XML
or PHP files stored in some directory, etc.
Built-in Route Loaders
Symfony provides several route loaders for the most common needs:
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# config/routes.yaml
app_file:
# loads routes from the given routing file stored in some bundle
resource: '@AcmeBundle/Resources/config/routing.yaml'
app_psr4:
# loads routes from the PHP attributes of the controllers found in the given PSR-4 namespace root
resource:
path: '../src/Controller/'
namespace: App\Controller
type: attribute
app_attributes:
# loads routes from the PHP attributes of the controllers found in that directory
resource: '../src/Controller/'
type: attribute
app_class_attributes:
# loads routes from the PHP attributes of the given class
resource: App\Controller\MyController
type: attribute
app_directory:
# loads routes from the YAML, XML or PHP files found in that directory
resource: '../legacy/routing/'
type: directory
app_bundle:
# loads routes from the YAML, XML or PHP files found in some bundle directory
resource: '@AcmeOtherBundle/Resources/config/routing/'
type: directory
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<!-- config/routes.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
https://symfony.com/schema/routing/routing-1.0.xsd">
<!-- loads routes from the given routing file stored in some bundle -->
<import resource="@AcmeBundle/Resources/config/routing.yaml"/>
<!-- loads routes from the PHP attributes of the controllers found in the given PSR-4 namespace root -->
<import type="attribute">
<resource path="../src/Controller/" namespace="App\Controller"/>
</import>
<!-- loads routes from the PHP attributes of the controllers found in that directory -->
<import resource="../src/Controller/" type="attribute"/>
<!-- loads routes from the PHP attributes of the given class -->
<import resource="App\Controller\MyController" type="attribute"/>
<!-- loads routes from the YAML or XML files found in that directory -->
<import resource="../legacy/routing/" type="directory"/>
<!-- loads routes from the YAML or XML files found in some bundle directory -->
<import resource="@AcmeOtherBundle/Resources/config/routing/" type="directory"/>
</routes>
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// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
return static function (RoutingConfigurator $routes): void {
// loads routes from the given routing file stored in some bundle
$routes->import('@AcmeBundle/Resources/config/routing.yaml');
// loads routes from the PHP attributes (#[Route(...)])
// of the controllers found in the given PSR-4 namespace root
$routes->import(
['path' => '../src/Controller/', 'namespace' => 'App\Controller'],
'attribute',
);
// loads routes from the PHP attributes (#[Route(...)])
// of the controllers found in that directory
$routes->import('../src/Controller/', 'attribute');
// loads routes from the PHP attributes (#[Route(...)]) of the given class
$routes->import('App\Controller\MyController', 'attribute');
// loads routes from the YAML or XML files found in that directory
$routes->import('../legacy/routing/', 'directory');
// loads routes from the YAML or XML files found in some bundle directory
$routes->import('@AcmeOtherBundle/Resources/config/routing/', 'directory');
};
6.1
The attribute
value of the second argument of import()
was introduced
in Symfony 6.1.
6.2
The feature to import routes from a PSR-4 namespace root was introduced in Symfony 6.2.
Note
When importing resources, the key (e.g. app_file
) is the name of the collection.
Just be sure that it's unique per file so no other lines override it.
If your application needs are different, you can create your own custom route loader as explained in the next section.
What is a Custom Route Loader
A custom route loader enables you to generate routes based on some conventions, patterns or integrations. An example for this use-case is the OpenAPI-Symfony-Routing library where routes are generated based on OpenAPI/Swagger annotations. Another example is the SonataAdminBundle that creates routes based on CRUD conventions.
Loading Routes
The routes in a Symfony application are loaded by the
DelegatingLoader.
This loader uses several other loaders (delegates) to load resources of
different types, for instance YAML files or #[Route]
attributes in controller
files. The specialized loaders implement
LoaderInterface
and therefore have two important methods:
supports()
and load().
Take these lines from the routes.yaml
:
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# config/routes.yaml
controllers:
resource: ../src/Controller/
type: attribute
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<!-- config/routes.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
https://symfony.com/schema/routing/routing-1.0.xsd">
<import resource="../src/Controller" type="attribute"/>
</routes>
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// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
return static function (RoutingConfigurator $routes): void {
$routes->import('../src/Controller', 'attribute');
};
When the main loader parses this, it tries all registered delegate loaders and calls
their supports()
method with the given resource (../src/Controller/
)
and type (attribute
) as arguments. When one of the loader returns true
,
its load() method
will be called, which should return a RouteCollection
containing Route objects.
Note
Routes loaded this way will be cached by the Router the same way as when they are defined in one of the default formats (e.g. XML, YAML, PHP file).
Loading Routes with a Custom Service
Using a regular Symfony service is the simplest way to load routes in a customized way. It's much easier than creating a full custom route loader, so you should always consider this option first.
To do so, define type: service
as the type of the loaded routing resource
and configure the service and method to call:
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# config/routes.yaml
admin_routes:
resource: 'admin_route_loader::loadRoutes'
type: service
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<!-- config/routes.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
https://symfony.com/schema/routing/routing-1.0.xsd">
<import resource="admin_route_loader::loadRoutes" type="service"/>
</routes>
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// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
return static function (RoutingConfigurator $routes): void {
$routes->import('admin_route_loader::loadRoutes', 'service');
};
In this example, the routes are loaded by calling the loadRoutes()
method
of the service whose ID is admin_route_loader
. Your service doesn't have to
extend or implement any special class, but the called method must return a
RouteCollection object.
