上两篇中分析了route是怎么被加进来的，以及如何被匹配的。这篇说一下route middleware是如何被加进来的，即add进来的。index.php的代码如下：
$app->get('/forbase', function ($request, $response, $args){
Example\Module\Base::instance()->init($request,$response);
return $response;
})->add(Example\MiddleWare\MyMiddleware::instance(Example\Module\Base::instance()));
首先，确定的是$app->get()返回的是一个route类型变量，即接下来的add方法是属于route 的。
Route类的定义：
/**
* Route
*/
class Route extends Routable implements RouteInterface
{
use MiddlewareAwareTrait;
继承了abstract Routable类，并实现了RouteInterface 接口。这个add方法是Routable抽象类的方法。
/**
* Prepend middleware to the middleware collection
*
* @param mixed $callable The callback routine
*
* @return static
*/
public function add($callable)
{
$callable = $this->resolveCallable($callable);
if ($callable instanceof Closure) {
$callable = $callable->bindTo($this->container);
} $this->middleware[] = $callable;
return $this;
}
将middleware加入了一个collection中了。在route被调用run的时候，就会将collection里的middleware都加入到middleware stack中。最后条用callMiddlewarestack()从栈顶执行到栈底。
/**
* Run route
*
* This method traverses the middleware stack, including the route's callable
* and captures the resultant HTTP response object. It then sends the response
* back to the Application.
*
* @param ServerRequestInterface $request
* @param ResponseInterface $response
*
* @return ResponseInterface
*/
public function run(ServerRequestInterface $request, ResponseInterface $response)
{
// Finalise route now that we are about to run it
$this->finalize(); // Traverse middleware stack and fetch updated response
return $this->callMiddlewareStack($request, $response);
}
$this->finalize(); 实现了将collection 中的middleware都加入到 middlewarestack中。
/**
* Finalize the route in preparation for dispatching
*/
public function finalize()
{
if ($this->finalized) {
return;
} $groupMiddleware = [];
foreach ($this->getGroups() as $group) {
$groupMiddleware = array_merge($group->getMiddleware(), $groupMiddleware);
} $this->middleware = array_merge($this->middleware, $groupMiddleware); foreach ($this->getMiddleware() as $middleware) {
$this->addMiddleware($middleware);
} $this->finalized = true;
}
最后callMiddlewareStack的时候会被执行。
从下一篇开始读读每一行代码，比这样走流程更细一些。只是，不知道我这样的方法是不是对的，和最效率的。求高人传授更好方法，先谢过。