1 files changed, 23 insertions, 9 deletions

diff --git a/src/DotNetOpenAuth.Core/Util.cs b/src/DotNetOpenAuth.Core/Util.cs
index 279b7d3..ff91df1 100644
--- a/src/DotNetOpenAuth.Core/Util.cs
+++ b/src/DotNetOpenAuth.Core/Util.cs
@@ -8,11 +8,11 @@ namespace DotNetOpenAuth {
 	using System.Collections.Generic;
 	using System.Globalization;
 	using System.Net;
+	using System.Net.Http.Headers;
 	using System.Reflection;
 	using System.Text;
 	using System.Web;
 	using System.Web.UI;
-
 	using DotNetOpenAuth.Configuration;
 	using DotNetOpenAuth.Messaging;
 	using DotNetOpenAuth.Messaging.Reflection;
@@ -32,20 +32,34 @@ namespace DotNetOpenAuth {
 		/// </summary>
 		private static IEmbeddedResourceRetrieval embeddedResourceRetrieval = MessagingElement.Configuration.EmbeddedResourceRetrievalProvider.CreateInstance(null, false, null);
 
+		private static readonly Lazy<string> libraryVersionLazy = new Lazy<string>(delegate {
+			var assembly = Assembly.GetExecutingAssembly();
+			string assemblyFullName = assembly.FullName;
+			bool official = assemblyFullName.Contains("PublicKeyToken=2780ccd10d57b246");
+			assemblyFullName = assemblyFullName.Replace(assembly.GetName().Version.ToString(), AssemblyFileVersion);
+
+			// We use InvariantCulture since this is used for logging.
+			return string.Format(CultureInfo.InvariantCulture, "{0} ({1})", assemblyFullName, official ? "official" : "private");
+		});
+
+		private static readonly Lazy<ProductInfoHeaderValue> libraryVersionHeaderLazy = new Lazy<ProductInfoHeaderValue>(delegate {
+			var assemblyName = Assembly.GetExecutingAssembly().GetName();
+			return new ProductInfoHeaderValue(assemblyName.Name, AssemblyFileVersion);
+		});
+
 		/// <summary>
 		/// Gets a human-readable description of the library name and version, including
 		/// whether the build is an official or private one.
 		/// </summary>
 		internal static string LibraryVersion {
-			get {
-				var assembly = Assembly.GetExecutingAssembly();
-				string assemblyFullName = assembly.FullName;
-				bool official = assemblyFullName.Contains("PublicKeyToken=2780ccd10d57b246");
-				assemblyFullName = assemblyFullName.Replace(assembly.GetName().Version.ToString(), AssemblyFileVersion);
+			get { return libraryVersionLazy.Value; }
+		}
 
-				// We use InvariantCulture since this is used for logging.
-				return string.Format(CultureInfo.InvariantCulture, "{0} ({1})", assemblyFullName, official ? "official" : "private");
-			}
+		/// <summary>
+		/// Gets an HTTP header that can be included in outbound requests.
+		/// </summary>
+		internal static ProductInfoHeaderValue LibraryVersionHeader {
+			get { return libraryVersionHeaderLazy.Value; }
 		}
 
 		/// <summary>