XmlDsigXPathTransform Classe
Definição
Importante
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Representa a transformação de XPath para uma assinatura digital, conforme definida pelo W3C.
public ref class XmlDsigXPathTransform : System::Security::Cryptography::Xml::Transformpublic class XmlDsigXPathTransform : System.Security.Cryptography.Xml.Transformtype XmlDsigXPathTransform = class
inherit TransformPublic Class XmlDsigXPathTransform
Inherits Transform- Herança
Exemplos
Esta seção contém dois exemplos de código. O primeiro exemplo de código mostra como assinar e verificar um documento XML usando a XmlDsigXPathTransform classe com uma assinatura de envelope. Este exemplo assina um documento XML e salva a assinatura em um novo documento XML. O segundo exemplo de código demonstra como chamar membros da XmlDsigXPathTransform classe .
Exemplo nº 1
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
#using <System.Xml.dll>
#using <System.Security.dll>
#using <System.dll>
using namespace System;
using namespace System::Security::Cryptography;
using namespace System::Security::Cryptography::X509Certificates;
using namespace System::Security::Cryptography::Xml;
using namespace System::Text;
using namespace System::Xml;
// Create the XML that represents the transform.
static XmlDsigXPathTransform^ CreateXPathTransform( String^ XPathString )
{
// Create a new XMLDocument object.
XmlDocument^ doc = gcnew XmlDocument;
// Create a new XmlElement.
XmlElement^ xPathElem = doc->CreateElement( L"XPath" );
// Set the element text to the value
// of the XPath string.
xPathElem->InnerText = XPathString;
// Create a new XmlDsigXPathTransform object.
XmlDsigXPathTransform^ xForm = gcnew XmlDsigXPathTransform;
// Load the XPath XML from the element.
xForm->LoadInnerXml( xPathElem->SelectNodes( L"." ) );
// Return the XML that represents the transform.
return xForm;
}
// Sign an XML file and save the signature in a new file.
static void SignXmlFile( String^ FileName, String^ SignedFileName, RSA^ Key, String^ XPathString )
{
// Create a new XML document.
XmlDocument^ doc = gcnew XmlDocument;
// Format the document to ignore white spaces.
doc->PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc->Load( gcnew XmlTextReader( FileName ) );
// Create a SignedXml object.
SignedXml^ signedXml = gcnew SignedXml( doc );
// Add the key to the SignedXml document.
signedXml->SigningKey = Key;
// Create a reference to be signed.
Reference^ reference = gcnew Reference;
reference->Uri = L"";
// Create an XmlDsigXPathTransform object using
// the helper method 'CreateXPathTransform' defined
// later in this sample.
XmlDsigXPathTransform^ XPathTransform = CreateXPathTransform( XPathString );
// Add the transform to the reference.
reference->AddTransform( XPathTransform );
// Add the reference to the SignedXml object.
signedXml->AddReference( reference );
// Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
KeyInfo^ keyInfo = gcnew KeyInfo;
keyInfo->AddClause( gcnew RSAKeyValue( dynamic_cast<RSA^>(Key) ) );
signedXml->KeyInfo = keyInfo;
// Compute the signature.
signedXml->ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement^ xmlDigitalSignature = signedXml->GetXml();
// Append the element to the XML document.
doc->DocumentElement->AppendChild( doc->ImportNode( xmlDigitalSignature, true ) );
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( SignedFileName,gcnew UTF8Encoding( false ) );
doc->WriteTo( xmltw );
xmltw->Close();
}
// Verify the signature of an XML file and return the result.
static Boolean VerifyXmlFile( String^ Name )
{
// Create a new XML document.
XmlDocument^ xmlDocument = gcnew XmlDocument;
// Format using white spaces.
xmlDocument->PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument->Load( Name );
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml^ signedXml = gcnew SignedXml( xmlDocument );
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList^ nodeList = xmlDocument->GetElementsByTagName( L"Signature" );
// Load the signature node.
signedXml->LoadXml( dynamic_cast<XmlElement^>(nodeList->Item( 0 )) );
// Check the signature and return the result.
return signedXml->CheckSignature();
}
// Create example data to sign.
static void CreateSomeXml( String^ FileName )
{
// Create a new XmlDocument object.
