php+laravel依賴注入淺析

$config = $container->make('config');
$connection = new Connection($this->config);

class TestController extends Controller
{
public function anyConsole(Request $request, Auth $input)
{
//todo
}
}

public function run(Request $request)
{
$this->container = $this->container ?: new Container;
try {
if (! is_string($this->action['uses'])) {
return $this->runCallable($request);
}

if ($this->customDispatcherIsBound()) {
return $this->runWithCustomDispatcher($request);
}

return $this->runController($request);
} catch (HttpResponseException $e) {
return $e->getResponse();
}
}


判斷 $this->action['uses']（格式行如：\App\Http\Controller\Datacenter\RealTimeController@anyConsole）是否字串, $this->customDispatcherIsBound判斷是否綁定了使用者自定義路由。然後跳轉到 $this->runController($request)。

protected function runController(Request $request)
{
list($class, $method) = explode('@', $this->action['uses']);

$parameters = $this->resolveClassMethodDependencies(
$this->parametersWithoutNulls(), $class, $method
);

if (! method_exists($instance = $this->container->make($class), $method)) {
throw new NotFoundHttpException;
}

return call_user_func_array([$instance, $method], $parameters);
}

$this->resolveClassMethodDependencies 這個方法一看名字就知道是我們要找的方法。$this->parametersWithoutNulls()是過濾空字元，$class、$method分別行如：\App\Http\Controller\Datacenter\RealTimeController 與 anyConsole。

protected function resolveClassMethodDependencies(array $parameters, $instance, $method)
{
if (! method_exists($instance, $method)) {
return $parameters;
}

return $this->resolveMethodDependencies(
$parameters, new ReflectionMethod($instance, $method)
);
}

new ReflectionMethod($instance, $method) 是拿到類方法的反射物件，參見文件：http://www.php.net/manual/zh/class.reflectionmethod.php

下面跳轉到Illuminate/Routing/RouteDependencyResolverTrait.php 第54行。

public function resolveMethodDependencies(array $parameters, ReflectionFunctionAbstract $reflector)
{
$originalParameters = $parameters;

foreach ($reflector->getParameters() as $key => $parameter) {
$instance = $this->transformDependency(
$parameter, $parameters, $originalParameters
);

if (! is_null($instance)) {
$this->spliceIntoParameters($parameters, $key, $instance);
}
}

return $parameters;
}

通過反射類方法得到類引數陣列，然後遍歷傳遞給 $this->transformDependency 方法。如果例項獲取不到則呼叫 $this->spliceIntoParameters 清楚該引數。

protected function transformDependency(ReflectionParameter $parameter, $parameters, $originalParameters)
{
$class = $parameter->getClass();
if ($class && ! $this->alreadyInParameters($class->name, $parameters)) {
return $this->container->make($class->name);
}
}