Question

我正在使用Elmah记录我的网站的异常，一切似乎一切正常，直到有一天我注意到500服务器错误未被正确捕获。我正在使用以下脚本来专门忽略ScriptResource.axd文件中的错误。

<errorFilter>
        <test>
            <or>
                <and>
                    <regex binding="FilterSourceType.Name" pattern="mail" />
                    <jscript>
                        <expression>
                            <![CDATA[
                            // @assembly mscorlib
                            // @assembly System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
                            // @import System.IO
                            // @import System.Web 
                            (Context.Request.ServerVariables["URL"].match(/ScriptResource\.axd/i) && BaseException instanceof System.FormatException)
                            ]]>
                        </expression>
                    </jscript>
                </and>
            </or>
        </test>

触发第一个错误时似乎工作正常。但是，下次触发此错误时，Elmah会停止过滤并无法发送电子邮件。我能够在本地重现这个问题，这是问题的根源：

Microsoft.JScript.JScriptException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Web.HttpServerVarsCollection.Get(String name)
   at invoker2.Invoke(Object , Object[] )
   at Microsoft.JScript.JSMethodInfo.Invoke(Object obj, BindingFlags options, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.JScript.LateBinding.CallOneOfTheMembers(MemberInfo[] members, Object[] arguments, Boolean construct, Object thisob, Binder binder, CultureInfo culture, String[] namedParameters, VsaEngine engine, Boolean& memberCalled)
   at Microsoft.JScript.LateBinding.Call(Binder binder, Object[] arguments, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters, Boolean construct, Boolean brackets, VsaEngine engine)
   at Microsoft.JScript.LateBinding.Call(Object[] arguments, Boolean construct, Boolean brackets, VsaEngine engine)
   at Microsoft.JScript.Call.Evaluate()
   --- End of inner exception stack trace ---
   at Microsoft.JScript.Block.Evaluate()
   at Microsoft.JScript.FunctionObject.CallASTFunc(Object[] args, Object thisob, ScriptObject enclosing_scope, Closure calleeClosure, Binder binder, CultureInfo culture)
   at Microsoft.JScript.FunctionObject.Call(Object[] args, Object thisob, ScriptObject enclosing_scope, Closure calleeClosure, Binder binder, CultureInfo culture)
   at Microsoft.JScript.Closure.Call(Object[] args, Object thisob, Binder binder, CultureInfo culture)
   at Microsoft.JScript.LateBinding.CallValue(Object val, Object[] arguments, Boolean construct, Boolean brackets, VsaEngine engine, Object thisob, Binder binder, CultureInfo culture, String[] namedParameters)
   at Microsoft.JScript.LateBinding.CallValue(Object thisob, Object val, Object[] arguments, Boolean construct, Boolean brackets, VsaEngine engine)
   at Elmah.Assertions.JScriptAssertion.FullTrustEvaluationStrategy.Eval(Object context) in C:\workspace\v2_psp\Elmah\src\Elmah\Assertions\JScriptAssertion.cs:line 312

我不明白的是这种情况发生的原因和原因。我还尝试了其他ServerVariables，到目前为止，我发现当第二次发生相同的异常时， HTTPS，HTTP_REFERER 将不会触发此错误。 网址，SCRIPT_NAME，PATH_INFO，PATH_TRANSLATED 将触发此错误。

思想？

Answer 1

好！在进一步挖掘之后，在使用Elmah的JScriptAssertion时，您似乎无法从ServerVariables [“XXX”]访问任何DynamicServerVariable。但是，我确实找到了一个解决方法，看起来这些DynamicServerVariable在HttpRequest对象上有公共属性映射!!

因此，在我想访问Context.Request.ServerVariables [“URL”]的情况下，我可以用Context.Request.FilePath替换代码，这是“URL”在HttpRequest中的映射方式宾语。这样，当第二次抛出异常时，JScriptAssertion不会抛出异常。

以下是DynamicServerVariable及其在HttpRequest中的属性映射。

ServerVariables     HttpRequest Property
URL                 FilePath
SCRIPT_NAME         FilePath (Same as URL)
PATH_INFO           Path
PATH_TRANSLATED     PhysicalPathInternal
QUERY_STRING        QueryStringText
AUTH_TYPE           if (_context.User != null && _context.User.Identity.IsAuthenticated) Context.User.Identity.AuthenticationType, otherwise String.empy
AUTH_USER           if (_context.User != null && _context.User.Identity.IsAuthenticated) Context.User.Identity.Name, otherwise String.empty
REMOTE_USER         if (_context.User != null && _context.User.Identity.IsAuthenticated) Context.User.Identity.Name, otherwise String.empty (Same as AUTH_USER)

访问Context.Request.ServerVariables时，Elmah抛出异常

1 个答案: