Fixes the OAuthServiceProvider sample issue with recognizing protected resource requests:

AArnott · AArnott · commit da9e554cd636 · 2013-06-09T17:56:16.000-07:00
Expected message DotNetOpenAuth.OAuth.Messages.AccessProtectedResourceRequest but received DotNetOpenAuth.OAuth.Messages.UserAuthorizationRequest instead.

The issue was that in converting a WCF message to an HttpRequestMessage, the Authorization header was truncated (sort of), but in a way we could reassemble the original message.
diff --git a/src/DotNetOpenAuth.Core/Messaging/MessagingUtilities.cs b/src/DotNetOpenAuth.Core/Messaging/MessagingUtilities.cs
@@ -1535,6 +1535,24 @@ internal static void AddExtraParameters(this MessageDictionary messageDictionary
 			}
 		}
 
+		/// <summary>
+		/// Reassembles multiple values in an HTTP request header as a comma-delimited list.
+		/// </summary>
+		/// <param name="headers">The headers from which to read a header.</param>
+		/// <param name="headerName">Name of the header to read.</param>
+		/// <returns>A comma-delimited list of values for the named header, or <c>null</c> if no header was included in the collection by the specified name.</returns>
+		internal static string GetJointValues(this System.Net.Http.Headers.HttpRequestHeaders headers, string headerName) {
+			Requires.NotNull(headers, "headers");
+			Requires.NotNullOrEmpty(headerName, "headerName");
+
+			IEnumerable<string> values;
+			if (headers.TryGetValues(headerName, out values)) {
+				return string.Join(",", values);
+			}
+
+			return null;
+		}
+
 		/// <summary>
 		/// Gets the URI that contains the entire payload that would be sent by the browser for the specified redirect-based request message.
 		/// </summary>
diff --git a/src/DotNetOpenAuth.OAuth/OAuth/ChannelElements/OAuthChannel.cs b/src/DotNetOpenAuth.OAuth/OAuth/ChannelElements/OAuthChannel.cs
@@ -120,7 +120,8 @@ protected static List<IChannelBindingElement> InitializeBindingElements(ITamperP
 		/// <returns>The deserialized message, if one is found.  Null otherwise.</returns>
 		protected override async Task<IDirectedProtocolMessage> ReadFromRequestCoreAsync(HttpRequestMessage request, CancellationToken cancellationToken) {
 			// First search the Authorization header.
-			var authorization = request.Headers.Authorization;
+			AuthenticationHeaderValue authorization;
+			AuthenticationHeaderValue.TryParse(request.Headers.GetJointValues("Authorization"), out authorization); 
 			var fields = MessagingUtilities.ParseAuthorizationHeader(Protocol.AuthorizationHeaderScheme, authorization).ToDictionary();
 			fields.Remove("realm"); // ignore the realm parameter, since we don't use it, and it must be omitted from signature base string.
 
