Exception handling 我应该如何处理WebAPI中控制器构造函数中的异常?
假设我有一个构造函数,它的初始化可能会由于我无法控制的原因引发异常Exception handling 我应该如何处理WebAPI中控制器构造函数中的异常?,exception-handling,asp.net-web-api,asp.net-4.5,Exception Handling,Asp.net Web Api,Asp.net 4.5,假设我有一个构造函数,它的初始化可能会由于我无法控制的原因引发异常 FantasticApiController(IAwesomeGenerator awesome, IBusinessRepository repository, IIceCreamFactory factory) { Awesome = awesome; Repository = repository; IceCream = factory.MakeIceCream();
FantasticApiController(IAwesomeGenerator awesome,
IBusinessRepository repository, IIceCreamFactory factory)
{
Awesome = awesome;
Repository = repository;
IceCream = factory.MakeIceCream();
DoSomeInitialization(); // this can throw an exception
}
通常,当WebAPI中的控制器操作引发异常时,我可以通过csutomExceptionFilterAttribute
来处理它:
public class CustomErrorHandler
{
public override void OnException(HttpActionExecutedContext context)
{
// Critical error, this is real bad.
if (context.Exception is BubonicPlagueException)
{
Log.Error(context.Exception, "CLOSE EVERYTHING!");
Madagascar.ShutdownAllPorts();
}
// No big deal, just show something user friendly
throw new HttpResponseException(new HttpResponseMessage
{
Content = new StringContent("Hey something bad happened. " +
"Not closing the ports though"),
StatusCode = HttpStatusCode.InternalServerError;
});
}
因此,如果我有一个have aBoardPlane
API方法抛出一个bubonicplagueeexception
,那么我的CustomerErrorHandler
将关闭到马达加斯加的端口,并按预期将其记录为错误。在其他情况下,如果不是很严重,我只会显示一些用户友好的消息,并返回一个500InternalServerError
但是在那些
DoSomeInitialization
抛出异常的情况下,这绝对不起任何作用如何处理WebAPI控制器构造函数中的异常?创建WebAPI控制器,并通过HttpControllerActivators调用构造函数。默认激活器是System.Web.Http.Dispatcher.DefaultHttpControllerActivator
这里是github上选项1和2的粗略示例
选项1很好地使用了DI容器(您可能已经在使用一个)。我在我的示例中使用了Ninject,并使用“拦截器”拦截和尝试/捕获对DefaultHttpControllerActivator上的Create方法的调用。据我所知,至少AutoFac和Ninject可以做一些类似的事情:
创建拦截器
public class ControllerCreationInterceptor : Ninject.Extensions.Interception.IInterceptor
{
private ILog _log;
private IMadagascar _madagascar;
public ControllerCreationInterceptor(ILog log, IMadagascar madagascar)
{
_log = log;
_madagascar = madagascar;
}
我不知道你的马达加斯加和日志项的生命周期范围是什么,但它们很可能被注入你的拦截器
public class ControllerCreationInterceptor : Ninject.Extensions.Interception.IInterceptor
{
private ILog _log;
private IMadagascar _madagascar;
public ControllerCreationInterceptor(ILog log, IMadagascar madagascar)
{
_log = log;
_madagascar = madagascar;
}
但请继续你问题中的例子,Log和Madagada是某种静态的全局变量
public class ControllerCreationInterceptor : Ninject.Extensions.Interception.IInterceptor
{
public void Intercept(Ninject.Extensions.Interception.IInvocation invocation)
{
try
{
invocation.Proceed();
}
catch(InvalidOperationException e)
{
if (e.InnerException is BubonicPlagueException)
{
Log.Error(e.InnerException, "CLOSE EVERYTHING!");
Madagascar.ShutdownAllPorts();
//DO SOMETHING WITH THE ORIGIONAL ERROR!
}
//DO SOMETHING WITH THE ORIGIONAL ERROR!
}
}
}
最后在全局asax或App_Start(NinjectWebCommon)中注册拦截器
拥有自己的自定义激活器后,默认激活器可以位于全局asax中:
GlobalConfiguration.Configuration.Services.Replace(typeof(IHttpControllerActivator), new YourCustomControllerActivator());
选项3当然,如果您在构造函数中的初始化不需要访问实际控制器方法、属性等。。。i、 假设它可以从构造函数中删除。。。然后,只需将初始化移动到过滤器(例如
public class MadagascarFilter : AbstractActionFilter
{
public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
{
try{
DoSomeInitialization(); // this can throw an exception
}
catch(BubonicPlagueException e){
Log.Error(e, "CLOSE EVERYTHING!");
Madagascar.ShutdownAllPorts();
//DO SOMETHING WITH THE ERROR
}
base.OnActionExecuting(actionContext);
}
public override void OnActionExecuted(System.Web.Http.Filters.HttpActionExecutedContext actionExecutedContext)
{
base.OnActionExecuted(actionExecutedContext);
}
public override bool AllowMultiple
{
get { return false; }
}
}
WebApi的一个有趣特性是,您可以轻松自定义异常返回到客户端的方式。同一操作方法中的状态和Html错误。显然,如果在构造函数中抛出异常,您将失去所有这些。我认为你应该避免这种情况发生。大多数逻辑应该放在webapi方法中,而不是构造函数中。也就是说,我认为您应该使用标准的asp.net错误处理,即在Web.Config中配置错误页面,或者在全局asax中拦截onerror事件
public class MadagascarFilter : AbstractActionFilter
{
public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
{
try{
DoSomeInitialization(); // this can throw an exception
}
catch(BubonicPlagueException e){
Log.Error(e, "CLOSE EVERYTHING!");
Madagascar.ShutdownAllPorts();
//DO SOMETHING WITH THE ERROR
}
base.OnActionExecuting(actionContext);
}
public override void OnActionExecuted(System.Web.Http.Filters.HttpActionExecutedContext actionExecutedContext)
{
base.OnActionExecuted(actionExecutedContext);
}
public override bool AllowMultiple
{
get { return false; }
}
}