I have recently started learning about sending UDP packets and I am encountering a challenge. I have successfully established communication between a Java client and server, as well as a Python client/server combo. However, I am struggling to figure out how to send a UDP packet from Java and receive it in Python. Below is the code for my Java client:
import java.io.*;
import java.net.*;
public class testclient {
public static void main(String[] args) throws IOException {
DatagramSocket socket = new DatagramSocket();
byte[] buf = new byte[256];
InetAddress address = InetAddress.getLocalHost();
DatagramPacket packet = new DatagramPacket(buf, buf.length, address, Integer.parseInt(args[0]));
System.out.println("Sending...");
socket.send(packet);
System.out.println("Receiving...");
packet = new DatagramPacket(buf, buf.length);
socket.receive(packet);
String received = new String(packet.getData(), 0, packet.getLength());
System.out.println(received);
System.out.println("Done!");
socket.close();
}
}
As for the Python server:
from sys import *
from socket import *
host = gethostname()
port = int(argv[1])
address = (host, port)
print "Binding..."
sock = socket(AF_INET, SOCK_DGRAM)
sock.bind(address)
print "Receiving..."
data, client = sock.recvfrom(256)
print "Sending to", client
sock.sendto("Hi", client)
print "Closing..."
sock.close()
print "Done!"
The goal here is to send a request from the Java client to the Python server, then have the Python server respond with "Hi" back to the Java client, which should print the string. However, when running this setup, the client sends the packet while the server seems to be stuck at sock.recvfrom(256) without receiving any data.
Any suggestions or insights on what might be causing this issue? My assumption is that there may be some discrepancy in how Java and Python handle UDP packets, but I'm not entirely sure.
EDIT: Just to clarify, the port number is passed in via command-line arguments for both applications.