Exception Logging In MVC Using Elmah

What is Elmah

According to Scott Mitchell, Error Logging Modules And Handlers (ELMAH) offers another approach to log runtime errors in a production environment. ELMAH is a free, open source error logging library that includes features like error filtering and the ability to view the error log from a web page, as an RSS feed, or to download it as a comma-delimited file.

What we will achieve through Elmah

• Logging of nearly all unhandled exceptions.

• Email notification of each error at the time error occurs.

• View the error log from a web page.

• RSS feed .

Step 1: Create a MVC web Application

Open Visual Studio create new project or press CTRL +SHIFT +N. Go to Web tab, select ASP.NET Web Application template. Give name as MVCExceptionLog as in the following screenshot,
 

Step 2: Add Elmah Package from Nuget,

Right click on project solution go to Manage NuGetPackages for Solution, click on it and search elmah and install it,

 

 

Step 3: Now open web config file and add the following code inside <system.web> </system.web>,

<!--add this-->
    < httpHandlers >
    < add verb = "POST,GET,HEAD"path = "elmah.axd"type = "Elmah.ErrorLogPageFactory, Elmah" / >
    < /httpHandlers>
<!--add this-->

Also, add the following code inside <system.webServer></system.webServer>,

<!--add this-->
    < handlers >
    < add name = "Elmah"verb = "POST,GET,HEAD"path = "elmah.axd"type = "Elmah.ErrorLogPageFactory, Elmah" / >
    < /handlers>
<!--add this-->

Step 4:  Create table and Stored Procedure,

Here I am using SQL Server database to log the exception.  I have already created database SQL Server named ExceptionLog. Open SQL Server Management Studio, run the following code in ExceptionLog database one by one.

For Table

CREATE TABLE[dbo].[ELMAH_Error]
(

    [ErrorId][uniqueidentifier] NOT NULL,

    [Application][nvarchar](60) NOT NULL,

    [Host][nvarchar](50) NOT NULL,

    [Type][nvarchar](100) NOT NULL,

    [Source][nvarchar](60) NOT NULL,

    [Message][nvarchar](500) NOT NULL,

    [User][nvarchar](50) NOT NULL,

    [StatusCode][int] NOT NULL,

    [TimeUtc][datetime] NOT NULL,

    [Sequence][int] IDENTITY(1, 1) NOT NULL,

    [AllXml][ntext] NOT NULL

)

Stored procedure

1. Create PROCEDURE[dbo].[ELMAH_GetErrorsXml]
   
   (
       @Application NVARCHAR(60),
       @PageIndex INT = 0,
       @PageSize INT = 15,
       @TotalCount INT OUTPUT
   
   )
   
   AS
   
   SET NOCOUNT ON
   
   DECLARE @FirstTimeUTC DATETIME
   DECLARE @FirstSequence INT
   DECLARE @StartRow INT
   DECLARE @StartRowIndex INT
   SELECT
   
   @TotalCount = COUNT(1)
   
   FROM
   
       [ELMAH_Error]
   
   WHERE
   
       [Application] = @Application
   SET @StartRowIndex = @PageIndex * @PageSize + 1
   IF @StartRowIndex <= @TotalCount
   
   BEGIN
   
   SET ROWCOUNT @StartRowIndex
   
   SELECT
   
   @FirstTimeUTC = [TimeUtc],
   
       @FirstSequence = [Sequence]
   
   FROM
   
       [ELMAH_Error]
   
   WHERE
   
       [Application] = @Application
   
   ORDER BY
   
       [TimeUtc] DESC,
       [Sequence] DESC
   
   END
   
   ELSE
   
   BEGIN
   
   SET @PageSize = 0
   
   END
   
   SET ROWCOUNT @PageSize
   
   SELECT
   
   errorId = [ErrorId],
   
       application = [Application],
       host = [Host],
       type = [Type],
       source = [Source],
       message = [Message],
       [user] = [User],
       statusCode = [StatusCode],
       time = CONVERT(VARCHAR(50), [TimeUtc], 126) + 'Z'
   
   FROM
   
       [ELMAH_Error] error
   
   WHERE
   
       [Application] = @Application
   
   AND
   
       [TimeUtc] <= @FirstTimeUTC
   
   AND
   
       [Sequence] <= @FirstSequence
   
   ORDER BY
   
       [TimeUtc] DESC,
   
       [Sequence] DESC
   
   FOR
   
   XML AUTO

   
   

2. Create PROCEDURE[dbo].[ELMAH_GetErrorXml]
   
   (
   
       @Application NVARCHAR(60),
       @ErrorId UNIQUEIDENTIFIER
   
   )
   
   AS
   
   SET NOCOUNT ON
   SELECT
   
       [AllXml]
   FROM
   
       [ELMAH_Error]
   WHERE
   
       [ErrorId] = @ErrorId
   AND
       [Application] = @Application

   
   

3. Create PROCEDURE[dbo].[ELMAH_LogError]
   
   (
   
       @ErrorId UNIQUEIDENTIFIER,
       @Application NVARCHAR(60),
       @Host NVARCHAR(30),
       @Type NVARCHAR(100),
       @Source NVARCHAR(60),
       @Message NVARCHAR(500),
       @User NVARCHAR(50),
       @AllXml NTEXT,
       @StatusCode INT,
       @TimeUtc DATETIME
   