XmlDocument^ document = gcnew XmlDocument;
// Create a new XmlNode object.
XmlNode^ node = document->CreateNode( XmlNodeType::Element, L"", L"MyXML", L"Don't_Sign" );
// Append the node to the document.
document->AppendChild( node );
// Create a new XmlNode object.
XmlNode^ subnode = document->CreateNode( XmlNodeType::Element, L"", L"TempElement", L"Sign" );
// Add some text to the node.
subnode->InnerText = L"Here is some data to sign.";
// Append the node to the document.
document->DocumentElement->AppendChild( subnode );
// Save the XML document to the file name specified.
XmlTextWriter^ xmltw = gcnew XmlTextWriter( FileName,gcnew UTF8Encoding( false ) );
document->WriteTo( xmltw );
xmltw->Close();
}
int main()
{
// Generate a signing key.
RSA^ Key = RSA::Create();
try
{
// Create an XML file to sign.
CreateSomeXml( L"Example.xml" );
Console::WriteLine( L"New XML file created." );
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile( L"Example.xml", L"SignedExample.xml", Key, L"ancestor-or-self::TempElement" );
Console::WriteLine( L"XML file signed." );
// Verify the signature of the signed XML.
Console::WriteLine( L"Verifying signature..." );
bool result = VerifyXmlFile( L"SignedExample.xml" );
// Display the results of the signature verification to \
// the console.
if ( result )
{
Console::WriteLine( L"The XML signature is valid." );
}
else
{
Console::WriteLine( L"The XML signature is not valid." );
}
}
catch ( CryptographicException^ e )
{
Console::WriteLine( e->Message );
}
finally
{
Key->Clear();
}
return 1;
}
//
// This example signs an XML file using an
// envelope signature. It then verifies the
// signed XML.
//
using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Security.Cryptography.Xml;
using System.Text;
using System.Xml;
public class SignVerifyEnvelope
{
public static void Main(String[] args)
{
// Generate a signing key.
RSA Key = RSA.Create();
try
{
// Create an XML file to sign.
CreateSomeXml("Example.xml");
Console.WriteLine("New XML file created.");
// Sign the XML that was just created and save it in a
// new file.
SignXmlFile("Example.xml", "SignedExample.xml", Key, "ancestor-or-self::TempElement");
Console.WriteLine("XML file signed.");
// Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...");
bool result = VerifyXmlFile("SignedExample.xml");
// Display the results of the signature verification to \
// the console.
if (result)
{
Console.WriteLine("The XML signature is valid.");
}
else
{
Console.WriteLine("The XML signature is not valid.");
}
}
catch (CryptographicException e)
{
Console.WriteLine(e.Message);
}
finally
{
Key.Clear();
}
}
// Sign an XML file and save the signature in a new file.
public static void SignXmlFile(string FileName, string SignedFileName, RSA Key, string XPathString)
{
// Create a new XML document.
XmlDocument doc = new XmlDocument();
// Format the document to ignore white spaces.
doc.PreserveWhitespace = false;
// Load the passed XML file using it's name.
doc.Load(new XmlTextReader(FileName));
// Create a SignedXml object.
SignedXml signedXml = new SignedXml(doc);
// Add the key to the SignedXml document.
signedXml.SigningKey = Key;
// Create a reference to be signed.
Reference reference = new Reference();
reference.Uri = "";
// Create an XmlDsigXPathTransform object using
// the helper method 'CreateXPathTransform' defined
// later in this sample.
XmlDsigXPathTransform XPathTransform = CreateXPathTransform(XPathString);
// Add the transform to the reference.
reference.AddTransform(XPathTransform);
// Add the reference to the SignedXml object.
signedXml.AddReference(reference);
// Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
KeyInfo keyInfo = new KeyInfo();
keyInfo.AddClause(new RSAKeyValue((RSA)Key));
signedXml.KeyInfo = keyInfo;
// Compute the signature.
signedXml.ComputeSignature();
// Get the XML representation of the signature and save
// it to an XmlElement object.
