(Tcl) FTP Connect, Examine Server Certificate, and then Authenticate

Demonstrates how to connect to an FTP server, examine the server's SSL/TLS certificate, and then, if it meets the application's security requirements, proceed to authenticate.

Note: This example requires Chilkat v11.0.0 or greater.

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load ./chilkat.dll

set success 0

# This example assumes Chilkat Ftp2 to have been previously unlocked.
# See Unlock Ftp2 for sample code.

set ftp [new_CkFtp2]

CkFtp2_put_Hostname $ftp "www.authtls-ftps-server.com"
CkFtp2_put_Username $ftp "FTP_LOGIN"
CkFtp2_put_Password $ftp "FTP_PASSWORD"
CkFtp2_put_AuthTls $ftp 1
CkFtp2_put_Port $ftp 21

# Connect to the FTP server using explicit TLS (AUTH TLS).
set success [CkFtp2_ConnectOnly $ftp]
if {$success == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    exit
}

# Get the FTP server's certificate.
set serverCert [new_CkCert]

set success [CkFtp2_GetServerCert $ftp $serverCert]
if {$success == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    delete_CkCert $serverCert
    exit
}

# Now that we have the certificate, we can check it in any way we desire.
# (See the online reference documentation for the certificate object's methods
# and properties)...

# Assuming the certificate is OK, proceed to authenticate with the FTP server.
set success [CkFtp2_LoginAfterConnectOnly $ftp]
if {$success == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    delete_CkCert $serverCert
    exit
}

# 
# Proceed with uploading/download files, etc...
# 

CkFtp2_Disconnect $ftp
puts "Success."

delete_CkFtp2 $ftp
delete_CkCert $serverCert