Logging to elmah.io from Xamarin

The Xamarin integration for elmah.io is currently in prerelease.

Integrating Xamarin with elmah.io is done by installing the Elmah.Io.Xamarin NuGet package:

Install-Package Elmah.Io.Xamarin -IncludePrerelease

dotnet add package Elmah.Io.Xamarin --prerelease

<PackageReference Include="Elmah.Io.Xamarin" Version="4.0.20-pre" />

paket add Elmah.Io.Xamarin

For each platform (Android and iOS) you will need to set up elmah.io as illustrated in the following sections. The code is the same for both Xamarin and Xamarin.Forms.

using System;
using Elmah.Io.Xamarin;

ElmahIoXamarin.Init(new ElmahIoXamarinOptions
{
    ApiKey = "API_KEY",
    LogId = new Guid("LOG_ID"),
});

using System;
using Elmah.Io.Xamarin;

ElmahIoXamarin.Init(new ElmahIoXamarinOptions
{
    ApiKey = "API_KEY",
    LogId = new Guid("LOG_ID"),
});

Log exceptions manually

Once the ElmahIoXamarin.Init method has been configured during initialization of the app, any exception can be logged manually using the Log methods available in the Elmah.Io.Xamarin namespace:

try
{
    // Code that may break
}
catch (Exception e)
{
    // Log the exception with the Log extension method:

    e.Log();

    // or use the Log method on ElmahIoXamarin:

    ElmahIoXamarin.Log(e);
}

Breadcrumbs

Breadcrumbs can be a great help when needing to figure out how a user ended up with an error. To log breadcrumbs, you can use the AddBreadcrumb method on ElmahIoXamarin. The following is a sample for Android which will log breadcrumbs on interesting events:

public class MainActivity : AppCompatActivity, BottomNavigationView.IOnNavigationItemSelectedListener
{
    public override void OnBackPressed()
    {
        ElmahIoXamarin.AddBreadcrumb("OnBackPressed", DateTime.UtcNow, action: "Navigation");
        base.OnBackPressed();
    }

    protected override void OnPause()
    {
        ElmahIoXamarin.AddBreadcrumb("OnPause", DateTime.UtcNow);
        base.OnPause();
    }

    // ...

    public bool OnNavigationItemSelected(IMenuItem item)
    {
        switch (item.ItemId)
        {
            case Resource.Id.navigation_home:
                ElmahIoXamarin.AddBreadcrumb("Navigate to Home", DateTime.UtcNow, action: "Navigation");
                textMessage.SetText(Resource.String.title_home);
                return true;
            case Resource.Id.navigation_dashboard:
                ElmahIoXamarin.AddBreadcrumb("Navigate to Dashboard", DateTime.UtcNow, action: "Navigation");
                textMessage.SetText(Resource.String.title_dashboard);
                return true;
            case Resource.Id.navigation_notifications:
                ElmahIoXamarin.AddBreadcrumb("Navigate to Notifications", DateTime.UtcNow, action: "Navigation");
                textMessage.SetText(Resource.String.title_notifications);
                return true;
        }
        return false;
    }
}

Additional configuration

Besides the mandatory properties ApiKey and LogId the ElmahIoXamarinOptions provide a range of other configuration parameters.

Application

The elmah.io integration for Xamarin will automatically use the package name for the Application field. To override this you can set the application name in settings:

ElmahIoXamarin.Init(new ElmahIoXamarinOptions
{
    // ...
    Application = "MyApp"
});

Version

The elmah.io integration for Xamarin will automatically use the package version for the Version field. To override this you can set the version string in settings:

ElmahIoXamarin.Init(new ElmahIoXamarinOptions
{
    // ...
    Version = "1.0.2"
});

Decorating all messages

All log messages logged through this integration can be decorated with the OnMessage action:

ElmahIoXamarin.Init(new ElmahIoXamarinOptions
{
    // ...
    OnMessage = msg =>
    {
        msg.Source = "Custom source";
    }
});

Filtering log messages

Log messages can be filtered directly on the device to avoid specific log messages from being sent to elmah.io with the OnFilter function:

ElmahIoXamarin.Init(new ElmahIoXamarinOptions
{
    // ...
    OnFilter = msg => msg.Title.Contains("foo")
});

This code will automatically ignore all log messages with the text foo in the title.