XmlElement xmlDigitalSignature = signedXml.GetXml();
// Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, true));
// Save the signed XML document to a file specified
// using the passed string.
XmlTextWriter xmltw = new XmlTextWriter(SignedFileName, new UTF8Encoding(false));
doc.WriteTo(xmltw);
xmltw.Close();
}
// Verify the signature of an XML file and return the result.
public static Boolean VerifyXmlFile(String Name)
{
// Create a new XML document.
XmlDocument xmlDocument = new XmlDocument();
// Format using white spaces.
xmlDocument.PreserveWhitespace = true;
// Load the passed XML file into the document.
xmlDocument.Load(Name);
// Create a new SignedXml object and pass it
// the XML document class.
SignedXml signedXml = new SignedXml(xmlDocument);
// Find the "Signature" node and create a new
// XmlNodeList object.
XmlNodeList nodeList = xmlDocument.GetElementsByTagName("Signature");
// Load the signature node.
signedXml.LoadXml((XmlElement)nodeList[0]);
// Check the signature and return the result.
return signedXml.CheckSignature();
}
// Create the XML that represents the transform.
private static XmlDsigXPathTransform CreateXPathTransform(string XPathString)
{
// Create a new XMLDocument object.
XmlDocument doc = new XmlDocument();
// Create a new XmlElement.
XmlElement xPathElem = doc.CreateElement("XPath");
// Set the element text to the value
// of the XPath string.
xPathElem.InnerText = XPathString;
// Create a new XmlDsigXPathTransform object.
XmlDsigXPathTransform xForm = new XmlDsigXPathTransform();
// Load the XPath XML from the element.
xForm.LoadInnerXml(xPathElem.SelectNodes("."));
// Return the XML that represents the transform.
return xForm;
}
// Create example data to sign.
public static void CreateSomeXml(string FileName)
{
// Create a new XmlDocument object.
XmlDocument document = new XmlDocument();
// Create a new XmlNode object.
XmlNode node = document.CreateNode(XmlNodeType.Element, "", "MyXML", "Don't_Sign");
// Append the node to the document.
document.AppendChild(node);
// Create a new XmlNode object.
XmlNode subnode = document.CreateNode(XmlNodeType.Element, "", "TempElement", "Sign");
// Add some text to the node.
subnode.InnerText = "Here is some data to sign.";
// Append the node to the document.
document.DocumentElement.AppendChild(subnode);
// Save the XML document to the file name specified.
XmlTextWriter xmltw = new XmlTextWriter(FileName, new UTF8Encoding(false));
document.WriteTo(xmltw);
xmltw.Close();
}
}
'
' This example signs an XML file using an
' envelope signature. It then verifies the
' signed XML.
'
Imports System.Security.Cryptography
Imports System.Security.Cryptography.X509Certificates
Imports System.Security.Cryptography.Xml
Imports System.Text
Imports System.Xml
Module SignVerifyEnvelope
Sub Main(ByVal args() As String)
' Generate a signing key.
Dim Key As RSA = RSA.Create()
Try
' Create an XML file to sign.
CreateSomeXml("Example.xml")
Console.WriteLine("New XML file created.")
' Sign the XML that was just created and save it in a
' new file.
SignXmlFile("Example.xml", "SignedExample.xml", Key, "ancestor-or-self::TempElement")
Console.WriteLine("XML file signed.")
' Verify the signature of the signed XML.
Console.WriteLine("Verifying signature...")
Dim result As Boolean = VerifyXmlFile("SignedExample.xml")
' Display the results of the signature verification to \
' the console.
If result Then
Console.WriteLine("The XML signature is valid.")
Else
Console.WriteLine("The XML signature is not valid.")
End If
Catch e As CryptographicException
Console.WriteLine(e.Message)
Finally
Key.Clear()
End Try
End Sub
' Sign an XML file and save the signature in a new file.
Sub SignXmlFile(ByVal FileName As String, ByVal SignedFileName As String, ByVal Key As RSA, ByVal XPathString As String)
' Create a new XML document.
