XmlFormatExtensionAttribute Class
Definition
Important
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Specifies that a service description format extension runs at one or more extension points. This class cannot be inherited.
public ref class XmlFormatExtensionAttribute sealed : Attribute[System.AttributeUsage(System.AttributeTargets.Class)]
public sealed class XmlFormatExtensionAttribute : Attribute[<System.AttributeUsage(System.AttributeTargets.Class)>]
type XmlFormatExtensionAttribute = class
inherit AttributePublic NotInheritable Class XmlFormatExtensionAttribute
Inherits Attribute- Inheritance
- Attributes
Examples
using System;
using System.Security.Permissions;
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, as it is
// called during the service description generation process.
[PermissionSet(SecurityAction.Demand, Name="FullTrust")]
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 XML Web service
// method, add 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, as it is called when a
// proxy class is generated for each XML 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.
[PermissionSet(SecurityAction.Demand, Name="FullTrust")]
public class YMLImporter : SoapExtensionImporter
{
public override void ImportMethod(
CodeAttributeDeclarationCollection metadata)
{
SoapProtocolImporter importer = ImportContext;
// Check 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 apply 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, as it is the
// class that is serialized into XML and is 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; }
}
}
Imports System.Security.Permissions
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.IO
Imports System.Text
Imports System.Web.Services.Configuration
Imports System.Web.Services.Description
Imports System.Xml.Serialization
Imports System.CodeDom
' 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
Inherits SoapExtensionAttribute
Dim _priority As Integer = 0
Dim _disabled As Boolean = False
Public Sub New()
Me.New(False)
End Sub
Public Sub New(ByVal Disabled As Boolean)
_disabled = Disabled
End Sub
Public Overrides ReadOnly Property ExtensionType() As Type
Get
Return GetType(YMLExtension)
End Get
End Property
Public Overrides Property Priority() As Integer
Get
Return _priority
End Get
Set(ByVal Value As Integer)
_priority = Value
End Set
End Property
Public Property Disabled() As Boolean
Get
Return _disabled
End Get
Set(ByVal Value As Boolean)
_disabled = Value
End Set
End Property
End Class
Public Class YMLExtension
Inherits SoapExtension
Dim _disabled As Boolean = False
Dim oldStream As Stream
Dim newStream As Stream
Public Overloads Overrides Function GetInitializer( _
ByVal methodInfo As LogicalMethodInfo, _
ByVal attribute As SoapExtensionAttribute) As Object
Dim attr As YMLAttribute = attribute
If (Not attr Is Nothing) Then
Return attr.Disabled
End If
Return False
End Function
Public Overloads Overrides Function GetInitializer( _
ByVal WebServiceType As Type) As Object
Return False
End Function
Public Overrides Sub Initialize(ByVal initializer As Object)
If (TypeOf initializer Is Boolean) Then
_disabled = CBool(initializer)
End If
End Sub
Public Overrides Function ChainStream(ByVal streamref As Stream) As Stream
If (_disabled) Then
Return CType(Me, SoapExtension).ChainStream(streamref)
End If
oldStream = streamref
newStream = New MemoryStream()
Return newStream
End Function
Public Overrides Sub ProcessMessage(ByVal message As SoapMessage)
If (_disabled) Then Return
Select Case (message.Stage)
Case SoapMessageStage.BeforeSerialize
Encode(message)
Case SoapMessageStage.AfterSerialize
newStream.Position = 0
Reverse(newStream, oldStream)
Case SoapMessageStage.BeforeDeserialize
Decode(message)
Case SoapMessageStage.AfterDeserialize
End Select
End Sub
Sub Encode(ByRef message As SoapMessage)
message.ContentType = "text/yml"
End Sub
Sub Decode(ByVal message As SoapMessage)
If (message.ContentType <> "text/yml") Then
Throw New Exception("invalid content type:" & message.ContentType)
End If
Reverse(oldStream, newStream)
newStream.Position = 0
message.ContentType = "text/xml"
End Sub
Sub Reverse(ByVal source As Stream, ByVal dest As Stream)
Dim reader As TextReader = New StreamReader(source)
Dim writer As TextWriter = New StreamWriter(dest)
Dim line As String
line = reader.ReadLine()
While (Not line Is Nothing)
writer.WriteLine(StrReverse(line))
line = reader.ReadLine()
End While
writer.Flush()
End Sub
End Class
' The YMLReflector class is part of the YML SDFE, as it is
' called during the service description generation process.
<PermissionSet(SecurityAction.Demand, Name:="FullTrust")> _
Public Class YMLReflector
Inherits SoapExtensionReflector
Public Overrides Sub ReflectMethod()
Dim reflector As ProtocolReflector = ReflectionContext
Dim attr As YMLAttribute = _
reflector.Method.GetCustomAttribute(GetType(YMLAttribute))
' If the YMLAttribute has been applied to this XML Web service
' method, add the XML defined in the YMLOperationBinding class.
If (Not attr Is Nothing) Then
Dim yml As YMLOperationBinding = New YMLOperationBinding()
yml.Reverse = Not attr.Disabled
reflector.OperationBinding.Extensions.Add(yml)
End If
End Sub
End Class
' The YMLImporter class is part of the YML SDFE, as it is called when a
' proxy class is generated for each XML 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.
