SSH Quick/Simple Shell Session

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Demonstrates the simplified way to run multiple commands in a shell session using QuickShell, which combines OpenSessionChannel, SendReqPty, and SendReqShell into one call. The commands are built in a StringBuilder, sent together, and the output is read up to a marker echoed by the final command.

import { Ssh, StringBuilder } from '@chilkat/react-native'

async function chilkatExample() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // Demonstrates the simplified way to run multiple commands in a shell session using QuickShell.
  // 
  // Note: QuickShell internally does OpenSessionChannel, SendReqPty, and SendReqShell, so it DOES
  // allocate a pseudo-terminal.  The remote shell therefore runs interactively: it prints a
  // command prompt and echoes back the commands that are sent to it.  Both the echoed input and
  // the real output appear in what is received.

  const ssh = new Ssh();

  const port = 22;
  try {
    await ssh.connectAsync('ssh.example.com', port);
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  // Normally you would not hard-code the password in source.  You should instead obtain it
  // from an interactive prompt, environment variable, or a secrets vault.
  const password = 'mySshPassword';

  try {
    await ssh.authenticatePwAsync('mySshLogin', password);
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  // Start the shell session.  A negative return value indicates failure.
  const channelNum = await ssh.quickShellAsync();
  if (channelNum < 0) {
    console.log(ssh.lastErrorText);
    return;
  }

  // Build the commands, one per line.  Line endings matter: Unix/Linux servers typically expect
  // a bare LF, while Windows servers may require CRLF.
  const sbCommands = new StringBuilder();
  sbCommands.append('echo hello world\n');
  sbCommands.append('date\n');
  sbCommands.append('df\n');

  // The final command echoes a marker used to detect the end of the output.  The single quotes
  // around 'IS' are a trick: the terminal echo of the typed command includes the quotes, while
  // the command's actual output does not.  Matching the unquoted form therefore matches the real
  // output rather than the echo.
  sbCommands.append('echo THIS \'IS\' THE END OF THE SCRIPT\n');

  const commands = sbCommands.getAsString();
  try {
    await ssh.channelSendStringAsync(channelNum, commands, 'utf-8');
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  // IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
  // which means no limit -- without it, this call waits forever if the received data never
  // contains a match.
  ssh.readTimeoutMs = 15000;

  const caseSensitive = true;
  try {
    await ssh.channelReceiveUntilMatchAsync(channelNum, 'THIS IS THE END OF THE SCRIPT', 'utf-8', caseSensitive);
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  // Indicate that no more commands will be sent, then close the channel.  Close only after the
  // desired output has been received.
  try {
    await ssh.channelSendEofAsync(channelNum);
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  try {
    await ssh.channelSendCloseAsync(channelNum);
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  // Collect any remaining output.
  try {
    await ssh.channelReceiveToCloseAsync(channelNum);
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  let sessionOutput: string;
  try {
    sessionOutput = ssh.getReceivedText(channelNum, 'utf-8');
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  console.log('--- output ----');
  console.log(sessionOutput);

  ssh.disconnect();
}