Telnet Component Example

/// <summary>
/// Summary description for Telnet Commander.
/// </summary>
public class TelnetCommander
{

private Telnet telnet = new Telnet();

public TelnetCommander()
{

// set the option negotiation to false, so telnet servers require this to be true (we just have to test)
telnet.OptionNegotiationEnabled = false;
// set up event handler for when status changes
telnet.OnConnectionStatusChanged += new Telnet.ConnectionStatusHandler(telnet_OnConnectionStatusChanged);
// set up event for whenever we recieve anything
telnet.OnReceive += new Telnet.ReceivedDataHandler(telnet_OnReceive);

}

public void Connect(string ipAddress, string password)
{

// enable welcome text, this means that we won't get a connected event, until the component, finds
// the first string of text sent out by the server.
telnet.WelcomeTextEnabled = true;
// this is the text token we're search for in order to say that we successfully found the welcome text,
// regex is supported, so we'll see if this system is password protected or not.
telnet.WelcomeTextEndToken = "(Password:)|(\r\nOK\r\n)";
// connect to the server on port 23
telnet.Connect(ipAddress, 23);

// if the server sends out it's welcome text and that text contains the string "password", we need to handle it.
if(telnet.ServerWelcomeText.IndexOf("Password") >= 0)
{

// send the password
string response = telnet.Send(password+"\r\n", new string[]{"(Password:)|(\r\nOK\r\n)"}, telnet.CommandTimeout);
// if we still get a password prompt from the server, we go it wrong, so throw a bad password exception
if(response.IndexOf("Password:")>=0)
throw new Exception("Bad Password");
}

}

public bool SendCommands(string data)
{

// make sure we're connected
if(telnet.ConnectionState != ConnectionState.Connected)
throw new Exception("Not connected to device!");

// set the tokens that we will use to delimit each command, for a normal
// shell into a server, we would probably have the prompt as our end token.
telnet.CommandEndTokens = new string[]{"(\r\nOK\r\n)|(\r\nERROR\r\n)"};
bool succeeded = true;
// in this case data is entered as one command per line, so we
// need to split up the commands
foreach(string command in data.Split('\n')) {

if(command.Trim()=="")
continue;
// send the command synchronously to the telnet server and wait for a response
// note that we must terminate each command with a \n character as the component
// sends EXACTLY what you give it.
string response = telnet.Send(command + "\n");
// if we get an error response, from the telnet server, flag it.
if(response.IndexOf("ERROR\r\n")>=0)
succeeded = false;
}
return succeeded;
}

public void Disconnect() {

telnet.Disconnect();
}

public string GetState() {

return telnet.ConnectionState.ToString();
}

private void telnet_OnConnectionStatusChanged(object o, ConnectionStatusEventArgs e)
{

Console.WriteLine("Status: {0}", e.ConnectionState.ToString());
}

private void telnet_OnReceive(object o, ReceivedDataEventArgs e)
{

Console.WriteLine("Rcd: {0}", e.ReceivedData);
}

}