(JavaScript) SSH Remote Shell

Demonstrates how to start a shell on a remote SSH server, run a command, and retrieve the output.

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.

var success = false;

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

var ssh = new CkSsh();

// Hostname may be an IP address or hostname:
var hostname = "www.some-ssh-server.com";
var port = 22;

// Connect to an SSH server:
success = ssh.Connect(hostname,port);
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Wait a max of 5 seconds when reading responses..
ssh.IdleTimeoutMs = 5000;

// Authenticate using login/password:
success = ssh.AuthenticatePw("myLogin","myPassword");
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Open a session channel.  (It is possible to have multiple
// session channels open simultaneously.)
var channelNum;
channelNum = ssh.OpenSessionChannel();
if (channelNum < 0) {
    console.log(ssh.LastErrorText);
    return;
}

// Some SSH servers require a pseudo-terminal
// If so, include the call to SendReqPty.  If not, then 
// comment out the call to SendReqPty.
// Note: The 2nd argument of SendReqPty is the terminal type,
// which should be something like "xterm", "vt100", "dumb", etc.
// A "dumb" terminal is one that cannot process escape sequences.
// Smart terminals, such as "xterm", "vt100", etc. process
// escape sequences.  If you select a type of smart terminal,
// your application will receive these escape sequences
// included in the command's output.  Use "dumb" if you do not
// want to receive escape sequences.  (Assuming your SSH
// server recognizes "dumb" as a standard dumb terminal.)
var termType = "dumb";
var widthInChars = 120;
var heightInChars = 40;
// Use 0 for pixWidth and pixHeight when the dimensions
// are set in number-of-chars.
var pixWidth = 0;
var pixHeight = 0;
success = ssh.SendReqPty(channelNum,termType,widthInChars,heightInChars,pixWidth,pixHeight);
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Start a shell on the channel:
success = ssh.SendReqShell(channelNum);
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Start a command in the remote shell.  This example
// will send a "ls" command to retrieve the directory listing.
success = ssh.ChannelSendString(channelNum,"ls\r\n","ansi");
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Send an EOF.  This tells the server that no more data will 
// be sent on this channel.  The channel remains open, and
// the SSH client may still receive output on this channel.
success = ssh.ChannelSendEof(channelNum);
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Read whatever output may already be available on the
// SSH connection.  ChannelReadAndPoll returns the number of bytes
// that are available in the channel's internal buffer that
// are ready to be "picked up" by calling GetReceivedText
// or GetReceivedData.
// A return value of -1 indicates failure.
// A return value of -2 indicates a failure via timeout.

// The ChannelReadAndPoll method waits
// for data to arrive on the connection usingi the IdleTimeoutMs
// property setting.  Once the first data arrives, it continues
// reading but instead uses the pollTimeoutMs passed in the 2nd argument:
// A return value of -2 indicates a timeout where no data is received.
var n;
var pollTimeoutMs = 2000;
n = ssh.ChannelReadAndPoll(channelNum,pollTimeoutMs);
if (n < 0) {
    console.log(ssh.LastErrorText);
    return;
}

// Close the channel:
success = ssh.ChannelSendClose(channelNum);
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Perhaps we did not receive all of the commands output.
// To make sure,  call ChannelReceiveToClose to accumulate any remaining
// output until the server's corresponding "channel close" is received.
success = ssh.ChannelReceiveToClose(channelNum);
if (success !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Let's pickup the accumulated output of the command:
var cmdOutput = ssh.GetReceivedText(channelNum,"ansi");
if (ssh.LastMethodSuccess !== true) {
    console.log(ssh.LastErrorText);
    return;
}

// Display the remote shell's command output:
console.log(cmdOutput);

// Disconnect
ssh.Disconnect();