docs/guide-ja/runtime-handling-errors.md - prepared for translation [ci skip]

docs/guide-ja/runtime-handling-errors.md

+Handling Errors
+===============
+
+Yii includes a built-in [[yii\web\ErrorHandler|error handler]] which makes error handling a much more pleasant
+experience than before. In particular, the Yii error handler does the followings to improve error handling:
+
+* All non-fatal PHP errors (e.g. warnings, notices) are converted into catchable exceptions.
+* Exceptions and fatal PHP errors are displayed with detailed call stack information and source code lines
+  in debug mode.
+* Supports using a dedicated [controller action](structure-actions.md) to display errors.
+* Supports different error response formats.
+
+The [[yii\web\ErrorHandler|error handler]] is enabled by default. You may disable it by defining the constant
+`YII_ENABLE_ERROR_HANDLER` to be false in the [entry script](structure-entry-scripts.md) of your application.
+
+
+## Using Error Handler <a name="using-error-handler"></a>
+
+The [[yii\web\ErrorHandler|error handler]] is registered as an [application component](structure-application-components.md) named `errorHandler`.
+You may configure it in the application configuration like the following:
+
+```php
+return [
+    'components' => [
+        'errorHandler' => [
+            'maxSourceLines' => 20,
+        ],
+    ],
+];
+```
+
+With the above configuration, the number of source code lines to be displayed in exception pages will be up to 20.
+
+As aforementioned, the error handler turns all non-fatal PHP errors into catchable exceptions. This means you can
+use the following code to deal with PHP errors:
+
+```php
+use Yii;
+use yii\base\ErrorException;
+
+try {
+    10/0;
+} catch (ErrorException $e) {
+    Yii::warning("Division by zero.");
+}
+
+// execution continues...
+```
+
+If you want to show an error page telling the user that his request is invalid or unexpected, you may simply
+throw an [[yii\web\HttpException|HTTP exception]], such as [[yii\web\NotFoundHttpException]]. The error handler
+will correctly set the HTTP status code of the response and use an appropriate error view to display the error
+message.
+
+```php
+use yii\web\NotFoundHttpException;
+
+throw new NotFoundHttpException();
+```
+
+
+## Customizing Error Display <a name="customizing-error-display"></a>
+
+The [[yii\web\ErrorHandler|error handler]] adjusts the error display according to the value of the constant `YII_DEBUG`.
+When `YII_DEBUG` is true (meaning in debug mode), the error handler will display exceptions with detailed call
+stack information and source code lines to help easier debugging. And when `YII_DEBUG` is false, only the error
+message will be displayed to prevent revealing sensitive information about the application.
+
+> Info: If an exception is a descendant of [[yii\base\UserException]], no call stack will be displayed regardless
+the value of `YII_DEBUG`. This is because such exceptions are considered to be caused by user mistakes and the
+developers do not need to fix anything.
+
+By default, the [[yii\web\ErrorHandler|error handler]] displays errors using two [views](structure-views.md):
+
+* `@yii/views/errorHandler/error.php`: used when errors should be displayed WITHOUT call stack information.
+  When `YII_DEBUG` is false, this is the only error view to be displayed.
+* `@yii/views/errorHandler/exception.php`: used when errors should be displayed WITH call stack information.
+
+You can configure the [[yii\web\ErrorHandler::errorView|errorView]] and [[yii\web\ErrorHandler::exceptionView|exceptionView]]
+properties of the error handler to use your own views to customize the error display.
+
+
+### Using Error Actions <a name="using-error-actions"></a>
+
+A better way of customizing the error display is to use dedicated error [actions](structure-controllers.md).
+To do so, first configure the [[yii\web\ErrorHandler::errorAction|errorAction]] property of the `errorHandler`
+component like the following:
+
+```php
+return [
+    'components' => [
+        'errorHandler' => [
+            'errorAction' => 'site/error',
+        ],
+    ]
+];
+```
+
+The [[yii\web\ErrorHandler::errorAction|errorAction]] property takes a [route](structure-controllers.md#routes)
+to an action. The above configuration states that when an error needs to be displayed without call stack information,
+the `site/error` action should be executed.
+
+You can create the `site/error` action as follows,
+
+```php
+namespace app\controllers;
+
+use Yii;
+use yii\web\Controller;
+
+class SiteController extends Controller
+{
+    public function actions()
+    {
+        return [
+            'error' => [
+                'class' => 'yii\web\ErrorAction',
+            ],
+        ];
+    }
+}
+```
+
+The above code defines the `error` action using the [[yii\web\ErrorAction]] class which renders an error
+using a view named `error`.
+
+Besides using [[yii\web\ErrorAction]], you may also define the `error` action using an action method like the following,
+
+```php
+public function actionError()
+{
+    $exception = Yii::$app->errorHandler->exception;
+    if ($exception !== null) {
+        return $this->render('error', ['exception' => $exception]);
+    }
+}
+```
+
+You should now create a view file located at `views/site/error.php`. In this view file, you can access
+the following variables if the error action is defined as [[yii\web\ErrorAction]]:
+
+* `name`: the name of the error;
+* `message`: the error message;
+* `exception`: the exception object through which you can more useful information, such as HTTP status code,
+  error code, error call stack, etc.
+
+> Info: If you are using the [basic application template](start-installation.md) or the [advanced application template](tutorial-advanced-app.md),
+the error action and the error view are already defined for you.
+
+
+### Customizing Error Response Format <a name="error-format"></a>
+
+The error handler displays errors according to the format setting of the [response](runtime-responses.md).
+If the the [[yii\web\Response::format|response format]] is `html`, it will use the error or exception view
+to display errors, as described in the last subsection. For other response formats, the error handler will
+assign the array representation of the exception to the [[yii\web\Response::data]] property which will then
+be converted to different formats accordingly. For example, if the response format is `json`, you may see
+the following response:
+
+```
+HTTP/1.1 404 Not Found
+Date: Sun, 02 Mar 2014 05:31:43 GMT
+Server: Apache/2.2.26 (Unix) DAV/2 PHP/5.4.20 mod_ssl/2.2.26 OpenSSL/0.9.8y
+Transfer-Encoding: chunked
+Content-Type: application/json; charset=UTF-8
+
+{
+    "name": "Not Found Exception",
+    "message": "The requested resource was not found.",
+    "code": 0,
+    "status": 404
+}
+```
+
+You may customize the error response format by responding to the `beforeSend` event of the `response` component
+in the application configuration:
+
+```php
+return [
+    // ...
+    'components' => [
+        'response' => [
+            'class' => 'yii\web\Response',
+            'on beforeSend' => function ($event) {
+                $response = $event->sender;
+                if ($response->data !== null) {
+                    $response->data = [
+                        'success' => $response->isSuccessful,
+                        'data' => $response->data,
+                    ];
+                    $response->statusCode = 200;
+                }
+            },
+        ],
+    ],
+];
+```
+
+The above code will reformat the error response like the following:
+
+```
+HTTP/1.1 200 OK
+Date: Sun, 02 Mar 2014 05:31:43 GMT
+Server: Apache/2.2.26 (Unix) DAV/2 PHP/5.4.20 mod_ssl/2.2.26 OpenSSL/0.9.8y
+Transfer-Encoding: chunked
+Content-Type: application/json; charset=UTF-8
+
+{
+    "success": false,
+    "data": {
+        "name": "Not Found Exception",
+        "message": "The requested resource was not found.",
+        "code": 0,
+        "status": 404
+    }
+}
+```