Dim doc As New XmlDocument()
' Format the document to ignore white spaces.
doc.PreserveWhitespace = False
' Load the passed XML file using it's name.
doc.Load(New XmlTextReader(FileName))
' Create a SignedXml object.
Dim signedXml As New SignedXml(doc)
' Add the key to the SignedXml document.
signedXml.SigningKey = Key
' Create a reference to be signed.
Dim reference As New Reference()
reference.Uri = ""
' Create an XmlDsigXPathTransform object using
' the helper method 'CreateXPathTransform' defined
' later in this sample.
Dim XPathTransform As XmlDsigXPathTransform = CreateXPathTransform(XPathString)
' Add the transform to the reference.
reference.AddTransform(XPathTransform)
' Add the reference to the SignedXml object.
signedXml.AddReference(reference)
' Add an RSAKeyValue KeyInfo (optional; helps recipient find key to validate).
Dim keyInfo As New KeyInfo()
keyInfo.AddClause(New RSAKeyValue(CType(Key, RSA)))
signedXml.KeyInfo = keyInfo
' Compute the signature.
signedXml.ComputeSignature()
' Get the XML representation of the signature and save
' it to an XmlElement object.
Dim xmlDigitalSignature As XmlElement = signedXml.GetXml()
' Append the element to the XML document.
doc.DocumentElement.AppendChild(doc.ImportNode(xmlDigitalSignature, True))
' Save the signed XML document to a file specified
' using the passed string.
Dim xmltw As New XmlTextWriter(SignedFileName, New UTF8Encoding(False))
doc.WriteTo(xmltw)
xmltw.Close()
End Sub
' Verify the signature of an XML file and return the result.
Function VerifyXmlFile(ByVal Name As String) As [Boolean]
' Create a new XML document.
Dim xmlDocument As New XmlDocument()
' Format using white spaces.
xmlDocument.PreserveWhitespace = True
' Load the passed XML file into the document.
xmlDocument.Load(Name)
' Create a new SignedXml object and pass it
' the XML document class.
Dim signedXml As New SignedXml(xmlDocument)
' Find the "Signature" node and create a new
' XmlNodeList object.
Dim nodeList As XmlNodeList = xmlDocument.GetElementsByTagName("Signature")
' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), XmlElement))
' Check the signature and return the result.
Return signedXml.CheckSignature()
End Function
' Create the XML that represents the transform.
Function CreateXPathTransform(ByVal XPathString As String) As XmlDsigXPathTransform
' Create a new XMLDocument object.
Dim doc As New XmlDocument()
' Create a new XmlElement.
Dim xPathElem As XmlElement = doc.CreateElement("XPath")
' Set the element text to the value
' of the XPath string.
xPathElem.InnerText = XPathString
' Create a new XmlDsigXPathTransform object.
Dim xForm As New XmlDsigXPathTransform()
' Load the XPath XML from the element.
xForm.LoadInnerXml(xPathElem.SelectNodes("."))
' Return the XML that represents the transform.
Return xForm
End Function
' Create example data to sign.
Sub CreateSomeXml(ByVal FileName As String)
' Create a new XmlDocument object.
Dim document As New XmlDocument()
' Create a new XmlNode object.
Dim node As XmlNode = document.CreateNode(XmlNodeType.Element, "", "MyXML", "Don't_Sign")
' Append the node to the document.
document.AppendChild(node)
' Create a new XmlNode object.
Dim subnode As XmlNode = document.CreateNode(XmlNodeType.Element, "", "TempElement", "Sign")
' Add some text to the node.
subnode.InnerText = "Here is some data to sign."
' Append the node to the document.
document.DocumentElement.AppendChild(subnode)
' Save the XML document to the file name specified.
Dim xmltw As New XmlTextWriter(FileName, New UTF8Encoding(False))
document.WriteTo(xmltw)
xmltw.Close()
End Sub
End Module
Exemplo nº 2
using System;
using System.IO;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Cryptography.Xml;
class Class1
{
[STAThread]
static void Main(string[] args)
{
// Encrypt a sample XML string.
XmlDocument productsXml = LoadProducts();
ShowTransformProperties(productsXml);
// Encrypt an XPath Xml string.
