(Swift) Examine Client Certificates for an Accepted TLS Connection

Demonstrates how to access the client certificates for a TLS connection accepted by your application acting as the server.

Note: This example requires Chilkat v11.0.0 or greater.

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func chilkatTest() {
    var success: Bool = false

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

    let listenSslSocket = CkoSocket()!

    // An SSL/TLS server needs a digital certificate.  This example loads it from a PFX file.
    // This is the server's certificate.

    let cert = CkoCert()!
    success = cert.loadPfxFile("qa_data/serverCert/myServerCert.pfx", password: "pfx_password")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    // To accept client client certificates in the TLS handshake,
    // we must indicate a list of acceptable client certificate root CA DN's
    // that are allowed.  (DN is an acronym for Distinguished Name.)
    // Call AddSslAcceptableClientCaDn once for each acceptable CA DN.
    // Here are a few examples so you can see the general format of a DN.
    listenSslSocket.addSslAcceptableClientCaDn("C=SE, O=AddTrust AB, OU=AddTrust External TTP Network, CN=AddTrust External CA Root")
    listenSslSocket.addSslAcceptableClientCaDn("O=Digital Signature Trust Co., CN=DST Root CA X3")

    // Initialize with our server's TLS certificate.
    success = listenSslSocket.initSslServer(cert)
    if success == false {
        print("\(listenSslSocket.lastErrorText!)")
        return
    }

    // Bind and listen on a port:
    var myPort: Int = 8123
    // Allow for a max of 5 queued connect requests.
    var backLog: Int = 5
    success = listenSslSocket.bindAndListen(myPort, backlog: backLog)
    if success == false {
        print("\(listenSslSocket.lastErrorText!)")
        return
    }

    // Accept the next incoming connection.
    var maxWaitMillisec: Int = 20000

    let clientSock = CkoSocket()!
    success = listenSslSocket.acceptNext(maxWaitMillisec, socket: clientSock)
    if success == false {
        print("\(listenSslSocket.lastErrorText!)")
        return
    }

    // Examine the client certs chain.  The 1st cert will be the client certificate, and
    // the subsequent certs will be the certs in the chain of authentication.
    var numClientCerts: Int = clientSock.numReceivedClientCerts.intValue
    print("numClientCerts = \(numClientCerts)")

    let clientCert = CkoCert()!
    var i: Int = 0
    while i < numClientCerts {
        clientSock.getRcvdClientCert(i, cert: clientCert)
        print("\(clientCert.subjectDN!)")
        i = i + 1
    }

    // Close the connection with the client
    success = clientSock.close(1000)

}