1 files changed, 52 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.OAuth2.ClientAuthorization/OAuth2/ChannelElements/OAuth2ChannelBase.cs b/src/DotNetOpenAuth.OAuth2.ClientAuthorization/OAuth2/ChannelElements/OAuth2ChannelBase.cs
new file mode 100644
index 0000000..269d330
--- /dev/null
+++ b/src/DotNetOpenAuth.OAuth2.ClientAuthorization/OAuth2/ChannelElements/OAuth2ChannelBase.cs
@@ -0,0 +1,52 @@
+//-----------------------------------------------------------------------
+// <copyright file="OAuth2ChannelBase.cs" company="Outercurve Foundation">
+//     Copyright (c) Outercurve Foundation. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.OAuth2.ChannelElements {
+	using System;
+	using System.Collections.Generic;
+	using System.Linq;
+	using System.Text;
+
+	using DotNetOpenAuth.Messaging;
+	using DotNetOpenAuth.OAuth2.Messages;
+
+	/// <summary>
+	/// The base messaging channel used by OAuth 2.0 parties.
+	/// </summary>
+	internal abstract class OAuth2ChannelBase : StandardMessageFactoryChannel {
+		/// <summary>
+		/// The protocol versions supported by this channel.
+		/// </summary>
+		private static readonly Version[] Versions = Protocol.AllVersions.Select(v => v.Version).ToArray();
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="OAuth2ChannelBase"/> class.
+		/// </summary>
+		/// <param name="channelBindingElements">The channel binding elements.</param>
+		internal OAuth2ChannelBase(Type[] messageTypes, params IChannelBindingElement[] channelBindingElements)
+			: base(Requires.NotNull(messageTypes, "messageTypes"), Versions, channelBindingElements) {
+		}
+
+		/// <summary>
+		/// Allows preprocessing and validation of message data before an appropriate message type is
+		/// selected or deserialized.
+		/// </summary>
+		/// <param name="fields">The received message data.</param>
+		protected override void FilterReceivedFields(IDictionary<string, string> fields) {
+			base.FilterReceivedFields(fields);
+
+			// Apply the OAuth 2.0 section 2.1 requirement:
+			// Parameters sent without a value MUST be treated as if they were omitted from the request.
+			// The authorization server SHOULD ignore unrecognized request parameters.
+			var emptyKeys = from pair in fields
+							where string.IsNullOrEmpty(pair.Value)
+							select pair.Key;
+			foreach (string emptyKey in emptyKeys.ToList()) {
+				fields.Remove(emptyKey);
+			}
+		}
+	}
+}