XmlDocument transformXml = LoadTransformByXml();
ShowTransformProperties(transformXml);
// Use XmlDsigXPathTransform to resolve a Uri.
Uri baseUri = new Uri("http://www.contoso.com");
string relativeUri = "xml";
Uri absoluteUri = ResolveUris(baseUri, relativeUri);
Console.WriteLine("This sample completed successfully; " +
"press Enter to exit.");
Console.ReadLine();
}
// Encrypt the text in the specified XmlDocument.
private static void ShowTransformProperties(XmlDocument xmlDoc)
{
// Create a new XMLDocument object.
XmlDocument doc = new XmlDocument();
// Create a new XmlElement.
XmlElement xPathElem = doc.CreateElement("XPath");
// Set the element text to the value
// of the XPath string.
xPathElem.InnerText = "ancestor-or-self::PRODUCTS";
// Create a new XmlDsigXPathTransform object.
XmlDsigXPathTransform xmlTransform = new XmlDsigXPathTransform();
// Load the XPath XML from the element.
xmlTransform.LoadInnerXml(xPathElem.SelectNodes("."));
// Ensure the transform is using the proper algorithm.
xmlTransform.Algorithm =
SignedXml.XmlDsigXPathTransformUrl;
// Retrieve the XML representation of the current transform.
XmlElement xmlInTransform = xmlTransform.GetXml();
Console.WriteLine("\nXml representation of the current transform: ");
Console.WriteLine(xmlInTransform.OuterXml);
// Retrieve the valid input types for the current transform.
Type[] validInTypes = xmlTransform.InputTypes;
// Verify the xmlTransform can accept the XMLDocument as an
// input type.
for (int i = 0; i < validInTypes.Length; i++)
{
if (validInTypes[i] == xmlDoc.GetType())
{
// Load the document into the transfrom.
xmlTransform.LoadInput(xmlDoc);
try
{
// This transform is created for demonstration purposes.
XmlDsigXPathTransform secondTransform =
new XmlDsigXPathTransform();
string classDescription = secondTransform.ToString();
xmlTransform.LoadInnerXml(xPathElem.SelectNodes(".")); ;
}
catch (CryptographicException)
{
Console.WriteLine("Caught exception while trying to " +
"load the specified Xml document. The document " +
"requires an XPath element to be valid.");
}
break;
}
}
Type[] validOutTypes = xmlTransform.OutputTypes;
for (int i = validOutTypes.Length - 1; i >= 0; i--)
{
if (validOutTypes[i] == typeof(System.Xml.XmlDocument))
{
try
{
Type xmlDocumentType = typeof(System.Xml.XmlDocument);
XmlDocument xmlDocumentOutput = (XmlDocument)
xmlTransform.GetOutput(xmlDocumentType);
// Display to the console the Xml before and after
// encryption.
Console.WriteLine("Result of the GetOutput method call" +
" from the current transform: " +
xmlDocumentOutput.OuterXml);
}
catch (Exception ex)
{
Console.WriteLine("Unexpected exception caught: " +
ex.ToString());
}
break;
}
else if (validOutTypes[i] == typeof(System.Xml.XmlNodeList))
{
try
{
Type xmlNodeListType = typeof(System.Xml.XmlNodeList);
XmlNodeList xmlNodes = (XmlNodeList)
xmlTransform.GetOutput(xmlNodeListType);
// Display to the console the Xml before and after
// encryption.
Console.WriteLine("Encoding the following message: " +
xmlDoc.InnerText);
Console.WriteLine("Nodes of the XmlNodeList retrieved " +
"from GetOutput:");
for (int j = 0; j < xmlNodes.Count; j++)
{
Console.WriteLine("Node " + j +
" has the following name: " +
xmlNodes.Item(j).Name +
" and the following InnerXml: " +
xmlNodes.Item(j).InnerXml);
}
}
catch (Exception ex)
{
Console.WriteLine("Unexpected exception caught: " +
ex.ToString());
}
break;
}
else
{
object outputObject = xmlTransform.GetOutput();
}
}
}
// Create an XML document for the dsig namespace.
