JavaScript

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.

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

JavaScript

var success = false;

//  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.

var ftp = new CkFtp2();

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";

success = ftp.Connect();
if (success == false) {
    console.log(ftp.LastErrorText);
    return;
}

success = ftp.ChangeRemoteDir("public_html");
if (success == false) {
    console.log(ftp.LastErrorText);
    return;
}

//  Only enable compression if the server advertises MODE Z support.
if (ftp.HasModeZ) {
    success = ftp.SetModeZ();
    if (success == false) {
        console.log(ftp.LastErrorText);
        return;
    }

    console.log("MODE Z compression enabled.");
}
else {
    console.log("The server does not support MODE Z.");
}

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

success = ftp.Disconnect();
if (success == false) {
    console.log(ftp.LastErrorText);
    return;
}