(MFC) Canonicalize XML Fragment

Demonstrates how to canonicalize a fragment of an XML document. The fragment is identified by the element having an Id attribute equal to a specified value. (The Id attribute can have any namespace, and the attribute name is case-insensitive (thus "ID", "Id", "id", etc. match).

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkHttp.h>
#include <CkStringBuilder.h>
#include <CkXmlDSig.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkHttp http;
    CkStringBuilder sbXml;
    CkXmlDSig canon;

    // Use exclusive XML canonicalization.
    const char *canonVersion = "EXCL_C14N";
    bool withComments = false;
    // The optional inclusive namespaces prefix list if using exclusive canonicalization.
    const char *prefixList = "";

    const char *url = "https://www.chilkatsoft.com/exampleData/canonicalizeFragmentTest.xml";
    bool success = http.QuickGetSb(url,sbXml);

    // This is the input XML:

    // <?xml version="1.0" encoding="UTF-8"?>
    // <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
    // <SignedInfo>
    //   <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
    //   <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
    //   <Reference URI="#object">
    //     <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
    //     <DigestValue>OPnpF/ZNLDxJ/I+1F3iHhlmSwgo=</DigestValue>
    //   </Reference>
    // </SignedInfo>
    // <SignatureValue>nihUFQg4mDhLgecvhIcKb9Gz8VRTOlw+adiZOBBXgK4JodEe5aFfCqm8WcRIT8GL
    // LXSk8PsUP4//SsKqUBQkpotcAqQAhtz2v9kCWdoUDnAOtFZkd/CnsZ1sge0ndha4
    // 0wWDV+nOWyJxkYgicvB8POYtSmldLLepPGMz+J7/Uws=</SignatureValue>
    // <KeyInfo>
    //   <KeyValue>
    //     <RSAKeyValue>
    //       <Modulus>4IlzOY3Y9fXoh3Y5f06wBbtTg94Pt6vcfcd1KQ0FLm0S36aGJtTSb6pYKfyX7PqC
    //       UQ8wgL6xUJ5GRPEsu9gyz8ZobwfZsGCsvu40CWoT9fcFBZPfXro1Vtlh/xl/yYHm
    //       +Gzqh0Bw76xtLHSfLfpVOrmZdwKmSFKMTvNXOFd0V18=</Modulus>
    //       <Exponent>AQAB</Exponent>
    //     </RSAKeyValue>
    //   </KeyValue>
    // </KeyInfo>
    // <Object Id="object">some text
    //   with spaces and CR-LF.</Object>
    // </Signature>

    // Canonicalize and return the fragment of XML starting at the element where the Id attribute equals "object".
    const char *xmlCanonFrag = canon.canonicalizeFragment(sbXml.getAsString(),"object",canonVersion,prefixList,withComments);
    strOut.append(xmlCanonFrag);
    strOut.append("\r\n");

    // The output is:
    // 
    // <Object xmlns="http://www.w3.org/2000/09/xmldsig#" Id="object">some text
    //   with spaces and CR-LF.</Object>
    // 


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }