In ASP.Net I can use a http handler or module to catch errors.
I need something equivalent for my windows service.
I'm thinking something like Application.OnError += ErrorHandlingMethod;
Any ideas?
The asp.net features this possibility, as it has a complex execution pipeline, where you want to catch a general error.
This is not the case in windows services, as it only provides you the OnStart method, to start your service stuff.
that also means, that you can easily wrap everything in there with a try ... catch block.
so no need for a general error handling method.
if you want it even more general, than go to the Program.cs, and add that catch block there...
Related
I have angular2 project, how can I catch errors on client side, error 'Failed to load'. I want to control situation if some of html files doesn't exists my page wouldn't fail, but I'll get exception in console.
Thank you.
As per my understanding, you want to handle exception, so you can done it in typescript using try catch and finally block. typescript allow us to use try catch.
A reference for Try Catch
https://www.c-sharpcorner.com/UploadFile/5089e0/try-catch-statement-in-typescript/
If you need in html, then you need to handle as case in html using some variables
I want to catch the exceptions thrown from item reader (e.g. reader not open , incorrect token exceptions etc) and handle it. Currently spring batch is throwing them as fatal exceptons and come out of the step.
Please let me know if there is any way to do it?
I faced the same issue whereby I wanted to catch the
org.springframework.batch.item.file.FlatFileParseException
thrown by the FlatFileItemReader and perform some custom handling & logging. Did some research and almost reached the conclusion that I might have to write a custom reader instead of the default reader I was currently using, until I stumbled upon a gem of a section in the Spring Batch documentation: http://docs.spring.io/spring-batch/reference/html/configureStep.html#interceptingStepExecution
You can write a custom implementation of the ItemReadListener<T> interface and over-ride the onReadError(Exception ex) method and then register this listener class in the corresponding step. As such, this method will then be called when the reader encounters an exception while reading from the file. The exception reference will be passed to the method as well using which you can do as you please like logging etc.
Similarly, writing a #OnReadError annotated method is also an alternative if you don't want to implement the ItemReadListener interface separately.
On a different note, if your whole purpose is to skip such exceptions that might occur while reading, you can try adding following to the chunk configuration in the XML:
<skippable-exception-classes>
<include class="org.springframework.batch.item.file.FlatFileParseException"/>
</skippable-exception-classes>
Ref: http://docs.spring.io/spring-batch/reference/html/configureStep.html#configuringSkip
Problem solved! :)
I created a custom component for a proprietary service. If this service is down i get noticed via a call of a callback function. I am throwing a custom exception at this point.
Sending exchanges to the producer/ consumer will yield no errors or exceptions (all seems to fine).
So i need to implement an emergency stop if my custom exception is thrown. I read a bit about exception handling in camel. I think i need a context-scoped onException(MyException.class).??? but what then?
Is this working on exceptions that are called without relation to an exchange? If this is working how to handle it. I want to stop certain routes in this case.
here you can find to stop routes from a route: http://camel.apache.org/how-can-i-stop-a-route-from-a-route.html.
If you do the call of the proprietary service in a route you do have an exchange btw.
kind regards,
soilworker
I created a little workaround: I set a boolean i the callback method is called. On each call of process i check this boolean and if true i throw an exception.
With this the exception is within normal camel exception handling and onException could be used.
My ejb3 application running on JBOSS6 already has a customized Exception handler "Ejbexception.java" which extends Exception class
I want to use the same to trap Exceptions with some number and send back the same to the Client Code for handling gentel message .
ex:
try{
.....
}catch(SQLException ex){
throw new EjbException("1001");
}
Now HOWto get the "1001" on the Client Code ?????
thx in advance
karthik
Did you write this Ejbexception class yourself? If so, that's a poor choice of name, because there's already a javax.ejb.EJBException in the library. However, it will work: when you throw it, the container will transport it to the client, who can then catch it. The string you inserted will be available from the exception's getMessage() method, just like normal.
If you're actually throwing a javax.ejb.EJBException here, then things are slightly different. That exception is aimed at the container, not the client. I actually don't know how it's made visible to the client. My suggestion would be to switch to using a custom exception, which the container will then pass to the client.
We are developing a proxy in WCF that will serve as a means of communication for some handhelds running our custom client application. I am curious what error handling strategies people use as I would rather not wrap EVERY proxy call in try/catch.
When I develop ASP .NET I dont catch the majority of exceptions, I leverage Application_Error in Global asax which can then log the exception, send an email, and redirect the user to a custom error landing page. What I am looking for in WCF is similar to this, except that it would allow me to pass a general faultreason to the client from a central location.
Basically I am curious how people centralize their exception handling in WCF apps.
Thanks
You might find the IErrorHandler interface useful here. We've been using this to do pretty much what you mention - centralised exception logging and providing generalised fault reasons without having to litter the code with numerous try/catches to try and deal with the problem locally.
So here is what I did. We have a few custom exceptions in our application such as BusinessRuleException and ProcessException, WCF supports both FaultException and FaultException<T>.
General practice seems to be that you always throw FaultException to the client in the case of a general error or an error that you dont want to display exactly what happened. In other cases you can pass FaultException<T> where T is a class with information about the particular exception.
I created this concept of Violations in the application, which basically meant that any custom exception had a property containing the corresponding Violation instance. This instance was then passed down to the client enabling the client to recognize when a recoverable error had occured.
This solved part of the problem, but I still wanted a general catch all that would allow me to centeralize logging. I found this by using the IErrorHandle interface and adding my own custom error handler to WCF. Here is the code:
public class ServiceHostGeneralErrorHandler : IErrorHandler
{
public void ProvideFault(Exception ex, MessageVersion version, ref Message fault)
{
if (ex is FaultException)
return;
// a general message to the client
var faultException = new FaultException("A General Error Occured");
MessageFault messageFault = faultException.CreateMessageFault();
fault = Message.CreateMessage(version, messageFault, null);
}
public bool HandleError(Exception ex)
{
// log the exception
// mark as handled
return true;
}
}
Using this method, I can convert the exception from whatever it is to something that can be easily displayed on the client while at the same time logging the real exception for the IT staff to see. So far this approach is working quite well and follows the same structure as other modules in the application.
We use the Exception Handling Application block and shield most faults from clients to avoid disclosing sensitive information, this article might be a good starting point for you, as with "best practices" - you should use what fits your domain.