private static XmlDocument LoadTransformByXml()
{
XmlDocument xmlDoc = new XmlDocument();
string transformXml = "<Signature><Reference URI=''><Transforms>";
transformXml += "<Transform><XPath ";
transformXml += "xmlns:dsig='http://www.w3.org/2000/09/xmldsig#'>";
transformXml += "not(ancestor-or-self::dsig:Signature)";
transformXml += "</XPath></Transform>";
transformXml += "</Transforms></Reference></Signature>";
xmlDoc.LoadXml(transformXml);
return xmlDoc;
}
// Create an XML document describing various products.
private static XmlDocument LoadProducts()
{
XmlDocument xmlDoc = new XmlDocument();
string contosoProducts = "<PRODUCTS>";
contosoProducts += "<PRODUCT><ID>123</ID>";
contosoProducts += "<DESCRIPTION>Router</DESCRIPTION></PRODUCT>";
contosoProducts += "<PRODUCT><ID>456</ID>";
contosoProducts += "<DESCRIPTION>Keyboard</DESCRIPTION></PRODUCT>";
contosoProducts += "<PRODUCT><ID>789</ID>";
contosoProducts += "<DESCRIPTION>Monitor</DESCRIPTION></PRODUCT>";
contosoProducts += "</PRODUCTS>";
xmlDoc.LoadXml(contosoProducts);
return xmlDoc;
}
// Resolve the specified base and relative Uri's .
private static Uri ResolveUris(Uri baseUri, string relativeUri)
{
XmlUrlResolver xmlResolver = new XmlUrlResolver();
xmlResolver.Credentials =
System.Net.CredentialCache.DefaultCredentials;
XmlDsigXPathTransform xmlTransform =
new XmlDsigXPathTransform();
xmlTransform.Resolver = xmlResolver;
Uri absoluteUri = xmlResolver.ResolveUri(baseUri, relativeUri);
if (absoluteUri != null)
{
Console.WriteLine(
"\nResolved the base Uri and relative Uri to the following:");
Console.WriteLine(absoluteUri.ToString());
}
else
{
Console.WriteLine(
"Unable to resolve the base Uri and relative Uri");
}
return absoluteUri;
}
}
Imports System.IO
Imports System.Xml
Imports System.Security.Cryptography
Imports System.Security.Cryptography.Xml
Class Class1
<STAThread()> _
Shared Sub Main(ByVal args() As String)
' Encrypt a sample XML string.
Dim productsXml As XmlDocument = LoadProducts()
ShowTransformProperties(productsXml)
' Encrypt an XPath Xml string.
Dim transformXml As XmlDocument = LoadTransformByXml()
ShowTransformProperties(transformXml)
' Use XmlDsigXPathTransform to resolve a Uri.
Dim baseUri As New Uri("http://www.contoso.com")
Dim relativeUri As String = "xml"
Dim absoluteUri As Uri = ResolveUris(baseUri, relativeUri)
Console.WriteLine("This sample completed successfully; " + "press Enter to exit.")
Console.ReadLine()
End Sub
' Encrypt the text in the specified XmlDocument.
Private Shared Sub ShowTransformProperties(ByVal xmlDoc As XmlDocument)
' Create a new XMLDocument object.
Dim doc As New XmlDocument()
' Create a new XmlElement.
Dim xPathElem As XmlElement = doc.CreateElement("XPath")
' Set the element text to the value
' of the XPath string.
xPathElem.InnerText = "ancestor-or-self::PRODUCTS"
' Create a new XmlDsigXPathTransform object.
Dim xmlTransform As New XmlDsigXPathTransform()
' Load the XPath XML from the element.
xmlTransform.LoadInnerXml(xPathElem.SelectNodes("."))
' Ensure the transform is using the proper algorithm.
xmlTransform.Algorithm = SignedXml.XmlDsigXPathTransformUrl
' Retrieve the XML representation of the current transform.
Dim xmlInTransform As XmlElement = xmlTransform.GetXml()
Console.WriteLine(vbLf + "Xml representation of the current transform: ")
Console.WriteLine(xmlInTransform.OuterXml)
' Retrieve the valid input types for the current transform.
