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Diffstat (limited to 'src/DotNetOpenAuth.Core/Messaging/StandardMessageFactory.cs')
| -rw-r--r-- | src/DotNetOpenAuth.Core/Messaging/StandardMessageFactory.cs | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/src/DotNetOpenAuth.Core/Messaging/StandardMessageFactory.cs b/src/DotNetOpenAuth.Core/Messaging/StandardMessageFactory.cs new file mode 100644 index 0000000..5db206e --- /dev/null +++ b/src/DotNetOpenAuth.Core/Messaging/StandardMessageFactory.cs @@ -0,0 +1,298 @@ +//----------------------------------------------------------------------- +// <copyright file="StandardMessageFactory.cs" company="Andrew Arnott"> +// Copyright (c) Andrew Arnott. All rights reserved. +// </copyright> +//----------------------------------------------------------------------- + +namespace DotNetOpenAuth.Messaging { + using System; + using System.Collections.Generic; + using System.Diagnostics.Contracts; + using System.Linq; + using System.Reflection; + using System.Text; + using DotNetOpenAuth.Messaging.Reflection; + + /// <summary> + /// A message factory that automatically selects the message type based on the incoming data. + /// </summary> + internal class StandardMessageFactory : IMessageFactory { + /// <summary> + /// The request message types and their constructors to use for instantiating the messages. + /// </summary> + private readonly Dictionary<MessageDescription, ConstructorInfo> requestMessageTypes = new Dictionary<MessageDescription, ConstructorInfo>(); + + /// <summary> + /// The response message types and their constructors to use for instantiating the messages. + /// </summary> + /// <value> + /// The value is a dictionary, whose key is the type of the constructor's lone parameter. + /// </value> + private readonly Dictionary<MessageDescription, Dictionary<Type, ConstructorInfo>> responseMessageTypes = new Dictionary<MessageDescription, Dictionary<Type, ConstructorInfo>>(); + + /// <summary> + /// Initializes a new instance of the <see cref="StandardMessageFactory"/> class. + /// </summary> + internal StandardMessageFactory() { + } + + /// <summary> + /// Adds message types to the set that this factory can create. + /// </summary> + /// <param name="messageTypes">The message types that this factory may instantiate.</param> + public virtual void AddMessageTypes(IEnumerable<MessageDescription> messageTypes) { + Requires.NotNull(messageTypes, "messageTypes"); + Requires.True(messageTypes.All(msg => msg != null), "messageTypes"); + + var unsupportedMessageTypes = new List<MessageDescription>(0); + foreach (MessageDescription messageDescription in messageTypes) { + bool supportedMessageType = false; + + // First see whether this message fits the recognized pattern for request messages. + if (typeof(IDirectedProtocolMessage).IsAssignableFrom(messageDescription.MessageType)) { + foreach (ConstructorInfo ctor in messageDescription.Constructors) { + ParameterInfo[] parameters = ctor.GetParameters(); + if (parameters.Length == 2 && parameters[0].ParameterType == typeof(Uri) && parameters[1].ParameterType == typeof(Version)) { + supportedMessageType = true; + this.requestMessageTypes.Add(messageDescription, ctor); + break; + } + } + } + + // Also see if this message fits the recognized pattern for response messages. + if (typeof(IDirectResponseProtocolMessage).IsAssignableFrom(messageDescription.MessageType)) { + var responseCtors = new Dictionary<Type, ConstructorInfo>(messageDescription.Constructors.Length); + foreach (ConstructorInfo ctor in messageDescription.Constructors) { + ParameterInfo[] parameters = ctor.GetParameters(); + if (parameters.Length == 1 && typeof(IDirectedProtocolMessage).IsAssignableFrom(parameters[0].ParameterType)) { + responseCtors.Add(parameters[0].ParameterType, ctor); + } + } + + if (responseCtors.Count > 0) { + supportedMessageType = true; + this.responseMessageTypes.Add(messageDescription, responseCtors); + } + } + + if (!supportedMessageType) { + unsupportedMessageTypes.Add(messageDescription); + } + } + + ErrorUtilities.VerifySupported( + !unsupportedMessageTypes.Any(), + MessagingStrings.StandardMessageFactoryUnsupportedMessageType, + unsupportedMessageTypes.ToStringDeferred()); + } + + #region IMessageFactory Members + + /// <summary> + /// Analyzes an incoming request message payload to discover what kind of + /// message is embedded in it and returns the type, or null if no match is found. + /// </summary> + /// <param name="recipient">The intended or actual recipient of the request message.</param> + /// <param name="fields">The name/value pairs that make up the message payload.