[php-di v7] Service Locator

src/CompiledContainer.php

@@ -112,4 +112,24 @@ protected function resolveFactory($callable, $entryName, array $extraParameters
             throw new InvalidDefinition("Entry \"$entryName\" cannot be resolved: " . $e->getMessage());
         }
     }
+
+    /**
+     * Resolve ServiceLocator for given subscriber class (based on \DI\Definition\ServiceLocatorDefinition::resolve).
+     *
+     * @param string $requestingName class name of a subscriber, implementing ServiceSubscriberInterface
+     * @param string $repositoryClass ServiceLocatorRepository
+     * @throws ServiceSubscriberException
+     */
+    protected function resolveServiceLocator(string $requestingName, string $repositoryClass) : ServiceLocator
+    {
+        if (!method_exists($requestingName, 'getSubscribedServices')) {
+            throw new ServiceSubscriberException(sprintf('The class %s does not implement ServiceSubscriberInterface.', $requestingName));
+        }
+
+        /** @var ServiceLocatorRepository $repository */
+        $repository = $this->delegateContainer->get($repositoryClass);
+        $services = $requestingName::getSubscribedServices();
+
+        return $repository->create($requestingName, $services);
+    }
 }

src/Compiler/Compiler.php

@@ -206,6 +206,12 @@ private function compileDefinition(string $entryName, Definition $definition) :
                 $code = 'return ' . $this->compileValue($value) . ';';
                 break;
             case $definition instanceof Reference:
+                if ($definition->isServiceLocatorEntry()) {
+                    $requestingEntry = $definition->getRequestingName();
+                    $serviceLocatorDefinition = $definition->getServiceLocatorDefinition();
+                    $code = 'return $this->resolveServiceLocator(' . $this->compileValue($requestingEntry) . ', ' . $this->compileValue($serviceLocatorDefinition::$serviceLocatorRepositoryClass) . ');';
+                    break;
+                }
                 $targetEntryName = $definition->getTargetEntryName();
                 $code = 'return $this->delegateContainer->get(' . $this->compileValue($targetEntryName) . ');';
                 // If this method is not yet compiled we store it for compilation

src/Definition/Reference.php

@@ -4,6 +4,8 @@
 
 namespace DI\Definition;
 
+use DI\Definition\Exception\InvalidDefinition;
+use DI\ServiceLocator;
 use Psr\Container\ContainerInterface;
 
 /**
@@ -13,15 +15,25 @@
  */
 class Reference implements Definition, SelfResolvingDefinition
 {
+    public static $serviceLocatorClass = ServiceLocator::class;
+
     /** Entry name. */
     private string $name = '';
 
-    /**
-     * @param string $targetEntryName Name of the target entry
-     */
+    private bool $isServiceLocatorEntry;
+
     public function __construct(
+        /**
+         * @var string Name of the target entry
+         */
         private string $targetEntryName,
+        /**
+         * @var string|null name of an entry - holder of a definition requesting this entry
+         */
+        private ?string $requestingName = null,
+        private ?ServiceLocatorDefinition $serviceLocatorDefinition = null
     ) {
+        $this->isServiceLocatorEntry = $targetEntryName === self::$serviceLocatorClass;
     }
 
     public function getName() : string
@@ -39,13 +51,50 @@ public function getTargetEntryName() : string
         return $this->targetEntryName;
     }
 
+    /**
+     * Returns the name of the entity requesting this entry.
+     */
+    public function getRequestingName() : ?string
+    {
+        return $this->requestingName;
+    }
+
+    public function isServiceLocatorEntry() : bool
+    {
+        return $this->isServiceLocatorEntry;
+    }
+
+    public function getServiceLocatorDefinition() : ServiceLocatorDefinition
+    {
+        if (!$this->isServiceLocatorEntry || $this->requestingName === null) {
+            throw new InvalidDefinition(sprintf(
+                "Invalid service locator definition ('%s' for '%s')",
+                $this->targetEntryName,
+                $this->requestingName
+            ));
+        }
+        if (!$this->serviceLocatorDefinition) {
+            $this->serviceLocatorDefinition = new ServiceLocatorDefinition($this->getTargetEntryName(), $this->requestingName);
+        }
+
+        return $this->serviceLocatorDefinition;
+    }
+
     public function resolve(ContainerInterface $container) : mixed
     {
+        if ($this->isServiceLocatorEntry) {
+            return $this->getServiceLocatorDefinition()->resolve($container);
+        }
+
         return $container->get($this->getTargetEntryName());
     }
 
     public function isResolvable(ContainerInterface $container) : bool
     {
+        if ($this->isServiceLocatorEntry) {
+            return $this->getServiceLocatorDefinition()->isResolvable($container);
+        }
+
         return $container->has($this->getTargetEntryName());
     }
 

