Adds extensibility points for authenticating OAuth 2 clients at the client and authorization server ends.

Fixes #105
Related to #75

2 files changed, 53 insertions, 2 deletions

diff --git a/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ChannelElements/IOAuth2ChannelWithClient.cs b/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ChannelElements/IOAuth2ChannelWithClient.cs
new file mode 100644
index 0000000..c802be6
--- /dev/null
+++ b/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ChannelElements/IOAuth2ChannelWithClient.cs
@@ -0,0 +1,27 @@
+//-----------------------------------------------------------------------
+// <copyright file="IOAuth2ChannelWithClient.cs" company="Andrew Arnott">
+//     Copyright (c) Andrew Arnott. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.OAuth2.ChannelElements {
+	using System;
+	using System.Collections.Generic;
+	using System.Linq;
+	using System.Text;
+
+	/// <summary>
+	/// An interface that defines the OAuth2 client specific channel additions.
+	/// </summary>
+	internal interface IOAuth2ChannelWithClient {
+		/// <summary>
+		/// Gets or sets the identifier by which this client is known to the Authorization Server.
+		/// </summary>
+		string ClientIdentifier { get; set; }
+
+		/// <summary>
+		/// Gets or sets the client credentials applicator extension to use.
+		/// </summary>
+		ClientCredentialApplicator ClientCredentialApplicator { get; set; }
+	}
+}
diff --git a/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ChannelElements/OAuth2ClientChannel.cs b/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ChannelElements/OAuth2ClientChannel.cs
index 54fc110..8ad2ed9 100644
--- a/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ChannelElements/OAuth2ClientChannel.cs
+++ b/src/DotNetOpenAuth.OAuth2.Client/OAuth2/ChannelElements/OAuth2ClientChannel.cs
@@ -18,7 +18,7 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 	/// <summary>
 	/// The messaging channel used by OAuth 2.0 Clients.
 	/// </summary>
-	internal class OAuth2ClientChannel : OAuth2ChannelBase {
+	internal class OAuth2ClientChannel : OAuth2ChannelBase, IOAuth2ChannelWithClient {
 		/// <summary>
 		/// The messages receivable by this channel.
 		/// </summary>
@@ -34,10 +34,22 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 		/// <summary>
 		/// Initializes a new instance of the <see cref="OAuth2ClientChannel"/> class.
 		/// </summary>
-		internal OAuth2ClientChannel() : base(MessageTypes) {
+		internal OAuth2ClientChannel()
+			: base(MessageTypes) {
 		}
 
 		/// <summary>
+		/// Gets or sets the identifier by which this client is known to the Authorization Server.
+		/// </summary>
+		public string ClientIdentifier { get; set; }
+
+		/// <summary>
+		/// Gets or sets the tool to use to apply client credentials to authenticated requests to the Authorization Server.
+		/// </summary>
+		/// <value>May be <c>null</c> if this client has no client secret.</value>
+		public ClientCredentialApplicator ClientCredentialApplicator { get; set; }
+
+		/// <summary>
 		/// Prepares an HTTP request that carries a given message.
 		/// </summary>
 		/// <param name="request">The message to send.</param>
@@ -131,5 +143,17 @@ namespace DotNetOpenAuth.OAuth2.ChannelElements {
 			// Clients don't ever send direct responses.
 			throw new NotImplementedException();
 		}
+
+		/// <summary>
+		/// Performs additional processing on an outgoing web request before it is sent to the remote server.
+		/// </summary>
+		/// <param name="request">The request.</param>
+		protected override void PrepareHttpWebRequest(HttpWebRequest request) {
+			base.PrepareHttpWebRequest(request);
+
+			if (this.ClientCredentialApplicator != null) {
+				this.ClientCredentialApplicator.ApplyClientCredential(this.ClientIdentifier, request);
+			}
+		}
 	}
 }