JavaScript

Detect End-of-File on a Remote SFTP File

Demonstrates the Chilkat SFtp.Eof method, which returns whether the most recent read for a handle received the SFTP end-of-file status. The only argument is the handle. This example reads until Eof is true.

Background: The timing here is worth understanding: reading exactly through the final byte does not immediately set EOF. The next read succeeds, returns zero bytes, sets the status to SSH_FX_EOF, and only then does Eof report true. That is why the loop tests Eof after each read rather than assuming a short read means the end — a short read can also just be the server returning less than requested.

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 SFtp.Eof method, which returns whether the most recent read for a handle
//  received the SFTP end-of-file status.  The only argument is the handle.

var sftp = new CkSFtp();

//  Connect, authenticate, and initialize the SFTP subsystem.
var port = 22;
success = sftp.Connect("sftp.example.com",port);
if (success == false) {
    console.log(sftp.LastErrorText);
    return;
}

//  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.
var password = "mySshPassword";

success = sftp.AuthenticatePw("mySshLogin",password);
if (success == false) {
    console.log(sftp.LastErrorText);
    return;
}

success = sftp.InitializeSftp();
if (success == false) {
    console.log(sftp.LastErrorText);
    return;
}

var handle = sftp.OpenFile("subdir/data.txt","readOnly","openExisting");
if (sftp.LastMethodSuccess == false) {
    console.log(sftp.LastErrorText);
    return;
}

//  Read until Eof reports the end of the file.  Note that reading exactly through the final byte
//  does not set EOF; the next read returns zero bytes and then Eof becomes true.
var sbContent = new CkStringBuilder();
var chunkSize = 4096;
var reading = true;
while (reading) {
    var chunk = sftp.ReadFileText(handle,chunkSize,"utf-8");
    if (sftp.LastReadFailed(handle)) {
        console.log(sftp.LastErrorText);
        return;
    }

    sbContent.Append(chunk);
    reading = !sftp.Eof(handle);
}

success = sftp.CloseHandle(handle);
if (success == false) {
    console.log(sftp.LastErrorText);
    return;
}

console.log(sbContent.GetAsString());

sftp.Disconnect();