Visual FoxPro

Enable FTP MODE Z Compression

Demonstrates the Chilkat Ftp2.SetModeZ method, which enables MODE Z compression for subsequent data connections. It takes no arguments. Call it after connecting and only when the HasModeZ property is true.

Background: MODE Z compresses data on the fly (using zlib) as it crosses the wire, which can meaningfully speed up transfers of compressible content — text, HTML, logs — over a slow link. It is a server extension, so check HasModeZ first and expect it to be unavailable on many servers. There is little benefit for already-compressed data such as images or archives, where the CPU cost of compression buys almost nothing.

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LOCAL lnSuccess
LOCAL loFtp

lnSuccess = 0

*  Demonstrates the Ftp2.SetModeZ method, which enables MODE Z compression for subsequent data
*  connections.  It takes no arguments.  Call it after connecting, and only when the HasModeZ
*  property indicates the server supports it.

loFtp = CreateObject('Chilkat.Ftp2')

loFtp.Hostname = "ftp.example.com"
loFtp.Username = "myFtpLogin"

*  Normally you would not hard-code the password in source.  You should instead obtain it
*  from an interactive prompt, environment variable, or a secrets vault.
loFtp.Password = "myPassword"

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

lnSuccess = loFtp.ChangeRemoteDir("public_html")
IF (lnSuccess = 0) THEN
    ? loFtp.LastErrorText
    RELEASE loFtp
    CANCEL
ENDIF

*  Only enable compression if the server advertises MODE Z support.
IF (loFtp.HasModeZ) THEN
    lnSuccess = loFtp.SetModeZ()
    IF (lnSuccess = 0) THEN
        ? loFtp.LastErrorText
        RELEASE loFtp
        CANCEL
    ENDIF

    ? "MODE Z compression enabled."
ELSE
    ? "The server does not support MODE Z."
ENDIF

*  Subsequent uploads, downloads, and listings are transferred compressed.

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

RELEASE loFtp