Handling errors

You may want to handle the scenario where the device cannot communicate with the elmah.io API. You can use the OnError action:

ElmahIoXamarin.Init(new ElmahIoXamarinOptions
{
    // ...
    OnError = (msg, ex) =>
    {
        // Do something with ex
    }
});

Legacy integration

If you prefer you can configure elmah.io manually without the use of the Elmah.Io.Xamarin package. This is not the recommended way to integrate with elmah.io from Xamarin and this approach will be discontinued.

Start by installing the Elmah.Io.Client NuGet package:

Install-Package Elmah.Io.Client

dotnet add package Elmah.Io.Client

<PackageReference Include="Elmah.Io.Client" Version="4.*" />

paket add Elmah.Io.Client

If you are targeting a single platform, you can install the package directly in the startup project. If you are targeting multiple platforms, you can either install the package in all platform-specific projects or a shared project.

Additional steps will vary from platform to platform.

protected override void OnCreate(Bundle savedInstanceState)
{
    // ...

    AndroidEnvironment.UnhandledExceptionRaiser += AndroidEnvironment_UnhandledExceptionRaiser;
    AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
    TaskScheduler.UnobservedTaskException += TaskScheduler_UnobservedTaskException;

    // ... LoadApplication(new App()); etc.
}

private void LogExceptionToElmahIo(Exception exception)
{
    if (exception == null) return;

    if (elmahIoClient == null)
    {
        elmahIoClient = ElmahioAPI.Create("API_KEY");
    }

    var packageInfo = PackageManager.GetPackageInfo(PackageName, PackageInfoFlags.MetaData);

    var baseException = exception?.GetBaseException();
    var errorMessage = baseException?.Message ?? "Unhandled exception";
    try
    {
        elmahIoClient.Messages.Create("LOG_ID", new CreateMessage
        {
            Data = exception?.ToDataList(),
            DateTime = DateTime.UtcNow,
            Detail = exception?.ToString(),
            Severity = "Error",
            Source = baseException?.Source,
            Title = errorMessage,
            Type = baseException?.GetType().FullName,
            Version = packageInfo.VersionName,
            Application = packageInfo.PackageName,
        });
    }
    catch (Exception inner)
    {
        Android.Util.Log.Error("elmahio", inner.Message);
    }

    // Log to Android Device Logging.
    Android.Util.Log.Error("crash", errorMessage);
}

private void TaskScheduler_UnobservedTaskException(object sender, UnobservedTaskExceptionEventArgs e)
{
    LogExceptionToElmahIo(e.Exception);
    e.SetObserved();
}

private void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
{
    LogExceptionToElmahIo(e.ExceptionObject as Exception);
}

private void AndroidEnvironment_UnhandledExceptionRaiser(object sender, RaiseThrowableEventArgs e)
{
    LogExceptionToElmahIo(e.Exception);
    e.Handled = true;
}

static void Main(string[] args)
{
    // ...

    AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
    TaskScheduler.UnobservedTaskException += TaskScheduler_UnobservedTaskException;
}

private static void LogExceptionToElmahIo(Exception exception)
{
    if (exception == null) return;

    if (elmahIoClient == null)
    {
        elmahIoClient = ElmahioAPI.Create("API_KEY");
    }

    var baseException = exception?.GetBaseException();
    elmahIoClient.Messages.Create("LOG_ID", new CreateMessage
    {
        Data = exception?.ToDataList(),
        DateTime = DateTime.UtcNow,
        Detail = exception?.ToString(),
        Severity = "Error",
        Source = baseException?.Source,
        Title = baseException?.Message ?? "Unhandled exception",
        Type = baseException?.GetType().FullName,
    });
}

private static void TaskScheduler_UnobservedTaskException(
    object sender, UnobservedTaskExceptionEventArgs e)
{
    LogExceptionToElmahIo(e.Exception);
    e.SetObserved();
}

private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
{
    LogExceptionToElmahIo(e.ExceptionObject as Exception);
}

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