Upgrade an FTP Control Channel to TLS (ConvertToTls)

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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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#include <C_CkFtp2.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkFtp2 ftp;

    success = FALSE;

    //  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.

    ftp = CkFtp2_Create();

    CkFtp2_putHostname(ftp,"ftp.example.com");
    CkFtp2_putPort(ftp,21);

    //  Connect in clear text first (Ssl is false).
    success = CkFtp2_ConnectOnly(ftp);
    if (success == FALSE) {
        printf("%s\n",CkFtp2_lastErrorText(ftp));
        CkFtp2_Dispose(ftp);
        return;
    }

    //  Upgrade the control channel to explicit TLS (AUTH TLS).
    success = CkFtp2_ConvertToTls(ftp);
    if (success == FALSE) {
        printf("%s\n",CkFtp2_lastErrorText(ftp));
        CkFtp2_Dispose(ftp);
        return;
    }

    //  Now authenticate over the encrypted control channel.
    CkFtp2_putUsername(ftp,"myFtpLogin");
    CkFtp2_putPassword(ftp,"myPassword");
    success = CkFtp2_LoginAfterConnectOnly(ftp);
    if (success == FALSE) {
        printf("%s\n",CkFtp2_lastErrorText(ftp));
        CkFtp2_Dispose(ftp);
        return;
    }

    printf("Control channel upgraded to TLS and logged in.\n");

    success = CkFtp2_Disconnect(ftp);
    if (success == FALSE) {
        printf("%s\n",CkFtp2_lastErrorText(ftp));
        CkFtp2_Dispose(ftp);
        return;
    }



    CkFtp2_Dispose(ftp);

    }