Extract HandlerProvider to own class

config/services.yaml

@@ -23,7 +23,7 @@ services:
     # this creates a service per class whose id is the fully-qualified class name
     App\:
         resource: '../src/*'
-        exclude: '../src/{DependencyInjection,Exception,Modifiers,Entity,Model,Migrations,Tests,Functions,Kernel.php}'
+        exclude: '../src/{DependencyInjection,Exception,Modifie,Entity,Model,Migrations,Tests,Functions,Handler,Kernel.php}'
 
     # controllers are imported separately to make sure services can be injected
     # as action arguments even if you don't extend any base controller class
@@ -35,6 +35,10 @@ services:
         resource: '../src/Provider'
         public: true
 
+    App\Handler\:
+        resource: '../src/Handler'
+        tags: [ app.handler ]
+
     # add more service definitions when explicit configuration is needed
     # please note that last definitions always *replace* previous ones
 
@@ -90,3 +94,7 @@ services:
     # other servces
     App\Service\ProviderResolver:
         arguments: [!tagged app.provider, '%kernel.debug%']
+
+    App\Service\HandlerProvider:
+        arguments: [!tagged_locator app.handler]
+        shared: false

src/Controller/Api/v1/StopsController.php

@@ -4,12 +4,12 @@ namespace App\Controller\Api\v1;
 
 use App\Controller\Controller;
 use App\Model\Stop;
-use App\Model\TrackStop;
 use App\Model\StopGroup;
-use App\Modifier\IdFilter;
+use App\Model\TrackStop;
 use App\Modifier\FieldFilter;
-use App\Modifier\IncludeDestinations;
+use App\Modifier\IdFilter;
 use App\Modifier\RelatedFilter;
+use App\Modifier\With;
 use App\Provider\StopRepository;
 use App\Provider\TrackRepository;
 use Nelmio\ApiDocBundle\Annotation\Model;
@@ -95,7 +95,7 @@ class StopsController extends Controller
      */
     public function one(Request $request, StopRepository $stops, $id)
     {
-        return $this->json($stops->first(new IdFilter($id), new IncludeDestinations()));
+        return $this->json($stops->first(new IdFilter($id), new With("destinations")));
     }
 
     /**
@@ -137,7 +137,7 @@ class StopsController extends Controller
         }
 
         if ($request->query->has('include-destinations')) {
-            yield new IncludeDestinations();
+            yield new With("destinations");
         }
     }
 }

src/Exception/UnsupportedModifierException.php

@@ -3,12 +3,11 @@
 namespace App\Exception;
 
 use App\Modifier\Modifier;
-use App\Provider\Repository;
 
 class UnsupportedModifierException extends \LogicException
 {
-    public static function createFromModifier(Modifier $modifier, Repository $repository)
+    public static function createFromModifier(Modifier $modifier)
     {
-        return new static(sprintf("Modifier %s is not supported by %s.", get_class($modifier), get_class($repository)));
+        return new static(sprintf("Modifier %s is not supported.", get_class($modifier)));
     }
 }

src/Handler/Database/WithDestinationsDatabaseHandler.php

@@ -10,11 +10,11 @@ use App\Model\Stop;
 use App\Service\Converter;
 use App\Service\IdUtils;
 use Doctrine\ORM\EntityManagerInterface;
-use Tightenco\Collect\Support\Collection;
 use Kadet\Functional as f;
 use Kadet\Functional\Transforms as t;
+use Tightenco\Collect\Support\Collection;
 
-class IncludeDestinationsDatabaseHandler implements PostProcessingHandler
+class WithDestinationsDatabaseHandler implements PostProcessingHandler
 {
     private $em;
     private $converter;

src/Modifier/IncludeDestinations.php

@@ -1,7 +0,0 @@
-<?php
-
-namespace App\Modifier;
-
-class IncludeDestinations implements Modifier
-{
-}

src/Modifier/With.php

@@ -0,0 +1,18 @@
+<?php
+
+namespace App\Modifier;
+
+class With implements Modifier
+{
+    private $relationship;
+
+    public function __construct(string $relationship)
+    {
+        $this->relationship = $relationship;
+    }
+
+    public function getRelationship(): string
+    {
+        return $this->relationship;
+    }
+}

src/Provider/Database/DatabaseRepository.php

@@ -5,28 +5,26 @@ namespace App\Provider\Database;
 use App\Entity\ProviderEntity;
 use App\Event\HandleDatabaseModifierEvent;
 use App\Event\PostProcessEvent;
-use App\Exception\UnsupportedModifierException;
+use App\Handler\Database\FieldFilterDatabaseHandler;
 use App\Handler\Database\IdFilterDatabaseHandler;
 use App\Handler\Database\LimitDatabaseHandler;
-use App\Handler\Database\FieldFilterDatabaseHandler;
 use App\Handler\Database\RelatedFilterDatabaseGenericHandler;
 use App\Handler\ModifierHandler;
 use App\Handler\PostProcessingHandler;
 use App\Model\Referable;
+use App\Modifier\FieldFilter;
 use App\Modifier\IdFilter;
 use App\Modifier\Limit;
 use App\Modifier\Modifier;
-use App\Modifier\FieldFilter;
 use App\Modifier\RelatedFilter;
 use App\Provider\Repository;
 use App\Service\Converter;
+use App\Service\HandlerProvider;
 use App\Service\IdUtils;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\QueryBuilder;
-use Psr\Container\ContainerInterface;
-use Symfony\Contracts\Service\ServiceSubscriberInterface;
 
-abstract class DatabaseRepository implements ServiceSubscriberInterface, Repository
+abstract class DatabaseRepository implements Repository
 {
     const DEFAULT_LIMIT = 100;
 
