translating runtime-routing.md WIP

docs/guide-zh-CN/runtime-routing.md

+路由
+=======
+
+当[入口脚本](structure-entry-scripts.md)在调用 [[yii\web\Application::run()|run()]] 
+方法时，它进行的第一个操作就是解析输入的请求，然后实例化对应的[控制器操作](structure-controllers.md)处理这个请求。该过程就被称为**引导路由（routing）**。（译者注：中文里既是动词也是名词）
+
+
+## 解析路由 <a name="resolving-route"></a>
+
+引导路由第一步，是解析输入请求为一个路由。如 [控制器（Controllers）](structure-controllers.md#routes)
+所描述的那样，路由是一个用于定位控制器操作的地址。这个过程通过 `request` 应用组件的 [[yii\web\Request::resolve()|resolve()]] 
+方法实现，该方法会调用 [URL 管理器](runtime-url-handling.md) 进行实质上的请求解析工作。
+ 
+The first step of routing is to parse the incoming request into a route which, as described in
+the [Controllers](structure-controllers.md#routes) section, is used to address a controller action.
+This is done by [[yii\web\Request::resolve()|resolve()]] method of the `request` application component.
+The method invokes the [URL manager](runtime-url-handling.md) to do the actual request parsing work.
+
+默认情况下，输入请求会包含一个名为 `r` 的 `GET` 参数，它的值即被视为路由。但是如果启用
+[[yii\web\UrlManager::enablePrettyUrl|pretty URL feature]]，确定请求路由时则会进行更多处理。具体的细节请参考
+[URL 的解析与生成](runtime-url-handling.md) 章节。
+
+By default, if the incoming request contains a `GET` parameter named `r`, its value will be considered
+as the route. However, if the [[yii\web\UrlManager::enablePrettyUrl|pretty URL feature]] is enabled,
+more work will be done to determine the requested route. For more details, please refer to
+the [URL Parsing and Generation](runtime-url-handling.md) section.
+
+若好死不死地路由最终无法被确定，那么 `request` 组件会抛出 [[yii\web\NotFoundHttpException]] 异常（译者注：大名鼎鼎的 404）。
+
+In case a route cannot be determined, the `request` component will throw a [[yii\web\NotFoundHttpException]].
+
+
+### 默认路由 <a name="default-route"></a>
+
+If an incoming request does not specify a route, which often happens to the request for homepages,
+the route specified by [[yii\web\Application::defaultRoute]] will be used. The default value of this property
+is `site/index`, which refers to the `index` action of the `site` controller. You may customize this property
+in the application configuration like the following:
+
+```php
+return [
+    // ...
+    'defaultRoute' => 'main/index',
+];
+```
+
+
+### `catchAll` 路由（全拦截路由） <a name="catchall-route"></a>
+
+Sometimes, you may want to put your Web application in maintenance mode temporarily and display the same
+informational page for all requests. There are many ways to accomplish this goal. But one of the simplest
+ways is to configure the [[yii\web\Application::catchAll]] property like the following in the application configuration:
+
+```php
+return [
+    // ...
+    'catchAll' => ['site/offline'],
+];
+```
+
+The `catchAll` property should take an array whose first element specifies a route, and
+the rest of the elements (name-value pairs) specify the parameters to be bound to the action.
+
+When the `catchAll` property is set, it will replace any route resolved from the incoming requests.
+With the above configuration, the same `site/offline` action will be used to handle all incoming requests.
+
+
+## 创建一个操作 <a name="creating-action"></a>
+
+Once the requested route is determined, the next step is to create the action object corresponding to the route.
+
+The route is broken down into multiple parts by the slashes in it. For example, `site/index` will be
+broken into `site` and `index`. Each part is an ID which may refer to a module, a controller or an action.
+
+Starting from the first part in the route, the application conducts the following steps to create modules (if any),
+the controller and the action:
+
+1. Set the application as the current module.
+2. Check if the [[yii\base\Module::controllerMap|controller map]] of the current module contains the current ID.
+   If so, a controller object will be created according to the controller configuration found in the map,
+   and do Step 5 with the rest parts of the route.
+3. Check if the ID refers to a module listed in the [[yii\base\Module::modules|modules]] property of
+   the current module. If so, a module is created according to the configuration found in the module list,
+   and do Step 2 with the next part in the route under the context of the newly created module.
+4. Treat the ID as a controller ID and create a controller object. Do the next step with the rest part of
+   the route.
+5. The controller looks for the current ID in its [[yii\base\Controller::actions()|action map]]. If found,
+   it creates an action according to the configuration found in the map. Otherwise, the controller will
+   attempt to create an inline action which is defined by an action method corresponding to the current ID.
+
+Among the above steps, if any error occurs, a [[yii\web\NotFoundHttpException]] will be thrown, indicating
+failure of the routing.