If you're using autoconfigure, your class should
implement the RouteLoaderInterface
interface to be tagged automatically. If you're not using autoconfigure,
tag it manually with routing.route_loader
.
Note
The routes defined using service route loaders will be automatically cached by the framework. So whenever your service should load new routes, don't forget to clear the cache.
Tip
If your service is invokable, you don't need to specify the method to use.
Creating a custom Loader
To load routes from some custom source (i.e. from something other than attributes, YAML or XML files), you need to create a custom route loader. This loader has to implement LoaderInterface.
In most cases it is easier to extend from Loader instead of implementing LoaderInterface yourself.
The sample loader below supports loading routing resources with a type of
extra
. The type name should not clash with other loaders that might
support the same type of resource. Make up any name specific to what
you do. The resource name itself is not actually used in the example:
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// src/Routing/ExtraLoader.php
namespace App\Routing;
use Symfony\Component\Config\Loader\Loader;
use Symfony\Component\Routing\Route;
use Symfony\Component\Routing\RouteCollection;
class ExtraLoader extends Loader
{
private bool $isLoaded = false;
public function load($resource, string $type = null): RouteCollection
{
if (true === $this->isLoaded) {
throw new \RuntimeException('Do not add the "extra" loader twice');
}
$routes = new RouteCollection();
// prepare a new route
$path = '/extra/{parameter}';
$defaults = [
'_controller' => 'App\Controller\ExtraController::extra',
];
$requirements = [
'parameter' => '\d+',
];
$route = new Route($path, $defaults, $requirements);
// add the new route to the route collection
$routeName = 'extraRoute';
$routes->add($routeName, $route);
$this->isLoaded = true;
return $routes;
}
public function supports($resource, string $type = null): bool
{
return 'extra' === $type;
}
}
Make sure the controller you specify really exists. In this case you
have to create an extra()
method in the ExtraController
:
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// src/Controller/ExtraController.php
namespace App\Controller;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Response;
class ExtraController extends AbstractController
{
public function extra(mixed $parameter): Response
{
return new Response($parameter);
}
}
Now define a service for the ExtraLoader
:
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# config/services.yaml
services:
# ...
App\Routing\ExtraLoader:
tags: [routing.loader]
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<!-- config/services.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://symfony.com/schema/dic/services
https://symfony.com/schema/dic/services/services-1.0.xsd">
<services>
<!-- ... -->
<service id="App\Routing\ExtraLoader">
<tag name="routing.loader"/>
</service>
</services>
</container>
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// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;
use App\Routing\ExtraLoader;
return static function (ContainerConfigurator $container): void {
$services = $container->services();
$services->set(ExtraLoader::class)
->tag('routing.loader')
;
};
Notice the tag routing.loader
. All services with this tag will be marked
as potential route loaders and added as specialized route loaders to the
routing.loader
service, which is an instance of
DelegatingLoader.
Using the Custom Loader
If you did nothing else, your custom routing loader would not be called. What remains to do is adding a few lines to the routing configuration:
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# config/routes.yaml
app_extra:
resource: .
type: extra
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<!-- config/routes.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
https://symfony.com/schema/routing/routing-1.0.xsd">
<import resource="." type="extra"/>
</routes>
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// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
return static function (RoutingConfigurator $routes): void {
$routes->import('.', 'extra');
};
The important part here is the type
key. Its value should be extra
as
this is the type which the ExtraLoader
supports and this will make sure
its load()
method gets called. The resource
key is insignificant
for the ExtraLoader
, so it is set to .
(a single dot).
Note
The routes defined using custom route loaders will be automatically cached by the framework. So whenever you change something in the loader class itself, don't forget to clear the cache.
More Advanced Loaders
If your custom route loader extends from Loader as shown above, you can also make use of the provided resolver, an instance of LoaderResolver, to load secondary routing resources.
You still need to implement supports() and load(). Whenever you want to load another resource - for instance a YAML routing configuration file - you can call the import() method:
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// src/Routing/AdvancedLoader.php
namespace App\Routing;
use Symfony\Component\Config\Loader\Loader;
use Symfony\Component\Routing\RouteCollection;
class AdvancedLoader extends Loader
{
public function load($resource, string $type = null): RouteCollection
{
$routes = new RouteCollection();
$resource = '@ThirdPartyBundle/Resources/config/routes.yaml';
$type = 'yaml';
$importedRoutes = $this->import($resource, $type);
$routes->addCollection($importedRoutes);
return $routes;
}
public function supports($resource, string $type = null): bool
{
return 'advanced_extra' === $type;
}
}
Note
The resource name and type of the imported routing configuration can be anything that would normally be supported by the routing configuration loader (YAML, XML, PHP, attribute, etc.).
Note
For more advanced uses, check out the ChainRouter provided by the Symfony CMF project. This router allows applications to use two or more routers combined, for example to keep using the default Symfony routing system when writing a custom router.