ElmahLog.NetCore.Common 3.0.0

This project is licensed under the terms of the Apache License 2.0.

ElmahLog.NetCore

ELMAH for ASP.NET Core (.NET Standard 2.0 / .NET 8+)

Forked from ElmahCore/ElmahCore and republished as ElmahLog.NetCore v3.0.0 with updated dependencies, security fixes, and .NET 8/10 support.

Installation

Install the main NuGet package:

dotnet add package ElmahLog.NetCore

Optional storage providers:

Supported Frameworks

• .NET Standard 2.0 (compatible with .NET Framework 4.6.1+, .NET Core 2.0+)
• .NET 8.0 and above

Simple Usage

Program.cs (minimal hosting, .NET 6+):

builder.Services.AddElmah();  // in service registration
app.UseElmah();               // in middleware pipeline

Startup.cs (traditional):

// ConfigureServices
services.AddElmah();

// Configure - must be after UseExceptionHandler / UseDeveloperExceptionPage
app.UseElmah();

Default Elmah path: ~/elmah

Change URL Path

services.AddElmah(options => options.Path = "errors")

Restrict Access

services.AddElmah(options =>
{
    options.OnPermissionCheck = context => context.User.Identity.IsAuthenticated;
});

Note: app.UseElmah() must come after app.UseAuthentication() and app.UseAuthorization().

Change Error Log Type

Implement your own:

class MyErrorLog : ErrorLog { ... }

Built-in options:

• MemoryErrorLog — in-memory (default)
• XmlFileErrorLog — XML files on disk
• SqlErrorLog — MS SQL Server (requires ElmahLog.NetCore.Sql)
• MySqlErrorLog — MySQL (requires ElmahLog.NetCore.MySql)
• PgsqlErrorLog — PostgreSQL (requires ElmahLog.NetCore.Postgresql)

services.AddElmah<XmlFileErrorLog>(options =>
{
    options.LogPath = "~/log"; // or options.LogPath = @"C:\errors";
});

services.AddElmah<SqlErrorLog>(options =>
{
    options.ConnectionString = "connection_string";
    options.SqlServerDatabaseSchemaName = "Errors";   // default: dbo
    options.SqlServerDatabaseTableName  = "ElmahError"; // default: ELMAH_Error
});

Raise Exception Manually

public IActionResult Test()
{
    HttpContext.RaiseError(new InvalidOperationException("Test"));
    ...
}

Microsoft.Extensions.Logging Support

Since v2.0, ElmahLog.NetCore integrates with Microsoft.Extensions.Logging.

Source Preview

Since v2.0.1 — configure source file paths:

services.AddElmah(options =>
{
    options.SourcePaths = new[]
    {
        @"D:\src\MyProject",
        @"D:\src\MyProject.Mvc"
    };
});

Log the Request Body

Since v2.0.5, ElmahLog.NetCore can log the HTTP request body.

SQL Query Logging

Since v2.0.6, ElmahLog.NetCore intercepts and logs SQL commands via DiagnosticSource.

Method Parameter Logging

Since v2.0.6:

using ElmahCore;

public void TestMethod(string p1, int p2)
{
    this.LogParams((nameof(p1), p1), (nameof(p2), p2));
    // ...
}

Developer Exception Page

if (app.Environment.IsDevelopment())
{
    // app.UseDeveloperExceptionPage();
    app.UseElmahExceptionPage();
}

Notifiers

Implement IErrorNotifier or IErrorNotifierWithId and register:

services.AddElmah<XmlFileErrorLog>(options =>
{
    options.Notifiers.Add(new ErrorMailNotifier("Email", emailOptions));
});

Filters

XML-based or code-based error filtering:

services.AddElmah<XmlFileErrorLog>(options =>
{
    options.FiltersConfig = "elmah.xml";
    options.Filters.Add(new MyFilter());
});

XML filter example:

<?xml version="1.0" encoding="utf-8" ?>
<elmah>
  <errorFilter>
    <notifiers>
      <notifier name="Email"/>
    </notifiers>
    <test>
      <and>
        <greater binding="HttpStatusCode" value="399" type="Int32" />
        <lesser  binding="HttpStatusCode" value="500" type="Int32" />
      </and>
    </test>
  </errorFilter>
</elmah>

See more at elmah.github.io.

Search and Filters

Since v2.2.0 — full-text search and multi-column filtering.

Currently supported by Memory and XmlFile error logs only.

Demo Projects

License

Apache License 2.0 — Copyright 2018 ElmahCore, Portions Copyright © 2026 Lawrence Shen