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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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llSuccess = .F.

loSocket = createobject("CkSocket")

//  Connect as plain TCP (no TLS yet).
llBTls = .F.
lnMaxWaitMs = 5000
llSuccess = loSocket.Connect("example.com",5000,llBTls,lnMaxWaitMs)
if (llSuccess = .F.) then
    ? loSocket.LastErrorText
    release loSocket
    return
endif

//  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.
llSuccess = loSocket.ConvertToSsl()
if (llSuccess = .F.) then
    ? loSocket.LastErrorText
    release loSocket
    return
endif

? "Connection upgraded to TLS."


release loSocket