In .NET Core you can easily add a detailed exception page for developers:
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
This then gives you the exception details:
However, I'd like to include additional exception detail - for instance the SQL query attempted when the exception is a SqlException.
I can write my own exception handler from scratch with app.UseExceptionHandler, but I'd rather extend the built-in error. For instance by adding a tab to the results including additional info.
Is it possible to extend the information on this exception page?
Related
I am running one MVC application where i found one exception in specific method. I will provide here complete details about it.
I am loading some third party grid control from view. to load it i used below code:
#{Html.RenderAction("MasterGridAction", "MyController");}
Now when i access this report from development then this view load and it hits this action method where i used some piece of code there it is throwing error, To catch the error i used try catch block in the method where in catch section i used below code to throw the actual exception like below:
catch (Exception ex)
{
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(ex).Throw(); throw;
}
When exception get catched it sends this to the Application_Error method in global.asax page where i used below code to find out the actual exception like below:
void Application_Error(object sender, EventArgs e)
{
HttpServerUtility server = HttpContext.Current.Server;
if (server.GetLastError() != null)
{
Exception exception = server.GetLastError();
if (exception.GetBaseException() != null)
{
exception = exception.GetBaseException();
ExceptionType(server, exception);
}
else
{
ExceptionType(server, exception);
}
}
}
In this ExceptionType method i get the exception stack and log to the file using "Log4Net". After logging to the file i could see the exception in notepad like below:
Object reference not set to an instance of an object.
Source File: /MyController/MasterGridAction
Stack Trace:
at 3D.Controllers.MyController.MasterGridAction() in D:\MyUser\3D_MVC\Application\3D_OnlyRelease\3D\Controllers\MyController.cs:line 405
--- End of stack trace from previous location where exception was thrown ---
As we can see in above exception it is clearly shown the line number also where this exception get caught.
But once i host this application in IIS server and access the same page then i could see the logged file
There it shows exception like below:
Exception Message: Object reference not set to an instance of an object.
Stack Trace: at 3D.Controllers.MyController.MasterGridAction()
--- End of stack trace from previous location where exception was thrown ---
As you can see the logged exception of IIS server is not having much information when compare to other exception details.
Am i missing anything there to get the complete exception when host in IIS?
Please suggest.
As you can see the logged exception of IIS server is not having much information when compare to other exception details.
This could be because you don't include the PDB files in production.
It might not be a great idea to include them, since that way one can reverse engineer you app with more precision if they hack your server, but it is up to you to decide. I have seen organizations that include them in their production environments.
Try publishing and deploying on a test environment with and without the PDB files to verify this.
I have a requirement which I want to solve using Mule. My flow design follows like:
A main-flow with request-response HTTP inbound endpoint. After applying couple of transformations on the current payload this main flow invokes two private flows namely private-flow1 and private-flow2, which are mule private flows whose processing strategy is synchronous.
The private-flow1 invokes an external service using request-response HTTP outbound endpoint.
The private-flow2 places the response from the external service on Database using Database Connector.
If there is any exception in each of the private flows, I want to handle them in the corresponding private flow itself using Catch Exception Strategy.
I have this design to separate the concerns, so that each flow performs a single responsibility.
Suppose there is an exception like IOException, SQLException or any, in any one of the private flows, how can I re-throw my custom exception, for example, org.mycompany.CustomException including the underlying cause. So main-flow will have to handle only org.mycompany.CustomException and build the related exception response.
Say for example, if private-flow1 throws org.mycompany.CustomException which is caused by IOException, the realted exception response would be:
{"exceptionMessage" : External Service unavailable, "exceptionCode" : 101}
and, if private-flow2 throws org.mycompany.CustomException which is caused by SQLException, the realted exception response would be
{"exceptionMessage" : Database unavailable, "exceptionCode" : 102}
Each private flow will have their own exception strategy and you can throw an exception using Groovy component from the flows ..
Here is a link how to do it :- How do I force an exception in mule
for custom exception create java-class which would extend DefaultMessagingExceptionStrategy
Update:-
An example to use custom-exception-strategy:- Why is Mule exception strategy so chatty?
In the EFContextProvider (EF6) SaveChangesCore method, the exception handling looks like this:
} catch (Exception e) {
while (e.InnerException != null) {
e = e.InnerException;
}
throw e;
}
This throws only the most internal exception and hides the relevant information revealed by the external exceptions.
When the SaveChanges process goes through multiple layers the next direct layer exception is lost, and only the last exception in the chain is thrown. It doesn't allow to handle well the exceptions for the caller.
Updated Post
As of Breeze 1.4.6, any .NET Exceptions thrown on the server are now available in their original form in the httpResponse.data property of any async breeze result. Breeze will still drill down to extract a "good" error message, but will no longer obscure the initial exception.
Original Post Below -------------------
It's an interesting point. The reason we did this was because most client side apps aren't written to navigate thru the exception chain and we wanted to expose the most 'relevant' error to the client. Most of the apps we looked at just exposed the client "error.message" property directly and with EF errors this was almost always useless.
However, your point is well taken. I think what we need to do is create a new Exception that has a top level message that is the innermost exception message but still expose the entire exception chain for those that want to drill. I've added an internal feature request for this and will try to get it into a near term release ( probably not the next one because we are already in testing for that one).
And thanks for the input.
Does anybody know how to print full stack trace on the Browser, when a Runtime Exception occurs in MULE..??
When a runtime Exception occurs, MULE throws a 500 Server Error to the client , but shows no details to the client. It prints the whole stack trace in Console or Log Files (like the following) :
Root Exception stack trace:
java.sql.SQLException: Invalid column name
at oracle.jdbc.driver.OracleStatement.getColumnIndex(OracleStatement.java:3677)
at oracle.jdbc.driver.OracleResultSetImpl.findColumn(OracleResultSetImpl.java:2749)
at oracle.jdbc.driver.OracleResultSet.getString(OracleResultSet.java:494)
+ 3 more (set debug level logging or '-Dmule.verbose.exceptions=true'
for everything)
Can i show the same stack Trace on the Browser (to the client)..??
And if possible , then also tell me how to switch ON or OFF printing of Stack Trace on Browser..??
(It may be possible that sometime in future , i dont want to show stack trace on browser)
Yes this is possible. I assume you are using a regular HTTP endpoint and this is a REST type service(?) If so, you can simply put a try/catch around the code causing the exception and return whatever text you want.
There are also exception strategies (http://www.mulesoft.org/documentation/display/MULE3USER/Error+Handling) for doing more sophisticated error handling, but it sounds like you are looking for the simple answer above.
If this doesn't answer your question, please provide more info about your mule config and the service that is raising the exception.
There is nothing out of the box in Mule to do that. You have to implement an exception handler that will format the stacktrace in the Message exception payload and return it to the caller.
In your case, the HTTP transport has a particularity that can be found in the HttpMessageReceiver code:
try
{
conn.writeResponse(processRequest(request));
}
catch (Exception e)
{
...
conn.writeResponse(buildFailureResponse(request.getRequestLine().getHttpVersion(), httpStatus, e.getMessage()));
This means that when an exception crops-up to the top level, the creation of the failure message response is not customizable: you get this pretty technical message back and that is all.
I see two options to solve your problem:
sub-class HttpMessageReceiver and make the response message customizable in your version,
drop the HTTP transport in favor of the Jetty one (look at the bookstore example) and customize the response error messages at the web container level.
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.