src/Definition/ServiceLocatorDefinition.php

@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DI\Definition;
+
+use DI\ServiceLocator;
+use DI\ServiceLocatorRepository;
+use DI\ServiceSubscriberException;
+use Psr\Container\ContainerInterface;
+
+class ServiceLocatorDefinition implements Definition, SelfResolvingDefinition
+{
+    public static $serviceLocatorRepositoryClass = ServiceLocatorRepository::class;
+
+    /**
+     * @param string $name           Entry name
+     * @param string $requestingName name of an entry - holder of a definition requesting service locator
+     */
+    public function __construct(
+        private string $name,
+        private string $requestingName
+    ) {
+    }
+
+    /**
+     * Returns the name of the entry in the container.
+     */
+    public function getName() : string
+    {
+        return $this->name;
+    }
+
+    public function setName(string $name) : void
+    {
+        $this->name = $name;
+    }
+
+    /**
+     * Returns the name of the holder of the definition requesting service locator.
+     */
+    public function getRequestingName() : string
+    {
+        return $this->requestingName;
+    }
+
+    /**
+     * Resolve the definition and return the resulting value.
+     *
+     * @throws ServiceSubscriberException
+     */
+    public function resolve(ContainerInterface $container) : ServiceLocator
+    {
+        if (!method_exists($this->requestingName, 'getSubscribedServices')) {
+            throw new ServiceSubscriberException(sprintf('The class %s does not implement ServiceSubscriberInterface.', $this->requestingName));
+        }
+
+        /** @var ServiceLocatorRepository $repository */
+        $repository = $container->get(self::$serviceLocatorRepositoryClass);
+        $services = $this->requestingName::getSubscribedServices();
+
+        return $repository->create($this->requestingName, $services);
+    }
+
+    /**
+     * Check if a definition can be resolved.
+     */
+    public function isResolvable(ContainerInterface $container) : bool
+    {
+        return method_exists($this->requestingName, 'getSubscribedServices');
+    }
+
+    public function replaceNestedDefinitions(callable $replacer) : void
+    {
+        // no nested definitions
+    }
+
+    /**
+     * Definitions can be cast to string for debugging information.
+     */
+    public function __toString() : string
+    {
+        return sprintf(
+            'get(%s) for \'%s\'',
+            $this->name,
+            $this->requestingName
+        );
+    }
+}

src/Definition/Source/AttributeBasedAutowiring.php

@@ -177,7 +177,7 @@ private function readProperty(ReflectionProperty $property, ObjectDefinition $de
         }
 
         $definition->addPropertyInjection(
-            new PropertyInjection($property->getName(), new Reference($entryName), $classname)
+            new PropertyInjection($property->getName(), new Reference($entryName, $classname), $classname)
         );
     }
 
@@ -312,7 +312,7 @@ private function readConstructor(ReflectionClass $class, ObjectDefinition $defin
             $entryName = $this->getMethodParameter($index, $parameter, []);
 
             if ($entryName !== null) {
-                $parameters[$index] = new Reference($entryName);
+                $parameters[$index] = new Reference($entryName, $class->getName());
             }
         }
 

src/Definition/Source/ReflectionBasedAutowiring.php

@@ -30,7 +30,7 @@ public function autowire(string $name, ObjectDefinition $definition = null) : Ob
         $class = new \ReflectionClass($className);
         $constructor = $class->getConstructor();
         if ($constructor && $constructor->isPublic()) {
-            $constructorInjection = MethodInjection::constructor($this->getParametersDefinition($constructor));
+            $constructorInjection = MethodInjection::constructor($this->getParametersDefinition($constructor, $class->getName()));
             $definition->completeConstructorInjection($constructorInjection);
         }
 
@@ -53,7 +53,7 @@ public function getDefinitions() : array
     /**
      * Read the type-hinting from the parameters of the function.
      */
-    private function getParametersDefinition(\ReflectionFunctionAbstract $constructor) : array
+    private function getParametersDefinition(\ReflectionFunctionAbstract $constructor, string $className) : array
     {
         $parameters = [];
 
@@ -77,7 +77,7 @@ private function getParametersDefinition(\ReflectionFunctionAbstract $constructo
                 continue;
             }
 
-            $parameters[$index] = new Reference($parameterType->getName());
+            $parameters[$index] = new Reference($parameterType->getName(), $className);
         }
 
         return $parameters;

src/ServiceLocator.php

@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DI;
+
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Container\ContainerInterface;
+use Psr\Container\NotFoundExceptionInterface;
+
+/**
+ * Class ServiceLocator.
+ *
+ * Serving "lazy" dependencies for classes using ServiceSubscriberInterface.
+ * Suggested as a lightweight alternative for heavyweight proxies from ocramius/proxy-manager
+ */
+class ServiceLocator implements ContainerInterface
+{
+    private array $services = [];
+
+    public function __construct(
+        private ContainerInterface $container,
+        array $services,
+        /** @var string|null className of a ServiceSubscriber to which this service locator instance belongs to */
+        private ?string $subscriber = null
+    ) {
+        $this->setServices($services);
+    }
+
+    protected function setServices(array $services) : void
+    {
+        foreach ($services as $key => $value) {
+            if (is_numeric($key)) {
+                $key = $value;
+            }
+            $this->services[$key] = $value;
+        }
+    }
+
+    /**
+     * Get defined services.
+     */
+    public function getServices() : array
+    {
+        return $this->services;
+    }
+
+    /**
+     * Get name of a class to which this service locator instance belongs to.
+     */
+    public function getSubscriber() : string
+    {
+        return $this->subscriber;
+    }
+
+    /**
+     * Finds a service by its identifier.
+     *
+     * @param string $id Identifier of the entry to look for.
+     *
+     * @throws NotFoundExceptionInterface  No entry was found for **this** identifier.
+     * @throws ContainerExceptionInterface Error while retrieving the entry.
+     */
+    public function get(string $id) : mixed
+    {
+        if (!isset($this->services[$id])) {
+            throw new NotFoundException("Service '$id' is not defined.");
+        }
+
+        return $this->container->get($this->services[$id]);
+    }
+
+    /**
+     * Returns true if the container can return an entry for the given identifier.
+     * Returns false otherwise.
+     *
+     * `has($id)` returning true does not mean that `get($id)` will not throw an exception.
+     * It does however mean that `get($id)` will not throw a `NotFoundExceptionInterface`.
+     *
+     * @param string $id Identifier of the entry to look for.
+     */
+    public function has(string $id) : bool
+    {
+        if (!isset($this->services[$id])) {
+            return false;
+        }
+
+        return $this->container->has($this->services[$id]);
+    }
+}