Lua

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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Lua

local chilkat = require("chilkat")

local socket = chilkat.Socket.new()

-- Connect as plain TCP (no TLS yet).
local bTls = false
local maxWaitMs = 5000
local success = socket:connect("example.com", 5000, bTls, maxWaitMs)
if not success then
    print(socket.last_error_text)
    return
end

-- 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:convert_to_ssl()
if not success then
    print(socket.last_error_text)
    return
end

print("Connection upgraded to TLS.")