It sounds like he's suggesting you fix your site instead of the codebase?  If 
there's definitely a fix that needs to be in place, I would explore the 
httpContext to see if you can infer whether get_Request would throw an NRE and 
check that instead of try/catch - it's just a code smell everyone should try to 
avoid in general

From: George Chung [mailto:geo...@glympse.com]
Sent: Friday, March 30, 2012 3:50 PM
To: Log4NET Dev
Subject: Re: Proposed bug fix for AspNetRequestPatternConverter.Convert()

Yes, that is exactly the issue. Just my humble opinion, but Log4Net would only 
incur the try/catch perf penalty during user logging inside Application_Start, 
which is a very tiny percentage of the lifetime of an ASP.Net application.

The issue for log4net is that people staticly define their layout patterns that 
they want in the web.config. It's not obvious to me how they could "instruct" 
log4net to ignore the aspnet layout patterns while inside Application_Start.

I don't know any other way to test the viability of calling through 
get_Request() before the fact.

Cheers,
George
On Fri, Mar 30, 2012 at 2:30 PM, Alessandro Ghizzardi 
<box.ml...@phaseit.com<mailto:box.ml...@phaseit.com>> wrote:
Hi George,

It  seems more like an architecture problem in logging that point, instead of a 
bug. It used to work in older version, but probably you're using IIS7 in 
integrated mode and request is not available anymore.
If you really need to log in application start probably this workaround can 
help you

http://mvolo.com/blogs/serverside/archive/2007/11/10/Integrated-mode-Request-is-not-available-in-this-context-in-Application_5F00_Start.aspx

Best
Alessandro Ghizzardi
Moving...

Il giorno 30/mar/2012, alle ore 22:59, George Chung 
<geo...@glympse.com<mailto:geo...@glympse.com>> ha scritto:
The subtlety is that in Application_Startup(), httpContext is indeed not null 
and httpContext.Request is really httpContext.get_Request().

And it is the act of calling get_Request() that throws the HttpException.
On Fri, Mar 30, 2012 at 1:51 PM, Johnson, Thomas 
<thomas.john...@lpsvcs.com<mailto:thomas.john...@lpsvcs.com>> wrote:
Sorry: if (httpContext != null && httpContext.Request != null)

Since you're in c# the second statement won't be evaluated if the first is 
false and you will avoid NRE

From: Johnson, Thomas
Sent: Friday, March 30, 2012 2:50 PM
To: log4net-dev@logging.apache.org<mailto:log4net-dev@logging.apache.org>
Subject: RE: Proposed bug fix for AspNetRequestPatternConverter.Convert()


Typically you want to avoid code like this // maybe just do:  if (httpContext 
!= null) { //the entirety of your method } else 
writer.Write(SystemInfo.NotAvailableText);



            try

            {

                request = httpContext.Request;

                if (request == null)



                    requestExists = false;

            }

            catch (System.Web.HttpException)



            {

                requestExists = false;

            }


From: George Chung [mailto:geo...@glympse.com<mailto:geo...@glympse.com>]
Sent: Friday, March 30, 2012 1:29 PM
To: log4net-dev@logging.apache.org<mailto:log4net-dev@logging.apache.org>
Subject: Proposed bug fix for AspNetRequestPatternConverter.Convert()

Hello,
I'm new to this mailing list. Sorry if this is not the appropriate way to 
report a bug fix. Dereferencing HttpContext.Request will throw an exception if 
you call it in an Asp.net<http://Asp.net> application's Application_Start().

Thus, if you have log4net logging *and* you use a pattern layout format like 
%aspnet-request{REMOTE_ADDR} *and* you call Log4net inside Application_Start(), 
Log4net will throw an exception trying to log the message. The stack will look 
like this:

log4net:ERROR [RollingFileAppender] ErrorCode: GenericFailure. Failed in 
DoAppend
System.Web.HttpException (0x80004005): Request is not available in this context
   at System.Web.HttpContext.get_Request()
   at log4net.Layout.Pattern.AspNetRequestPatternConverter.Convert(TextWriter 
writer, LoggingEvent loggingEvent, HttpContext httpContext)
   at log4net.Layout.Pattern.AspNetPatternLayoutConverter.Convert(TextWriter 
writer, LoggingEvent loggingEvent)
   at log4net.Layout.Pattern.PatternLayoutConverter.Convert(TextWriter writer, 
Object state)
   at log4net.Util.PatternConverter.Format(TextWriter writer, Object state)
   at log4net.Layout.PatternLayout.Format(TextWriter writer, LoggingEvent 
loggingEvent)
   at log4net.Layout.Layout2RawLayoutAdapter.Format(LoggingEvent loggingEvent)


Here is my proposed fix:




internal sealed class AspNetRequestPatternConverter : 
AspNetPatternLayoutConverter

    {

        /// <summary>

        /// Write the ASP.Net<http://ASP.Net> Cache item to the output

        /// </summary>



        /// <param name="writer"><see cref="TextWriter" /> that will receive 
the formatted result.</param>

        /// <param name="loggingEvent">The <see cref="LoggingEvent" /> on which 
the pattern converter should be executed.</param>

        /// <param name="httpContext">The <see cref="HttpContext" /> under 
which the ASP.Net<http://ASP.Net> request is running.</param>

        /// <remarks>



        /// <para>

        /// Writes out the value of a named property. The property name

        /// should be set in the <see 
cref="log4net.Util.PatternConverter.Option"/>

        /// property.

        /// </para>

        /// </remarks>



        protected override void Convert(TextWriter writer, LoggingEvent 
loggingEvent, HttpContext httpContext)

        {

            bool requestExists = true;



            HttpRequest request = null;

            try

            {

                request = httpContext.Request;

                if (request == null)

                    requestExists = false;

            }

            catch (System.Web.HttpException)



            {

                requestExists = false;

            }





            if (requestExists)

            {

                if (Option != null)



                {

                    WriteObject(writer, loggingEvent.Repository, 
request.Params[Option]);

                }

                else

                {

                    WriteObject(writer, loggingEvent.Repository, 
request.Params);

                }

            }



            else

            {



                writer.Write(SystemInfo.NotAvailableText);

            }

        }

    }
The information contained in this message is proprietary and/or confidential. 
If you are not the intended recipient, please: (i) delete the message and all 
copies; (ii) do not disclose, distribute or use the message in any manner; and 
(iii) notify the sender immediately. In addition, please be aware that any 
message addressed to our domain is subject to archiving and review by persons 
other than the intended recipient. Thank you.


The information contained in this message is proprietary and/or confidential. 
If you are not the intended recipient, please: (i) delete the message and all 
copies; (ii) do not disclose, distribute or use the message in any manner; and 
(iii) notify the sender immediately. In addition, please be aware that any 
message addressed to our domain is subject to archiving and review by persons 
other than the intended recipient. Thank you.

Reply via email to