(Lianja) Get Certificate CRL Distribution Points

Demonstrates how to get a certificate's CRL Distribution Points extension data (assuming it exists). In the vast majority of cases, there will be one CRL Distribution Point.

Note: This example requires Chilkat v9.5.0.76 or greater.

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loCert = createobject("CkCert")

llSuccess = loCert.LoadFromFile("qa_data/certs/test_haswdt.cer")
if (llSuccess <> .T.) then
    ? loCert.LastErrorText
    release loCert
    return
endif

//  Get the CRL Distribution Points extension, which is at OID 2.5.29.31
lcExtensionXmlStr = loCert.GetExtensionAsXml("2.5.29.31")
if (loCert.LastMethodSuccess = .F.) then
    ? "Certificate does not have the CDP extension."
    release loCert
    return
endif

loXml = createobject("CkXml")
loXml.LoadXml(lcExtensionXmlStr)

//  See what we have..
? loXml.GetXml()

//  We should get XML like this:

//  <?xml version="1.0" encoding="utf-8" ?>
//  <sequence>
//      <sequence>
//          <contextSpecific tag="0" constructed="1">
//              <contextSpecific tag="0" constructed="1">
//                  <contextSpecific tag="6" constructed="0">aHR0cDovL2NybC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRTZWN1
//  cmVFbWFpbENBLmNybA==</contextSpecific>
//              </contextSpecific>
//          </contextSpecific>
//      </sequence>
//  </sequence>
// 

//  Assuming there is one CRL Distribution Point...
loSbDistPoint = createobject("CkStringBuilder")
llSuccess = loXml.GetChildContentSb("sequence|contextSpecific|contextSpecific|contextSpecific",loSbDistPoint)
if (llSuccess = .T.) then
    loSbDistPoint.Decode("base64","utf-8")
    ? "CRL Distribution Point:  " + loSbDistPoint.GetAsString()
endif

//  Sample output:
//  CRL Distribution Point:  http://crl.comodoca.com/COMODORSAClientAuthenticationandSecureEmailCA.crl


release loCert
release loXml
release loSbDistPoint