Merge pull request #97 from clue-labs/container-factory

Support dependency injection for factory functions in `Container` config

Author: SimonFrings

docs/best-practices/controllers.md

@@ -270,6 +270,28 @@ name to a factory function that will be invoked when this class is first
 requested. The factory function is responsible for returning an instance that
 implements the given class name.
 
+Factory functions used in the container configuration map may reference other
+classes that will automatically be injected from the container. This can be
+particularly useful when combining autowiring with some manual configuration
+like this:
+
+```php title="public/index.php"
+<?php
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$container = new FrameworkX\Container([
+    Acme\Todo\UserController::class => function (React\Http\Browser $browser) {
+        // example UserController class requires two arguments:
+        // - first argument will be autowired based on class reference
+        // - second argument expects some manual value
+        return new Acme\Todo\UserController($browser, 42);
+    }
+]);
+
+// …
+```
+
 The container configuration may also be used to map a class name to a different
 class name that implements the same interface, either by mapping between two
 class names or using a factory function that returns a class name. This is

src/Container.php

@@ -90,7 +90,12 @@ private function load(string $name, int $depth = 64)
     {
         if (isset($this->container[$name])) {
             if ($this->container[$name] instanceof \Closure) {
-                $value = ($this->container[$name])();
+                // build list of factory parameters based on parameter types
+                $closure = new \ReflectionFunction($this->container[$name]);
+                $params = $this->loadFunctionParams($closure, $depth);
+
+                // invoke factory with list of parameters
+                $value = $params === [] ? ($this->container[$name])() : ($this->container[$name])(...$params);
 
                 if (\is_string($value)) {
                     if ($depth < 1) {
@@ -127,10 +132,17 @@ private function load(string $name, int $depth = 64)
         }
 
         // build list of constructor parameters based on parameter types
-        $params = [];
         $ctor = $class->getConstructor();
-        assert($ctor === null || $ctor instanceof \ReflectionMethod);
-        foreach ($ctor !== null ? $ctor->getParameters() : [] as $parameter) {
+        $params = $ctor === null ? [] : $this->loadFunctionParams($ctor, $depth);
+
+        // instantiate with list of parameters
+        return $this->container[$name] = $params === [] ? new $name() : $class->newInstance(...$params);
+    }
+
+    private function loadFunctionParams(\ReflectionFunctionAbstract $function, int $depth): array
+    {
+        $params = [];
+        foreach ($function->getParameters() as $parameter) {
             assert($parameter instanceof \ReflectionParameter);
 
             // stop building parameters when encountering first optional parameter
@@ -166,15 +178,19 @@ private function load(string $name, int $depth = 64)
                 throw new \BadMethodCallException(self::parameterError($parameter) . ' is recursive');
             }
 
-            $params[] = $this->load($type->getName(), --$depth);
+            $params[] = $this->load($type->getName(), $depth - 1);
         }
 
-        // instantiate with list of parameters
-        return $this->container[$name] = $params === [] ? new $name() : $class->newInstance(...$params);
+        return $params;
     }
 
     private static function parameterError(\ReflectionParameter $parameter): string
     {
-        return 'Argument ' . ($parameter->getPosition() + 1) . ' ($' . $parameter->getName() . ') of ' . explode("\0", $parameter->getDeclaringClass()->getName())[0] . '::' . $parameter->getDeclaringFunction()->getName() . '()';
+        $name = $parameter->getDeclaringFunction()->getShortName();
+        if (!$parameter->getDeclaringFunction()->isClosure() && ($class = $parameter->getDeclaringClass()) !== null) {
+            $name = explode("\0", $class->getName())[0] . '::' . $name;
+        }
+
+        return 'Argument ' . ($parameter->getPosition() + 1) . ' ($' . $parameter->getName() . ') of ' . $name . '()';
     }
 }

tests/ContainerTest.php

@@ -202,6 +202,40 @@ public function __invoke(ServerRequestInterface $request)
         $this->assertEquals('{"name":"Alice"}', (string) $response->getBody());
     }
 
+    public function testCallableReturnsCallableForClassNameWithSubclassMappedFromFactoryWithClassDependency()
+    {
+        $request = new ServerRequest('GET', 'http://example.com/');
+
+        $controller = new class(new Response()) {
+            private $response;
+
+            public function __construct(ResponseInterface $response)
+            {
+                $this->response = $response;
+            }
+
+            public function __invoke()
+            {
+                return $this->response;
+            }
+        };
+
+        $container = new Container([
+            ResponseInterface::class => function (\stdClass $dto) {
+                return new Response(200, [], json_encode($dto));
+            },
+            \stdClass::class => function () { return (object)['name' => 'Alice']; }
+        ]);
+
+        $callable = $container->callable(get_class($controller));
+        $this->assertInstanceOf(\Closure::class, $callable);
+
+        $response = $callable($request);
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertEquals(200, $response->getStatusCode());
+        $this->assertEquals('{"name":"Alice"}', (string) $response->getBody());
+    }
+
     public function testCtorThrowsWhenMapContainsInvalidInteger()
     {
         $this->expectException(\BadMethodCallException::class);
@@ -242,6 +276,51 @@ public function testCallableReturnsCallableThatThrowsWhenFactoryReturnsInvalidIn
         $callable($request);
     }
 
+    public function testCallableReturnsCallableThatThrowsWhenFactoryRequiresInvalidClassName()
+    {
+        $request = new ServerRequest('GET', 'http://example.com/');
+
+        $container = new Container([
+            \stdClass::class => function (self $instance) { return $instance; }
+        ]);
+
+        $callable = $container->callable(\stdClass::class);
+
+        $this->expectException(\BadMethodCallException::class);
+        $this->expectExceptionMessage('Class self not found');
+        $callable($request);
+    }
+
+    public function testCallableReturnsCallableThatThrowsWhenFactoryRequiresUntypedArgument()
+    {
+        $request = new ServerRequest('GET', 'http://example.com/');
+
+        $container = new Container([
+            \stdClass::class => function ($data) { return $data; }
+        ]);
+
+        $callable = $container->callable(\stdClass::class);
+
+        $this->expectException(\BadMethodCallException::class);
+        $this->expectExceptionMessage('Argument 1 ($data) of {closure}() has no type');
+        $callable($request);
+    }
+
+    public function testCallableReturnsCallableThatThrowsWhenFactoryRequiresRecursiveClass()
+    {
+        $request = new ServerRequest('GET', 'http://example.com/');
+
+        $container = new Container([
+            \stdClass::class => function (\stdClass $data) { return $data; }
+        ]);
+
+        $callable = $container->callable(\stdClass::class);
+
+        $this->expectException(\BadMethodCallException::class);
+        $this->expectExceptionMessage('Argument 1 ($data) of {closure}() is recursive');
+        $callable($request);
+    }
+
     public function testCallableReturnsCallableThatThrowsWhenFactoryIsRecursive()
     {
         $request = new ServerRequest('GET', 'http://example.com/');