feature #15742 Using a service as a router resource (weaverryan)

This PR was squashed before being merged into the 2.8 branch (closes #15742).

Discussion
----------

Using a service as a router resource

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | almost
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | not yet...

Hi guys!

This adds the ability to use a service as a routing resource. In other words, instead of loading `routing.yml`, you could load `my_route_loader`, and then a method would be called on your service to return a RouteCollection.

Specifically, I'm interested in this because it would allow a user to point their main router resource to the kernel itself, making it possible to load routes inside the kernel (making a single-file full-stack app more possible).

Thanks!

Commits
-------

79e210f Using a service as a router resource

src/Symfony/Bundle/FrameworkBundle/Resources/config/routing.xml

@@ -50,6 +50,11 @@
             <argument type="service" id="file_locator" />
         </service>
 
+        <service id="routing.loader.service" class="Symfony\Component\Routing\Loader\DependencyInjection\ServiceRouterLoader" public="false">
+            <tag name="routing.loader" />
+            <argument type="service" id="service_container" />
+        </service>
+
         <service id="routing.loader" class="%routing.loader.class%">
             <tag name="monolog.logger" channel="router" />
             <argument type="service" id="controller_name_converter" />

src/Symfony/Component/Routing/CHANGELOG.md

@@ -5,6 +5,8 @@ CHANGELOG
 -----
 
  * allowed specifying a directory to recursively load all routing configuration files it contains
+ * Added ObjectRouteLoader and ServiceRouteLoader that allow routes to be loaded
+   by calling a method on an object/service.
 
 2.5.0
 -----

src/Symfony/Component/Routing/Loader/DependencyInjection/ServiceRouterLoader.php

@@ -0,0 +1,41 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Loader\DependencyInjection;
+
+use Symfony\Component\Config\Loader\Loader;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+use Symfony\Component\Routing\Loader\ObjectRouteLoader;
+
+/**
+ * A route loader that executes a service to load the routes.
+ *
+ * This depends on the DependencyInjection component.
+ *
+ * @author Ryan Weaver <ryan@knpuniversity.com>
+ */
+class ServiceRouterLoader extends ObjectRouteLoader
+{
+    /**
+     * @var ContainerInterface
+     */
+    private $container;
+
+    public function __construct(ContainerInterface $container)
+    {
+        $this->container = $container;
+    }
+
+    protected function getServiceObject($id)
+    {
+        return $this->container->get($id);
+    }
+}

src/Symfony/Component/Routing/Loader/ObjectRouteLoader.php

@@ -0,0 +1,95 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Loader;
+
+use Symfony\Component\Config\Loader\Loader;
+use Symfony\Component\Config\Resource\FileResource;
+use Symfony\Component\Routing\RouteCollection;
+
+/**
+ * A route loader that calls a method on an object to load the routes.
+ *
+ * @author Ryan Weaver <ryan@knpuniversity.com>
+ */
+abstract class ObjectRouteLoader extends Loader
+{
+    /**
+     * Returns the object that the method will be called on to load routes.
+     *
+     * For example, if your application uses a service container,
+     * the $id may be a service id.
+     *
+     * @param string $id
+     *
+     * @return object
+     */
+    abstract protected function getServiceObject($id);
+
+    /**
+     * Calls the service that will load the routes.
+     *
+     * @param mixed       $resource Some value that will resolve to a callable
+     * @param string|null $type     The resource type
+     *
+     * @return RouteCollection
+     */
+    public function load($resource, $type = null)
+    {
+        $parts = explode(':', $resource);
+        if (count($parts) != 2) {
+            throw new \InvalidArgumentException(sprintf('Invalid resource "%s" passed to the "service" route loader: use the format "service_name:methodName"', $resource));
+        }
+
+        $serviceString = $parts[0];
+        $method = $parts[1];
+
+        $loaderObject = $this->getServiceObject($serviceString);
+
+        if (!is_object($loaderObject)) {
+            throw new \LogicException(sprintf('%s:getServiceObject() must return an object: %s returned', get_class($this), gettype($loaderObject)));
+        }
+
+        if (!method_exists($loaderObject, $method)) {
+            throw new \BadMethodCallException(sprintf('Method "%s" not found on "%s" when importing routing resource "%s"', $method, get_class($loaderObject), $resource));
+        }
+
+        $routeCollection = call_user_func(array($loaderObject, $method), $this);
+
+        if (!$routeCollection instanceof RouteCollection) {
+            $type = is_object($routeCollection) ? get_class($routeCollection) : gettype($routeCollection);
+
+            throw new \LogicException(sprintf('The %s::%s method must return a RouteCollection: %s returned', get_class($loaderObject), $method, $type));
+        }
+
+        // make the service file tracked so that if it changes, the cache rebuilds
+        $this->addClassResource(new \ReflectionClass($loaderObject), $routeCollection);
+
+        return $routeCollection;
+    }
+
+    /**
+     * {@inheritdoc}
+     *
+     * @api
+     */
+    public function supports($resource, $type = null)
+    {
+        return 'service' === $type;
+    }
+
+    private function addClassResource(\ReflectionClass $class, RouteCollection $collection)
+    {
+        do {
+            $collection->addResource(new FileResource($class->getFileName()));
+        } while ($class = $class->getParentClass());
+    }
+}

