Lua

FTP Socket Buffer and Address Options

Demonstrates the SoRcvBuf, SoSndBuf, PreferIpv6, and ClientIpAddress properties.

Background: These are low-level knobs for specific situations. Larger send/receive buffers can improve throughput on high-bandwidth, high-latency links, though the defaults suit the common case. PreferIpv6 only matters when a hostname resolves to both address families, choosing which to try first. ClientIpAddress is normally left unset; set it on a multihomed host to bind the outgoing connection to a particular local interface. Change any of these only with a concrete reason.

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Lua

local chilkat = require("chilkat")

local ftp = chilkat.Ftp2.new()

ftp.hostname = "ftp.example.com"
ftp.username = "myFtpLogin"

-- SoRcvBuf and SoSndBuf set the TCP socket receive/send buffer sizes.  The defaults are tuned for
-- the common case; larger values can sometimes help throughput on high-latency links.
ftp.so_rcv_buf = 4194304
ftp.so_snd_buf = 524288

-- PreferIpv6 (default false) chooses IPv6 over IPv4 when a hostname resolves to both.
ftp.prefer_ipv6 = false

-- ClientIpAddress is normally left unset; set it on a multihomed host to bind the outgoing
-- connection to a specific local interface.
ftp.client_ip_address = "192.168.1.50"

-- 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

print("Connected with custom socket options.")

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