</param> + /// <returns> + /// A newly instantiated <see cref="IProtocolMessage"/>-derived object that this message can + /// deserialize to. Null if the request isn't recognized as a valid protocol message. + /// </returns> + public virtual IDirectedProtocolMessage GetNewRequestMessage(MessageReceivingEndpoint recipient, IDictionary<string, string> fields) { + MessageDescription matchingType = this.GetMessageDescription(recipient, fields); + if (matchingType != null) { + return this.InstantiateAsRequest(matchingType, recipient); + } else { + return null; + } + } + + /// <summary> + /// Analyzes an incoming request message payload to discover what kind of + /// message is embedded in it and returns the type, or null if no match is found. + /// </summary> + /// <param name="request">The message that was sent as a request that resulted in the response.</param> + /// <param name="fields">The name/value pairs that make up the message payload.</param> + /// <returns> + /// A newly instantiated <see cref="IProtocolMessage"/>-derived object that this message can + /// deserialize to. Null if the request isn't recognized as a valid protocol message. + /// </returns> + public virtual IDirectResponseProtocolMessage GetNewResponseMessage(IDirectedProtocolMessage request, IDictionary<string, string> fields) { + MessageDescription matchingType = this.GetMessageDescription(request, fields); + if (matchingType != null) { + return this.InstantiateAsResponse(matchingType, request); + } else { + return null; + } + } + + #endregion + + /// <summary> + /// Gets the message type that best fits the given incoming request data. + /// </summary> + /// <param name="recipient">The recipient of the incoming data. Typically not used, but included just in case.</param> + /// <param name="fields">The data of the incoming message.</param> + /// <returns> + /// The message type that matches the incoming data; or <c>null</c> if no match. + /// </returns> + /// <exception cref="ProtocolException">May be thrown if the incoming data is ambiguous.</exception> + protected virtual MessageDescription GetMessageDescription(MessageReceivingEndpoint recipient, IDictionary<string, string> fields) { + Requires.NotNull(recipient, "recipient"); + Requires.NotNull(fields, "fields"); + + var matches = this.requestMessageTypes.Keys + .Where(message => message.CheckMessagePartsPassBasicValidation(fields)) + .OrderByDescending(message => CountInCommon(message.Mapping.Keys, fields.Keys)) + .ThenByDescending(message => message.Mapping.Count) + .CacheGeneratedResults(); + var match = matches.FirstOrDefault(); + if (match != null) { + if (Logger.Messaging.IsWarnEnabled && matches.Count() > 1) { + Logger.Messaging.WarnFormat( + "Multiple message types seemed to fit the incoming data: {0}", + matches.ToStringDeferred()); + } + + return match; + } else { + // No message type matches the incoming data. + return null; + } + } + + /// <summary> + /// Gets the message type that best fits the given incoming direct response data. + /// </summary> + /// <param name="request">The request message that prompted the response data.</param> + /// <param name="fields">The data of the incoming message.</param> + /// <returns> + /// The message type that matches the incoming data; or <c>null</c> if no match. + /// </returns> + /// <exception cref="ProtocolException">May be thrown if the incoming data is ambiguous.</exception> + protected virtual MessageDescription GetMessageDescription(IDirectedProtocolMessage request, IDictionary<string, string> fields) { + Requires.NotNull(request, "request"); + Requires.NotNull(fields, "fields"); + + var matches = (from responseMessageType in this.responseMessageTypes + let message = responseMessageType.Key + where message.CheckMessagePartsPassBasicValidation(fields) + let ctors = this.FindMatchingResponseConstructors(message, request.GetType()) + where ctors.Any() + orderby GetDerivationDistance(ctors.First().GetParameters()[0].ParameterType, request.GetType()), + CountInCommon(message.Mapping.Keys, fields.Keys) descending, + message.Mapping.Count descending + select message).CacheGeneratedResults(); + var match = matches.FirstOrDefault(); + if (match != null) { + if (Logger.Messaging.IsWarnEnabled && matches.Count() > 1) { + Logger.Messaging.WarnFormat( + "Multiple message types seemed to fit the incoming data: {0}", + matches.ToStringDeferred()); + } + + return match; + } else { + // No message type matches the incoming data. + return null; + } + } + + /// <summary> + /// Instantiates the given request message type. + /// </summary> + /// <param name="messageDescription">The message description.