(Tcl) 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.

Chilkat Tcl Extension Downloads Chilkat Tcl Extension Downloads

load ./chilkat.dll

set cert [new_CkCert]

set success [CkCert_LoadFromFile $cert "qa_data/certs/test_haswdt.cer"]
if {$success != 1} then {
    puts [CkCert_lastErrorText $cert]
    delete_CkCert $cert
    exit
}

# Get the CRL Distribution Points extension, which is at OID 2.5.29.31
set extensionXmlStr [CkCert_getExtensionAsXml $cert "2.5.29.31"]
if {[CkCert_get_LastMethodSuccess $cert] == 0} then {
    puts "Certificate does not have the CDP extension."
    delete_CkCert $cert
    exit
}

set xml [new_CkXml]

CkXml_LoadXml $xml $extensionXmlStr

# See what we have..
puts [CkXml_getXml $xml]

# 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...
set sbDistPoint [new_CkStringBuilder]

set success [CkXml_GetChildContentSb $xml "sequence|contextSpecific|contextSpecific|contextSpecific" $sbDistPoint]
if {$success == 1} then {
    CkStringBuilder_Decode $sbDistPoint "base64" "utf-8"
    puts "CRL Distribution Point:  [CkStringBuilder_getAsString $sbDistPoint]"
}

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

delete_CkCert $cert
delete_CkXml $xml
delete_CkStringBuilder $sbDistPoint