Laravel源码解析之路由的使用和示例详解

前言

我的解析文章并非深层次多领域的解析攻略。但是参考着开发文档看此类文章会让你在日常开发中更上一层楼。

废话不多说，我们开始本章的讲解。

入口

Laravel启动后，会先加载服务提供者、中间件等组件，在查找路由之前因为我们使用的是门面，所以先要查到Route的实体类。

注册

第一步当然还是通过服务提供者，因为这是laravel启动的关键，在 RouteServiceProvider 内加载路由文件。

protected function mapApiRoutes()
{
  Route::prefix('api')
     ->middleware('api')
     ->namespace($this->namespace) // 设置所处命名空间
     ->group(base_path('routes/api.php')); //所得路由文件绝对路径
}

首先require是不可缺少的。因路由文件中没有命名空间。 Illuminate\Routing\Router 下方法

protected function loadRoutes($routes)
{
  if ($routes instanceof Closure) {
    $routes($this);
  } else {
    $router = $this;

    require $routes;
  }
}

随后通过路由找到指定方法,依旧是 Illuminate\Routing\Router 内有你所使用的所有路由相关方法，例如get、post、put、patch等等，他们都调用了统一的方法 addRoute

public function addRoute($methods, $uri, $action)
{
  return $this->routes->add($this->createRoute($methods, $uri, $action));
}

之后通过 Illuminate\Routing\RouteCollection addToCollections 方法添加到集合中

protected function addToCollections($route)
{
  $domainAndUri = $route->getDomain().$route->uri();

  foreach ($route->methods() as $method) {
    $this->routes[$method][$domainAndUri] = $route;
  }

  $this->allRoutes[$method.$domainAndUri] = $route;
}

添加后的结果如下图所示

实例化

依旧通过反射加载路由指定的控制器,这个时候build的参数$concrete = App\Api\Controllers\XxxController

public function build($concrete)
{
  // If the concrete type is actually a Closure, we will just execute it and
  // hand back the results of the functions, which allows functions to be
  // used as resolvers for more fine-tuned resolution of these objects.
  if ($concrete instanceof Closure) {
    return $concrete($this, $this->getLastParameterOverride());
  }

  $reflector = new ReflectionClass($concrete);
  // If the type is not instantiable, the developer is attempting to resolve
  // an abstract type such as an Interface of Abstract Class and there is
  // no binding registered for the abstractions so we need to bail out.
  if (! $reflector->isInstantiable()) {
    return $this->notInstantiable($concrete);
  }

  $this->buildStack[] = $concrete;

  $constructor = $reflector->getConstructor();
  // If there are no constructors, that means there are no dependencies then
  // we can just resolve the instances of the objects right away, without
  // resolving any other types or dependencies out of these containers.
  if (is_null($constructor)) {

      array_pop($this->buildStack);

      return new $concrete;
  }

  $dependencies = $constructor->getParameters();
  // Once we have all the constructor's parameters we can create each of the
  // dependency instances and then use the reflection instances to make a
  // new instance of this class, injecting the created dependencies in.
  $instances = $this->resolveDependencies(
    $dependencies
  );

  array_pop($this->buildStack);

  return $reflector->newInstanceArgs($instances);
}

这时将返回控制器的实例，下面将通过url访问指定方法，一般控制器都会继承父类 Illuminate\Routing\Controller ,laravel为其设置了别名 BaseController

public function dispatch(Route $route, $controller, $method)
{

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

  if (method_exists($controller, 'callAction')) {

      return $controller->callAction($method, $parameters);
  }

  return $controller->{$method}(...array_values($parameters));
}

Laravel通过controller继承的callAction去调用子类的指定方法，也就是我们希望调用的自定义方法。

public function callAction($method, $parameters)
{
  return call_user_func_array([$this, $method], $parameters);
}

致谢

感谢你看到这里，本篇文章源码解析靠个人理解。如有出入请拍砖。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。