Tcl

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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Tcl


load ./chilkat.dll

set success 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.

set ftp [new_CkFtp2]

CkFtp2_put_Hostname $ftp "ftp.example.com"
CkFtp2_put_Username $ftp "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.
CkFtp2_put_Password $ftp "myPassword"

set success [CkFtp2_Connect $ftp]
if {$success == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    exit
}

set success [CkFtp2_ChangeRemoteDir $ftp "public_html"]
if {$success == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    exit
}

#  Only enable compression if the server advertises MODE Z support.
if {CkFtp2_get_HasModeZ $ftp} then {
    set success [CkFtp2_SetModeZ $ftp]
    if {$success == 0} then {
        puts [CkFtp2_lastErrorText $ftp]
        delete_CkFtp2 $ftp
        exit
    }

    puts "MODE Z compression enabled."
} else {
    puts "The server does not support MODE Z."
}

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

set success [CkFtp2_Disconnect $ftp]
if {$success == 0} then {
    puts [CkFtp2_lastErrorText $ftp]
    delete_CkFtp2 $ftp
    exit
}


delete_CkFtp2 $ftp