(PureBasic) 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).

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IncludeFile "CkHttp.pb"
IncludeFile "CkStringBuilder.pb"
IncludeFile "CkXmlDSig.pb"

Procedure ChilkatExample()

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

    http.i = CkHttp::ckCreate()
    If http.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    sbXml.i = CkStringBuilder::ckCreate()
    If sbXml.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    canon.i = CkXmlDSig::ckCreate()
    If canon.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Use exclusive XML canonicalization.
    canonVersion.s = "EXCL_C14N"
    withComments.i = 0
    ; The optional inclusive namespaces prefix list if using exclusive canonicalization.
    prefixList.s = ""

    url.s = "https://www.chilkatsoft.com/exampleData/canonicalizeFragmentTest.xml"
    success.i = CkHttp::ckQuickGetSb(http,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".
    xmlCanonFrag.s = CkXmlDSig::ckCanonicalizeFragment(canon,CkStringBuilder::ckGetAsString(sbXml),"object",canonVersion,prefixList,withComments)
    Debug xmlCanonFrag

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


    CkHttp::ckDispose(http)
    CkStringBuilder::ckDispose(sbXml)
    CkXmlDSig::ckDispose(canon)


    ProcedureReturn
EndProcedure