ELMAH.MVC is a useful NuGet package that provides an HTTP module to automatically log unhandled ("Yellow Screen Of Death") exceptions in your website, and provides a page (elmah.axd) to allow the exceptions to be reviewed. However, your MVC project is likely to use the built-in HandleErrorAttribute filter which, when custom errors are enabled, c…

ELMAH-1.2-db-SQLServer.sql

/*
  
   ELMAH - Error Logging Modules and Handlers for ASP.NET
   Copyright (c) 2004-9 Atif Aziz. All rights reserved.
  
    Author(s):
  
        Atif Aziz, http://www.raboof.com
        Phil Haacked, http://haacked.com
  
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
  
*/

-- ELMAH DDL script for Microsoft SQL Server 2000 or later.

-- $Id: SQLServer.sql 677 2009-09-29 18:02:39Z azizatif $

DECLARE @DBCompatibilityLevel INT
DECLARE @DBCompatibilityLevelMajor INT
DECLARE @DBCompatibilityLevelMinor INT

SELECT 
    @DBCompatibilityLevel = cmptlevel 
FROM 
    master.dbo.sysdatabases 
WHERE 
    name = DB_NAME()

IF @DBCompatibilityLevel <> 80
BEGIN

    SELECT @DBCompatibilityLevelMajor = @DBCompatibilityLevel / 10, 
           @DBCompatibilityLevelMinor = @DBCompatibilityLevel % 10
           
    PRINT N'
    ===========================================================================
    WARNING! 
    ---------------------------------------------------------------------------
    
    This script is designed for Microsoft SQL Server 2000 (8.0) but your 
    database is set up for compatibility with version ' 
    + CAST(@DBCompatibilityLevelMajor AS NVARCHAR(80)) 
    + N'.' 
    + CAST(@DBCompatibilityLevelMinor AS NVARCHAR(80)) 
    + N'. Although 
    the script should work with later versions of Microsoft SQL Server, 
    you can ensure compatibility by executing the following statement:
    
    ALTER DATABASE [' 
    + DB_NAME() 
    + N'] 
    SET COMPATIBILITY_LEVEL = 80

    If you are hosting ELMAH in the same database as your application 
    database and do not wish to change the compatibility option then you 
    should create a separate database to host ELMAH where you can set the 
    compatibility level more freely.
    
    If you continue with the current setup, please report any compatibility 
    issues you encounter over at:
    
    http://code.google.com/p/elmah/issues/list

    ===========================================================================
'
END
GO

/* ------------------------------------------------------------------------ 
        TABLES
   ------------------------------------------------------------------------ */

CREATE TABLE [dbo].[ELMAH_Error]
(
    [ErrorId]     UNIQUEIDENTIFIER NOT NULL,
    [Application] NVARCHAR(60)  COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [Host]        NVARCHAR(50)  COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [Type]        NVARCHAR(100) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [Source]      NVARCHAR(60)  COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [Message]     NVARCHAR(500) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [User]        NVARCHAR(50)  COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
    [StatusCode]  INT NOT NULL,
    [TimeUtc]     DATETIME NOT NULL,
    [Sequence]    INT IDENTITY (1, 1) NOT NULL,
    [AllXml]      NTEXT COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL 
) 
ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO

ALTER TABLE [dbo].[ELMAH_Error] WITH NOCHECK ADD 
    CONSTRAINT [PK_ELMAH_Error] PRIMARY KEY NONCLUSTERED ([ErrorId]) ON [PRIMARY] 
GO

ALTER TABLE [dbo].[ELMAH_Error] ADD 
    CONSTRAINT [DF_ELMAH_Error_ErrorId] DEFAULT (NEWID()) FOR [ErrorId]
GO

CREATE NONCLUSTERED INDEX [IX_ELMAH_Error_App_Time_Seq] ON [dbo].[ELMAH_Error] 
(
    [Application]   ASC,
    [TimeUtc]       DESC,
    [Sequence]      DESC
) 
ON [PRIMARY]
GO

/* ------------------------------------------------------------------------ 
        STORED PROCEDURES                                                      
   ------------------------------------------------------------------------ */

SET QUOTED_IDENTIFIER ON 
GO
SET ANSI_NULLS ON 
GO

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

GO
SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO

SET QUOTED_IDENTIFIER ON 
GO
SET ANSI_NULLS ON 
GO

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

    -- Get the ID of the first error for the requested page

    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

    -- Now set the row count to the requested page size and get
    -- all records below it for the pertaining application.

    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

GO
SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO

SET QUOTED_IDENTIFIER ON 
GO
SET ANSI_NULLS ON 
GO

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
        )

GO
SET QUOTED_IDENTIFIER OFF 
GO
SET ANSI_NULLS ON 
GO

ELMAHHandleErrorAttribute.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Web;
using System.Web.Mvc;
using Elmah;

namespace Web.Filters
{
    public class ELMAHHandleErrorAttribute : HandleErrorAttribute
    {
        public override void OnException(ExceptionContext context)
        {
            // Set TrySkipIisCustomErrors = true to tell IIS not to interfere
            context.HttpContext.Response.TrySkipIisCustomErrors = true;

            if (context.HttpContext.Request.IsAjaxRequest())
            {
                context.Result = new ContentResult
                {
                    Content = context.Exception.Message,
                    ContentEncoding = System.Text.Encoding.UTF8,
                    ContentType = "text/plain"
                };

                context.ExceptionHandled = true;
                context.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            }
            else
            {
                base.OnException(context);
            }

            var e = context.Exception;
            if (!context.ExceptionHandled   // if unhandled, will be logged anyhow
                || RaiseErrorSignal(e)      // prefer signaling, if possible
                || IsFiltered(context))     // filtered?
                return;

            LogException(e);
        }

        // Check that elmah.mvc.disableHandleErrorFilter = "true" in web.config otherwise the exception may be logged twice
        private static bool RaiseErrorSignal(Exception e)
        {
            var context = HttpContext.Current;
            if (context == null)
                return false;
            var signal = ErrorSignal.FromContext(context);
            if (signal == null)
                return false;
            signal.Raise(e, context);
            return true;
        }

        private static bool IsFiltered(ExceptionContext context)
        {
            var config = context.HttpContext.GetSection("elmah/errorFilter")
                         as ErrorFilterConfiguration;

            if (config == null)
                return false;

            var testContext = new ErrorFilterModule.AssertionHelperContext(
                                      context.Exception, HttpContext.Current);

            return config.Assertion.Test(testContext);
        }

        private static void LogException(Exception e)
        {
            var context = HttpContext.Current;
            ErrorLog.GetDefault(context).Log(new Error(e, context));
        }
    }
}

Global.asax.cs

// In ASP.NET 4.5 and onwards, this will be in App_Start\FilterConfig.cs
public static void RegisterGlobalFilters(GlobalFilterCollection filters)
{
    filters.Add(new ELMAHHandleErrorAttribute());
}

web.config

<?xml version="1.0" encoding="utf-8"?>
<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="errorFilter" requirePermission="false" type="Elmah.ErrorFilterSectionHandler, Elmah" />
    </sectionGroup>
  </configSections>
  <connectionStrings>
    <!-- local DB connection string -->
    <add name="Elmah.Sql" connectionString="Data Source=.;Initial Catalog=MyApplicationDB;User ID=MyUser;Password=User123" />
  </connectionStrings>
  <appSettings>
    <add key="elmah.mvc.disableHandler" value="false" />
    <!-- Set disableHandleErrorFilter to false as we want to use TORHandleErrorAttribute instead of ELMAH's own filter.
         See http://stackoverflow.com/a/14507920/589827 and https://github.com/alexanderbeletsky/elmah-mvc/blob/master/src/Elmah.Mvc/HandleErrorAttribute.cs -->
    <add key="elmah.mvc.disableHandleErrorFilter" value="true" />
    <add key="elmah.mvc.requiresAuthentication" value="true" />
    <add key="elmah.mvc.allowedRoles" value="TheDomain\Admins" />
    <add key="elmah.mvc.route" value="elmah" />
  </appSettings>
  <system.web>
    <httpHandlers>
      <add verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" />
    </httpHandlers>
    <customErrors mode="On" redirectMode="ResponseRewrite">
    </customErrors>
    <httpModules>
      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />
      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" />
    </httpModules>
  </system.web>
  <system.webServer>
    <validation validateIntegratedModeConfiguration="false" />
    <modules runAllManagedModulesForAllRequests="true">
      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" preCondition="managedHandler" />
      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" preCondition="managedHandler" />
    </modules>
    <handlers>
      <add name="Elmah" verb="POST,GET,HEAD" path="elmah.axd" preCondition="integratedMode" type="Elmah.ErrorLogPageFactory, Elmah" />
    </handlers>
  </system.webServer>
  <elmah>
    <errorLog type="Elmah.SqlErrorLog, Elmah" connectionStringName="Elmah.Sql" />
    <security allowRemoteAccess="1" />
  </elmah>
</configuration>