Multiple SendReqExec on Same Connection

Shows how to execute a series of commands on an SSH server and retrieve each command's output (using SendReqExec). Each call to SendReqExec requires its own logical session channel. This is not a separate TCP/IP connection -- it's simply a new session channel on the existing connection. The sequence of Chilkat SSH calls would look like this:

Connect
AuthenticatePw (or AuthenticatePk)

OpenSessionChannel
SendReqExec
<retrieve command output...>
SendChannelClose
ChannelReceiveToClose (to make sure all remaining output is received)

OpenSessionChannel
SendReqExec
<retrieve command output...>
SendChannelClose
ChannelReceiveToClose (to make sure all remaining output is received)

...

OpenSessionChannel
SendReqExec
<retrieve command output...>
SendChannelClose
ChannelReceiveToClose (to make sure all remaining output is received)

Disconnect

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//  Important: It is helpful to send the contents of the
//  ssh.LastErrorText property when requesting support.

Chilkat.Ssh ssh = new Chilkat.Ssh();

//  Any string automatically begins a fully-functional 30-day trial.
bool success;
success = ssh.UnlockComponent("Anything for 30-day trial");
if (success != true) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

//  Connect to an SSH server:
string hostname;
int port;

//  Hostname may be an IP address or hostname:
hostname = "192.168.1.108";
port = 22;

success = ssh.Connect(hostname,port);
if (success != true) {
    MessageBox.Show(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) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

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

//  Request a directory listing on the remote server:
//  If your server is Linux/UNIX, change the string from "dir" to "ls"
//  Note: Some SSH servers require a CRLF instead of a bare-LF
string cmd;
cmd = "ls -al" + lf;
success = ssh.SendReqExec(channelNum,cmd);
if (success != true) {
    MessageBox.Show(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.
int n;
int pollTimeoutMs;
pollTimeoutMs = 2000;
n = ssh.ChannelReadAndPoll(channelNum,pollTimeoutMs);
if (n < 0) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

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

//  Let's pickup the accumulated output of the command:
string cmdOutput;
cmdOutput = ssh.GetReceivedText(channelNum,"ansi");
if (cmdOutput == null ) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

//  Display the remote shell's command output:
textBox1.Text += cmdOutput + "\r\n";
textBox1.Text += "----" + "\r\n";

//  -----------------------------------------------------------------
//  Now for the 2nd SendReqExe (on the same connection,
//  but on a separate logical channel).
//  -----------------------------------------------------------------

channelNum = ssh.OpenSessionChannel();
if (channelNum < 0) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

cmd = "nslookup chilkatsoft.com" + lf;
success = ssh.SendReqExec(channelNum,cmd);
if (success != true) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

pollTimeoutMs = 2000;
n = ssh.ChannelReadAndPoll(channelNum,pollTimeoutMs);
if (n < 0) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

success = ssh.ChannelSendClose(channelNum);
if (success != true) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

success = ssh.ChannelReceiveToClose(channelNum);
if (success != true) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

cmdOutput = ssh.GetReceivedText(channelNum,"ansi");
if (cmdOutput == null ) {
    MessageBox.Show(ssh.LastErrorText);
    return;
}

textBox1.Text += cmdOutput + "\r\n";

//  Disconnect
ssh.Disconnect();