Laravel 4 中的异常处理 - 理解流程的问题
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Exception handling in Laravel 4 - Problems understanding flow
提问by grange
I have problems understanding how Laravel handles exceptions. I registered Exception handlers in global.php like this:
我在理解 Laravel 如何处理异常时遇到问题。我在 global.php 中注册了异常处理程序，如下所示：
use MyNamespace\Custom\Exceptions\NotAllowedException;
App::error(function(NotAllowedException $exception, $code)
{
die("MyNamespace\Custom\Exceptions\NotAllowedException catched");
});
App::error(function(\Exception $exception)
{
echo "general exception thrown<br/>";
});
In a controller action I now throw a NotAllowedException. The strange part however is, that first Exception is catched and NotFoundException afterwards.
在控制器操作中，我现在抛出 NotAllowedException。然而，奇怪的部分是，第一个 Exception 被捕获，然后 NotFoundException 被捕获。
The output thus is:
因此输出是：
general exception thrown
MyNamespace\Custom\Exceptions\NotAllowedException catched
I thought that exception handlers stack and therefore only NotAllowedException is being handled. But I'm wrong. Do I misunderstand the concepts of error handling in Laravel or is this unexpected behaviour?
我认为异常处理程序堆栈，因此只处理 NotAllowedException。但我错了。我是否误解了 Laravel 中错误处理的概念，或者这是意外行为？
Another thing: I am not able to set http response header to 401. There are other threads on SO regarding this problem but without a solution so far. If anyone knows something about that either, I would appreciate.
另一件事：我无法将 http 响应标头设置为 401。关于此问题，SO 上还有其他线程，但到目前为止还没有解决方案。如果有人对此有所了解，我将不胜感激。
Thank you for you time and every response! Cheers
感谢您的时间和每一个回复！干杯
回答by DerLola
Exception handling can be seen as a reversed waterfall. The last handler that is defined, is checked first. Take this example:
异常处理可以看作是一个反向瀑布。首先检查定义的最后一个处理程序。拿这个例子：
// Custom Exception
class CustomException extends Exception {}
// Error handler in global.php
App::error(function(Exception $exception, $code)
{
echo 'Debug: Exception<br/>';
});
App::error(function(CustomException $exception, $code)
{
echo 'Debug: CustomException<br/>';
});
// Exception in routes.php (or any other place)
throw new CustomException();
Both types match the Exception type, so this outputs: Debug: CustomException Debug: Exception
两种类型都匹配 Exception 类型，因此输出： Debug: CustomException Debug: Exception
However, if you return something from within your handler, ONLY the first matching handler is triggered. To return a JSON response with a HTTP 401 response code, do something like:
但是，如果您从处理程序中返回某些内容，则只会触发第一个匹配的处理程序。要返回带有 HTTP 401 响应代码的 JSON 响应，请执行以下操作：
App::error(function(Exception $exception, $code)
{
return Response::json(array(
'error' => 'Something went wrong (Exception)'
), 500);
});
App::error(function(NotAllowedException $exception, $code)
{
return Response::json(array(
'error' => 'Something went wrong (NotAllowedException)'
), 401);
});
So, in general, you'd want the Exception handler defined first.
因此，一般而言，您希望首先定义异常处理程序。
