Lua

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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Lua

local chilkat = require("chilkat")

-- 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.

local ftp = chilkat.Ftp2.new()

ftp.hostname = "ftp.example.com"
ftp.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.
ftp.password = "myPassword"

local success = ftp:connect()
if not success then
    print(ftp.last_error_text)
    return
end

success = ftp:change_remote_dir("public_html")
if not success then
    print(ftp.last_error_text)
    return
end

-- Only enable compression if the server advertises MODE Z support.
if ftp.has_mode_z then
    success = ftp:set_mode_z()
    if not success then
        print(ftp.last_error_text)
        return
    end

    print("MODE Z compression enabled.")
else
    print("The server does not support MODE Z.")
end

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

success = ftp:disconnect()
if not success then
    print(ftp.last_error_text)
    return
end