WCF/Web Service Encoding

using System;using System.CodeDom;using System.IO;using System.Text;using System.Web.Services.Configuration;using System.Web.Services.Description;using System.Web.Services.Protocols;using System.Xml.Serialization; // The YMLAttribute allows a developer to specify that the YML SOAP// extension run on a per-method basis.  The disabled property// turns reversing the XML on and off. [AttributeUsage(AttributeTargets.Method, AllowMultiple=false)]public class YMLAttribute : SoapExtensionAttribute {  int priority = 0;  bool disabled = false;         public YMLAttribute() : this(false) {}  public YMLAttribute(bool disabled)   {     this.disabled = disabled;  }        public override Type ExtensionType   {    get { return typeof(YMLExtension); }  }  public override int Priority   {    get { return priority; }    set { priority = value; }  }  public bool Disabled   {     get { return disabled; }    set { disabled = value; }  }}public class YMLExtension : SoapExtension {  bool disabled = false;  Stream oldStream;  Stream newStream;  public override object GetInitializer(LogicalMethodInfo methodInfo,                                        SoapExtensionAttribute attribute)  {    YMLAttribute attr = attribute as YMLAttribute;    if (attr != null) return attr.Disabled;       return false;  }  public override object GetInitializer(Type serviceType)   {        return false;  }  public override void Initialize(object initializer)   {     if (initializer is Boolean) disabled = (bool)initializer;  }  public override Stream ChainStream(Stream stream)   {     if (disabled) return base.ChainStream(stream);     oldStream = stream;     newStream = new MemoryStream();     return newStream;  }  public override void ProcessMessage(SoapMessage message)   {    if (disabled) return;    switch (message.Stage)     {      case SoapMessageStage.BeforeSerialize:        Encode(message);        break;      case SoapMessageStage.AfterSerialize:        newStream.Position = 0;        Reverse(newStream, oldStream);        break;      case SoapMessageStage.BeforeDeserialize:        Decode(message);        break;      case SoapMessageStage.AfterDeserialize:        break;    }  }          void Encode(SoapMessage message)   {     message.ContentType = "text/yml";  }  void Decode(SoapMessage message)   {   if (message.ContentType != "text/yml")      throw new Exception("invalid content type:" + message.ContentType);   Reverse(oldStream, newStream);   newStream.Position = 0;   message.ContentType = "text/xml";  }  void Reverse(Stream from, Stream to)   {    TextReader reader = new StreamReader(from);    TextWriter writer = new StreamWriter(to);    string line;    while ((line = reader.ReadLine()) != null)     {      StringBuilder builder = new StringBuilder();      for (int i = line.Length - 1; i >= 0; i--)       {        builder.Append(line[i]);      }      writer.WriteLine(builder.ToString());    }    writer.Flush();  }}// The YMLReflector class is part of the YML SDFE; it is// called during the service description generation process.public class YMLReflector : SoapExtensionReflector {  public override void ReflectMethod()   {    ProtocolReflector reflector = ReflectionContext;    YMLAttribute attr = (YMLAttribute)reflector.Method.GetCustomAttribute(                        typeof(YMLAttribute));    // If the YMLAttribute has been applied to this Web service    // method, adds the XML defined in the YMLOperationBinding class.    if (attr != null)     {      YMLOperationBinding yml = new YMLOperationBinding();      yml.Reverse = !(attr.Disabled);      reflector.OperationBinding.Extensions.Add(yml);    }  }}  // The YMLImporter class is part of the YML SDFE; it is called when// a proxy class is generated for each Web service method the proxy// class communicates with.  The class checks whether the service// description contains the XML that this SDFE adds to a service// description.  If it exists, then the YMLExtension is applied to the// method in the proxy class.public class YMLImporter : SoapExtensionImporter {  public override void ImportMethod(CodeAttributeDeclarationCollection                                    metadata) {    SoapProtocolImporter importer = ImportContext;   // Checks whether the XML specified in the YMLOperationBinding is in   // the service description.   YMLOperationBinding yml = (YMLOperationBinding)       importer.OperationBinding.Extensions.Find(       typeof(YMLOperationBinding));   if (yml != null)   {     // Only applies the YMLAttribute to the method when the XML should     // be reversed.     if (yml.Reverse)     {       CodeAttributeDeclaration attr = new CodeAttributeDeclaration(            typeof(YMLAttribute).FullName);       attr.Arguments.Add(new CodeAttributeArgument(new         CodePrimitiveExpression(true)));       metadata.Add(attr);     }   } }}// The YMLOperationBinding class is part of the YML SDFE; it is the// class that is serialized into XML and placed in the service// description.[XmlFormatExtension("action", YMLOperationBinding.YMLNamespace,                    typeof(OperationBinding))][XmlFormatExtensionPrefix("yml", YMLOperationBinding.YMLNamespace)]public class YMLOperationBinding : ServiceDescriptionFormatExtension {   private Boolean reverse;   public const string YMLNamespace = "http://www.contoso.com/yml";   [XmlElement("Reverse")]   public Boolean Reverse    {     get { return reverse; }     set { reverse = value; }   }}