   )
   
   AS
   
   SET NOCOUNT ON
   
   INSERT
   
   INTO
   
       [ELMAH_Error]
   (
   
       [ErrorId],
       [Application],
       [Host],
       [Type],
       [Source],
       [Message],
       [User],
       [AllXml],
       [StatusCode],
       [TimeUtc]
   
   )
   
   VALUES
   
       (
   
       @ErrorId,
       @Application,
       @Host,
       @Type,
       @Source,
       @Message,
       @User,
       @AllXml,
       @StatusCode,
       @TimeUtc
   
   )

After creating the database table and stored procedure. The schema will look like the following:

Now again  open web config file, add the following code inside in <configuration>, 

</configuration>
<elmah>
    <!--. If allowRemoteAccess value is set to 0, then the error log web page can only be viewed locally. If allowRemoteAccess attribute is set to 1 then the error log web page is enabled for both remote and local visitors.-->
    <!--add this-->
    <security allowRemoteAccess="0" />
    <!--  DefaultConnection is the name of database connection string -->
    <errorLog type="Elmah.SqlErrorLog, Elmah" connectionStringName="DefaultConnection" />
    <!--add this-->
</elmah>

Now my final webconfig file look like the following, 

<?xml version="1.0" encoding="utf-8"?>
    <!--
For more information on how to configure your ASP.NET application, please visit
http://go.microsoft.com/fwlink/?LinkId=301880
-->
    <configuration>
        <configSections>
            <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
            <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
            <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>
        <connectionStrings>
            <add name="DefaultConnection" connectionString="Data Source=.;Initial Catalog=ExceptionLog;Integrated Security=True" providerName="System.Data.SqlClient" />
        </connectionStrings>
        <appSettings>
            <add key="webpages:Version" value="3.0.0.0" />
            <add key="webpages:Enabled" value="false" />
            <add key="ClientValidationEnabled" value="true" />
            <add key="UnobtrusiveJavaScriptEnabled" value="true" />
            <add key="elmah.mvc.disableHandler" value="false" />
            <add key="elmah.mvc.disableHandleErrorFilter" value="false" />
            <add key="elmah.mvc.requiresAuthentication" value="false" />
            <add key="elmah.mvc.IgnoreDefaultRoute" value="false" />
            <add key="elmah.mvc.allowedRoles" value="*" />
            <add key="elmah.mvc.allowedUsers" value="*" />
            <add key="elmah.mvc.route" value="elmah" />
            <add key="elmah.mvc.UserAuthCaseSensitive" value="true" />
        </appSettings>
        <system.web>
            <authentication mode="None" />
            <compilation debug="true" targetFramework="4.5.1" />
            <httpRuntime targetFramework="4.5.1" />

            <!--add this-->
            <httpHandlers>
                <add verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" />
            </httpHandlers>

            <!--add this-->
            <httpModules>
                <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />
                <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" />
                <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" />
            </httpModules>
        </system.web>
        <system.webServer>
            <!--add this-->
            <handlers>
                <add name="Elmah" verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" />
            </handlers>
            <!--add this-->
            <modules>
                <remove name="FormsAuthentication" />
                <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" preCondition="managedHandler" />
                <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" preCondition="managedHandler" />
                <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" preCondition="managedHandler" />
            </modules>
            <validation validateIntegratedModeConfiguration="false" />

        </system.webServer>
        <runtime>
            <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
                <dependentAssembly>
                    <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="Microsoft.Owin.Security.OAuth" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="Microsoft.Owin.Security.Cookies" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="Microsoft.Owin.Security" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="0.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
                    <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="0.0.0.0-5.2.2.0" newVersion="5.2.2.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />
                </dependentAssembly>
                <dependentAssembly>
                    <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
                    <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
                </dependentAssembly>
            </assemblyBinding>
        </runtime>
        <entityFramework>
            <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
                <parameters>
                    <parameter value="mssqllocaldb" />
                </parameters>
            </defaultConnectionFactory>
            <providers>
                <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
            </providers>
        </entityFramework>
        <elmah>

            <!--add this-->
            <!--. If allowRemoteAccess value is set to 0, then the error log web page can only be viewed locally. If this attribute is set to 1 then the error log web page is enabled for both remote and local visitors.-->
            <security allowRemoteAccess="0" />
            <errorLog type="Elmah.SqlErrorLog, Elmah" connectionStringName="DefaultConnection" />
            <!--add this-->
        </elmah>

    </configuration>

Step 5: Let us create some exception

1. Suppose I want to open a page that are not in our application. Let us say About2 page: localhost:55776/Home/About2
2. Create divide by zero exception in contact page

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
namespace MVCExceptionLog.Controllers
{
    public class HomeController: Controller
    {
        public ActionResult Index()
        {
            return View();
        }
        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";
            return View();
        }
        public ActionResult Contact()
        {
            int a = 0;
            int b;
            b = 1 / a;
            ViewBag.Message = "Your contact page.";
            return View();
        }
    }
}

 

Step 5: Run the application,

Click on F5 and register a user.
 

Step 6: View the Error Log from a Web Page,

You can view the error log web page through the url localhost:portno/elmah.axd like, localhost:55776/elmah.axd.
 

Check the error log in database.
 

 

Point of Interest

In this article we learned how to log Exception in SQL Server and  view error log details from web page.