Dim validInTypes As Type() = xmlTransform.InputTypes
' Verify the xmlTransform can accept the XMLDocument as an
' input type.
Dim i As Integer
For i = 0 To validInTypes.Length
If validInTypes(i).Equals(xmlDoc.GetType()) Then
' Load the document into the transfrom.
xmlTransform.LoadInput(xmlDoc)
Try
' This transform is created for demonstration purposes.
Dim secondTransform As New XmlDsigXPathTransform()
Dim classDescription As String = secondTransform.ToString()
xmlTransform.LoadInnerXml(xPathElem.SelectNodes("."))
Catch
Console.WriteLine("Caught exception while trying to " + "load the specified Xml document. The document " + "requires an XPath element to be valid.")
End Try
Exit For
End If
Next i
Dim validOutTypes As Type() = xmlTransform.OutputTypes
For i = validOutTypes.Length - 1 To 0 Step -1
If validOutTypes(i).Equals(GetType(System.Xml.XmlDocument)) Then
Try
Dim xmlDocumentType As Type = GetType(System.Xml.XmlDocument)
Dim xmlDocumentOutput As XmlDocument = CType(xmlTransform.GetOutput(xmlDocumentType), XmlDocument)
' Display to the console the Xml before and after
' encryption.
Console.WriteLine("Result of the GetOutput method call" + " from the current transform: " + xmlDocumentOutput.OuterXml)
Catch ex As Exception
Console.WriteLine("Unexpected exception caught: " + ex.ToString())
End Try
Exit For
ElseIf validOutTypes(i).Equals(GetType(System.Xml.XmlNodeList)) Then
Try
Dim xmlNodeListType As Type = GetType(System.Xml.XmlNodeList)
Dim xmlNodes As XmlNodeList = CType(xmlTransform.GetOutput(xmlNodeListType), XmlNodeList)
' Display to the console the Xml before and after
' encryption.
Console.WriteLine("Encoding the following message: " + xmlDoc.InnerText)
Console.WriteLine("Nodes of the XmlNodeList retrieved " + "from GetOutput:")
For j As Integer = 0 To xmlNodes.Count - 1
Console.WriteLine("Node " + j + " has the following name: " + xmlNodes.Item(j).Name + " and the following InnerXml: " + xmlNodes.Item(j).InnerXml)
Next
Catch ex As Exception
Console.WriteLine("Unexpected exception caught: " + ex.ToString())
End Try
Exit For
Else
Dim outputObject As Object = xmlTransform.GetOutput()
End If
Next i
End Sub
' Create an XML document for the dsig namespace.
Private Shared Function LoadTransformByXml() As XmlDocument
Dim xmlDoc As New XmlDocument()
Dim transformXml As String = "<Signature><Reference URI=''><Transforms>"
transformXml += "<Transform><XPath "
transformXml += "xmlns:dsig='http://www.w3.org/2000/09/xmldsig#'>"
transformXml += "not(ancestor-or-self::dsig:Signature)"
transformXml += "</XPath></Transform>"
transformXml += "</Transforms></Reference></Signature>"
xmlDoc.LoadXml(transformXml)
Return xmlDoc
End Function 'LoadTransformByXml
' Create an XML document describing various products.
Private Shared Function LoadProducts() As XmlDocument
Dim xmlDoc As New XmlDocument()
Dim contosoProducts As String = "<PRODUCTS>"
contosoProducts += "<PRODUCT><ID>123</ID>"
contosoProducts += "<DESCRIPTION>Router</DESCRIPTION></PRODUCT>"
contosoProducts += "<PRODUCT><ID>456</ID>"
contosoProducts += "<DESCRIPTION>Keyboard</DESCRIPTION></PRODUCT>"
contosoProducts += "<PRODUCT><ID>789</ID>"
contosoProducts += "<DESCRIPTION>Monitor</DESCRIPTION></PRODUCT>"
contosoProducts += "</PRODUCTS>"
xmlDoc.LoadXml(contosoProducts)
Return xmlDoc
End Function 'LoadProducts
' Resolve the specified base and relative Uri's .
