WebUserAgentTelemetryInitializer without unit tests

src/ApplicationInsights.AspNet/ApplicationInsightsExtensions.cs

@@ -5,8 +5,6 @@
 	using Microsoft.AspNet.Builder;
 	using Microsoft.Framework.ConfigurationModel;
 	using Microsoft.Framework.DependencyInjection;
-	using System;
-	using Microsoft.AspNet.Mvc;
 	using Microsoft.AspNet.Mvc.Rendering;
 	using Microsoft.ApplicationInsights.AspNet.DataCollection;
 	using Microsoft.ApplicationInsights.AspNet.Implementation;
@@ -37,7 +35,8 @@
 
 			services.AddSingleton<TelemetryClient>((svcs) => {
 				TelemetryConfiguration.Active.TelemetryInitializers.Add(new WebClientIpHeaderTelemetryInitializer(svcs));
-                return new TelemetryClient();
+				TelemetryConfiguration.Active.TelemetryInitializers.Add(new WebUserAgentTelemetryInitializer(svcs));
+				return new TelemetryClient();
             });
 
 			services.AddScoped<RequestTelemetry>((svcs) => {

src/ApplicationInsights.AspNet/DataCollection/WebUserAgentTelemetryInitializer.cs

@@ -0,0 +1,35 @@
+namespace Microsoft.ApplicationInsights.AspNet.DataCollection
+{
+	using System;
+	using Microsoft.ApplicationInsights.AspNet.Implementation;
+	using Microsoft.ApplicationInsights.Channel;
+	using Microsoft.ApplicationInsights.DataContracts;
+	using Microsoft.ApplicationInsights.Extensibility;
+	using Microsoft.Framework.DependencyInjection;
+
+	/// <summary>
+	/// Telemetry initializer populates user agent (telemetry.Context.User.UserAgent) for 
+	/// all telemetry data items.
+	/// </summary>
+	public class WebUserAgentTelemetryInitializer : ITelemetryInitializer
+	{
+		private IServiceProvider serviceProvider;
+
+		public WebUserAgentTelemetryInitializer(IServiceProvider serviceProvider)
+		{
+			this.serviceProvider = serviceProvider;
+		}
+
+		public void Initialize(ITelemetry telemetry)
+		{
+			var request = this.serviceProvider.GetService<RequestTelemetry>();
+			if (string.IsNullOrEmpty(request.Context.User.UserAgent))
+			{
+				var context = this.serviceProvider.GetService<HttpContextHolder>().Context;
+				var userAgent = context.Request.Headers["User-Agent"];
+				request.Context.User.UserAgent = userAgent;
+			}
+			telemetry.Context.User.UserAgent = request.Context.User.UserAgent;
+		}
+	}
+}

test/ApplicationInsights.AspNet.Tests/WebUserAgentTelemetryInitializerTests.cs

@@ -0,0 +1,15 @@
+namespace Microsoft.ApplicationInsights.AspNet.Tests
+{
+	using System;
+	using Xunit;
+
+	public class WebUserAgentTelemetryInitializerTests
+    {
+		[Fact]
+		public void WebUserAgentTelemetryInitializerReadsProperHeader()
+		{
+			//TODO: need to implement after Anastasia will create an example on how it should be implemented
+			Assert.True(true);
+		}
+	}
+}