Lots of design work on the channel stack.

1 files changed, 167 insertions, 0 deletions

diff --git a/src/DotNetOAuth/Messaging/MessageSerializer.cs b/src/DotNetOAuth/Messaging/MessageSerializer.cs
new file mode 100644
index 0000000..ac40232
--- /dev/null
+++ b/src/DotNetOAuth/Messaging/MessageSerializer.cs
@@ -0,0 +1,167 @@
+//-----------------------------------------------------------------------

+// <copyright file="MessageSerializer.cs" company="Andrew Arnott">

+//     Copyright (c) Andrew Arnott. All rights reserved.

+// </copyright>

+//-----------------------------------------------------------------------

+

+namespace DotNetOAuth.Messaging {

+	using System;

+	using System.Collections.Generic;

+	using System.Globalization;

+	using System.Linq;

+	using System.Runtime.Serialization;

+	using System.Xml;

+	using System.Xml.Linq;

+

+	/// <summary>

+	/// Serializes/deserializes OAuth messages for/from transit.

+	/// </summary>

+	internal class MessageSerializer {

+		/// <summary>

+		/// The serializer that will be used as a reflection engine to extract

+		/// the OAuth message properties out of their containing <see cref="IProtocolMessage"/>

+		/// objects.

+		/// </summary>

+		private readonly DataContractSerializer serializer;

+

+		/// <summary>

+		/// The specific <see cref="IProtocolMessage"/>-derived type

+		/// that will be serialized and deserialized using this class.

+		/// </summary>

+		private readonly Type messageType;

+

+		/// <summary>

+		/// An AppDomain-wide cache of shared serializers for optimization purposes.

+		/// </summary>

+		private static Dictionary<Type, MessageSerializer> prebuiltSerializers = new Dictionary<Type, MessageSerializer>();

+

+		/// <summary>

+		/// Backing field for the <see cref="RootElement"/> property

+		/// </summary>

+		private XName rootElement;

+

+		/// <summary>

+		/// Initializes a new instance of the MessageSerializer class.

+		/// </summary>

+		/// <param name="messageType">The specific <see cref="IProtocolMessage"/>-derived type

+		/// that will be serialized and deserialized using this class.</param>

+		private MessageSerializer(Type messageType) {

+			if (messageType == null) {

+				throw new ArgumentNullException("messageType");

+			}

+			if (!typeof(IProtocolMessage).IsAssignableFrom(messageType)) {

+				throw new ArgumentException(

+					string.Format(

+						CultureInfo.CurrentCulture,

+						MessagingStrings.UnexpectedType,

+						typeof(IProtocolMessage).FullName,

+						messageType.FullName),

+						"messageType");

+			}

+

+			this.messageType = messageType;

+			this.serializer = new DataContractSerializer(

+				messageType, this.RootElement.LocalName, this.RootElement.NamespaceName);

+		}

+

+		/// <summary>

+		/// Gets the XML element that is used to surround all the XML values from the dictionary.

+		/// </summary>

+		private XName RootElement {

+			get {

+				if (this.rootElement == null) {

+					DataContractAttribute attribute = this.messageType.GetCustomAttributes(typeof(DataContractAttribute), false).OfType<DataContractAttribute>().Single();

+					this.rootElement = XName.Get("root", attribute.Namespace);

+				}

+

+				return this.rootElement;

+			}

+		}

+

+		/// <summary>

+		/// Returns a message serializer from a reusable collection of serializers.

+		/// </summary>

+		/// <param name="messageType">The type of message that will be serialized/deserialized.</param>

+		/// <returns>A previously created serializer if one exists, or a newly created one.</returns>

+		internal static MessageSerializer Get(Type messageType) {

+			if (messageType == null) {

+				throw new ArgumentNullException("messageType");

+			}

+

+			// We do this as efficiently as possible by first trying to fetch the

+			// serializer out of the dictionary without taking a lock.

+			MessageSerializer serializer;

+			if (prebuiltSerializers.TryGetValue(messageType, out serializer)) {

+				return serializer;

+			}

+			

+			// Since it wasn't there, we'll be trying to write to the dictionary so

+			// we take a lock and try reading again first, then creating the serializer

+			// and storing it when we're sure it absolutely necessary.

+			lock (prebuiltSerializers) {

+				if (prebuiltSerializers.TryGetValue(messageType, out serializer)) {

+					return serializer;

+				}

+				serializer = new MessageSerializer(messageType);

+				prebuiltSerializers.Add(messageType, serializer);

+			}

+			return serializer;

+		}

+

+		/// <summary>

+		/// Reads the data from a message instance and returns a series of name=value pairs for the fields that must be included in the message.

+		/// </summary>

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

+		/// <returns>The dictionary of values to send for the message.</returns>

+		internal IDictionary<string, string> Serialize(IProtocolMessage message) {

+			if (message == null) {

+				throw new ArgumentNullException("message");

+			}

+

+			var fields = new Dictionary<string, string>(StringComparer.Ordinal);

+			this.Serialize(fields, message);

+			return fields;

+		}

+

+		/// <summary>

+		/// Saves the [DataMember] properties of a message to an existing dictionary.

+		/// </summary>

+		/// <param name="fields">The dictionary to save values to.</param>

+		/// <param name="message">The message to pull values from.</param>

+		internal void Serialize(IDictionary<string, string> fields, IProtocolMessage message) {

+			if (fields == null) {

+				throw new ArgumentNullException("fields");

+			}

+			if (message == null) {

+				throw new ArgumentNullException("message");

+			}

+

+			message.EnsureValidMessage();

+			using (XmlWriter writer = DictionaryXmlWriter.Create(fields)) {

+				this.serializer.WriteObjectContent(writer, message);

+			}

+		}

+

+		/// <summary>

+		/// Reads name=value pairs into an OAuth message.

+		/// </summary>

+		/// <param name="fields">The name=value pairs that were read in from the transport.</param>

+		/// <returns>The instantiated and initialized <see cref="IProtocolMessage"/> instance.</returns>

+		internal IProtocolMessage Deserialize(IDictionary<string, string> fields) {

+			if (fields == null) {

+				throw new ArgumentNullException("fields");

+			}

+

+			var reader = DictionaryXmlReader.Create(this.RootElement, fields);

+			IProtocolMessage result;

+			try {

+				result = (IProtocolMessage)this.serializer.ReadObject(reader, false);

+			} catch (SerializationException ex) {

+				// Missing required fields is one cause of this exception.

+				throw new ProtocolException(Strings.InvalidIncomingMessage, ex);

+			}

+			result.EnsureValidMessage();

+			return result;

+		}

+	}

+}