src/Symfony/Component/Routing/Tests/Loader/ObjectRouteLoaderTest.php

@@ -0,0 +1,116 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Loader;
+
+use Symfony\Component\Routing\Loader\ObjectRouteLoader;
+use Symfony\Component\Routing\Route;
+use Symfony\Component\Routing\RouteCollection;
+
+class ObjectRouteLoaderTest extends \PHPUnit_Framework_TestCase
+{
+    public function testLoadCallsServiceAndReturnsCollection()
+    {
+        $loader = new ObjectRouteLoaderForTest();
+
+        // create a basic collection that will be returned
+        $collection = new RouteCollection();
+        $collection->add('foo', new Route('/foo'));
+
+        // create some callable object
+        $service = $this->getMockBuilder('stdClass')
+            ->setMethods(array('loadRoutes'))
+            ->getMock();
+        $service->expects($this->once())
+            ->method('loadRoutes')
+            ->with($loader)
+            ->will($this->returnValue($collection));
+
+        $loader->loaderMap = array(
+            'my_route_provider_service' => $service,
+        );
+
+        $actualRoutes = $loader->load(
+            'my_route_provider_service:loadRoutes',
+            'service'
+        );
+
+        $this->assertSame($collection, $actualRoutes);
+        // the service file should be listed as a resource
+        $this->assertNotEmpty($actualRoutes->getResources());
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     * @dataProvider getBadResourceStrings
+     */
+    public function testExceptionWithoutSyntax($resourceString)
+    {
+        $loader = new ObjectRouteLoaderForTest();
+        $loader->load($resourceString);
+    }
+
+    public function getBadResourceStrings()
+    {
+        return array(
+            array('Foo'),
+            array('Bar::baz'),
+            array('Foo:Bar:baz'),
+        );
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testExceptionOnNoObjectReturned()
+    {
+        $loader = new ObjectRouteLoaderForTest();
+        $loader->loaderMap = array('my_service' => 'NOT_AN_OBJECT');
+        $loader->load('my_service:method');
+    }
+
+    /**
+     * @expectedException \BadMethodCallException
+     */
+    public function testExceptionOnBadMethod()
+    {
+        $loader = new ObjectRouteLoaderForTest();
+        $loader->loaderMap = array('my_service' => new \stdClass());
+        $loader->load('my_service:method');
+    }
+
+    /**
+     * @expectedException \LogicException
+     */
+    public function testExceptionOnMethodNotReturningCollection()
+    {
+        $service = $this->getMockBuilder('stdClass')
+            ->setMethods(array('loadRoutes'))
+            ->getMock();
+        $service->expects($this->once())
+            ->method('loadRoutes')
+            ->will($this->returnValue('NOT_A_COLLECTION'));
+
+        $loader = new ObjectRouteLoaderForTest();
+        $loader->loaderMap = array('my_service' => $service);
+        $loader->load('my_service:loadRoutes');
+    }
+}
+
+class ObjectRouteLoaderForTest extends ObjectRouteLoader
+{
+    public $loaderMap = array();
+
+    protected function getServiceObject($id)
+    {
+        return isset($this->loaderMap[$id]) ? $this->loaderMap[$id] : null;
+    }
+}

src/Symfony/Component/Routing/composer.json

@@ -35,7 +35,8 @@
         "symfony/config": "For using the all-in-one router or any loader",
         "symfony/yaml": "For using the YAML loader",
         "symfony/expression-language": "For using expression matching",
-        "doctrine/annotations": "For using the annotation loader"
+        "doctrine/annotations": "For using the annotation loader",
+        "symfony/dependency-injection": "For loading routes from a service"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Routing\\": "" }