Swift

Upgrade a Plain TCP Connection to TLS

Demonstrates Socket.ConvertToSsl, which upgrades an already-connected plain TCP socket to TLS by performing a client-side TLS handshake over the existing connection.

Background. This supports STARTTLS-style upgrades, where a protocol begins in plaintext and switches to TLS at a defined point. Perform the protocol-specific negotiation first, then call ConvertToSsl.

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Swift


func chilkatTest() {
    var success: Bool = false

    let socket = CkoSocket()!

    //  Connect as plain TCP (no TLS yet).
    var bTls: Bool = false
    var maxWaitMs: Int = 5000
    success = socket.connect(hostname: "example.com", port: 5000, ssl: bTls, maxWaitMs: maxWaitMs)
    if success == false {
        print("\(socket.lastErrorText!)")
        return
    }

    //  At the point where the application protocol permits a STARTTLS-style upgrade, perform any required
    //  negotiation, then upgrade the existing connection to TLS with a client-side handshake.
    success = socket.convertToSsl()
    if success == false {
        print("\(socket.lastErrorText!)")
        return
    }

    print("Connection upgraded to TLS.")

}