(Lianja) Get Certificate Authority Information Access

Demonstrates how to get a certificate's Authority Information Access extension data (if it exists).

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 Authority Information Access extension, which is at OID 1.3.6.1.5.5.7.1.1
lcExtensionXmlStr = loCert.GetExtensionAsXml("1.3.6.1.5.5.7.1.1")
if (loCert.LastMethodSuccess = .F.) then
    ? "Certificate does not have the AuthInfoAccess 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>
//          <oid>1.3.6.1.5.5.7.48.2</oid>
//          <contextSpecific tag="6" constructed="0">aHR0cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRTZWN1
//  cmVFbWFpbENBLmNydA==</contextSpecific>
//      </sequence>
//      <sequence>
//          <oid>1.3.6.1.5.5.7.48.1</oid>
//          <contextSpecific tag="6" constructed="0">aHR0cDovL29jc3AuY29tb2RvY2EuY29t</contextSpecific>
//      </sequence>
//  </sequence>

//  Typically, a certificate AIA(Authority Information access) contains 2 parts:
// 
//      On-line Certificate Status Protocol (1.3.6.1.5.5.7.48.1)
//      Certification Authority Issuer (1.3.6.1.5.5.7.48.2)
// 
//  The base64 content for each OID (in this case) is just a string.
//  The data can be accessed and decoded like this:

loSbOcsp = createobject("CkStringBuilder")
llSuccess = loXml.GetChildContentSb("/C/oid,1.3.6.1.5.5.7.48.1|++",loSbOcsp)
if (llSuccess = .T.) then
    loSbOcsp.Decode("base64","utf-8")
    ? "1.3.6.1.5.5.7.48.1:  " + loSbOcsp.GetAsString()
endif

loSbIssuer = createobject("CkStringBuilder")
llSuccess = loXml.GetChildContentSb("/C/oid,1.3.6.1.5.5.7.48.2|++",loSbIssuer)
if (llSuccess = .T.) then
    loSbIssuer.Decode("base64","utf-8")
    ? "1.3.6.1.5.5.7.48.2:  " + loSbIssuer.GetAsString()
endif

//  The output looks like this:

//  1.3.6.1.5.5.7.48.1:  http://ocsp.comodoca.com
//  1.3.6.1.5.5.7.48.2:  http://crt.comodoca.com/COMODORSAClientAuthenticationandSecureEmailCA.crt

//  -------------------------------------------------------------------------------
//  Note: The Chilkat path passed to GetChildContentSb is composed of two commands:
//  The first command is "/C/oid,1.3.6.1.5.5.7.48.1".   It says "traverse the XML tree from the caller
// node and stop at the 1st node having tag = "oid" and content = "1.3.6.1.5.5.7.48.1".
//  The "|" char separates the 1st command from the 2nd.
//  The 2nd command is "++" and says "move to the next sibling".


release loCert
release loXml
release loSbOcsp
release loSbIssuer