I am attempting to configure ELMAH to filter 404 errors and I am running into difficulties with the XML-provided filter rules in my Web.config file. I followed the tutorial here and here and added an <is-type binding="BaseException" type="System.IO.FileNotFoundException" />
declaration under my <test><or>...
declaration, but that completely failed.
When I tested it locally I stuck a breakpoint in protected void ErrorLog_Filtering() {} of the Global.asax found that the System.Web.HttpException that gets fired by ASP.NET for a 404 doesn't have a base type of System.IO.FileNotFound, but rather it is simply a System.Web.HttpException.
Next I decided to try a <regex binding="BaseException.Message" pattern="The file '/[^']+' does not exist" /> in the hopes that any exception matching the pattern "The file '/foo.ext' does not exist" would get filtered, but that too having no effect. As a last resort I tried <is-type binding="BaseException" type="System.Exception" />, and even that is entirely disregarded.
I'm inclined to think there's a configuration error with ELMAH, but I fail to see any. Am I missing something blatantly obvious?
Here's the relevant stuff from my web.config:
<configuration>
<configSections>
<sectionGroup name="elmah">
<section name="security" requirePermission="false" type="Elmah.SecuritySectionHandler, Elmah"/>
<section name="errorLog" requirePermission="false" type="Elmah.ErrorLogSectionHandler, Elmah"/>
<section name="errorMail" requirePermission="false" type="Elmah.ErrorMailSectionHandler, Elmah"/>
<section name="errorFilter" requirePermission="false" type="Elmah.ErrorFilterSectionHandler, Elmah" />
</sectionGroup>
</configSections>
<elmah>
<errorFilter>
<test>
<or>
<equal binding="HttpStatusCode" value="404" type="Int32" />
<regex binding="BaseException.Message" pattern="The file '/[^']+' does not exist" />
</or>
</test>
</errorFilter>
<errorLog type="Elmah.XmlFileErrorLog, Elmah" logPath="~/App_Data/logs/elmah" />
</elmah>
<system.web>
<httpModules>
<add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah"/>
<add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah"/>
</httpModules>
</system.web>
<system.webServer>
<modules>
<add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah"/>
<add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />
</modules>
</system.webServer>
</configuration>