@@ -42,7 +40,7 @@ abstract class DatabaseRepository implements ServiceSubscriberInterface, Reposit
     /** @var Converter */
     protected $converter;
 
-    /** @var ContainerInterface */
+    /** @var HandlerProvider */
     protected $handlers;
 
     /**
@@ -54,12 +52,19 @@ abstract class DatabaseRepository implements ServiceSubscriberInterface, Reposit
         EntityManagerInterface $em,
         IdUtils $id,
         Converter $converter,
-        ContainerInterface $handlers
+        HandlerProvider $handlers
     ) {
         $this->em        = $em;
         $this->id        = $id;
         $this->converter = $converter;
         $this->handlers  = $handlers;
+
+        $this->handlers->loadConfiguration(array_merge([
+            IdFilter::class      => IdFilterDatabaseHandler::class,
+            Limit::class         => LimitDatabaseHandler::class,
+            FieldFilter::class   => FieldFilterDatabaseHandler::class,
+            RelatedFilter::class => RelatedFilterDatabaseGenericHandler::class,
+        ], static::getHandlers()));
     }
 
     /** @return static */
@@ -88,7 +93,7 @@ abstract class DatabaseRepository implements ServiceSubscriberInterface, Reposit
         $reducers = [];
 
         foreach ($modifiers as $modifier) {
-            $handler = $this->getHandler($modifier);
+            $handler = $this->handlers->get($modifier);
 
             if ($handler instanceof ModifierHandler) {
                 $event = new HandleDatabaseModifierEvent($modifier, $this, $builder, array_merge([
@@ -120,10 +125,11 @@ abstract class DatabaseRepository implements ServiceSubscriberInterface, Reposit
         $builder->setMaxResults(self::DEFAULT_LIMIT);
 
         $reducers = $this->processQueryBuilder($builder, $modifiers, $meta);
+        $result   = collect($builder->getQuery()->execute())->map(\Closure::fromCallable([$this, 'convert']));
 
         return $reducers->reduce(function ($result, $reducer) {
             return $reducer($result);
-        }, collect($builder->getQuery()->execute())->map(\Closure::fromCallable([$this, 'convert'])));
+        }, $result);
     }
 
     public function first(Modifier ...$modifiers)
@@ -131,17 +137,6 @@ abstract class DatabaseRepository implements ServiceSubscriberInterface, Reposit
         return $this->all(Limit::count(1), ...$modifiers)->first();
     }
 
-    protected function getHandler(Modifier $modifier)
-    {
-        $class = get_class($modifier);
-
-        if (!$this->handlers->has($class)) {
-            throw UnsupportedModifierException::createFromModifier($modifier, $this);
-        }
-
-        return $this->handlers->get($class);
-    }
-
     /**
      * Returns array describing handlers for each modifier type. Syntax is as follows:
      * [ IdFilter::class => IdFilterDatabaseHandler::class ]
@@ -154,17 +149,4 @@ abstract class DatabaseRepository implements ServiceSubscriberInterface, Reposit
     {
         return [];
     }
-
-    /**
-     * @inheritDoc
-     */
-    public static function getSubscribedServices()
-    {
-        return array_merge([
-            IdFilter::class      => IdFilterDatabaseHandler::class,
-            Limit::class         => LimitDatabaseHandler::class,
-            FieldFilter::class   => FieldFilterDatabaseHandler::class,
-            RelatedFilter::class => RelatedFilterDatabaseGenericHandler::class,
-        ], static::getHandlers());
-    }
 }

src/Provider/Database/GenericStopRepository.php

@@ -3,10 +3,10 @@
 namespace App\Provider\Database;
 
 use App\Entity\StopEntity;
-use App\Handler\Database\IncludeDestinationsDatabaseHandler;
+use App\Handler\Database\WithDestinationsDatabaseHandler;
 use App\Model\Stop;
 use App\Modifier\Modifier;
-use App\Modifier\IncludeDestinations;
+use App\Modifier\With;
 use App\Provider\StopRepository;
 use Tightenco\Collect\Support\Collection;
 
@@ -30,7 +30,11 @@ class GenericStopRepository extends DatabaseRepository implements StopRepository
     protected static function getHandlers()
     {
         return array_merge(parent::getHandlers(), [
-            IncludeDestinations::class => IncludeDestinationsDatabaseHandler::class,
+            With::class => function (With $modifier) {
+                return $modifier->getRelationship() === 'destinations'
+                    ? WithDestinationsDatabaseHandler::class
+                    : GenericWithHandler::class;
+            },
         ]);
     }
 }

src/Service/HandlerProvider.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Service;
+
+use App\Exception\UnsupportedModifierException;
+use App\Modifier\Modifier;
+use Symfony\Component\DependencyInjection\ServiceLocator;
+
+class HandlerProvider
+{
+    private $configuration = [];
+    private $handlerLocator;
+
+    public function __construct(ServiceLocator $handlerLocator)
+    {
+        $this->handlerLocator = $handlerLocator;
+    }
+
+    public function loadConfiguration(array $providers)
+    {
+        $this->configuration = $providers;
+    }
+
+    public function get(Modifier $modifier)
+    {
+        $class = get_class($modifier);
+
+        if (!array_key_exists($class, $this->configuration)) {
+            throw UnsupportedModifierException::createFromModifier($modifier);
+        }
+
+        $handler = $this->configuration[$class];
+
+        if (is_callable($handler)) {
+            $handler = $handler($modifier);
+        }
+
+        if (is_string($handler)) {
+            return $this->handlerLocator->get($handler);
+        }
+
+        return $handler;
+    }
+}