# Hosting: howto get the nice ruby backtrace on exception thrown from ruby? **URL:** \ **Category:** IronRuby\ **Created:** [February 18, 2009, 12:29am UTC](https://www.ruby-forum.com/t/hosting-howto-get-the-nice-ruby-backtrace-on-exception-thrown-from-ruby/160585 "2009-02-18T00:29:53Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Meinrad\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ecae2f/32.png) [@Meinrad\_R](https://www.ruby-forum.com/u/Meinrad_R)\ **Post date:** [February 18, 2009, 12:29am UTC](https://www.ruby-forum.com/t/hosting-howto-get-the-nice-ruby-backtrace-on-exception-thrown-from-ruby/160585/1 "2009-02-18T00:29:53Z")
hello, I am now currently using this ugly hack to get a reasonable (let’s say user friendly) exception backtrace from an error in executed code: ``` public object Execute(string code, ScriptScope scope) { code = @"begin ``` \_=( “+code+@” ) rescue Exception self. **message** =$!.message.to\_clr\_string self. **backtrace** = $!.backtrace throw end"; object result = null; try { LogManager.GetLogger(“Ruby”).Debug("\r\n" + code); result = m\_engine.Execute(code, scope); ``` } catch (Exception e) { var backtrace = ``` scope.GetVariable(“ **backtrace** ”); string msg = scope.GetVariable(“ **message** ”) +"\r\n" + string.Join("\r\n", backtrace.Select(s =\> s.ToString()).ToArray()); ``` LogManager.GetLogger("Ruby").Error(msg); } return result; } ``` Even though it seems to work well I am absolutely not satisfied with it. Is there a better way to do this? – henon ---
**Author:** ![Meinrad\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ecae2f/32.png) [@Meinrad\_R](https://www.ruby-forum.com/u/Meinrad_R)\ **Post date:** [February 18, 2009, 10:29am UTC](https://www.ruby-forum.com/t/hosting-howto-get-the-nice-ruby-backtrace-on-exception-thrown-from-ruby/160585/2 "2009-02-18T10:29:43Z")
I’ve given it some thought. I would like to avoid wrapping the code in “begin - rescue” and instead catch the exception in c#. Then just send the ruby methods “message” and “backtrace” to the Ruby-exception-object from C#. How would that be done? Any other hints?-- Henon On Tue, Feb 17, 2009 at 11:36 PM, Meinrad R. \ **Author:** ![Meinrad\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ecae2f/32.png) [@Meinrad\_R](https://www.ruby-forum.com/u/Meinrad_R)\ **Post date:** [February 19, 2009, 3:46am UTC](https://www.ruby-forum.com/t/hosting-howto-get-the-nice-ruby-backtrace-on-exception-thrown-from-ruby/160585/3 "2009-02-19T03:46:48Z") You can use ExceptionService: ``` var engine = Ruby.CreateEngine(); try { engine.Execute(@" ``` def foo goo end def goo raise ‘hello’ end foo "); } catch (Exception e) { var exceptionService = engine.GetService(); string message, typeName; exceptionService.GetExceptionMessage(e, out message, out typeName); Console.WriteLine(message); Console.WriteLine(typeName); Console.WriteLine(exceptionService.FormatException(e)); } The current implementation is not ideal. If you’re missing some features on the service let us know. We might consider adding them. Tomas From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Meinrad Recheis Sent: Wednesday, February 18, 2009 1:25 AM To: ironruby-core Subject: Re: [Ironruby-core] hosting: howto get the nice ruby backtrace on exception thrown from ruby? I’ve given it some thought. I would like to avoid wrapping the code in “begin - rescue” and instead catch the exception in c#. Then just send the ruby methods “message” and “backtrace” to the Ruby-exception-object from C#. How would that be done? Any other hints? – Henon On Tue, Feb 17, 2009 at 11:36 PM, Meinrad R. \ wrote: hello, I am now currently using this ugly hack to get a reasonable (let’s say user friendly) exception backtrace from an error in executed code: public object Execute(string code, ScriptScope scope) { code = @“begin \_=( “+code+@” ) rescue Exception self. **message** =$!.message.to\_clr\_string self. **backtrace** = $!.backtrace throw end”; object result = null; try { LogManager.GetLogger(“Ruby”).Debug(“\r\n” + code); result = m\_engine.Execute(code, scope); ``` } catch (Exception e) { var backtrace = ``` scope.GetVariable(“ **backtrace** ”); string msg = scope.GetVariable(“ **message** ”) +“\r\n” + string.Join(“\r\n”, backtrace.Select(s =\> s.ToString()).ToArray()); ``` LogManager.GetLogger("Ruby").Error(msg); } return result; } ``` Even though it seems to work well I am absolutely not satisfied with it. Is there a better way to do this? – henon ---
