Visual FoxPro

Upgrade an FTP Control Channel to TLS (ConvertToTls)

Demonstrates the Chilkat Ftp2.ConvertToTls method, which upgrades an already-connected clear FTP control channel to explicit TLS. It takes no arguments and is used with a manually staged connection created by ConnectOnly while Ssl is disabled.

Background: This exposes the explicit-FTPS AUTH TLS upgrade as a discrete step for the rare case where you need to do something on the clear connection first — inspect the greeting, apply a workaround — before securing it. In the normal case you simply set AuthTls and let Connect perform the upgrade automatically; this manual path exists for staged control.

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LOCAL lnSuccess
LOCAL loFtp

lnSuccess = 0

*  Demonstrates the Ftp2.ConvertToTls method, which upgrades an already-connected clear FTP control
*  channel to explicit TLS.  It takes no arguments.  It is used with a manually staged connection
*  created by ConnectOnly while Ssl is disabled.

loFtp = CreateObject('Chilkat.Ftp2')

loFtp.Hostname = "ftp.example.com"
loFtp.Port = 21

*  Connect in clear text first (Ssl is false).
lnSuccess = loFtp.ConnectOnly()
IF (lnSuccess = 0) THEN
    ? loFtp.LastErrorText
    RELEASE loFtp
    CANCEL
ENDIF

*  Upgrade the control channel to explicit TLS (AUTH TLS).
lnSuccess = loFtp.ConvertToTls()
IF (lnSuccess = 0) THEN
    ? loFtp.LastErrorText
    RELEASE loFtp
    CANCEL
ENDIF

*  Now authenticate over the encrypted control channel.
loFtp.Username = "myFtpLogin"
loFtp.Password = "myPassword"
lnSuccess = loFtp.LoginAfterConnectOnly()
IF (lnSuccess = 0) THEN
    ? loFtp.LastErrorText
    RELEASE loFtp
    CANCEL
ENDIF

? "Control channel upgraded to TLS and logged in."

lnSuccess = loFtp.Disconnect()
IF (lnSuccess = 0) THEN
    ? loFtp.LastErrorText
    RELEASE loFtp
    CANCEL
ENDIF

RELEASE loFtp