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From "Johnson, Thomas" <Thomas.John...@lpsvcs.com>
Subject RE: Proposed bug fix for AspNetRequestPatternConverter.Convert()
Date Fri, 30 Mar 2012 20:51:49 GMT
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
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:george@glympse.com]
Sent: Friday, March 30, 2012 1:29 PM
To: 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 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 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 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);

            }

        }

    }
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