CkPython

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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CkPython

import sys
import chilkat

success = False

socket = chilkat.CkSocket()

#  Connect as plain TCP (no TLS yet).
bTls = False
maxWaitMs = 5000
success = socket.Connect("example.com",5000,bTls,maxWaitMs)
if (success == False):
    print(socket.lastErrorText())
    sys.exit()

#  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())
    sys.exit()

print("Connection upgraded to TLS.")