(new yii\web\Application($config))->run();


public function run()
{
    try {

        $this->state = self::STATE_BEFORE_REQUEST;
        $this->trigger(self::EVENT_BEFORE_REQUEST);

        $this->state = self::STATE_HANDLING_REQUEST;
        $response = $this->handleRequest($this->getRequest());

        $this->state = self::STATE_AFTER_REQUEST;
        $this->trigger(self::EVENT_AFTER_REQUEST);

        $this->state = self::STATE_SENDING_RESPONSE;
        $response->send();

        $this->state = self::STATE_END;

        return $response->exitStatus;

    } catch (ExitException $e) {

        $this->end($e->statusCode, isset($response) ? $response : null);
        return $e->statusCode;

    }
}

       
 public function handleRequest($request)
{
    if (empty($this->catchAll)) {
        try {
            list ($route, $params) = $request->resolve();
        } catch (UrlNormalizerRedirectException $e) {
            $url = $e->url;
            if (is_array($url)) {
                if (isset($url[0])) {
                    // ensure the route is absolute
                    $url[0] = '/' . ltrim($url[0], '/');
                }
                $url += $request->getQueryParams();
            }
            return $this->getResponse()->redirect(Url::to($url, $e->scheme), $e->statusCode);
        }
    } else {
        $route = $this->catchAll[0];
        $params = $this->catchAll;
        unset($params[0]);
    }
    try {
        Yii::trace("Route requested: '$route'", __METHOD__);
        $this->requestedRoute = $route;
        $result = $this->runAction($route, $params);
        if ($result instanceof Response) {
            return $result;
        } else {
            $response = $this->getResponse();
            if ($result !== null) {
                $response->data = $result;
            }

            return $response;
        }
    } catch (InvalidRouteException $e) {
        throw new NotFoundHttpException(Yii::t('yii', 'Page not found.'), $e->getCode(), $e);
    }
}



public function runAction($route, $params = [])
{
    $parts = $this->createController($route);
    if (is_array($parts)) {
        /* @var $controller Controller */
        list($controller, $actionID) = $parts;
        $oldController = Yii::$app->controller;
        Yii::$app->controller = $controller;
        $result = $controller->runAction($actionID, $params);
        if ($oldController !== null) {
            Yii::$app->controller = $oldController;
        }

        return $result;
    } else {
        $id = $this->getUniqueId();
        throw new InvalidRouteException('Unable to resolve the request "' . ($id === '' ? $route : $id . '/' . $route) . '".');
    }
}

if ($this->validate()) {

        return Yii::$app->user->login($this->getUser(), $this->rememberMe ? 3600*24*30 : 0);
        
根据以下规则验证

public function rules()
    {
        return [
            // username and password are both required
            [['username', 'password'], 'required'],
            // rememberMe must be a boolean value
            ['rememberMe', 'boolean'],
            // password is validated by validatePassword()
            ['password', 'validatePassword'],
        ];