Added infrastructure for message signing support to base Channel class.

1 files changed, 59 insertions, 5 deletions

diff --git a/src/DotNetOAuth/Messaging/Channel.cs b/src/DotNetOAuth/Messaging/Channel.cs
index d294816..9ade2de 100644
--- a/src/DotNetOAuth/Messaging/Channel.cs
+++ b/src/DotNetOAuth/Messaging/Channel.cs
@@ -98,6 +98,7 @@ namespace DotNetOAuth.Messaging {
 			if (message == null) {

 				throw new ArgumentNullException("message");

 			}

+			this.SignIfApplicable(message);

 

 			switch (message.Transport) {

 				case MessageTransport.Direct:

@@ -149,10 +150,12 @@ namespace DotNetOAuth.Messaging {
 		/// <summary>

 		/// Gets the protocol message that may be embedded in the given HTTP request.

 		/// </summary>

-		/// <param name="request">The request to search for an embedded message.</param>

+		/// <param name="httpRequest">The request to search for an embedded message.</param>

 		/// <returns>The deserialized message, if one is found.  Null otherwise.</returns>

-		protected internal IProtocolMessage ReadFromRequest(HttpRequestInfo request) {

-			return this.ReadFromRequestInternal(request);

+		protected internal IProtocolMessage ReadFromRequest(HttpRequestInfo httpRequest) {

+			IProtocolMessage requestMessage = this.ReadFromRequestInternal(httpRequest);

+			this.VerifySignatureIfApplicable(requestMessage);

+			return requestMessage;

 		}

 

 		/// <summary>

@@ -161,7 +164,10 @@ namespace DotNetOAuth.Messaging {
 		/// <param name="request">The message to send.</param>

 		/// <returns>The remote party's response.</returns>

 		protected internal IProtocolMessage Request(IDirectedProtocolMessage request) {

-			return this.RequestInternal(request);

+			this.SignIfApplicable(request);

+			IProtocolMessage response = this.RequestInternal(request);

+			this.VerifySignatureIfApplicable(response);

+			return response;

 		}

 

 		/// <summary>

@@ -170,7 +176,9 @@ namespace DotNetOAuth.Messaging {
 		/// <param name="responseStream">The response that is anticipated to contain an OAuth message.</param>

 		/// <returns>The deserialized message, if one is found.  Null otherwise.</returns>

 		protected internal IProtocolMessage ReadFromResponse(Stream responseStream) {

-			return this.ReadFromResponseInternal(responseStream);

+			IProtocolMessage message = this.ReadFromResponseInternal(responseStream);

+			this.VerifySignatureIfApplicable(message);

+			return message;

 		}

 

 		/// <summary>

@@ -313,6 +321,26 @@ namespace DotNetOAuth.Messaging {
 		}

 

 		/// <summary>

+		/// Signs a given message according to the rules of the channel.

+		/// </summary>

+		/// <param name="message">The message to sign.</param>

+		protected virtual void Sign(ISignedProtocolMessage message) {

+			Debug.Assert(message != null, "message == null");

+			throw new NotSupportedException(MessagingStrings.SigningNotSupported);

+		}

+

+		/// <summary>

+		/// Gets whether the signature of a signed message is valid or not

+		/// according to the rules of the channel.

+		/// </summary>

+		/// <param name="message">The message whose signature should be verified.</param>

+		/// <returns>True if the signature is valid.  False otherwise.</returns>

+		protected virtual bool IsSignatureValid(ISignedProtocolMessage message) {

+			Debug.Assert(message != null, "message == null");

+			throw new NotSupportedException(MessagingStrings.SigningNotSupported);

+		}

+

+		/// <summary>

 		/// Gets the protocol message that may be in the given HTTP response stream.

 		/// </summary>

 		/// <param name="responseStream">The response that is anticipated to contain an OAuth message.</param>

@@ -369,5 +397,31 @@ namespace DotNetOAuth.Messaging {
 			}

 			return size;

 		}

+

+		/// <summary>

+		/// Signs a given message if the message requires one.

+		/// </summary>

+		/// <param name="message">The message to sign.</param>

+		private void SignIfApplicable(IProtocolMessage message) {

+			ISignedProtocolMessage signedMessage = message as ISignedProtocolMessage;

+			if (signedMessage != null) {

+				this.Sign(signedMessage);

+			}

+		}

+

+		/// <summary>

+		/// Verifies that a given message has a valid signature if the message requires one.

+		/// </summary>

+		/// <param name="message">The message to verify the signature on.</param>

+		/// <exception cref="ProtocolException">Thrown when the signature is invalid.</exception>

+		private void VerifySignatureIfApplicable(IProtocolMessage message) {

+			ISignedProtocolMessage signedMessage = message as ISignedProtocolMessage;

+			if (signedMessage != null) {

+				if (!this.IsSignatureValid(signedMessage)) {

+					// TODO: add inResponseTo and remoteReceiver where applicable

+					throw new ProtocolException(MessagingStrings.SignatureInvalid);

+				}

+			}

+		}

 	}

 }