Dart

Socket Receive String Until Specific Byte Value is Received

Demonstrates the Chilkat Socket ReceiveStringUntilByte method. Dart

import 'package:chilkat/chilkat.dart';

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

  final sock = CkSocket();

  // --------------------------------------------------------------------
  // This example uses the public TCP echo service at https://tcpbin.com/
  // --------------------------------------------------------------------

  final useTls = false;
  final port = 4242;
  var maxWaitMs = 5000;
  try {
    sock.connect('tcpbin.com', port, useTls, maxWaitMs);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Wait a max of 2 seconds for a response..
  sock.maxReadIdleMs = 2000;

  // Send some strings, each terminated by a 0 byte.
  sock.sendString('This is the 1st string');
  sock.sendByte(0);
  sock.sendString('This is string number 2');
  sock.sendByte(0);

  // The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
  sock.sendByte(10);

  // Now let's receive what is echoed back....
  // Receive each string and the NULL byte.
  // The call to ReceiveStringUntilByte will receive incoming data until the lookForByte is encountered.
  // The lookForByte is receive and discarded (it is not returned in the string)
  final lookForByte = 0;
  final String s1;
  try {
    s1 = sock.receiveStringUntilByte(lookForByte);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(s1);

  final String s2;
  try {
    s2 = sock.receiveStringUntilByte(lookForByte);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print(s2);

  // The echo server will also echo back the final LF
  sock.receiveByte(true);
  maxWaitMs = 100;
  sock.close(100);

  // Output:
  // This is the 1st string
  // This is string number 2
}