Re: Proposed bug fix for AspNetRequestPatternConverter.Convert()

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 <george@...> 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.Johnson@...> 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@...
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@...]

Sent: Friday, March 30, 2012 1:29 PM
To: log4net-dev@...
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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