How to Create a custom Route Loader ¶

Built-in Route Loaders ¶

Symfony provides several route loaders for the most common needs:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

# 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

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

<!-- 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>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;

return function (RoutingConfigurator $routes) {
    // 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');
};

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:

1
2
3
4

# config/routes.yaml
controllers:
    resource: ../src/Controller/
    type: attribute

1
2
3
4
5
6
7
8
9

<!-- 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>

1
2
3
4
5
6

// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;

return function (RoutingConfigurator $routes) {
    $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.

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:

1
2
3
4

# config/routes.yaml
admin_routes:
    resource: 'admin_route_loader::loadRoutes'
    type: service

1
2
3
4
5
6
7
8
9

<!-- 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>

1
2
3
4
5
6

// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;

return function (RoutingConfigurator $routes) {
    $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.

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:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

// 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 $isLoaded = false;

    public function load($resource, string $type = null)
    {
        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)
    {
        return 'extra' === $type;
    }
}

Make sure the controller you specify really exists. In this case you have to create an extra() method in the ExtraController:

1
2
3
4
5
6
7
8
9
10
11
12
13

// 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($parameter)
    {
        return new Response($parameter);
    }
}

Now define a service for the ExtraLoader:

1
2
3
4
5
6

# config/services.yaml
services:
    # ...

    App\Routing\ExtraLoader:
        tags: [routing.loader]

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

<!-- 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>

1
2
3
4
5
6
7
8
9
10
11
12

// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;

use App\Routing\ExtraLoader;

return static function (ContainerConfigurator $container) {
    $services = $configurator->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.

1
2
3
4

# config/routes.yaml
app_extra:
    resource: .
    type: extra

1
2
3
4
5
6
7
8
9

<!-- 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>

1
2
3
4
5
6

// config/routes.php
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;

return function (RoutingConfigurator $routes) {
    $routes->import('.', 'extra');
};

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:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

// 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)
    {
        $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)
    {
        return 'advanced_extra' === $type;
    }
}