SoapExtension Class
The base class for SOAP extensions for XML Web services created using ASP.NET.
Assembly: System.Web.Services (in System.Web.Services.dll)
The SoapExtension type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | ChainStream | When overridden in a derived class, allows a SOAP extension access to the memory buffer containing the SOAP request or response. |
![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetInitializer(Type) | When overridden in a derived class, allows a SOAP extension to initialize data specific to a class implementing an XML Web service at a one time performance cost. |
![]() | GetInitializer(LogicalMethodInfo, SoapExtensionAttribute) | When overridden in a derived class, allows a SOAP extension to initialize data specific to an XML Web service method using an attribute applied to the XML Web service method at a one time performance cost. |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | Initialize | When overridden in a derived class, allows a SOAP extension to initialize itself using the data cached in the GetInitializer method. |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | ProcessMessage | When overridden in a derived class, allows a SOAP extension to receive a SoapMessage to process at each SoapMessageStage. |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
ASP.NET allows a SOAP-related infrastructure to be built by means of an extensibility mechanism. The ASP.NET SOAP extension architecture revolves around an extension that can inspect or modify a message at specific stages in message processing on either the client or the server.
ASP.NET SOAP extensions derive from the SoapExtension class. The GetInitializer and Initialize methods provide alternative mechanisms for initializing the SOAP extension to enhance performance. ProcessMessage is the heart of most SOAP extensions, as the method is called at each stage defined in SoapMessageStage, allowing the SOAP extension to perform the desired behavior of that specific SOAP extension. For SOAP extensions that need to modify the SOAP request or SOAP response, ChainStream provides an opportunity to receive the proposed data to be sent across the wire.
The following TraceExtension SOAP extension outputs the SOAP request and SOAP response to a specified file when applied to an XML Web service method. If the following SOAP extension is installed to run with an XML Web service, the ASPNET user account must have permission to write to the directory in which the log file is written.
#using <System.dll> #using <System.Web.Services.dll> using namespace System; using namespace System::Web::Services; using namespace System::Web::Services::Protocols; using namespace System::IO; using namespace System::Net; ref class TraceExtension; // Create a SoapExtensionAttribute for the SOAP Extension that can be // applied to an XML Web service method. [AttributeUsage(AttributeTargets::Method)] public ref class TraceExtensionAttribute: public SoapExtensionAttribute { private: String^ filename; int priority; public: TraceExtensionAttribute() : filename( "c:\\log.txt" ) {} property Type^ ExtensionType { virtual Type^ get() override { return TraceExtension::typeid; } } property int Priority { virtual int get() override { return priority; } virtual void set( int value ) override { priority = value; } } property String^ Filename { String^ get() { return filename; } void set( String^ value ) { filename = value; } } }; // Define a SOAP Extension that traces the SOAP request and SOAP // response for the XML Web service method the SOAP extension is // applied to. public ref class TraceExtension: public SoapExtension { private: Stream^ oldStream; Stream^ newStream; String^ filename; public: // Save the Stream representing the SOAP request or SOAP response into // a local memory buffer. virtual Stream^ ChainStream( Stream^ stream ) override { oldStream = stream; newStream = gcnew MemoryStream; return newStream; } // When the SOAP extension is accessed for the first time, the XML Web // service method it is applied to is accessed to store the file // name passed in, using the corresponding SoapExtensionAttribute. virtual Object^ GetInitializer( LogicalMethodInfo^ /*methodInfo*/, SoapExtensionAttribute^ attribute ) override { return (dynamic_cast<TraceExtensionAttribute^>(attribute))->Filename; } // The SOAP extension was configured to run using a configuration file // instead of an attribute applied to a specific XML Web service // method. virtual Object^ GetInitializer( Type^ WebServiceType ) override { // Return a file name to log the trace information to, based on the // type. return String::Format( "C:\\{0}.log", WebServiceType->FullName ); } // Receive the file name stored by GetInitializer and store it in a // member variable for this specific instance. virtual void Initialize( Object^ initializer ) override { filename = dynamic_cast<String^>(initializer); } // If the SoapMessageStage is such that the SoapRequest or // SoapResponse is still in the SOAP format to be sent or received, // save it out to a file. virtual void ProcessMessage( SoapMessage^ message ) override { switch ( message->Stage ) { case SoapMessageStage::BeforeSerialize: break; case SoapMessageStage::AfterSerialize: WriteOutput( message ); break; case SoapMessageStage::BeforeDeserialize: WriteInput( message ); break; case SoapMessageStage::AfterDeserialize: break; } } void WriteOutput( SoapMessage^ message ) { newStream->Position = 0; FileStream^ fs = gcnew FileStream( filename, FileMode::Append, FileAccess::Write ); StreamWriter^ w = gcnew StreamWriter( fs ); String^ soapString = ( (SoapServerMessage^)( message ) ) ? (String^)"SoapResponse" : "SoapRequest"; w->WriteLine( "-----{0} at {1}", soapString, DateTime::Now ); w->Flush(); Copy( newStream, fs ); w->Close(); newStream->Position = 0; Copy( newStream, oldStream ); } void WriteInput( SoapMessage^ message ) { Copy( oldStream, newStream ); FileStream^ fs = gcnew FileStream( filename,FileMode::Append,FileAccess::Write ); StreamWriter^ w = gcnew StreamWriter( fs ); String^ soapString = (dynamic_cast<SoapServerMessage^>(message)) ? (String^)"SoapRequest" : "SoapResponse"; w->WriteLine( "-----{0} at {1}", soapString, DateTime::Now ); w->Flush(); newStream->Position = 0; Copy( newStream, fs ); w->Close(); newStream->Position = 0; } void Copy( Stream^ from, Stream^ to ) { TextReader^ reader = gcnew StreamReader( from ); TextWriter^ writer = gcnew StreamWriter( to ); writer->WriteLine( reader->ReadToEnd() ); writer->Flush(); } };
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

