I have a legacy app the needs to connect to a remove server on port 22 to establish the connection with userName and PWD. Then need to connect to a different port to send a request and receive response and close the session. At the moment I am using JSCH library to create a session and a channel then using Telnet command to submit request and receive response. But this call is taking 2-5s and doesn't scale well also.
Here is the sample code that I have:
public static void telnetConnection(String payload, int targetPOrt) throws JSchException, Exception {
// Session session = null;
DataOutputStream dataOut = null;
DataInputStream dataIn = null;
BufferedReader reader = null;
Channel channel = null;
StopWatch stopWatch = new StopWatch();
stopWatch.start();
Session JSCH_SESSION = null;
try {
JSch jsch = new JSch();
JSCH_SESSION = jsch.getSession(userName, HOST, 22);
JSCH_SESSION.setPassword(password);
// It must not be recommended, but if you want to skip host-userName check,
JSCH_SESSION.setConfig("StrictHostKeyChecking", "no");
JSCH_SESSION.connect(30000);
JSCH_SESSION.setServerAliveInterval(2000);
JSCH_SESSION.sendKeepAliveMsg();
StringBuffer buffer = new StringBuffer(" (");
buffer.append("echo ");
buffer.append("\'" + payload + "'");
buffer.append(" && echo && sleep 2 ) | ");
buffer.append(" telnet localhost " + targetPOrt + " \r\n ");
channel = JSCH_SESSION.openChannel("shell");
channel.connect(30000);
dataOut = new DataOutputStream(channel.getOutputStream());
System.out.println("Starting telnet connection...");
String command = buffer.toString();
dataOut.writeBytes(" bash \r\n");
dataOut.flush();
dataIn = new DataInputStream(channel.getInputStream());
reader = new BufferedReader(new InputStreamReader(dataIn));
dataOut.writeBytes(command);
dataOut.flush();
String line = reader.readLine();
String result = line + "\n";
while (!(line = reader.readLine()).contains("Connection closed by foreign host")) {
result += line + "\n";
}
handleResponse(result);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (dataIn != null) {
dataIn.close();
}
if (dataOut != null) {
dataOut.close();
}
if (channel != null) {
channel.disconnect();
}
if (JSCH_SESSION != null) {
JSCH_SESSION.disconnect();
}
}
}
Telnet connection command is working but doesn't scale well and is taking too long. I even cached the session and try to reuse it w/o creating for every request by just closing the Readers and channel for every request. I am wondering if there is any other API that I can use to make this work.