<PermissionSet(SecurityAction.Demand, Name:="FullTrust")> _
Public Class YMLImporter
Inherits SoapExtensionImporter
Public Overrides Sub ImportMethod( _
ByVal metadata As CodeAttributeDeclarationCollection)
Dim importer As SoapProtocolImporter = ImportContext
' Check whether the XML specified in the YMLOperationBinding is
' in the service description.
Dim yml As YMLOperationBinding = _
importer.OperationBinding.Extensions.Find( _
GetType(YMLOperationBinding))
If (Not yml Is Nothing) Then
' Only apply the YMLAttribute to the method when the XML
' should be reversed.
If (yml.Reverse) Then
Dim attr As CodeAttributeDeclaration = _
New CodeAttributeDeclaration(GetType(YMLAttribute).FullName)
attr.Arguments.Add( _
New CodeAttributeArgument(New CodePrimitiveExpression(True)))
metadata.Add(attr)
End If
End If
End Sub
End Class
' The YMLOperationBinding class is part of the YML SDFE, as it is the
' class that is serialized into XML and is placed in the service
' description.
<XmlFormatExtension("action", YMLOperationBinding.YMLNamespace, _
GetType(OperationBinding)), _
XmlFormatExtensionPrefix("yml", YMLOperationBinding.YMLNamespace)> _
Public Class YMLOperationBinding
Inherits ServiceDescriptionFormatExtension
Private _reverse As Boolean
Public Const YMLNamespace As String = "http://www.contoso.com/yml"
<XmlElement("Reverse")> _
Public Property Reverse() As Boolean
Get
Return _reverse
End Get
Set(ByVal Value As Boolean)
_reverse = Value
End Set
End Property
End Class
Remarks
A service description format extension extends how a service description is generated for an XML Web service created using ASP.NET. Specifically, a service description format extension adds XML elements to the service description. This is useful when a SOAP extension is built to run on both the client and server side of an XML Web service, as information about SOAP extensions is not placed in the service description. If you want to add information about the SOAP extension to the service description, a client can interpret that it must run the specific SOAP extension. An example of a SOAP extension that must run on both the client and server is an encryption SOAP extension. If an encryption SOAP extension runs only on the server and it encrypts return values before sending them back to the client, the client must have the SOAP extension running to decrypt the SOAP message. Otherwise, the client cannot process the return value.
Use the following steps to build a service description format extension:
Build a class that derives from ServiceDescriptionFormatExtension.
Apply a XmlFormatExtensionAttribute to the class and specify the extension points at which the service description format extension should run.
Optionally, apply a XmlFormatExtensionPointAttribute to the class and specify a member within the class that acts as a new extension point.
Optionally, apply a XmlFormatExtensionPrefixAttribute to the class and specify the XML namespace prefix to be associated with XML elements generated by the service description format extension.
Configure the service description format extension to run within the
serviceDescriptionFormatExtensionTypessection of the configuration file.
Constructors
| XmlFormatExtensionAttribute() |
Initializes a new instance of the XmlFormatExtensionAttribute class. |
| XmlFormatExtensionAttribute(String, String, Type, Type, Type, Type) |
Initializes a new instance of the XmlFormatExtensionAttribute class that specifies the XML element and namespace to add when running at the specified extension points. |
| XmlFormatExtensionAttribute(String, String, Type, Type, Type) |
Initializes a new instance of the XmlFormatExtensionAttribute class that specifies the XML element and namespace to add when running at the specified extension points. |
| XmlFormatExtensionAttribute(String, String, Type, Type) |
Initializes a new instance of the XmlFormatExtensionAttribute class that specifies the XML element and namespace to add when running at the specified extension points. |
| XmlFormatExtensionAttribute(String, String, Type) |
Initializes a new instance of the XmlFormatExtensionAttribute class that specifies the XML element and namespace to add when running at the specified extension point. |
| XmlFormatExtensionAttribute(String, String, Type[]) |
Initializes a new instance of the XmlFormatExtensionAttribute class that specifies the XML element and namespace to add when running at the specified extension points. |
Properties
| ElementName |
Gets or sets the XML element added to the service description by the service description format extension. |
| ExtensionPoints |
The stages at which the service description format extension is to run. |
| Namespace |
Gets or sets the XML namespace for the XML element added to the service description by the service description format extension. |
| TypeId |
When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute) |
Methods
| Equals(Object) |
Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute) |
| GetHashCode() |
Returns the hash code for this instance. (Inherited from Attribute) |
| GetType() |
Gets the Type of the current instance. (Inherited from Object) |
| IsDefaultAttribute() |
When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute) |
| Match(Object) |
When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute) |
| MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
| ToString() |
Returns a string that represents the current object. (Inherited from Object) |
Explicit Interface Implementations
| _Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr) |
Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute) |
| _Attribute.GetTypeInfo(UInt32, UInt32, IntPtr) |
Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute) |
| _Attribute.GetTypeInfoCount(UInt32) |
Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute) |
| _Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr) |
Provides access to properties and methods exposed by an object. (Inherited from Attribute) |
