I begged and borrowed some code and tried to make somewhere I can send a command
to a server and then retrieve the results. The problem I am having is that the
results is always delayed. Note I put >>><<< to separate results:
Sent carriage return, retrieved:
[joe@flos] ~ #
Sent "who" command, retrieved empty line and prompt:
[joe@flos] ~ #
Sent carriage return, retrieved results I expected from previous command:
who
bob ttyS0 Dec 23 20:44
joe pts/0 Jan 14 01:57 (192.168.1.87)
joe pts/1 Jan 14 07:16 (192.168.1.100)
[joe@flos] ~ #
This seems like real odd behavior to me. For example, if I send a command like
"who", I will get the command prompt. But if I send an empty command (carriage
return) afterward then I will get the "who" command results.
I first do a write to the channel outputstream:
System.out.println(">>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<");
stdOut.write("\n".getBytes());
results = getstuff(in,buffer,bos,channel);
System.out.println(results);
stdOut.flush(); results = "";
I have a method that processes the results via means I saw in various postings:
while (in.available() > 0) {
int count = in.read(buffer, 0, DEFAULT_BUFFER_SIZE);
if (count >= 0) {
bos.write(buffer, 0, count);
} else {
break;
}
}
The buffer is passed back. It makes me wonder, what is in the channel
OutputStream before I start sending commands. How do I clear the buffer, I
assumed stdOut.flush() should do the trick. How do I allign the InputStream such
that it has the results of the completed command sent to the OutputStream
A more complete code snippet follows
try {
session = jsch.getSession(username, hostname, port);
session.setPassword(password);
java.util.Hashtable config = new java.util.Hashtable();
config.put("StrictHostKeyChecking", "no");
session.setConfig(config);
session.setDaemonThread(true);
session.connect(3 * 1000); // making a connection with timeout.
channel = (ChannelShell)session.openChannel("shell");
channel.setPtyType("vt102");
Hashtable env = new Hashtable();
channel.setEnv(env);
channel.connect(5 * 1000);
OutputStream stdOut = channel.getOutputStream();
InputStream in = channel.getInputStream();
// read command output
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
ByteArrayOutputStream bos = new ByteArrayOutputStream();
String results = "";
System.out.println(">>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<");
stdOut.write("\n".getBytes());
results = getstuff(in,buffer,bos,channel);
System.out.println(results);
stdOut.flush(); results = "";
System.out.println(">>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<");
stdOut.write("who \n".getBytes());
results = getstuff(in,buffer,bos,channel);
System.out.println(results);
stdOut.flush(); results = "";
System.out.println(">>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<");
stdOut.write("\n".getBytes());
results = getstuff(in,buffer,bos,channel);
System.out.println(results);
stdOut.flush();
channel.disconnect();
} catch (JSchException jse) {
// TODO: Add catch code
jse.printStackTrace();
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
public String getstuff(InputStream in,byte[] buffer, ByteArrayOutputStream
bos, ChannelShell channel){
int exitStatus = 0;
try {
final long endTime = System.currentTimeMillis() + TIMEOUT;
while (System.currentTimeMillis() < endTime) {
while (in.available() > 0) {
int count = in.read(buffer, 0, DEFAULT_BUFFER_SIZE);
if (count >= 0) {
bos.write(buffer, 0, count);
} else {
break;
}
}
if (channel.isClosed()) {
exitStatus = channel.getExitStatus();
break;
}
try {
Thread.sleep(POLL_TIMEOUT);
} catch (InterruptedException e) {
//("Ignoring interrupt.");
}
}
} catch (IOException ioe) {
// TODO: Add catch code
ioe.printStackTrace();
}
String stuff = bos.toString();
bos.reset();
return stuff;
}
}
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