</param> + /// <param name="recipient">The recipient.</param> + /// <returns>The instantiated message. Never null.</returns> + protected virtual IDirectedProtocolMessage InstantiateAsRequest(MessageDescription messageDescription, MessageReceivingEndpoint recipient) { + Requires.NotNull(messageDescription, "messageDescription"); + Requires.NotNull(recipient, "recipient"); + Contract.Ensures(Contract.Result<IDirectedProtocolMessage>() != null); + + ConstructorInfo ctor = this.requestMessageTypes[messageDescription]; + return (IDirectedProtocolMessage)ctor.Invoke(new object[] { recipient.Location, messageDescription.MessageVersion }); + } + + /// <summary> + /// Instantiates the given request message type. + /// </summary> + /// <param name="messageDescription">The message description.</param> + /// <param name="request">The request that resulted in this response.</param> + /// <returns>The instantiated message. Never null.</returns> + protected virtual IDirectResponseProtocolMessage InstantiateAsResponse(MessageDescription messageDescription, IDirectedProtocolMessage request) { + Requires.NotNull(messageDescription, "messageDescription"); + Requires.NotNull(request, "request"); + Contract.Ensures(Contract.Result<IDirectResponseProtocolMessage>() != null); + + Type requestType = request.GetType(); + var ctors = this.FindMatchingResponseConstructors(messageDescription, requestType); + ConstructorInfo ctor = null; + try { + ctor = ctors.Single(); + } catch (InvalidOperationException) { + if (ctors.Any()) { + ErrorUtilities.ThrowInternal("More than one matching constructor for request type " + requestType.Name + " and response type " + messageDescription.MessageType.Name); + } else { + ErrorUtilities.ThrowInternal("Unexpected request message type " + requestType.FullName + " for response type " + messageDescription.MessageType.Name); + } + } + return (IDirectResponseProtocolMessage)ctor.Invoke(new object[] { request }); + } + + /// <summary> + /// Gets the hierarchical distance between a type and a type it derives from or implements. + /// </summary> + /// <param name="assignableType">The base type or interface.</param> + /// <param name="derivedType">The concrete class that implements the <paramref name="assignableType"/>.</param> + /// <returns>The distance between the two types. 0 if the types are equivalent, 1 if the type immediately derives from or implements the base type, or progressively higher integers.</returns> + private static int GetDerivationDistance(Type assignableType, Type derivedType) { + Requires.NotNull(assignableType, "assignableType"); + Requires.NotNull(derivedType, "derivedType"); + Requires.True(assignableType.IsAssignableFrom(derivedType), "assignableType"); + + // If this is the two types are equivalent... + if (derivedType.IsAssignableFrom(assignableType)) + { + return 0; + } + + int steps; + derivedType = derivedType.BaseType; + for (steps = 1; assignableType.IsAssignableFrom(derivedType); steps++) + { + derivedType = derivedType.BaseType; + } + + return steps; + } + + /// <summary> + /// Counts how many strings are in the intersection of two collections. + /// </summary> + /// <param name="collection1">The first collection.</param> + /// <param name="collection2">The second collection.</param> + /// <param name="comparison">The string comparison method to use.</param> + /// <returns>A non-negative integer no greater than the count of elements in the smallest collection.</returns> + private static int CountInCommon(ICollection<string> collection1, ICollection<string> collection2, StringComparison comparison = StringComparison.Ordinal) { + Requires.NotNull(collection1, "collection1"); + Requires.NotNull(collection2, "collection2"); + Contract.Ensures(Contract.Result<int>() >= 0 && Contract.Result<int>() <= Math.Min(collection1.Count, collection2.Count)); + + return collection1.Count(value1 => collection2.Any(value2 => string.Equals(value1, value2, comparison))); + } + + /// <summary> + /// Finds constructors for response messages that take a given request message type. + /// </summary> + /// <param name="messageDescription">The message description.</param> + /// <param name="requestType">Type of the request message.</param> + /// <returns>A sequence of matching constructors.</returns> + private IEnumerable<ConstructorInfo> FindMatchingResponseConstructors(MessageDescription messageDescription, Type requestType) { + Requires.NotNull(messageDescription, "messageDescription"); + Requires.NotNull(requestType, "requestType"); + + return this.responseMessageTypes[messageDescription].Where(pair => pair.Key.IsAssignableFrom(requestType)).Select(pair => pair.Value); + } + } +} |