Replaces ResourceServer.VerifyAccess with a better pattern for error handling.

Fixes #122

2 files changed, 82 insertions, 4 deletions

diff --git a/src/DotNetOpenAuth.Core/Messaging/ProtocolException.cs b/src/DotNetOpenAuth.Core/Messaging/ProtocolException.cs
index e26d15e..982e1c0 100644
--- a/src/DotNetOpenAuth.Core/Messaging/ProtocolException.cs
+++ b/src/DotNetOpenAuth.Core/Messaging/ProtocolException.cs
@@ -42,10 +42,10 @@ namespace DotNetOpenAuth.Messaging {
 		/// such that it can be sent as a protocol message response to a remote caller.
 		/// </summary>
 		/// <param name="message">The human-readable exception message.</param>
-		/// <param name="faultedMessage">The message that was the cause of the exception.  Must not be null.</param>
-		protected internal ProtocolException(string message, IProtocolMessage faultedMessage)
-			: base(message) {
-			Requires.NotNull(faultedMessage, "faultedMessage");
+		/// <param name="faultedMessage">The message that was the cause of the exception.  May be null.</param>
+		/// <param name="innerException">The inner exception to include.</param>
+		protected internal ProtocolException(string message, IProtocolMessage faultedMessage, Exception innerException = null)
+			: base(message, innerException) {
 			this.FaultedMessage = faultedMessage;
 		}
 
diff --git a/src/DotNetOpenAuth.Core/Messaging/ProtocolFaultResponseException.cs b/src/DotNetOpenAuth.Core/Messaging/ProtocolFaultResponseException.cs
new file mode 100644
index 0000000..515414b
--- /dev/null
+++ b/src/DotNetOpenAuth.Core/Messaging/ProtocolFaultResponseException.cs
@@ -0,0 +1,78 @@
+//-----------------------------------------------------------------------
+// <copyright file="ProtocolFaultResponseException.cs" company="Andrew Arnott">
+//     Copyright (c) Andrew Arnott. All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace DotNetOpenAuth.Messaging {
+	using System;
+	using System.Collections.Generic;
+	using System.Linq;
+	using System.Text;
+
+	/// <summary>
+	/// An exception to represent errors in the local or remote implementation of the protocol
+	/// that includes the response message that should be returned to the HTTP client to comply
+	/// with the protocol specification.
+	/// </summary>
+	public class ProtocolFaultResponseException : ProtocolException {
+		/// <summary>
+		/// The channel that produced the error response message, to be used in constructing the actual HTTP response.
+		/// </summary>
+		private readonly Channel channel;
+
+		/// <summary>
+		/// A cached value for the <see cref="ErrorResponse"/> property.
+		/// </summary>
+		private OutgoingWebResponse response;
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ProtocolFaultResponseException"/> class
+		/// such that it can be sent as a protocol message response to a remote caller.
+		/// </summary>
+		/// <param name="channel">The channel to use when encoding the response message.</param>
+		/// <param name="errorResponse">The message to send back to the HTTP client.</param>
+		/// <param name="faultedMessage">The message that was the cause of the exception.  May be null.</param>
+		/// <param name="innerException">The inner exception.</param>
+		/// <param name="message">The message for the exception.</param>
+		protected internal ProtocolFaultResponseException(Channel channel, IDirectResponseProtocolMessage errorResponse, IProtocolMessage faultedMessage = null, Exception innerException = null, string message = null)
+			: base(message ?? (innerException != null ? innerException.Message : null), faultedMessage, innerException) {
+			Requires.NotNull(channel, "channel");
+			Requires.NotNull(errorResponse, "errorResponse");
+			this.channel = channel;
+			this.ErrorResponseMessage = errorResponse;
+		}
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ProtocolFaultResponseException"/> class.
+		/// </summary>
+		/// <param name="info">The <see cref="System.Runtime.Serialization.SerializationInfo"/> 
+		/// that holds the serialized object data about the exception being thrown.</param>
+		/// <param name="context">The System.Runtime.Serialization.StreamingContext 
+		/// that contains contextual information about the source or destination.</param>
+		protected ProtocolFaultResponseException(
+		  System.Runtime.Serialization.SerializationInfo info,
+		  System.Runtime.Serialization.StreamingContext context)
+			: base(info, context) {
+			throw new NotImplementedException();
+		}
+
+		/// <summary>
+		/// Gets the protocol message to send back to the client to report the error.
+		/// </summary>
+		public IDirectResponseProtocolMessage ErrorResponseMessage { get; private set; }
+
+		/// <summary>
+		/// Gets the HTTP response to forward to the client to report the error.
+		/// </summary>
+		public OutgoingWebResponse ErrorResponse {
+			get {
+				if (this.response == null) {
+					this.response = this.channel.PrepareResponse(this.ErrorResponseMessage);
+				}
+
+				return this.response;
+			}
+		}
+	}
+}