Private Shared Function ResolveUris(ByVal baseUri As Uri, ByVal relativeUri As String) As Uri
Dim xmlResolver As New XmlUrlResolver()
xmlResolver.Credentials = System.Net.CredentialCache.DefaultCredentials
Dim xmlTransform As New XmlDsigXPathTransform()
xmlTransform.Resolver = xmlResolver
Dim absoluteUri As Uri = xmlResolver.ResolveUri(baseUri, relativeUri)
If Not (absoluteUri Is Nothing) Then
Console.WriteLine(vbLf + "Resolved the base Uri and relative Uri to the following:")
Console.WriteLine(absoluteUri.ToString())
Else
Console.WriteLine("Unable to resolve the base Uri and relative Uri")
End If
Return absoluteUri
End Function
End Class
Comentários
A XmlDsigXPathTransform classe permite que você resolva um documento XML usando a linguagem XPath. Essa classe usa uma expressão XPath para selecionar os nós XML que você deseja assinar ou criptografar ao remover todos os outros de qualquer operação criptográfica.
Use a XmlDsigXPathTransform classe para assinar ou criptografar partes específicas de um documento XML usando uma expressão XPath. Para obter informações sobre como inicializar a XmlDsigXPathTransform classe para o valor de uma cadeia de caracteres de transformação XPath, consulte o LoadInnerXml método .
O URI (Uniform Resource Identifier) que descreve a XmlDsigXPathTransform classe é definido pelo XmlDsigXPathTransformUrl campo .
Para obter mais informações sobre a transformação XPath, consulte a Seção 6.6.3 da especificação XMLDSIG do W3C.
Construtores
| XmlDsigXPathTransform() |
Inicializa uma nova instância da classe XmlDsigXPathTransform. |
Propriedades
| Algorithm |
Obtém ou define o URI (Uniform Resource Identifier) que identifica o algoritmo executado pela transformação atual. (Herdado de Transform) |
| Context |
Obtém ou define um objeto XmlElement que representa o contexto do documento em que o objeto Transform atual está em execução. (Herdado de Transform) |
| InputTypes |
Obtém uma matriz de tipos que são entradas válidas para o método LoadInput(Object) do objeto XmlDsigXPathTransform atual. |
| OutputTypes |
Obtém uma matriz de tipos que são possíveis saídas provenientes de métodos GetOutput() do objeto XmlDsigXPathTransform atual. |
| PropagatedNamespaces |
Obtém ou define um objeto Hashtable que contém os namespaces propagados na assinatura. (Herdado de Transform) |
| Resolver |
Define o objeto XmlResolver atual. (Herdado de Transform) |
Métodos
| Equals(Object) |
Determina se o objeto especificado é igual ao objeto atual. (Herdado de Object) |
| GetDigestedOutput(HashAlgorithm) |
Quando substituído em uma classe derivada, retorna o resumo da mensagem associado a um objeto Transform. (Herdado de Transform) |
| GetHashCode() |
Serve como a função de hash padrão. (Herdado de Object) |
| GetInnerXml() |
Retorna uma representação XML dos parâmetros de um objeto XmlDsigXPathTransform adequados para serem incluídos como subelementos de um elemento |
| GetOutput() |
Retorna a saída do objeto XmlDsigXPathTransform atual. |
| GetOutput(Type) |
Retorna a saída do objeto XmlDsigXPathTransform atual do tipo XmlNodeList. |
| GetType() |
Obtém o Type da instância atual. (Herdado de Object) |
| GetXml() |
Retorna a representação XML do objeto Transform atual. (Herdado de Transform) |
| LoadInnerXml(XmlNodeList) |
Analisa o objeto XmlNodeList especificado como conteúdo específico da transformação de um elemento |
| LoadInput(Object) |
Carrega a entrada especificada no objeto XmlDsigXPathTransform atual. |
| MemberwiseClone() |
Cria uma cópia superficial do Object atual. (Herdado de Object) |
| ToString() |
Retorna uma cadeia de caracteres que representa o objeto atual. (Herdado de Object) |
Aplica-se a
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