(PureBasic) Secure FTP with Client Certificate

Chilkat FTP2 provides the ability to use a client certificate with secure FTP (implicit or explicit SSL/TLS). This example demonstrates how to load a certificate from a .pfx and use it as the client-side SSL cert. Note: Client-side certificates are only needed in situations where the server demands one.

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IncludeFile "CkCertStore.pb"
IncludeFile "CkCert.pb"
IncludeFile "CkFtp2.pb"

Procedure ChilkatExample()

    ; This example requires the Chilkat API to have been previously unlocked.
    ; See Global Unlock Sample for sample code.

    ftp.i = CkFtp2::ckCreate()
    If ftp.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkFtp2::setCkHostname(ftp, "ftp.***.com")
    CkFtp2::setCkPort(ftp, 21)
    CkFtp2::setCkUsername(ftp, "test")
    CkFtp2::setCkPassword(ftp, "test")

    ; This example will use explict TLS/SSL.
    ; Establish an explicit secure channel after connection
    ; on the standard FTP port 21.
    CkFtp2::setCkAuthTls(ftp, 1)

    ; The Ssl property is for establishing an implicit SSL connection
    ; on port 990.  Because this example uses explicit SSL, it 
    ; should remain 0.
    CkFtp2::setCkSsl(ftp, 0)

    ; Load a certificate from a .pfx
    ; A PFX may contain several certs, including the certificates
    ; in a chain of authority.
    certStore.i = CkCertStore::ckCreate()
    If certStore.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    password.s
    password = "***"
    ; Load the certs from a PFX into an in-memory certificate store:
    success.i = CkCertStore::ckLoadPfxFile(certStore,"chilkat.pfx",password)
    If success <> 1
        Debug CkCertStore::ckLastErrorText(certStore)
        CkFtp2::ckDispose(ftp)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    ; Find the exact cert we'll use:
    cert.i
    cert = CkCertStore::ckFindCertBySubject(certStore,"Chilkat Software, Inc.")
    If CkCertStore::ckLastMethodSuccess(certStore) = 0
        Debug "Certificate not found!"
        CkFtp2::ckDispose(ftp)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    EndIf

    ; Use this certificate for our secure (SSL/TLS) connection:
    success = CkFtp2::ckSetSslClientCert(ftp,cert)
    CkCert::ckDispose(cert)

    ; Connect and login to the FTP server.  The connection is 
    ; made secure because of the AuthTls setting.
    success = CkFtp2::ckConnect(ftp)
    If success <> 1
        Debug CkFtp2::ckLastErrorText(ftp)
        CkFtp2::ckDispose(ftp)
        CkCertStore::ckDispose(certStore)
        ProcedureReturn
    Else
        ; LastErrorText contains information even when
        ; successful. This allows you to visually verify
        ; that the secure connection actually occurred.
        Debug CkFtp2::ckLastErrorText(ftp)
    EndIf

    Debug "Secure FTP Channel Established!"

    ; Do whatever you're doing to do ...
    ; upload files, download files, etc...

    ; .....
    ; .....

    success = CkFtp2::ckDisconnect(ftp)


    CkFtp2::ckDispose(ftp)
    CkCertStore::ckDispose(certStore)


    ProcedureReturn
EndProcedure