Is anybody can correct this irule syntaxe. Thanks

I realize this is an old thread, but I tried following this today, and wondered why the need to remove then add back in the BEGIN and END certificate rather than just do something like:

HTTP::header insert "NSClientCert" [string trim [X509::whole [X509::whole [SSL::cert 0]]]

to replace 

set CLIENT "[join [string trim [string map {"--BEGIN CERTIFICATE--" "" "--END CERTIFICATE--" ""} [X509::whole $client_cert]]] ""]" 
        HTTP::header insert "NSClientCert" "—–BEGIN CERTIFICATE—– $CLIENT —–END CERTIFICATE—–" 

I believe if you validate the [SSL::cert 0] at CLIENTSSL_CLIENTCERT, you don't need to add the insert header at the ClIENTSSL_CLIENTCERT and at HTTP_REQUEST, it seems redundant