gistfile1.txt

const net = require('net');
const readline = require('readline');

const COLUMN_WIDTH = 13;
const COLORS = {
  red: '31',
  green: '32',
  cyan: '36',
};
const TIMEOUT = 60 * 1000;
const PORT = 14000;
const LOCALHOST = '172.16.88.19';

const pipes = {
  1: {
    port: 64000,
    server: null
  },
}

const ts = () => Math.floor(new Date() / 1000)

// TUI

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

readline.cursorTo(process.stdout, 0, 0);
readline.clearScreenDown(process.stdout);

rl.setPrompt('\npipes> ');

rl.prompt();

const lastActivity = server => {
  return `${ts() - server.lastActivity} seconds ago`
}

const printStatus = (done) => {
    Object.entries(pipes).forEach(([i, pipe], index) => {
      const log = (status, color) => {
        const padded = status.padEnd(COLUMN_WIDTH)
        console.log(
          `\x1b[${color}m%s\x1b[0m`,
          `[${i}]: ${pipe.port} => ${PORT} | ${padded} | ${lastActivity(pipe.server)}`
        )
      }
      if (pipe.server) {
        pipe.server.getConnections((err, count) => {
          const isListening = pipe.server.listening;
          log(
            isListening ? `${count} connection${count === 1 ? '' : 's'}` : 'closed',
            isListening ? (count === 0 ? COLORS.cyan : COLORS.green) : COLORS.red
          )
          if (index === Object.keys(pipes).length - 1) {
            done()
          }
        });
      } else if (pipe.server === null) {
        log('uninitialized', COLORS.red)
        done()
      } else {
        log('unknown', COLORS.red)
        done()
      }
    });
}

rl.on('line', line => {
  const cmd = line.trim();

  const matchPipeNumber = startOrStop => {
    const match = cmd.match(new RegExp(`^${startOrStop}\\s?(\\d)$`));
    if (match) {
      return match[1];
    }

    return null;
  }

  const startPipeNumber = matchPipeNumber('start');
  const stopPipeNumber = matchPipeNumber('stop');

  if (cmd === 'status') {
    printStatus(() => rl.prompt());
  } else if (startPipeNumber) {
    const pipe = pipes[startPipeNumber];

    if (!pipe) {
      console.log('Pipe not found');
      rl.prompt();
      return;
    }

    const { server, port } = pipe

    server.listen(port);
    printStatus(() => rl.prompt());
  } else if (stopPipeNumber) {
    const pipe = pipes[stopPipeNumber];

    if (!pipe) {
      console.log('Pipe not found');
      rl.prompt();
      return;
    }

    const { server, port } = pipe

    if (server) {
      server.destroy();
    } else {
      console.log(`No pipe open: ${port}`)
      rl.prompt();
    }
  } else {
    console.log('Invalid command')
    rl.prompt();
  }
}).on('close', () => {
  console.log('\n\nBye!');
  // This will kill the connections/servers anyway
  process.exit(0);
});

const statusUpdate = (msg) => {
  console.log(msg || '');
  printStatus(() => {
    console.log('');
    rl.prompt()
  });
}

const createServer = port => {
  const server = net.createServer(socket => {
    const client = new net.Socket();
    client.connect(PORT, LOCALHOST, () => {
      socket.pipe(client);
      client.pipe(socket);
    });
    client.on('data', () => {
      server.lastActivity = ts();
    });
    socket.on('error', e => {
      if (e.code === 'ECONNRESET' && e.syscall === 'read') {
        statusUpdate();
      } else {
        throw e;
      }
    });
    socket.setTimeout(TIMEOUT, () => {
      statusUpdate();
      socket.end();
    });
  });

  const connections = {}

  server.on('connection', c => {
    const { remoteAddress, remotePort } = c;
    const key = `${remoteAddress}:${remotePort}`;
    connections[key] = c;
    statusUpdate();
    c.on('close', () => {
      delete connections[key];
      statusUpdate();
    });
  });

  server.destroy = (cb) => {
    for (const key in connections) {
      connections[key].destroy();
    }
    server.close(cb);
    statusUpdate();
  };

  server.listen(port);

  return server;
}

for (const key in pipes) {
  const pipe = pipes[key]
  pipe.server = createServer(pipe.port)
}