**Author:** ![Meinrad\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ecae2f/32.png) [@Meinrad\_R](https://www.ruby-forum.com/u/Meinrad_R)\ **Post date:** [February 19, 2009, 10:06am UTC](https://www.ruby-forum.com/t/hosting-howto-get-the-nice-ruby-backtrace-on-exception-thrown-from-ruby/160585/4 "2009-02-19T10:06:56Z")
Thanks Thomas, thats very good. As for a suggestion about ExceptionService features: It would be quite useful to retrieve the exception backtrace as string[] in order to be able format it to one’s needs. For instance, I like using the VisualStudio error parser to be able to jump from the backtrace in the output right into the right line in the source file (see my blog post: [Navigating in Exception Stack Traces in Visual C-Sharp - eqqon](http://www.eqqon.com/index.php/Navigating_in_Exception_Stack_Traces_in_Visual_C-Sharp)). To do that, currently, I would need to parse the formatted backtrace and re-format it. No big deal. Just would be nice to have. Cheers, – henon On Thu, Feb 19, 2009 at 3:30 AM, Tomas M. \< ---
**Author:** ![Meinrad\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ecae2f/32.png) [@Meinrad\_R](https://www.ruby-forum.com/u/Meinrad_R)\ **Post date:** [February 19, 2009, 6:11pm UTC](https://www.ruby-forum.com/t/hosting-howto-get-the-nice-ruby-backtrace-on-exception-thrown-from-ruby/160585/5 "2009-02-19T18:11:08Z")
I completely agree with that. I think we should add a method GetStackTrace() that returns an instance of some StackTrace class, which is an array of StackFrames, where StackFrame is some struct/class that contains method name, file name and line number. Tomas From: removed\_email\_address@domain.invalid [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Meinrad Recheis Sent: Thursday, February 19, 2009 1:06 AM To: removed\_email\_address@domain.invalid Subject: Re: [Ironruby-core] hosting: howto get the nice ruby backtrace on exception thrown from ruby? Thanks Thomas, thats very good. As for a suggestion about ExceptionService features: It would be quite useful to retrieve the exception backtrace as string[] in order to be able format it to one’s needs. For instance, I like using the VisualStudio error parser to be able to jump from the backtrace in the output right into the right line in the source file (see my blog post: [Navigating in Exception Stack Traces in Visual C-Sharp - eqqon](http://www.eqqon.com/index.php/Navigating_in_Exception_Stack_Traces_in_Visual_C-Sharp)). To do that, currently, I would need to parse the formatted backtrace and re-format it. No big deal. Just would be nice to have. Cheers, – henon On Thu, Feb 19, 2009 at 3:30 AM, Tomas M. \ wrote: You can use ExceptionService: ``` var engine = Ruby.CreateEngine(); try { engine.Execute(@" ``` def foo goo end def goo raise ‘hello’ end foo "); ``` } catch (Exception e) { var exceptionService = ``` engine.GetService(); ``` string message, typeName; exceptionService.GetExceptionMessage(e, out message, out ``` typeName); ``` Console.WriteLine(message); Console.WriteLine(typeName); Console.WriteLine(exceptionService.FormatException(e)); } ``` The current implementation is not ideal. If you’re missing some features on the service let us know. We might consider adding them. Tomas From: removed\_email\_address@domain.invalid[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] On Behalf Of Meinrad R. Sent: Wednesday, February 18, 2009 1:25 AM To: ironruby-core Subject: Re: [Ironruby-core] hosting: howto get the nice ruby backtrace on exception thrown from ruby? I’ve given it some thought. I would like to avoid wrapping the code in “begin - rescue” and instead catch the exception in c#. Then just send the ruby methods “message” and “backtrace” to the Ruby-exception-object from C#. How would that be done? Any other hints? – Henon On Tue, Feb 17, 2009 at 11:36 PM, Meinrad R. \ wrote: hello, I am now currently using this ugly hack to get a reasonable (let’s say user friendly) exception backtrace from an error in executed code: ``` public object Execute(string code, ScriptScope scope) { code = @"begin ``` \_=( “+code+@” ) rescue Exception self. **message** =$!.message.to\_clr\_string self. **backtrace** = $!.backtrace throw end"; ``` object result = null; try { LogManager.GetLogger("Ruby").Debug("\r\n" + code); result = m_engine.Execute(code, scope); } catch (Exception e) { var backtrace = ``` scope.GetVariable(“ **backtrace** ”); ``` string msg = scope.GetVariable(" __message__") ``` +“\r\n” + string.Join(“\r\n”, backtrace.Select(s =\> s.ToString()).ToArray()); ``` LogManager.GetLogger("Ruby").Error(msg); } return result; } ``` Even though it seems to work well I am absolutely not satisfied with it. Is there a better way to do this? – henon