React Native

Get Received SSH Text into a StringBuilder

Demonstrates the Chilkat Ssh.GetReceivedSb method, which decodes a channel's receive buffer and appends the text to a StringBuilder. The arguments are the channel number, the charset, and the StringBuilder. The receive buffer is cleared afterward.

Background: Because this appends rather than replaces, it is the natural choice for accumulating output across repeated reads — call it in a loop and the StringBuilder grows into the complete transcript. It also avoids creating a new string on every retrieval, which matters when a command produces a large amount of text.

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React Native

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

async function chilkatExample() {
  // Demonstrates the Ssh.GetReceivedSb method, which decodes the channel's receive buffer and
  // appends the text to a StringBuilder.  The 1st argument is the channel number, the 2nd is the
  // charset, and the 3rd is the StringBuilder.  The receive buffer is cleared afterward.

  const ssh = new Ssh();

  const sshPort = 22;
  try {
    await ssh.connectAsync('ssh.example.com', sshPort);
  } 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;
  }

  const channelNum = await ssh.openSessionChannelAsync();
  if (channelNum < 0) {
    console.log(ssh.lastErrorText);
    return;
  }

  try {
    await ssh.sendReqExecAsync(channelNum, 'ls -l /tmp');
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  // IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
  // it, this call waits forever if the server never sends channel close.
  ssh.readTimeoutMs = 15000;

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

  // Append the received text to a StringBuilder.  Existing content is preserved.
  const sb = new StringBuilder();
  try {
    ssh.getReceivedSb(channelNum, 'utf-8', sb);
  } catch {
    console.log(ssh.lastErrorText);
    return;
  }

  console.log(`Characters received: ${sb.length}`);
  const output = sb.getAsString();
  console.log(output);

  ssh.disconnect();
}